Z8F041AQB020SC

High-Performance 8-Bit Microcontrollers Z8 Encore! XP® F082A Series Product Specification PS022825-0908 Copyright ©2008 by Zilog®, Inc. All rights reserved. www.zilog.com Warning: DO NOT USE IN LIFE SUPPORT LIFE SUPPORT POLICY ZILOG'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF ZILOG CORPORATION. As used herein Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. Document Disclaimer ©2008 by Zilog, Inc. All rights reserved. Information in this publication concerning the devices, applications, or technology described is intended to suggest possible uses and may be superseded. ZILOG, INC. DOES NOT ASSUME LIABILITY FOR OR PROVIDE A REPRESENTATION OF ACCURACY OF THE INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED IN THIS DOCUMENT. Z I L O G A L S O D O E S N O T A S S U M E L I A B I L I T Y F O R I N T E L L E C T U A L P R O P E RT Y INFRINGEMENT RELATED IN ANY MANNER TO USE OF INFORMATION, DEVICES, OR TECHNOLOGY DESCRIBED HEREIN OR OTHERWISE. The information contained within this document has been verified according to the general principles of electrical and mechanical engineering. Z8, Z8 Encore!, and Z8 Encore! XP are registered trademarks of Zilog, Inc. All other product or service names are the property of their respective owners. PS022825-0908 Z8 Encore! XP® F082A Series Product Specification iii Revision History Each instance in Revision History reflects a change to this document from its previous revision. For more details, refer to the corresponding pages and appropriate links in the table below. Date PS022825-0908 Revision Level Description Page Number September 2008 25 Added the references to F042A series back 3, 9, 16, 19, 37, 251 in Table 1, Available Packages, Table 5, Table 7, Table 13, Ordering Information sections. May 2008 24 Changed title to Z8 Encore! XP F082A Series and removed references to F042A series in Table 1, Available Packages, Table 5, Table 7, Table 13, Ordering Information sections. All December 2007 23 Updated Figure 3, Table 14, Table 58 through Table 60. 10, 41, and 95 July 2007 22 Updated Table 15 and Table 128. Updated 44, 221 Power consumption in Electrical Characteristics chapter. June 2007 21 Revision number update. All Revision History Z8 Encore! XP® F082A Series Product Specification iv Table of Contents Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Part Selection Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CPU and Peripheral Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eZ8 CPU Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-Bit Analog-to-Digital Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low-Power Operational Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internal Precision Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analog Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low Voltage Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-Chip Debugger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Universal Asynchronous Receiver/Transmitter . . . . . . . . . . . . . . . . . . . . . . . Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General-Purpose Input/Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Direct LED Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Non-Volatile Data Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 4 5 5 5 6 6 6 6 6 6 6 7 7 7 7 7 7 8 8 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Available Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Pin Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Signal Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Pin Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Address Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Register File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Program Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Information Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 15 17 17 Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 PS022825-0908 Table of Contents Z8 Encore! XP® F082A Series Product Specification v Reset, Stop Mode Recovery, and Low Voltage Detection . . . . . . . . . . . . . . 23 Reset Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Voltage Brownout Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Reset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Reset Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-Chip Debugger Initiated Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stop Mode Recovery Using Watchdog Timer Time-Out . . . . . . . . . . . . . . . Stop Mode Recovery Using a GPIO Port Pin Transition . . . . . . . . . . . . . . . Stop Mode Recovery Using the External RESET Pin . . . . . . . . . . . . . . . . . Low Voltage Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reset Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 25 25 26 27 27 28 28 28 29 29 30 30 30 Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 STOP Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HALT Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peripheral-Level Power Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 34 34 34 General-Purpose Input/Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 GPIO Port Availability By Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPIO Alternate Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Direct LED Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shared Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shared Debug Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Crystal Oscillator Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V Tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Clock Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPIO Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPIO Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A–D Address Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A–D Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A–D Data Direction Sub-Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A–D Alternate Function Sub-Registers . . . . . . . . . . . . . . . . . . . . . . . . PS022825-0908 37 38 38 39 39 39 40 40 40 45 45 46 46 47 47 Table of Contents Z8 Encore! XP® F082A Series Product Specification vi Port A–C Input Data Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Port A–D Output Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Drive Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Drive Level High Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LED Drive Level Low Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 52 52 53 53 Interrupt Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Interrupt Vector Listing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Master Interrupt Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Vectors and Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Assertion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Software Interrupt Assertion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Interrupt Assertion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Request 0 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Request 1 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Request 2 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IRQ0 Enable High and Low Bit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . IRQ1 Enable High and Low Bit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . IRQ2 Enable High and Low Bit Registers . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Edge Select Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shared Interrupt Select Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupt Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 57 57 57 58 58 59 59 60 60 61 62 62 63 65 66 66 67 Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reading the Timer Count Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Pin Signal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer 0–1 Control Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer 0–1 High and Low Byte Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . Timer Reload High and Low Byte Registers . . . . . . . . . . . . . . . . . . . . . . . . Timer 0-1 PWM High and Low Byte Registers . . . . . . . . . . . . . . . . . . . . . . 69 70 70 82 82 83 83 87 87 88 Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Watchdog Timer Refresh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 PS022825-0908 Table of Contents Z8 Encore! XP® F082A Series Product Specification vii Watchdog Timer Time-Out Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Reload Unlock Sequence . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Reload Upper, High and Low Byte Registers . . . . . . . . . . 92 93 93 94 94 94 Universal Asynchronous Receiver/Transmitter . . . . . . . . . . . . . . . . . . . . . . 97 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Transmitting Data using the Polled Method . . . . . . . . . . . . . . . . . . . . . . . . 99 Transmitting Data using the Interrupt-Driven Method . . . . . . . . . . . . . . . . 100 Receiving Data using the Polled Method . . . . . . . . . . . . . . . . . . . . . . . . . 101 Receiving Data using the Interrupt-Driven Method . . . . . . . . . . . . . . . . . . 102 Clear To Send (CTS) Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 MULTIPROCESSOR (9-bit) Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 External Driver Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 UART Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 UART Baud Rate Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 UART Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 UART Control 0 and Control 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . 108 UART Status 0 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 UART Status 1 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 UART Transmit Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 UART Receive Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 UART Address Compare Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 UART Baud Rate High and Low Byte Registers . . . . . . . . . . . . . . . . . . . . 114 Infrared Encoder/Decoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmitting IrDA Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Receiving IrDA Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Infrared Encoder/Decoder Control Register Definitions . . . . . . . . . . . . . . . . . 117 117 118 119 120 Analog-to-Digital Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 PS022825-0908 Table of Contents Z8 Encore! XP® F082A Series Product Specification viii Hardware Overflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Automatic Powerdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single-Shot Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calibration and Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Compensation Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Input Buffer Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Control Register 0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Control/Status Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Data High Byte Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Data Low Byte Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 123 123 124 125 125 127 129 130 130 132 132 133 Low Power Operational Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 Comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Comparator Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 Temperature Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Temperature Sensor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Flash Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Information Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Operation Timing Using the Flash Frequency Registers . . . . . . . . . Flash Code Protection Against External Access . . . . . . . . . . . . . . . . . . . . Flash Code Protection Against Accidental Program and Erasure . . . . . . . Byte Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page Erase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mass Erase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Controller Bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Controller Behavior in DEBUG Mode . . . . . . . . . . . . . . . . . . . . . . . Flash Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Page Select Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PS022825-0908 141 142 143 145 145 145 147 147 147 148 148 149 149 150 150 Table of Contents Z8 Encore! XP® F082A Series Product Specification ix Flash Sector Protect Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Flash Frequency High and Low Byte Registers . . . . . . . . . . . . . . . . . . . . 152 Flash Option Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Option Bit Configuration By Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Option Bit Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reading the Flash Information Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Option Bit Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Option Bit Address Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Program Memory Address 0000H . . . . . . . . . . . . . . . . . . . . . . . . . . Flash Program Memory Address 0001H . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address 0000H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address 0001H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address 0002H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address 0003H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trim Bit Address 0004H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zilog Calibration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ADC Calibration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature Sensor Calibration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer Calibration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serialization Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Randomized Lot Identifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 153 154 155 155 155 156 156 156 158 158 158 159 159 159 161 161 161 164 164 165 166 Non-Volatile Data Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NVDS Code Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Byte Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Byte Read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Failure Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optimizing NVDS Memory Usage for Execution Speed . . . . . . . . . . . . . . 169 169 169 170 171 171 On-Chip Debugger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OCD Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DEBUG Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PS022825-0908 173 174 174 175 Table of Contents Z8 Encore! XP® F082A Series Product Specification x OCD Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OCD Auto-Baud Detector/Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OCD Serial Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OCD Unlock Sequence (8-Pin Devices Only) . . . . . . . . . . . . . . . . . . . . . . Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Runtime Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-Chip Debugger Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-Chip Debugger Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . OCD Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OCD Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 176 177 178 178 179 179 184 184 185 Oscillator Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System Clock Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clock Failure Detection and Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . Oscillator Control Register Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 187 189 190 Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Crystal Oscillator Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Oscillator Operation with an External RC Network . . . . . . . . . . . . . . . . . . . . . 195 Internal Precision Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 eZ8 CPU Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 Assembly Language Programming Introduction . . . . . . . . . . . . . . . . . . . . . . . Assembly Language Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eZ8 CPU Instruction Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eZ8 CPU Instruction Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eZ8 CPU Instruction Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 200 200 202 207 Opcode Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . On-Chip Peripheral AC and DC Electrical Characteristics . . . . . . . . . . . . . . . General Purpose I/O Port Input Data Sample Timing . . . . . . . . . . . . . . . . PS022825-0908 221 222 227 229 234 Table of Contents Z8 Encore! XP® F082A Series Product Specification xi General Purpose I/O Port Output Timing . . . . . . . . . . . . . . . . . . . . . . . . . 236 On-Chip Debugger Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 UART Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261 Customer Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 PS022825-0908 Table of Contents Z8 Encore! XP® F082A Series Product Specification 1 Overview Zilog’s Z8 Encore!® MCU family of products are the first in a line of Zilog® microcontroller products based upon the 8-bit eZ8 CPU. Zilog’s Z8 Encore! XP® F082A Series products expand upon Zilog’s extensive line of 8-bit microcontrollers. The Flash in-circuit programming capability allows for faster development time and program changes in the field. The new eZ8 CPU is upward compatible with existing Z8® instructions. The rich peripheral set of the Z8 Encore! XP F082A Series makes it suitable for a variety of applications including motor control, security systems, home appliances, personal electronic devices, and sensors. Features The key features of Z8 Encore! XP F082A Series products include: PS022825-0908 • • • • • • • • • • • • 20 MHz eZ8 CPU • Infrared Data Association (IrDA)-compliant infrared encoder/decoders, integrated with UART • • • • Two enhanced 16-bit timers with capture, compare, and PWM capability 1 KB, 2 KB, 4 KB, or 8 KB Flash memory with in-circuit programming capability 256 B, 512 B, or 1 KB register RAM Up to 128 B non-volatile data storage (NVDS) Internal precision oscillator trimmed to ±1% accuracy External crystal oscillator, operating up to 20 MHz Optional 8-channel, 10-bit analog-to-digital converter (ADC) Optional on-chip temperature sensor On-chip analog comparator Optional on-chip low-power operational amplifier (LPO) Full-duplex UART The UART baud rate generator (BRG) can be configured and used as a basic 16-bit timer Watchdog Timer (WDT) with dedicated internal RC oscillator Up to 20 vectored interrupts 6 to 25 I/O pins depending upon package Overview Z8 Encore! XP® F082A Series Product Specification 2 • • • • • • Up to thirteen 5 V-tolerant input pins • • • • Power-On Reset (POR) Up to 8 ports capable of direct LED drive with no current limit resistor required On-Chip Debugger (OCD) Voltage Brownout (VBO) protection Programmable low battery detection (LVD) (8-pin devices only) Bandgap generated precision voltage references available for the ADC, comparator, VBO, and LVD 2.7 V to 3.6 V operating voltage 8-, 20-, and 28-pin packages 0 °C to +70 °C and -40 °C to +105 °C for operating temperature ranges Part Selection Guide Table 1 on page 3 identifies the basic features and package styles available for each device within the Z8 Encore! XP® F082A Series product line. PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 3 Table 1. Z8 Encore! XP® F082A Series Family Part Selection Guide Part Number Flash RAM (KB) (B) NVDS1 (B) I/O Comparator Advanced ADC Analog2 Inputs Packages Z8F082A 8 1024 0 6–23 Yes Yes 4–8 8-, 20- and 28-pin Z8F081A 8 1024 0 6–25 Yes No 0 8-, 20- and 28-pin Z8F042A 4 1024 128 6–23 Yes Yes 4–8 8-, 20- and 28-pin Z8F041A 4 1024 128 6–25 Yes No 0 8-, 20- and 28-pin Z8F022A 2 512 64 6–23 Yes Yes 4–8 8-, 20- and 28-pin Z8F021A 2 512 64 6–25 Yes No 0 8-, 20- and 28-pin Z8F012A 1 256 16 6–23 Yes Yes 4–8 8-, 20- and 28-pin Z8F011A 1 256 16 6–25 Yes No 0 8-, 20- and 28-pin 1Non-volatile 2Advanced data storage. Analog includes ADC, temperature sensor, and low-power operational amplifier. PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 4 Block Diagram Figure 1 displays the block diagram of the architecture of the Z8 Encore! XP® F082A Series devices. System Clock Oscillator Control XTAL/RC Oscillator Internal Precision Oscillator Low Power RC Oscillator On-Chip Debugger eZ8 CPU Interrupt Controller POR/VBO and Reset Controller WDT Memory Busses Register Bus UART Timers IrDA Comparator Temperature Sensor ADC Low Power Op Amp NVDS Controller Flash Controller Flash Memory RAM Controller RAM GPIO Figure 1. Z8 Encore! XP F082A Series Block Diagram PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 5 CPU and Peripheral Overview eZ8 CPU Features The eZ8 CPU, Zilog’s latest 8-bit Central Processing Unit (CPU), meets the continuing demand for faster and more code-efficient microcontrollers. The eZ8 CPU executes a superset of the original Z8® instruction set. The features of eZ8 CPU include: • Direct register-to-register architecture allows each register to function as an accumulator, improving execution time and decreasing the required program memory. • Software stack allows much greater depth in subroutine calls and interrupts than hardware stacks. • • • Compatible with existing Z8 code. • • Pipelined instruction fetch and execution. • • • • New instructions support 12-bit linear addressing of the Register File. Expanded internal Register File allows access of up to 4 KB. New instructions improve execution efficiency for code developed using higherlevel programming languages, including C. New instructions for improved performance including BIT, BSWAP, BTJ, CPC, LDC, LDCI, LEA, MULT, and SRL. Up to 10 MIPS operation. C-Compiler friendly. 2 to 9 clock cycles per instruction. For more information on eZ8 CPU, refer to eZ8 CPU Core User Manual (UM0128) available for download at www.zilog.com. 10-Bit Analog-to-Digital Converter The optional analog-to-digital converter (ADC) converts an analog input signal to a 10-bit binary number. The ADC accepts inputs from eight different analog input pins in both single-ended and differential modes. The ADC also features a unity gain buffer when high input impedance is required. PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 6 Low-Power Operational Amplifier The optional low-power operational amplifier (LPO) is a general-purpose amplifier primarily targeted for current sense applications. The LPO output may be routed internally to the ADC or externally to a pin. Internal Precision Oscillator The internal precision oscillator (IPO) is a trimmable clock source that requires no external components. Temperature Sensor The optional temperature sensor produces an analog output proportional to the device temperature. This signal can be sent to either the ADC or the analog comparator. Analog Comparator The analog comparator compares the signal at an input pin with either an internal programmable voltage reference or a second input pin. The comparator output can be used to drive either an output pin or to generate an interrupt. External Crystal Oscillator The crystal oscillator circuit provides highly accurate clock frequencies with the use of an external crystal, ceramic resonator or RC network. Low Voltage Detector The low voltage detector (LVD) is able to generate an interrupt when the supply voltage drops below a user-programmable level. The LVD is available on 8-pin devices only. On-Chip Debugger The Z8 Encore! XP® F082A Series products feature an integrated on-chip debugger (OCD) accessed via a single-pin interface. The OCD provides a rich-set of debugging capabilities, such as reading and writing registers, programming Flash memory, setting breakpoints, and executing code. PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 7 Universal Asynchronous Receiver/Transmitter The full-duplex universal asynchronous receiver/transmitter (UART) is included in all Z8 Encore! XP package types. The UART supports 8- and 9-bit data modes and selectable parity. The UART also supports multi-drop address processing in hardware. The UART baud rate generator (BRG) can be configured and used as a basic 16-bit timer. Timers Two enhanced 16-bit reloadable timers can be used for timing/counting events or for motor control operations. These timers provide a 16-bit programmable reload counter and operate in ONE-SHOT, CONTINUOUS, GATED, CAPTURE, CAPTURE RESTART, COMPARE, CAPTURE and COMPARE, PWM SINGLE OUTPUT and PWM DUAL OUTPUT modes. General-Purpose Input/Output The Z8 Encore! XP F082A Series features 6 to 25 port pins (Ports A–D) for general- purpose input/output (GPIO). The number of GPIO pins available is a function of package, and each pin is individually programmable. 5 V tolerant input pins are available on all I/Os on 8-pin devices and most I/Os on other package types. Direct LED Drive The 20- and 28-pin devices support controlled current sinking output pins capable of driving LEDs without the need for a current limiting resistor. These LED drivers are independently programmable to four different intensity levels. Flash Controller The Flash Controller programs and erases Flash memory. The Flash Controller supports several protection mechanisms against accidental program and erasure, as well as factory serialization and read protection. Non-Volatile Data Storage The non-volatile data storage (NVDS) uses a hybrid hardware/software scheme to implement a byte programmable data memory and is capable of over 100,000 write cycles. Note: PS022825-0908 Devices with 8 KB Flash memory do not include the NVDS feature. Overview Z8 Encore! XP® F082A Series Product Specification 8 Interrupt Controller The Z8 Encore! XP® F082A Series products support up to 20 interrupts. These interrupts consist of 8 internal peripheral interrupts and 12 general-purpose I/O pin interrupt sources. The interrupts have three levels of programmable interrupt priority. Reset Controller The Z8 Encore! XP F082A Series products can be reset using the RESET pin, Power-On Reset, Watchdog Timer (WDT) time-out, STOP mode exit, or Voltage Brownout (VBO) warning signal. The RESET pin is bi-directional, that is, it functions as reset source as well as a reset indicator. PS022825-0908 Overview Z8 Encore! XP® F082A Series Product Specification 9 Pin Description The Z8 Encore! XP® F082A Series products are available in a variety of packages styles and pin configurations. This chapter describes the signals and available pin configurations for each of the package styles. For information on physical package specifications, see Packaging on page 241. Available Packages The following package styles are available for each device in the Z8 Encore! XP F082A Series product line: • SOIC – 8-, 20-, and 28-pin • PDIP – 8-, 20-, and 28-pin • SSOP – 20- and 28- pin • QFN (this is an MLF-S, a QFN style package with an 8-pin SOIC footprint) – 8-pin In addition, the Z8 Encore! XP F082A Series devices are available both with and without advanced analog capability (ADC, temperature sensor and op amp). Devices Z8F082A, Z8F042A, Z8F022A, and Z8F012A contain the advanced analog, while devices Z8F081A, Z8F041A, Z8F021A, and Z8F011A do not have the advanced analog capability. Pin Configurations Figure 2 through Figure 4 display the pin configurations for all the packages available in the Z8 Encore! XP F082A Series. See Table 2 on page 11 for a description of the signals. The analog input alternate functions (ANAx) are not available on the Z8F081A, Z8F041A, Z8F021A, and Z8F011A devices. The analog supply pins (AVDD and AVSS) are also not available on these parts, and are replaced by PB6 and PB7. At reset, all Port A, B and C pins default to an input state. In addition, any alternate functionality is not enabled, so the pins function as general purpose input ports until programmed otherwise. At powerup, the PD0 pin defaults to the RESET alternate function. PS022825-0908 Pin Description Z8 Encore! XP® F082A Series Product Specification 10 The pin configurations listed are preliminary and subject to change based on manufacturing limitations. VDD PA0/T0IN/T0OUT/XIN//DBG PA1/T0OUT/XOUT/ANA3/VREF/CLKIN PA2/RESET/DE0/T1OUT 1 2 3 4 8 7 6 5 VSS PA5/TXD0/T1OUT/ANA0/CINP/AMPOUT PA4/RXD0/ANA1/CINN/AMPINN PA3/CTS0/ANA2/COUT/AMPINP/T1IN Figure 2. Z8F08xA, Z8F04xA, Z8F02xA, and Z8F01xA in 8-Pin SOIC, QFN/MLF-S, or PDIP Package PB1/ANA1/AMPINN PB2/ANA2/AMPINP PB3/CLKIN/ANA3 VDD PA0/T0IN/T0OUT/XIN PA1/T0OUT/XOUT VSS PA2/DE0 PA3/CTS0 PA4/RXD0 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 PB0/ANA0/AMPOUT PC3/COUT/LED PC2/ANA6/LED/VREF PC1/ANA5/CINN/LED PC0/ANA4/CINP/LED DBG RESET/PD0 PA7/T1OUT PA6/T1IN/T1OUT PA5/TXD0 Figure 3. Z8F08xA, Z8F04xA, Z8F02xA, and Z8F01xA in 20-Pin SOIC, SSOP or PDIP Package PB2/ANA2/AMPINP PB4/ANA7 PB5/VREF PB3/CLKIN/ANA3 (PB6) AVDD VDD PA0/T0IN/T0OUT/XIN PA1/T0OUT/XOUT VSS (PB7) AVSS PA2/DE0 PA3/CTS0 PA4/RXD0 PA5/TXD0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 PB1/ANA1/AMPINN PB0/ANA0/AMPOUT PC3/COUT/LED PC2/ANA6/LED PC1/ANA5/CINN/LED PC0/ANA4/CINP/LED DBG RESET/PD0 PC7/LED PC6/LED PA7/T1OUT PC5/LED PC4/LED PA6/T1IN/T1OUT Figure 4. Z8F08xA, Z8F04xA, Z8F02xA, and Z8F01xA in 28-Pin SOIC, SSOP or PDIP Package PS022825-0908 Pin Description Z8 Encore! XP® F082A Series Product Specification 11 Signal Descriptions Table 2 describes the Z8 Encore! XP F082A Series signals. See Pin Configurations on page 9 to determine the signals available for the specific package styles. Table 2. Signal Descriptions Signal Mnemonic I/O Description General-Purpose I/O Ports A–D PA[7:0] I/O Port A. These pins are used for general-purpose I/O. PB[7:0] I/O Port B. These pins are used for general-purpose I/O. PB6 and PB7 are available only in those devices without an ADC. PC[7:0] I/O Port C. These pins are used for general-purpose I/O. PD[0] I/O Port D. This pin is used for general-purpose output only. Note: PB6 and PB7 are only available in 28-pin packages without ADC. In 28-pin packages with ADC, they are replaced by AVDD and AVSS. UART Controllers TXD0 O Transmit Data. This signal is the transmit output from the UART and IrDA. RXD0 I Receive Data. This signal is the receive input for the UART and IrDA. CTS0 I Clear To Send. This signal is the flow control input for the UART. DE O Driver Enable. This signal allows automatic control of external RS-485 drivers. This signal is approximately the inverse of the TXE (Transmit Empty) bit in the UART Status 0 register. The DE signal may be used to ensure the external RS-485 driver is enabled when data is transmitted by the UART. T0OUT/T1OUT O Timer Output 0–1. These signals are outputs from the timers. T0OUT/T1OUT O Timer Complement Output 0–1. These signals are output from the timers in PWM Dual Output mode. T0IN/T1IN I Timer Input 0–1. These signals are used as the capture, gating and counter inputs. CINP/CINN I Comparator Inputs. These signals are the positive and negative inputs to the comparator. COUT O Comparator Output. Timers Comparator PS022825-0908 Pin Description Z8 Encore! XP® F082A Series Product Specification 12 Table 2. Signal Descriptions (Continued) Signal Mnemonic I/O Description Analog ANA[7:0] VREF I I/O Analog Port. These signals are used as inputs to the analog-to-digital converter (ADC). Analog-to-digital converter reference voltage input, or buffered output for internal reference. Low-Power Operational Amplifier (LPO) AMPINP/AMPINN I LPO inputs. If enabled, these pins drive the positive and negative amplifier inputs respectively. AMPOUT O LPO output. If enabled, this pin is driven by the on-chip LPO. XIN I External Crystal Input. This is the input pin to the crystal oscillator. A crystal can be connected between it and the XOUT pin to form the oscillator. In addition, this pin is used with external RC networks or external clock drivers to provide the system clock. XOUT O External Crystal Output. This pin is the output of the crystal oscillator. A crystal can be connected between it and the XIN pin to form the oscillator. I Clock Input Signal. This pin may be used to input a TTL-level signal to be used as the system clock. O Direct LED drive capability. All port C pins have the capability to drive an LED without any other external components. These pins have programmable drive strengths set by the GPIO block. I/O Debug. This signal is the control and data input and output to and from the On-Chip Debugger. Oscillators Clock Input CLKIN LED Drivers LED On-Chip Debugger DBG Caution: The DBG pin is open-drain and requires a pull-up resistor to ensure proper operation. Reset RESET PS022825-0908 I/O RESET. Generates a Reset when asserted (driven Low). Also serves as a reset indicator; the Z8 Encore! XP forces this pin low when in reset. This pin is open-drain and features an enabled internal pull-up resistor. Pin Description Z8 Encore! XP® F082A Series Product Specification 13 Table 2. Signal Descriptions (Continued) Signal Mnemonic I/O Description Power Supply VDD I Digital Power Supply. AVDD I Analog Power Supply. VSS I Digital Ground. AVSS I Analog Ground. Note: The AVDD and AVSS signals are available only in 28-pin packages with ADC. They are replaced by PB6 and PB7 on 28-pin packages without ADC. Pin Characteristics Table 3 describes the characteristics for each pin available on the Z8 Encore! XP F082A Series 20- and 28-pin devices. Data in Table 3 is sorted alphabetically by the pin symbol mnemonic. Table 4 on page 14 provides detailed information about the characteristics for each pin available on the Z8 Encore! XP F082A Series 8-pin devices. All six I/O pins on the 8-pin packages are 5 V-tolerant (unless the pull-up devices are enabled). The column in Table 3 below describes 5 V-tolerance for the 20- and 28-pin packages only. Note: Table 3. Pin Characteristics (20- and 28-pin Devices) Direction Reset Direction Active Low or Active High Tristate Output AVDD N/A N/A N/A N/A N/A AVSS N/A N/A N/A N/A DBG I/O I N/A PA[7:0] I/O I PB[7:0] I/O I Symbol Mnemonic PS022825-0908 Internal Pull- Schmittup Trigger or Pull-down Input Open Drain Output 5V Tolerance N/A N/A N/A N/A N/A N/A NA Yes Yes Yes Yes No N/A Yes Programmable Pull-up Yes Yes, Programmable PA[7:2] unless pullups enabled N/A Yes Programmable Pull-up Yes Yes, Programmable PB[7:6] unless pullups enabled Pin Description Z8 Encore! XP® F082A Series Product Specification 14 Table 3. Pin Characteristics (20- and 28-pin Devices) (Continued) Direction Reset Direction Active Low or Active High Tristate Output PC[7:0] I/O I N/A Yes RESET/PD0 I/O I/O (defaults to RESET) Low (in Reset mode) VDD N/A N/A N/A N/A N/A N/A VSS N/A N/A N/A N/A N/A N/A Open Drain Output 5V Tolerance Symbol Mnemonic Internal Pull- Schmittup Trigger or Pull-down Input Open Drain Output 5V Tolerance PC[7:3] unless pullups enabled Programmable Pull-up Yes Yes, Programmable Yes (PD0 Programmable only) for PD0; always on for RESET Yes Programmable Yes, unless for PD0; always pullups on for RESET enabled PB6 and PB7 are available only in those devices without ADC. Note: Table 4. Pin Characteristics (8-Pin Devices) ) Symbol Mnemonic Direction Reset Direction Active Low or Active High Tristate Output Internal Pullup or Pull-down SchmittTrigger Input PA0/DBG I/O I (but can change during reset if key sequence detected) N/A Yes Programmable Pull-up Yes Yes, Yes, unless Programmable pull-ups enabled PA1 I/O I N/A Yes Programmable Pull-up Yes Yes, Yes, unless Programmable pull-ups enabled RESET/PA2 I/O I/O (defaults to RESET) Low (in Reset mode) Yes Programmable for PA2; always on for RESET Yes Programmable Yes, unless for PA2; always pull-ups on for RESET enabled PA[5:3] I/O I N/A Yes Programmable Pull-up Yes Yes, Yes, unless Programmable pull-ups enabled VDD N/A N/A N/A N/A N/A N/A N/A N/A VSS N/A N/A N/A N/A N/A N/A N/A N/A PS022825-0908 Pin Description Z8 Encore! XP® F082A Series Product Specification 15 Address Space The eZ8 CPU can access the following three distinct address spaces: 1. The Register File contains addresses for the general-purpose registers and the eZ8 CPU, peripheral, and general-purpose I/O port control registers. 2. The Program Memory contains addresses for all memory locations having executable code and/or data. 3. The Data Memory contains addresses for all memory locations that contain data only. These three address spaces are covered briefly in the following subsections. For more information on eZ8 CPU and its address space, refer to eZ8 CPU Core User Manual (UM0128) available for download at www.zilog.com. Register File The Register File address space in the Z8 Encore!® MCU is 4 KB (4096 bytes). The Register File is composed of two sections: control registers and general-purpose registers. When instructions are executed, registers defined as sources are read, and registers defined as destinations are written. The architecture of the eZ8 CPU allows all general-purpose registers to function as accumulators, address pointers, index registers, stack areas, or scratch pad memory. The upper 256 bytes of the 4 KB Register File address space are reserved for control of the eZ8 CPU, the on-chip peripherals, and the I/O ports. These registers are located at addresses from F00H to FFFH. Some of the addresses within the 256 B control register section are reserved (unavailable). Reading from a reserved Register File address returns an undefined value. Writing to reserved Register File addresses is not recommended and can produce unpredictable results. The on-chip RAM always begins at address 000H in the Register File address space. The Z8 Encore! XP® F082A Series devices contain 256 B to 1 KB of on-chip RAM. Reading from Register File addresses outside the available RAM addresses (and not within the control register address space) returns an undefined value. Writing to these Register File addresses produces no effect. Program Memory The eZ8 CPU supports 64 KB of Program Memory address space. The Z8 Encore! XP F082A Series devices contain 1 KB to 8 KB of on-chip Flash memory in the Program Memory address space, depending on the device. Reading from Program Memory PS022825-0908 Address Space Z8 Encore! XP® F082A Series Product Specification 16 addresses outside the available Flash memory addresses returns FFH. Writing to these unimplemented Program Memory addresses produces no effect. Table 5 describes the Program Memory Maps for the Z8 Encore! XP F082A Series products. Table 5. Z8 Encore! XP F082A Series Program Memory Maps Program Memory Address (Hex) Function Z8F082A and Z8F081A Products 0000–0001 Flash Option Bits 0002–0003 Reset Vector 0004–0005 WDT Interrupt Vector 0006–0007 Illegal Instruction Trap 0008–0037 Interrupt Vectors* 0038–0039 Reserved 003A–003D Oscillator Fail Trap Vectors 003E–1FFF Program Memory Z8F042A and Z8F041A Products PS022825-0908 0000–0001 Flash Option Bits 0002–0003 Reset Vector 0004–0005 WDT Interrupt Vector 0006–0007 Illegal Instruction Trap 0008–0037 Interrupt Vectors* 0038–0039 Reserved 003A–003D Oscillator Fail Trap Vectors 003E–0FFF Program Memory Address Space Z8 Encore! XP® F082A Series Product Specification 17 Table 5. Z8 Encore! XP F082A Series Program Memory Maps (Continued) Program Memory Address (Hex) Function Z8F022A and Z8F021A Products 0000–0001 Flash Option Bits 0002–0003 Reset Vector 0004–0005 WDT Interrupt Vector 0006–0007 Illegal Instruction Trap 0008–0037 Interrupt Vectors* 0038–0039 Reserved 003A–003D Oscillator Fail Trap Vectors 003E–07FF Program Memory Z8F012A and Z8F011A Products 0000–0001 Flash Option Bits 0002–0003 Reset Vector 0004–0005 WDT Interrupt Vector 0006–0007 Illegal Instruction Trap 0008–0037 Interrupt Vectors* 0038–0039 Reserved 003A–003D Oscillator Fail Trap Vectors 003E–03FF Program Memory * See Table 32 on page 56 for a list of the interrupt vectors. Data Memory The Z8 Encore! XP F082A Series does not use the eZ8 CPU’s 64 KB Data Memory address space. Flash Information Area Table 6 on page 18 describes the Z8 Encore! XP F082A Series Flash Information Area. This 128 B Information Area is accessed by setting bit 7 of the Flash Page Select Register to 1. When access is enabled, the Flash Information Area is mapped into the Program Memory and overlays the 128 bytes at addresses FE00H to FF7FH. When the Information Area access is enabled, all reads from these Program Memory addresses return the InforPS022825-0908 Address Space Z8 Encore! XP® F082A Series Product Specification 18 mation Area data rather than the Program Memory data. Access to the Flash Information Area is read-only. Table 6. Z8 Encore! XP F082A Series Flash Memory Information Area Map Program Memory Address (Hex) Function PS022825-0908 FE00–FE3F Zilog Option Bits/Calibration Data FE40–FE53 Part Number 20-character ASCII alphanumeric code Left justified and filled with FFH FE54–FE5F Reserved FE60–FE7F Zilog Calibration Data FE80–FFFF Reserved Address Space Z8 Encore! XP® F082A Series Product Specification 19 Register Map Table 7 provides the address map for the Register File of the Z8 Encore! XP® F082A Series devices. Not all devices and package styles in the Z8 Encore! XP F082A Series support the ADC, or all of the GPIO Ports. Consider registers for unimplemented peripherals as Reserved. Table 7. Register File Address Map Address (Hex) Register Description Mnemonic Reset (Hex) Page No General-Purpose RAM Z8F082A/Z8F081A Devices 000–3FF General-Purpose Register File RAM — XX 400–EFF Reserved — XX Z8F042A/Z8F041A Devices 000–3FF General-Purpose Register File RAM — XX 400–EFF Reserved — XX Z8F022A/Z8F021A Devices 000–1FF General-Purpose Register File RAM — XX 200–EFF Reserved — XX Z8F012A/Z8F011A Devices 000–0FF General-Purpose Register File RAM — XX 100–EFF Reserved — XX F00 Timer 0 High Byte T0H 00 87 F01 Timer 0 Low Byte T0L 01 87 F02 Timer 0 Reload High Byte T0RH FF 88 F03 Timer 0 Reload Low Byte T0RL FF 88 F04 Timer 0 PWM High Byte T0PWMH 00 88 Timer 0 F05 Timer 0 PWM Low Byte T0PWML 00 89 F06 Timer 0 Control 0 T0CTL0 00 83 F07 Timer 0 Control 1 T0CTL1 00 84 F08 Timer 1 High Byte T1H 00 87 F09 Timer 1 Low Byte T1L 01 87 F0A Timer 1 Reload High Byte T1RH FF 88 Timer 1 XX=Undefined PS022825-0908 Register Map Z8 Encore! XP® F082A Series Product Specification 20 Table 7. Register File Address Map (Continued) Address (Hex) Register Description Mnemonic Reset (Hex) Page No F0B Timer 1 Reload Low Byte T1RL FF 88 F0C Timer 1 PWM High Byte T1PWMH 00 88 F0D Timer 1 PWM Low Byte T1PWML 00 89 F0E Timer 1 Control 0 T1CTL0 00 83 F0F Timer 1 Control 1 T1CTL1 00 84 F10–F6F Reserved — XX F40 UART Transmit/Receive Data Registers TXD, RXD XX 113 F41 UART Status 0 Register U0STAT0 00 111 F42 UART Control 0 Register U0CTL0 00 108 F43 UART Control 1 Register U0CTL1 00 108 F44 UART Status 1 Register U0STAT1 00 112 F45 UART Address Compare Register U0ADDR 00 114 F46 UART Baud Rate High Byte Register U0BRH FF 114 F47 UART Baud Rate Low Byte Register U0BRL FF 114 ADC Control 0 ADCCTL0 00 130 F71 ADC Control 1 ADCCTL1 80 130 F72 ADC Data High Byte ADCD_H XX 133 F73 ADC Data Low Bits ADCD_L XX 133 F74–F7F Reserved — XX UART Analog-to-Digital Converter (ADC) F70 Low Power Control F80 Power Control 0 PWRCTL0 80 35 F81 Reserved — XX F82 LED Drive Enable LEDEN 00 52 F83 LED Drive Level High Byte LEDLVLH 00 53 F84 LED Drive Level Low Byte LEDLVLL 00 54 F85 Reserved — XX LED Controller Oscillator Control F86 Oscillator Control OSCCTL A0 F87–F8F Reserved — XX Comparator 0 Control CMP0 14 190 Comparator 0 F90 136 XX=Undefined PS022825-0908 Register Map Z8 Encore! XP® F082A Series Product Specification 21 Table 7. Register File Address Map (Continued) Address (Hex) Register Description Mnemonic Reset (Hex) F91–FBF — XX Reserved Page No Interrupt Controller FC0 Interrupt Request 0 IRQ0 00 60 FC1 IRQ0 Enable High Bit IRQ0ENH 00 63 FC2 IRQ0 Enable Low Bit IRQ0ENL 00 63 FC3 Interrupt Request 1 IRQ1 00 61 FC4 IRQ1 Enable High Bit IRQ1ENH 00 64 FC5 IRQ1 Enable Low Bit IRQ1ENL 00 64 FC6 Interrupt Request 2 IRQ2 00 62 FC7 IRQ2 Enable High Bit IRQ2ENH 00 65 FC8 IRQ2 Enable Low Bit IRQ2ENL 00 65 FC9–FCC Reserved — XX FCD Interrupt Edge Select IRQES 00 67 FCE Shared Interrupt Select IRQSS 00 67 FCF Interrupt Control IRQCTL 00 67 Port A Address PAADDR 00 45 GPIO Port A FD0 FD1 Port A Control PACTL 00 47 FD2 Port A Input Data PAIN XX 47 FD3 Port A Output Data PAOUT 00 47 FD4 Port B Address PBADDR 00 45 FD5 Port B Control PBCTL 00 47 FD6 Port B Input Data PBIN XX 47 FD7 Port B Output Data PBOUT 00 47 FD8 Port C Address PCADDR 00 45 FD9 Port C Control PCCTL 00 47 FDA Port C Input Data PCIN XX 47 FDB Port C Output Data PCOUT 00 47 FDC Port D Address PDADDR 00 45 FDD Port D Control PDCTL 00 47 FDE Reserved — XX GPIO Port B GPIO Port C GPIO Port D XX=Undefined PS022825-0908 Register Map Z8 Encore! XP® F082A Series Product Specification 22 Table 7. Register File Address Map (Continued) Address (Hex) Register Description Mnemonic Reset (Hex) Page No FDF Port D Output Data PDOUT 00 47 FE0–FEF Reserved — XX Watchdog Timer (WDT) FF0 Reset Status (Read-only) RSTSTAT X0 30 Watchdog Timer Control (Write-only) WDTCTL N/A 94 FF1 Watchdog Timer Reload Upper Byte WDTU 00 95 FF2 Watchdog Timer Reload High Byte WDTH 04 95 95 FF3 Watchdog Timer Reload Low Byte WDTL 00 FF4–FF5 Reserved — XX Trim Bit Control FF6 Trim Bit Address TRMADR 00 155 FF7 Trim Bit Data TRMDR 00 156 Flash Memory Controller FF8 Flash Control FCTL 00 149 FF8 Flash Status FSTAT 00 150 Flash Page Select FPS 00 151 Flash Sector Protect FPROT 00 151 FF9 FFA Flash Programming Frequency High Byte FFREQH 00 152 FFB Flash Programming Frequency Low Byte FFREQL 00 152 Flags XX Refer to eZ8 CPU Core User Manual (UM0128) eZ8 CPU FFC — FFD Register Pointer RP XX FFE Stack Pointer High Byte SPH XX FFF Stack Pointer Low Byte SPL XX XX=Undefined PS022825-0908 Register Map Z8 Encore! XP® F082A Series Product Specification 23 Reset, Stop Mode Recovery, and Low Voltage Detection The Reset Controller within the Z8 Encore! XP® F082A Series controls Reset and Stop Mode Recovery operation and provides indication of low supply voltage conditions. In typical operation, the following events cause a Reset: • • • Power-On Reset (POR) • External RESET pin assertion (when the alternate RESET function is enabled by the GPIO register) • On-chip debugger initiated Reset (OCDCTL[0] set to 1) Voltage Brownout (VBO) Watchdog Timer time-out (when configured by the WDT_RES Flash Option Bit to initiate a reset) When the device is in STOP mode, a Stop Mode Recovery is initiated by either of the following: • • Watchdog Timer time-out GPIO Port input pin transition on an enabled Stop Mode Recovery source The low voltage detection circuitry on the device (available on the 8-pin product versions only) performs the following functions: • Generates the VBO reset when the supply voltage drops below a minimum safe level. • Generates an interrupt when the supply voltage drops below a user-defined level (8-pin devices only). Reset Types The Z8 Encore! XP F082A Series provides several different types of Reset operation. Stop Mode Recovery is considered as a form of Reset. Table 8 lists the types of Reset and their operating characteristics. The System Reset is longer if the external crystal oscillator is enabled by the Flash option bits, allowing additional time for oscillator start-up. PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 24 Table 8. Reset and Stop Mode Recovery Characteristics and Latency Reset Characteristics and Latency Reset Type Control Registers eZ8 CPU Reset Latency (Delay) System Reset Reset (as applicable) Reset 66 Internal Precision Oscillator Cycles System Reset with Crystal Reset (as applicable) Oscillator Enabled Reset 5000 Internal Precision Oscillator Cycles Stop Mode Recovery Reset 66 Internal Precision Oscillator Cycles + IPO startup time Unaffected, except WDT_CTL and OSC_CTL registers Stop Mode Recovery with Unaffected, except Crystal Oscillator Enabled WDT_CTL and OSC_CTL registers Reset 5000 Internal Precision Oscillator Cycles During a System Reset or Stop Mode Recovery, the Internal Precision Oscillator requires 4 µs to start up. Then the Z8 Encore! XP F082A Series device is held in Reset for 66 cycles of the Internal Precision Oscillator. If the crystal oscillator is enabled in the Flash option bits, this reset period is increased to 5000 IPO cycles. When a reset occurs because of a low voltage condition or Power-On Reset (POR), this delay is measured from the time that the supply voltage first exceeds the POR level. If the external pin reset remains asserted at the end of the reset period, the device remains in reset until the pin is deasserted. At the beginning of Reset, all GPIO pins are configured as inputs with pull-up resistor disabled, except PD0 (or PA2 on 8-pin devices) which is shared with the reset pin. On reset, the PD0 is configured as a bidirectional open-drain reset. The pin is internally driven low during port reset, after which the user code may reconfigure this pin as a general purpose output. During Reset, the eZ8 CPU and on-chip peripherals are idle; however, the on-chip crystal oscillator and Watchdog Timer oscillator continue to run. Upon Reset, control registers within the Register File that have a defined Reset value are loaded with their reset values. Other control registers (including the Stack Pointer, Register Pointer, and Flags) and general-purpose RAM are undefined following Reset. The eZ8 CPU fetches the Reset vector at Program Memory addresses 0002H and 0003H and loads that value into the Program Counter. Program execution begins at the Reset vector address. As the control registers are re-initialized by a system reset, the system clock after reset is always the IPO. The software must reconfigure the oscillator control block, such that the correct system clock source is enabled and selected. PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 25 Reset Sources Table 9 lists the possible sources of a system reset. Table 9. Reset Sources and Resulting Reset Type Operating Mode Reset Source Special Conditions NORMAL or HALT modes Power-On Reset/Voltage Brownout Reset delay begins after supply voltage exceeds POR level. Watchdog Timer time-out when configured for Reset None. RESET pin assertion All reset pulses less than three system clocks in width are ignored. On-Chip Debugger initiated Reset System Reset, except the On-Chip Debugger (OCDCTL[0] set to 1) is unaffected by the reset. STOP mode Power-On Reset/Voltage Brownout Reset delay begins after supply voltage exceeds POR level. RESET pin assertion All reset pulses less than the specified analog delay are ignored. See Table 131 on page 229. DBG pin driven Low None. Power-On Reset Z8 Encore! XP F082A Series devices contain an internal Power-On Reset circuit. The POR circuit monitors the supply voltage and holds the device in the Reset state until the supply voltage reaches a safe operating level. After the supply voltage exceeds the POR voltage threshold (VPOR), the device is held in the Reset state until the POR Counter has timed out. If the crystal oscillator is enabled by the option bits, this timeout is longer. After the Z8 Encore! XP F082A Series device exits the Power-On Reset state, the eZ8 CPU fetches the Reset vector. Following Power-On Reset, the POR status bit in the Reset Status (RSTSTAT) register is set to 1. Figure 5 displays Power-On Reset operation. See Electrical Characteristics on page 221 for the POR threshold voltage (VPOR). PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 26 VCC = 3.3 V VPOR VVBO Program Execution VCC = 0.0 V Internal Precision Oscillator Crystal Oscillator Oscillator Start-up Internal RESET signal POR counter delay Note: Not to Scale optional XTAL counter delay Figure 5. Power-On Reset Operation Voltage Brownout Reset The devices in the Z8 Encore! XP F082A Series provide low Voltage Brownout (VBO) protection. The VBO circuit senses when the supply voltage drops to an unsafe level (below the VBO threshold voltage) and forces the device into the Reset state. While the supply voltage remains below the Power-On Reset voltage threshold (VPOR), the VBO block holds the device in the Reset. After the supply voltage again exceeds the Power-On Reset voltage threshold, the device progresses through a full System Reset sequence, as described in the Power-On Reset section. Following Power-On Reset, the POR status bit in the Reset Status (RSTSTAT) register is set to 1. Figure 6 displays Voltage Brownout operation. See Electrical Characteristics on page 221 for the VBO and POR threshold voltages (VVBO and VPOR). The Voltage Brownout circuit can be either enabled or disabled during STOP mode. Operation during STOP mode is set by the VBO_AO Flash Option Bit. See Flash Option Bits for information about configuring VBO_AO. PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 27 VCC = 3.3 V VCC = 3.3 V VPOR VVBO Program Execution Voltage Brownout Program Execution System Clock Internal RESET signal POR counter delay Note: Not to Scale Figure 6. Voltage Brownout Reset Operation The POR level is greater than the VBO level by the specified hysteresis value. This ensures that the device undergoes a Power-On Reset after recovering from a VBO condition. Watchdog Timer Reset If the device is in NORMAL or HALT mode, the Watchdog Timer can initiate a System Reset at time-out if the WDT_RES Flash Option Bit is programmed to 1. This is the unprogrammed state of the WDT_RES Flash Option Bit. If the bit is programmed to 0, it configures the Watchdog Timer to cause an interrupt, not a System Reset, at time-out. The WDT bit in the Reset Status (RSTSTAT) register is set to signify that the reset was initiated by the Watchdog Timer. External Reset Input The RESET pin has a Schmitt-Triggered input and an internal pull-up resistor. Once the RESET pin is asserted for a minimum of four system clock cycles, the device progresses through the System Reset sequence. Because of the possible asynchronicity of the system clock and reset signals, the required reset duration may be as short as three clock periods PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 28 and as long as four. A reset pulse three clock cycles in duration might trigger a reset; a pulse four cycles in duration always triggers a reset. While the RESET input pin is asserted Low, the Z8 Encore! XP® F082A Series devices remain in the Reset state. If the RESET pin is held Low beyond the System Reset timeout, the device exits the Reset state on the system clock rising edge following RESET pin deassertion. Following a System Reset initiated by the external RESET pin, the EXT status bit in the Reset Status (RSTSTAT) register is set to 1. External Reset Indicator During System Reset or when enabled by the GPIO logic (see Port A–D Control Registers on page 46), the RESET pin functions as an open-drain (active Low) reset mode indicator in addition to the input functionality. This reset output feature allows a Z8 Encore! XP F082A Series device to reset other components to which it is connected, even if that reset is caused by internal sources such as POR, VBO or WDT events. After an internal reset event occurs, the internal circuitry begins driving the RESET pin Low. The RESET pin is held Low by the internal circuitry until the appropriate delay listed in Table 8 has elapsed. On-Chip Debugger Initiated Reset A Power-On Reset can be initiated using the On-Chip Debugger by setting the RST bit in the OCD Control register. The On-Chip Debugger block is not reset but the rest of the chip goes through a normal system reset. The RST bit automatically clears during the system reset. Following the system reset the POR bit in the Reset Status (RSTSTAT) register is set. Stop Mode Recovery STOP mode is entered by execution of a STOP instruction by the eZ8 CPU. See LowPower Modes on page 33 for detailed STOP mode information. During Stop Mode Recovery (SMR), the CPU is held in reset for 66 IPO cycles if the crystal oscillator is disabled or 5000 cycles if it is enabled. The SMR delay (see Table 131 on page 229) TSMR, also includes the time required to start up the IPO. Stop Mode Recovery does not affect on-chip registers other than the Watchdog Timer Control register (WDTCTL) and the Oscillator Control register (OSCCTL). After any Stop Mode Recovery, the IPO is enabled and selected as the system clock. If another system clock source is required, the Stop Mode Recovery code must reconfigure the oscillator control block such that the correct system clock source is enabled and selected. The eZ8 CPU fetches the Reset vector at Program Memory addresses 0002H and 0003H and loads that value into the Program Counter. Program execution begins at the Reset PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 29 vector address. Following Stop Mode Recovery, the STOP bit in the Reset Status (RSTSTAT) Register is set to 1. Table 10 lists the Stop Mode Recovery sources and resulting actions. The text following provides more detailed information about each of the Stop Mode Recovery sources. Table 10. Stop Mode Recovery Sources and Resulting Action Operating Mode Stop Mode Recovery Source Action STOP mode Watchdog Timer time-out when configured for Reset Stop Mode Recovery Watchdog Timer time-out when configured for interrupt Stop Mode Recovery followed by interrupt (if interrupts are enabled) Data transition on any GPIO Port pin enabled as a Stop Mode Recovery source Stop Mode Recovery Assertion of external RESET Pin System Reset Debug Pin driven Low System Reset Stop Mode Recovery Using Watchdog Timer Time-Out If the Watchdog Timer times out during STOP mode, the device undergoes a Stop Mode Recovery sequence. In the Reset Status (RSTSTAT) register, the WDT and STOP bits are set to 1. If the Watchdog Timer is configured to generate an interrupt upon time-out and the Z8 Encore! XP F082A Series device is configured to respond to interrupts, the eZ8 CPU services the Watchdog Timer interrupt request following the normal Stop Mode Recovery sequence. Stop Mode Recovery Using a GPIO Port Pin Transition Each of the GPIO Port pins may be configured as a Stop Mode Recovery input source. On any GPIO pin enabled as a Stop Mode Recovery source, a change in the input pin value (from High to Low or from Low to High) initiates Stop Mode Recovery. Note: The SMR pulses shorter than specified does not trigger a recovery (see Table 131 on page 229). When this happens, the STOP bit in the Reset Status (RSTSTAT) register is set to 1. Caution: In STOP mode, the GPIO Port Input Data registers (PxIN) are disabled. The Port Input Data registers record the Port transition only if the signal stays on the Port pin through the end of the Stop Mode Recovery delay. As a result, short pulses on the Port pin can PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 30 initiate Stop Mode Recovery without being written to the Port Input Data register or without initiating an interrupt (if enabled for that pin). Stop Mode Recovery Using the External RESET Pin When the Z8 Encore! XP F082A Series device is in STOP mode and the external RESET pin is driven Low, a system reset occurs. Because of a glitch filter operating on the RESET pin, the Low pulse must be greater than the minimum width specified, or it is ignored. See Electrical Characteristics on page 221 for details. Low Voltage Detection In addition to the Voltage Brownout (VBO) Reset described above, it is also possible to generate an interrupt when the supply voltage drops below a user-selected value. For details about configuring the Low Voltage Detection (LVD) and the threshold levels available, see Trim Bit Address 0003H on page 159. The LVD function is available on the 8pin product versions only. When the supply voltage drops below the LVD threshold, the LVD bit of the Reset Status (RSTSTAT) register is set to one. This bit remains one until the low-voltage condition goes away. Reading or writing this bit does not clear it. The LVD circuit can also generate an interrupt when so enabled, see Interrupt Vectors and Priority on page 58. The LVD bit is NOT latched, so enabling the interrupt is the only way to guarantee detection of a transient low voltage event. The LVD functionality depends on circuitry shared with the VBO block; therefore, disabling the VBO also disables the LVD. Reset Register Definitions The following sections define the Reset registers. Reset Status Register The Reset Status (RSTSTAT) register is a read-only register that indicates the source of the most recent Reset event, indicates a Stop Mode Recovery event, and indicates a Watchdog Timer time-out. Reading this register resets the upper four bits to 0. This register shares its address with the Watchdog Timer control register, which is write-only (see Table 11 on page 31). PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 31 Table 11. Reset Status Register (RSTSTAT) 7 6 5 4 POR STOP WDT EXT BITS FIELD RESET R/W See descriptions below R R R 3 2 1 0 Reserved LVD 0 0 0 0 0 R R R R R FF0H ADDR POR STOP WDT EXT Power-On Reset 1 0 0 0 Reset using RESET pin assertion 0 0 0 1 Reset using Watchdog Timer time-out 0 0 1 0 Reset using the On-Chip Debugger (OCTCTL[1] set to 1) 1 0 0 0 Reset from STOP Mode using DBG Pin driven Low 1 0 0 0 Stop Mode Recovery using GPIO pin transition 0 1 0 0 Stop Mode Recovery using Watchdog Timer time-out 0 1 1 0 Reset or Stop Mode Recovery Event POR—Power-On Reset Indicator If this bit is set to 1, a Power-On Reset event occurs. This bit is reset to 0 if a WDT time-out or Stop Mode Recovery occurs. This bit is also reset to 0 when the register is read. STOP—Stop Mode Recovery Indicator If this bit is set to 1, a Stop Mode Recovery occurs. If the STOP and WDT bits are both set to 1, the Stop Mode Recovery occurs because of a WDT time-out. If the STOP bit is 1 and the WDT bit is 0, the Stop Mode Recovery was not caused by a WDT time-out. This bit is reset by a Power-On Reset or a WDT time-out that occurred while not in STOP mode. Reading this register also resets this bit. WDT—Watchdog Timer Time-Out Indicator If this bit is set to 1, a WDT time-out occurs. A POR resets this pin. A Stop Mode Recovery from a change in an input pin also resets this bit. Reading this register resets this bit. This read must occur before clearing the WDT interrupt. EXT—External Reset Indicator If this bit is set to 1, a Reset initiated by the external RESET pin occurs. A Power-On Reset or a Stop Mode Recovery from a change in an input pin resets this bit. Reading this register resets this bit. Reserved—Must be 0. LVD—Low Voltage Detection Indicator If this bit is set to 1 the current state of the supply voltage is below the low voltage detection threshold. This value is not latched but is a real-time indicator of the supply voltage level. PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 32 PS022825-0908 Reset, Stop Mode Recovery, and Low Voltage Detection Z8 Encore! XP® F082A Series Product Specification 33 Low-Power Modes The Z8 Encore! XP F082A Series products contain power-saving features. The highest level of power reduction is provided by the STOP mode, in which nearly all device functions are powered down. The next lower level of power reduction is provided by the HALT mode, in which the CPU is powered down. Further power savings can be implemented by disabling individual peripheral blocks while in Active mode (defined as being in neither STOP nor HALT mode). STOP Mode Executing the eZ8 CPU’s STOP instruction places the device into STOP mode, powering down all peripherals except the Voltage Brownout detector, the Low-power Operational Amplifier and the Watchdog Timer. These three blocks may also be disabled for additional power savings. Specifically, the operating characteristics are: • Primary crystal oscillator and internal precision oscillator are stopped; XIN and XOUT (if previously enabled) are disabled, and PA0/PA1 revert to the states programmed by the GPIO registers. • • • • System clock is stopped. • • If enabled, the Watchdog Timer logic continues to operate. • Low-power operational amplifier continues to operate if enabled by the Power Control register to do so. • All other on-chip peripherals are idle. eZ8 CPU is stopped. Program counter (PC) stops incrementing. Watchdog Timer’s internal RC oscillator continues to operate if enabled by the Oscillator Control register. If enabled for operation in STOP mode by the associated Flash Option Bit, the Voltage Brownout protection circuit continues to operate. To minimize current in STOP mode, all GPIO pins that are configured as digital inputs must be driven to one of the supply rails (VCC or GND). Additionally, any GPIOs configured as outputs must also be driven to one of the supply rails. The device can be brought out of STOP mode using Stop Mode Recovery. For more information on Stop Mode Recovery, see Reset, Stop Mode Recovery, and Low Voltage Detection on page 23. PS022825-0908 Low-Power Modes Z8 Encore! XP® F082A Series Product Specification 34 HALT Mode Executing the eZ8 CPU’s HALT instruction places the device into HALT mode, which powers down the CPU but leaves all other peripherals active. In HALT mode, the operating characteristics are: • • • • • • • Primary oscillator is enabled and continues to operate. System clock is enabled and continues to operate. eZ8 CPU is stopped. Program counter (PC) stops incrementing. Watchdog Timer’s internal RC oscillator continues to operate. If enabled, the Watchdog Timer continues to operate. All other on-chip peripherals continue to operate, if enabled. The eZ8 CPU can be brought out of HALT mode by any of the following operations: • • • • • Interrupt Watchdog Timer time-out (interrupt or reset) Power-On Reset Voltage Brownout reset External RESET pin assertion To minimize current in HALT mode, all GPIO pins that are configured as inputs must be driven to one of the supply rails (VCC or GND). Peripheral-Level Power Control In addition to the STOP and HALT modes, it is possible to disable each peripheral on each of the Z8 Encore! XP F082A Series devices. Disabling a given peripheral minimizes its power consumption. Power Control Register Definitions The following sections define the Power Control registers. Power Control Register 0 Each bit of the following registers disables a peripheral block, either by gating its system clock input or by removing power from the block. The default state of the low-power PS022825-0908 Low-Power Modes Z8 Encore! XP® F082A Series Product Specification 35 operational amplifier (LPO) is OFF. To use the LPO, clear the LPO bit, turning it ON. Clearing this bit might interfere with normal ADC measurements on ANA0 (the LPO output). This bit enables the amplifier even in STOP mode. If the amplifier is not required in STOP mode, disable it. Failure to perform this results in STOP mode currents greater than specified. This register is only reset during a POR sequence. Other system reset events do not affect it. Note: Table 12. Power Control Register 0 (PWRCTL0) BITS 6 FIELD 7 LPO RESET 1 R/W R/W 5 4 VBO 3 TEMP 2 ADC 1 COMP 0 Reserved 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W Reserved F80H ADDR LPO—Low-Power Operational Amplifier Disable 0 = LPO is enabled (this applies even in STOP mode). 1 = LPO is disabled. Reserved—Must be 0. VBO—Voltage Brownout Detector Disable This bit and the VBO_AO Flash option bit must both enable the VBO for the VBO to be active. 0 = VBO Enabled 1 = VBO Disabled TEMP—Temperature Sensor Disable 0 = Temperature Sensor Enabled 1 = Temperature Sensor Disabled ADC—Analog-to-Digital Converter Disable 0 = Analog-to-Digital Converter Enabled 1 = Analog-to-Digital Converter Disabled COMP—Comparator Disable 0 = Comparator is Enabled 1 = Comparator is Disabled Reserved—Must be 0. Note: PS022825-0908 Asserting any power control bit disables the targeted block, regardless of any enable bits contained in the target block’s control registers. Low-Power Modes Z8 Encore! XP® F082A Series Product Specification 36 PS022825-0908 Low-Power Modes Z8 Encore! XP® F082A Series Product Specification 37 General-Purpose Input/Output The Z8 Encore! XP® F082A Series products support a maximum of 25 port pins (Ports A– D) for general-purpose input/output (GPIO) operations. Each port contains control and data registers. The GPIO control registers determine data direction, open-drain, output drive current, programmable pull-ups, Stop Mode Recovery functionality, and alternate pin functions. Each port pin is individually programmable. In addition, the Port C pins are capable of direct LED drive at programmable drive strengths. GPIO Port Availability By Device Table 13 lists the port pins available with each device and package type. Table 13. Port Availability by Device and Package Type Devices Package ADC Port A Port B Port C Port D Total I/O Z8F082ASB, Z8F082APB, Z8F082AQB Z8F042ASB, Z8F042APB, Z8F042AQB Z8F022ASB, Z8F022APB, Z8F022AQB Z8F012ASB, Z8F012APB, Z8F012AQB 8-pin Yes [5:0] No No No 6 Z8F081ASB, Z8F081APB, Z8F081AQB Z8F041ASB, Z8F041APB, Z8F041AQB Z8F021ASB, Z8F021APB, Z8F021AQB Z8F011ASB, Z8F011APB, Z8F011AQB 8-pin No [5:0] No No No 6 Z8F082APH, Z8F082AHH, Z8F082ASH Z8F042APH, Z8F042AHH, Z8F042ASH Z8F022APH, Z8F022AHH, Z8F022ASH Z8F012APH, Z8F012AHH, Z8F012ASH 20-pin Yes [7:0] [3:0] [3:0] [0] 17 Z8F081APH, Z8F081AHH, Z8F081ASH Z8F041APH, Z8F041AHH, Z8F041ASH Z8F021APH, Z8F021AHH, Z8F021ASH Z8F011APH, Z8F011AHH, Z8F011ASH 20-pin No [7:0] [3:0] [3:0] [0] 17 Z8F082APJ, Z8F082ASJ, Z8F082AHJ Z8F042APJ, Z8F042ASJ, Z8F042AHJ Z8F022APJ, Z8F022ASJ, Z8F022AHJ Z8F012APJ, Z8F012ASJ, Z8F012AHJ 28-pin Yes [7:0] [5:0] [7:0] [0] 23 Z8F081APJ, Z8F081ASJ, Z8F081AHJ Z8F041APJ, Z8F041ASJ, Z8F041AHJ Z8F021APJ, Z8F021ASJ, Z8F021AHJ Z8F011APJ, Z8F011ASJ, Z8F011AHJ 28-pin No [7:0] [7:0] [7:0] [0] 25 PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 38 Architecture Figure 7 displays a simplified block diagram of a GPIO port pin. In this figure, the ability to accommodate alternate functions and variable port current drive strength is not displayed. Port Input Data Register Q D Schmitt-Trigger Q D System Clock VDD Port Output Control Port Output Data Register DATA Bus D Q Port Pin System Clock Port Data Direction GND Figure 7. GPIO Port Pin Block Diagram GPIO Alternate Functions Many of the GPIO port pins can be used for general-purpose I/O and access to on-chip peripheral functions such as the timers and serial communication devices. The Port A–D Alternate Function sub-registers configure these pins for either General-Purpose I/O or alternate function operation. When a pin is configured for alternate function, control of the port pin direction (input/output) is passed from the Port A–D Data Direction registers to the alternate function assigned to this pin. Table 14 on page 41 lists the alternate functions possible with each port pin. For those pins with more one alternate function, the alternate function is defined through Alternate Function Sets sub-registers AFS1 and AFS2. The crystal oscillator functionality is not controlled by the GPIO block. When the crystal oscillator is enabled in the oscillator control block, the GPIO functionality of PA0 and PA1 is overridden. In that case, those pins function as input and output for the crystal oscillator. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 39 PA0 and PA6 contain two different timer functions, a timer input and a complementary timer output. Both of these functions require the same GPIO configuration, the selection between the two is based on the timer mode. See Timers on page 69 for more details. Caution: For pin with multiple alternate functions, it is recommended to write to the AFS1 and AFS2 sub-registers before enabling the alternate function via the AF sub-register. This prevents spurious transitions through unwanted alternate function modes. Direct LED Drive The Port C pins provide a current sinked output capable of driving an LED without requiring an external resistor. The output sinks current at programmable levels of 3 mA, 7 mA, 13 mA and 20 mA. This mode is enabled through the Alternate Function sub-register AFS1 and is programmable through the LED control registers. The LED Drive Enable (LEDEN) register turns on the drivers. The LED Drive Level (LEDLVLH and LEDLVLL) registers select the sink current. For correct function, the LED anode must be connected to VDD and the cathode to the GPIO pin. Using all Port C pins in LED drive mode with maximum current may result in excessive total current. See Electrical Characteristics on page 221 for the maximum total current for the applicable package. Shared Reset Pin On the 20- and 28-pin devices, the PD0 pin shares function with a bi-directional reset pin. Unlike all other I/O pins, this pin does not default to GPIO function on power-up. This pin acts as a bi-directional reset until the software re-configures it. The PD0 pin is output-only when in GPIO mode. On the 8-pin product versions, the reset pin is shared with PA2, but the pin is not limited to output-only when in GPIO mode. Caution: If PA2 on the 8-pin product is reconfigured as an input, ensure that no external stimulus drives the pin low during any reset sequence. Since PA2 returns to its RESET alternate function during system resets, driving it Low holds the chip in a reset state until the pin is released. Shared Debug Pin On the 8-pin version of this device only, the Debug pin shares function with the PA0 GPIO pin. This pin performs as a general purpose input pin on power-up, but the debug logic monitors this pin during the reset sequence to determine if the unlock sequence occurs. If the unlock sequence is present, the debug function is unlocked and the pin no longer func- PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 40 tions as a GPIO pin. If it is not present, the debug feature is disabled until/unless another reset event occurs. For more details, see On-Chip Debugger on page 173. Crystal Oscillator Override For systems using a crystal oscillator, PA0 and PA1 are used to connect the crystal. When the crystal oscillator is enabled (see Oscillator Control Register Definitions on page 190), the GPIO settings are overridden and PA0 and PA1 are disabled. 5 V Tolerance All six I/O pins on the 8-pin devices are 5 V-tolerant, unless the programmable pull-ups are enabled. If the pull-ups are enabled and inputs higher than VDD are applied to these parts, excessive current flows through those pull-up devices and can damage the chip. Note: In the 20- and 28-pin versions of this device, any pin which shares functionality with an ADC, crystal or comparator port is not 5 V-tolerant, including PA[1:0], PB[5:0] and PC[2:0]. All other signal pins are 5 V-tolerant, and can safely handle inputs higher than VDD except when the programmable pull-ups are enabled. External Clock Setup For systems using an external TTL drive, PB3 is the clock source for 20- and 28-pin devices. In this case, configure PB3 for alternate function CLKIN. Write the Oscillator Control (OSCCTL) register (see Oscillator Control Register Definitions on page 190) such that the external oscillator is selected as the system clock. For 8-pin devices use PA1 instead of PB3. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 41 Table 14. Port Alternate Function Mapping (Non 8-Pin Parts) Alternate Function Set Register AFS1 Port Pin Mnemonic Alternate Function Description Port A PA0 T0IN/T0OUT* Timer 0 Input/Timer 0 Output Complement N/A Reserved PA1 T0OUT Timer 0 Output Reserved PA2 DE0 UART 0 Driver Enable Reserved PA3 CTS0 UART 0 Clear to Send Reserved PA4 RXD0/IRRX0 UART 0/IrDA 0 Receive Data Reserved PA5 TXD0/IRTX0 UART 0/IrDA 0 Transmit Data Reserved PA6 T1IN/T1OUT* Timer 1 Input/Timer 1 Output Complement Reserved PA7 T1OUT Timer 1 Output Reserved Note: Because there is only a single alternate function for each Port A pin, the Alternate Function Set registers are not implemented for Port A. Enabling alternate function selections as described in Port A–D Alternate Function Sub-Registers on page 47 automatically enables the associated alternate function. * Whether PA0/PA6 take on the timer input or timer output complement function depends on the timer configuration as described in Timer Pin Signal Operation on page 82. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 42 Table 14. Port Alternate Function Mapping (Non 8-Pin Parts) (Continued) Port Pin Mnemonic Port B PB0 Reserved ANA0/AMPOUT PB1 PB3 PB4 PB7 AFS1[0]: 1 AFS1[1]: 0 ADC Analog Input/LPO Input (N) AFS1[1]: 1 AFS1[2]: 0 ANA2/AMPINP ADC Analog Input/LPO Input (P) AFS1[2]: 1 CLKIN External Clock Input AFS1[3]: 0 ANA3 ADC Analog Input AFS1[3]: 1 Reserved AFS1[4]: 0 ADC Analog Input Reserved VREF* PB6 ADC Analog Input/LPO Output Reserved ANA7 PB5 Alternate Function Set Register AFS1 AFS1[0]: 0 Reserved ANA1/AMPINN PB2 Alternate Function Description AFS1[4]: 1 AFS1[5]: 0 ADC Voltage Reference AFS1[5]: 1 Reserved AFS1[6]: 0 Reserved AFS1[6]: 1 Reserved AFS1[7]: 0 Reserved AFS1[7]: 1 Note: Because there are at most two choices of alternate function for any pin of Port B, the Alternate Function Set register AFS2 is not used to select the function. Also, alternate function selection as described in Port A–D Alternate Function Sub-Registers on page 47 must also be enabled. * VREF is available on PB5 in 28-pin products only. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 43 Table 14. Port Alternate Function Mapping (Non 8-Pin Parts) (Continued) Alternate Function Set Register AFS1 Port Pin Mnemonic Port C PC0 Reserved AFS1[0]: 0 ANA4/CINP/LED ADC or Comparator Input, or LED drive Drive AFS1[0]: 1 Reserved AFS1[1]: 0 ANA5/CINN/ LED ADC or Comparator Input, or LED drive Drive AFS1[1]: 1 Reserved AFS1[2]: 0 PC1 PC2 PC3 PC4 ANA6/LED/ VREF* ADC Analog Input or LED Drive or ADC Voltage Reference AFS1[2]: 1 COUT Comparator Output AFS1[3]: 0 LED LED drive AFS1[3]: 1 Reserved LED PC5 LED Drive LED Drive AFS1[5]: 1 AFS1[6]: 0 LED Drive Reserved LED AFS1[4]: 1 AFS1[5]: 0 Reserved LED PC7 AFS1[4]: 0 Reserved LED PC6 Alternate Function Description AFS1[6]: 1 AFS1[7]: 0 LED Drive AFS1[7]: 1 Note: Because there are at most two choices of alternate function for any pin of Port C, the Alternate Function Set register AFS2 is not used to select the function. Also, alternate function selection as described in Port A–D Alternate Function Sub-Registers on page 47 must also be enabled. *VREF is available on PC2 in 20-pin parts only. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 44 Table 15. Port Alternate Function Mapping (8-Pin Parts) Alternate Function Select Register AFS2 Port Pin Mnemonic Alternate Function Description Alternate Function Select Register AFS1 Port A PA0 T0IN Timer 0 Input AFS1[0]: 0 AFS2[0]: 0 Reserved AFS1[0]: 0 AFS2[0]: 1 Reserved AFS1[0]: 1 AFS2[0]: 0 PA1 T0OUT Timer 0 Output Complement AFS1[0]: 1 AFS2[0]: 1 T0OUT Timer 0 Output AFS1[1]: 0 AFS2[1]: 0 AFS1[1]: 0 AFS2[1]: 1 AFS1[1]: 1 AFS2[1]: 0 Analog Functions* ADC Analog Input/VREF AFS1[1]: 1 AFS2[1]: 1 DE0 UART 0 Driver Enable AFS1[2]: 0 AFS2[2]: 0 RESET External Reset AFS1[2]: 0 AFS2[2]: 1 T1OUT Timer 1 Output AFS1[2]: 1 AFS2[2]: 0 AFS1[2]: 1 AFS2[2]: 1 Reserved CLKIN PA2 External Clock Input Reserved PA3 PA4 PA5 CTS0 UART 0 Clear to Send AFS1[3]: 0 AFS2[3]: 0 COUT Comparator Output AFS1[3]: 0 AFS2[3]: 1 T1IN Timer 1 Input AFS1[3]: 1 AFS2[3]: 0 Analog Functions* ADC Analog Input/LPO Input (P) AFS1[3]: 1 AFS2[3]: 1 RXD0 AFS1[4]: 0 AFS2[4]: 0 Reserved AFS1[4]: 0 AFS2[4]: 1 Reserved AFS1[4]: 1 AFS2[4]: 0 Analog Functions* ADC/Comparator Input (N)/LPO AFS1[4]: 1 Input (N) AFS2[4]: 1 TXD0 UART 0 Transmit Data AFS1[5]: 0 AFS2[5]: 0 T1OUT Timer 1 Output Complement AFS1[5]: 0 AFS2[5]: 1 AFS1[5]: 1 AFS2[5]: 0 Analog Functions* ADC/Comparator Input (P) LPO AFS1[5]: 1 Output AFS2[5]: 1 Reserved UART 0 Receive Data *Analog Functions include ADC inputs, ADC reference, comparator inputs and LPO ports. Note: Also, alternate function selection as described in Port A–D Alternate Function Sub-Registers on page 47 must be enabled. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 45 GPIO Interrupts Many of the GPIO port pins can be used as interrupt sources. Some port pins can be configured to generate an interrupt request on either the rising edge or falling edge of the pin input signal. Other port pin interrupt sources generate an interrupt when any edge occurs (both rising and falling). See Interrupt Controller on page 55 for more information about interrupts using the GPIO pins. GPIO Control Register Definitions Four registers for each Port provide access to GPIO control, input data, and output data. Table 16 lists these Port registers. Use the Port A–D Address and Control registers together to provide access to sub-registers for Port configuration and control. Table 16. GPIO Port Registers and Sub-Registers Port Register Mnemonic Port Register Name PxADDR Port A–D Address Register (Selects sub-registers) PxCTL Port A–D Control Register (Provides access to sub-registers) PxIN Port A–D Input Data Register PxOUT Port A–D Output Data Register Port Sub-Register Mnemonic Port Register Name PS022825-0908 PxDD Data Direction PxAF Alternate Function PxOC Output Control (Open-Drain) PxHDE High Drive Enable PxSMRE Stop Mode Recovery Source Enable PxPUE Pull-up Enable PxAFS1 Alternate Function Set 1 PxAFS2 Alternate Function Set 2 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 46 Port A–D Address Registers The Port A–D Address registers select the GPIO Port functionality accessible through the Port A–D Control registers. The Port A–D Address and Control registers combine to provide access to all GPIO Port controls (Table 17). Table 17. Port A–D GPIO Address Registers (PxADDR) 7 BITS 6 5 4 3 FIELD PADDR[7:0] RESET 00H R/W R/W R/W R/W R/W R/W 2 1 0 R/W R/W R/W FD0H, FD4H, FD8H, FDCH ADDR PADDR[7:0]—Port Address The Port Address selects one of the sub-registers accessible through the Port Control register. PADDR[7:0] Port Control sub-register accessible using the Port A–D Control Registers 00H No function. Provides some protection against accidental Port reconfiguration. 01H Data Direction. 02H Alternate Function. 03H Output Control (Open-Drain). 04H High Drive Enable. 05H Stop Mode Recovery Source Enable. 06H Pull-up Enable. 07H Alternate Function Set 1. 08H Alternate Function Set 2. 09H–FFH No function. Port A–D Control Registers The Port A–D Control registers set the GPIO port operation. The value in the corresponding Port A–D Address register determines which sub-register is read from or written to by a Port A–D Control register transaction (Table 18). PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 47 Table 18. Port A–D Control Registers (PxCTL) 7 BITS 6 5 4 FIELD PCTL RESET 00H R/W R/W R/W R/W R/W 3 2 1 0 R/W R/W R/W R/W FD1H, FD5H, FD9H, FDDH ADDR PCTL[7:0]—Port Control The Port Control register provides access to all sub-registers that configure the GPIO Port operation. Port A–D Data Direction Sub-Registers The Port A–D Data Direction sub-register is accessed through the Port A–D Control register by writing 01H to the Port A–D Address register (Table 19). Table 19. Port A–D Data Direction Sub-Registers (PxDD) 7 6 5 4 3 2 1 0 FIELD DD7 DD6 DD5 DD4 DD3 DD2 DD1 DD0 RESET 1 1 1 1 1 1 1 1 R/W R/W R/W R/W R/W R/W R/W R/W BITS R/W If 01H in Port A–D Address Register, accessible through the Port A–D Control Register ADDR DD[7:0]—Data Direction These bits control the direction of the associated port pin. Port Alternate Function operation overrides the Data Direction register setting. 0 = Output. Data in the Port A–D Output Data register is driven onto the port pin. 1 = Input. The port pin is sampled and the value written into the Port A–D Input Data Register. The output driver is tristated. Port A–D Alternate Function Sub-Registers The Port A–D Alternate Function sub-register (Table 20) is accessed through the Port A–D Control register by writing 02H to the Port A–D Address register. The Port A–D Alternate Function sub-registers enable the alternate function selection on pins. If disabled, pins functions as GPIO. If enabled, select one of four alternate functions using alternate function set subregisters 1 and 2 as described in the Port A–D Alternate Function PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 48 Set 1 Sub-Registers on page 50, GPIO Alternate Functions on page 38, and Port A–D Alternate Function Set 2 Sub-Registers on page 51. See GPIO Alternate Functions on page 38 to determine the alternate function associated with each port pin. Caution: Do not enable alternate functions for GPIO port pins for which there is no associated alternate function. Failure to follow this guideline can result in unpredictable operation. Table 20. Port A–D Alternate Function Sub-Registers (PxAF) 7 6 5 4 3 2 1 0 AF7 AF6 AF5 AF4 AF3 AF2 AF1 AF0 BITS FIELD 00H (Ports A–C); 01H (Port D); 04H (Port A of 8-pin device) RESET R/W R/W If 02H in Port A–D Address Register, accessible through the Port A–D Control Register ADDR AF[7:0]—Port Alternate Function enabled 0 = The port pin is in normal mode and the DDx bit in the Port A–D Data Direction sub-register determines the direction of the pin. 1 = The alternate function selected through Alternate Function Set sub-registers is enabled. Port pin operation is controlled by the alternate function. Port A–D Output Control Sub-Registers The Port A–D Output Control sub-register (Table 21) is accessed through the Port A–D Control register by writing 03H to the Port A–D Address register. Setting the bits in the Port A–D Output Control sub-registers to 1 configures the specified port pins for opendrain operation. These sub-registers affect the pins directly and, as a result, alternate functions are also affected. Table 21. Port A–D Output Control Sub-Registers (PxOC) 7 6 5 4 3 2 1 0 POC7 POC6 POC5 POC4 POC3 POC2 POC1 POC0 R/W R/W BITS FIELD 00H (Ports A-C); 01H (Port D) RESET R/W R/W ADDR R/W R/W R/W R/W R/W If 03H in Port A–D Address Register, accessible through the Port A–D Control Register POC[7:0]—Port Output Control These bits function independently of the alternate function bit and always disable the drains if set to 1. 0 = The source current is enabled for any output mode (unless overridden by the alternate PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 49 function). (Push-pull output) 1 = The source current for the associated pin is disabled (open-drain mode). Port A–D High Drive Enable Sub-Registers The Port A–D High Drive Enable sub-register (Table 22) is accessed through the Port A–D Control register by writing 04H to the Port A–D Address register. Setting the bits in the Port A–D High Drive Enable sub-registers to 1 configures the specified port pins for high current output drive operation. The Port A–D High Drive Enable sub-register affects the pins directly and, as a result, alternate functions are also affected. Table 22. Port A–D High Drive Enable Sub-Registers (PxHDE) 7 6 5 4 3 2 1 0 FIELD PHDE7 PHDE6 PHDE5 PHDE4 PHDE3 PHDE2 PHDE1 PHDE0 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W BITS R/W If 04H in Port A–D Address Register, accessible through the Port A–D Control Register ADDR PHDE[7:0]—Port High Drive Enabled 0 = The Port pin is configured for standard output current drive. 1 = The Port pin is configured for high output current drive. Port A–D Stop Mode Recovery Source Enable Sub-Registers The Port A–D Stop Mode Recovery Source Enable sub-register (Table 23) is accessed through the Port A–D Control register by writing 05H to the Port A–D Address register. Setting the bits in the Port A–D Stop Mode Recovery Source Enable sub-registers to 1 configures the specified Port pins as a Stop Mode Recovery source. During STOP mode, any logic transition on a Port pin enabled as a Stop Mode Recovery source initiates Stop Mode Recovery. Table 23. Port A–D Stop Mode Recovery Source Enable Sub-Registers (PxSMRE) 7 6 5 4 3 2 1 0 FIELD PSMRE7 PSMRE6 PSMRE5 PSMRE4 PSMRE3 PSMRE2 PSMRE1 PSMRE0 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W BITS R/W ADDR If 05H in Port A–D Address Register, accessible through the Port A–D Control Register PSMRE[7:0]—Port Stop Mode Recovery Source Enabled 0 = The Port pin is not configured as a Stop Mode Recovery source. Transitions on this pin PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 50 during STOP mode do not initiate Stop Mode Recovery. 1 = The Port pin is configured as a Stop Mode Recovery source. Any logic transition on this pin during STOP mode initiates Stop Mode Recovery. Port A–D Pull-up Enable Sub-Registers The Port A–D Pull-up Enable sub-register (Table 24) is accessed through the Port A–D Control register by writing 06H to the Port A–D Address register. Setting the bits in the Port A–D Pull-up Enable sub-registers enables a weak internal resistive pull-up on the specified Port pins. Table 24. Port A–D Pull-Up Enable Sub-Registers (PxPUE) 7 6 5 4 3 2 1 0 PPUE7 PPUE6 PPUE5 PPUE4 PPUE3 PPUE2 PPUE1 PPUE0 BITS FIELD 00H (Ports A-C); 01H (Port D); 04H (Port A of 8-pin device) RESET R/W R/W R/W R/W R/W R/W R/W R/W R/W If 06H in Port A–D Address Register, accessible through the Port A–D Control Register ADDR PPUE[7:0]—Port Pull-up Enabled 0 = The weak pull-up on the Port pin is disabled. 1 = The weak pull-up on the Port pin is enabled. Port A–D Alternate Function Set 1 Sub-Registers The Port A–D Alternate Function Set1 sub-register (Table 25) is accessed through the Port A–D Control register by writing 07H to the Port A–D Address register. The Alternate Function Set 1 sub-registers selects the alternate function available at a port pin. Alternate Functions selected by setting or clearing bits of this register are defined in GPIO Alternate Functions on page 38. Alternate function selection on port pins must also be enabled as described in Port A–D Alternate Function Sub-Registers on page 47. Note: Table 25. Port A–D Alternate Function Set 1 Sub-Registers (PxAFS1) 7 6 5 4 3 2 1 0 FIELD PAFS17 PAFS16 PAFS15 PAFS14 PAFS13 PAFS12 PAFS11 PAFS10 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W BITS R/W ADDR PS022825-0908 If 07H in Port A–D Address Register, accessible through the Port A–D Control Register General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 51 PAFS1[7:0]—Port Alternate Function Set 1 0 = Port Alternate Function selected as defined in Table 14 and Table 15 on page 44. 1 = Port Alternate Function selected as defined in Table 14 and Table 15 on page 44. Port A–D Alternate Function Set 2 Sub-Registers The Port A–D Alternate Function Set 2 sub-register (Table 26) is accessed through the Port A–D Control register by writing 08H to the Port A–D Address register. The Alternate Function Set 2 sub-registers selects the alternate function available at a port pin. Alternate Functions selected by setting or clearing bits of this register is defined in Table 15. Alternate function selection on port pins must also be enabled as described in Port A–D Alternate Function Sub-Registers on page 47. Note: Table 26. Port A–D Alternate Function Set 2 Sub-Registers (PxAFS2) 7 6 5 4 3 2 1 0 PAFS27 PAFS26 PAFS25 PAFS24 PAFS23 PAFS22 PAFS21 PAFS20 BITS FIELD 00H (all ports of 20/28 pin devices); 04H (Port A of 8-pin device) RESET R/W R/W R/W R/W R/W R/W R/W R/W R/W If 08H in Port A–D Address Register, accessible through the Port A–D Control Register ADDR PAFS2[7:0]—Port Alternate Function Set 2 0 = Port Alternate Function selected as defined in Table 15. 1 = Port Alternate Function selected as defined in Table 15. Port A–C Input Data Registers Reading from the Port A–C Input Data registers (Table 27) returns the sampled values from the corresponding port pins. The Port A–C Input Data registers are read-only. The value returned for any unused ports is 0. Unused ports include those missing on the 8- and 28-pin packages, as well as those missing on the ADC-enabled 28-pin packages. Table 27. Port A–C Input Data Registers (PxIN) 7 6 5 4 3 2 1 0 FIELD PIN7 PIN6 PIN5 PIN4 PIN3 PIN2 PIN1 PIN0 RESET X X X X X X X X R/W R R R R R R R R BITS ADDR FD2H, FD6H, FDAH X = Undefined. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 52 PIN[7:0]—Port Input Data Sampled data from the corresponding port pin input. 0 = Input data is logical 0 (Low). 1 = Input data is logical 1 (High). Port A–D Output Data Register The Port A–D Output Data register (Table 28) controls the output data to the pins. Table 28. Port A–D Output Data Register (PxOUT) 7 6 5 4 3 2 1 0 FIELD POUT7 POUT6 POUT5 POUT4 POUT3 POUT2 POUT1 POUT0 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W BITS R/W FD3H, FD7H, FDBH, FDFH ADDR POUT[7:0]—Port Output Data These bits contain the data to be driven to the port pins. The values are only driven if the corresponding pin is configured as an output and the pin is not configured for alternate function operation. 0 = Drive a logical 0 (Low). 1= Drive a logical 1 (High). High value is not driven if the drain has been disabled by setting the corresponding Port Output Control register bit to 1. LED Drive Enable Register The LED Drive Enable register (Table 29) activates the controlled current drive. The Port C pin must first be enabled by setting the Alternate Function register to select the LED function. Table 29. LED Drive Enable (LEDEN) 7 BITS 6 5 3 2 1 0 LEDEN[7:0] FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 4 ADDR PS022825-0908 F82H General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 53 LEDEN[7:0]—LED Drive Enable These bits determine which Port C pins are connected to an internal current sink. 0 = Tristate the Port C pin. 1= Enable controlled current sink on the Port C pin. LED Drive Level High Register The LED Drive Level registers contain two control bits for each Port C pin (Table 30). These two bits select between four programmable drive levels. Each pin is individually programmable. Table 30. LED Drive Level High Register (LEDLVLH) 7 BITS 6 5 3 2 1 0 LEDLVLH[7:0] FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 4 F83H ADDR LEDLVLH[7:0]—LED Level High Bit {LEDLVLH, LEDLVLL} select one of four programmable current drive levels for each Port C pin. 00 = 3 mA 01= 7 mA 10= 13 mA 11= 20 mA LED Drive Level Low Register The LED Drive Level registers contain two control bits for each Port C pin (Table 31). These two bits select between four programmable drive levels. Each pin is individually programmable. PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 54 Table 31. LED Drive Level Low Register (LEDLVLL) 7 BITS 6 5 3 2 1 0 LEDLVLL[7:0] FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 4 ADDR F84H LEDLVLL[7:0]—LED Level Low Bit {LEDLVLH, LEDLVLL} select one of four programmable current drive levels for each Port C pin. 00 = 3 mA 01 = 7 mA 10 = 13 mA 11 = 20 mA PS022825-0908 General-Purpose Input/Output Z8 Encore! XP® F082A Series Product Specification 55 Interrupt Controller The interrupt controller on the Z8 Encore! XP F082A Series products prioritizes the interrupt requests from the on-chip peripherals and the GPIO port pins. The features of interrupt controller include: • 20 possible interrupt sources with 18 unique interrupt vectors: – Twelve GPIO port pin interrupt sources (two interrupt vectors are shared). – Eight on-chip peripheral interrupt sources (two interrupt vectors are shared). • Flexible GPIO interrupts: – Eight selectable rising and falling edge GPIO interrupts. – Four dual-edge interrupts. • • • Three levels of individually programmable interrupt priority. Watchdog Timer and LVD can be configured to generate an interrupt. Supports vectored as well as polled interrupts Interrupt requests (IRQs) allow peripheral devices to suspend CPU operation in an orderly manner and force the CPU to start an interrupt service routine (ISR). Usually this interrupt service routine is involved with the exchange of data, status information, or control information between the CPU and the interrupting peripheral. When the service routine is completed, the CPU returns to the operation from which it was interrupted. The eZ8 CPU supports both vectored and polled interrupt handling. For polled interrupts, the interrupt controller has no effect on operation. For more information on interrupt servicing by the eZ8 CPU, refer to eZ8 CPU Core User Manual (UM0128) available for download at www.zilog.com. Interrupt Vector Listing Table 32 on page 56 lists all of the interrupts available in order of priority. The interrupt vector is stored with the most-significant byte (MSB) at the even Program Memory address and the least-significant byte (LSB) at the following odd Program Memory address. Note: PS022825-0908 Some port interrupts are not available on the 8- and 20-pin packages. The ADC interrupt is unavailable on devices not containing an ADC. Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 56 Table 32. Trap and Interrupt Vectors in Order of Priority Program Memory Priority Vector Address Interrupt or Trap Source Highest 0002H Reset (not an interrupt) 0004H Watchdog Timer (see Watchdog Timer on page 91) 003AH Primary Oscillator Fail Trap (not an interrupt) 003CH Watchdog Oscillator Fail Trap (not an interrupt) 0006H Illegal Instruction Trap (not an interrupt) 0008H Reserved 000AH Timer 1 000CH Timer 0 000EH UART 0 receiver 0010H UART 0 transmitter 0012H Reserved 0014H Reserved 0016H ADC 0018H Port A Pin 7, selectable rising or falling input edge or LVD (see Reset, Stop Mode Recovery, and Low Voltage Detection on page 23) 001AH Port A Pin 6, selectable rising or falling input edge or Comparator Output 001CH Port A Pin 5, selectable rising or falling input edge 001EH Port A Pin 4, selectable rising or falling input edge 0020H Port A Pin 3, selectable rising or falling input edge 0022H Port A Pin 2, selectable rising or falling input edge 0024H Port A Pin 1, selectable rising or falling input edge 0026H Port A Pin 0, selectable rising or falling input edge 0028H Reserved 002AH Reserved 002CH Reserved 002EH Reserved 0030H Port C Pin 3, both input edges 0032H Port C Pin 2, both input edges PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 57 Table 32. Trap and Interrupt Vectors in Order of Priority (Continued) Program Memory Priority Vector Address Interrupt or Trap Source Lowest 0034H Port C Pin 1, both input edges 0036H Port C Pin 0, both input edges 0038H Reserved Architecture Figure 8 displays the interrupt controller block diagram. Internal Interrupts Interrupt Request Latches and Control Port Interrupts High Priority Vector Medium Priority Priority Mux IRQ Request Low Priority Figure 8. Interrupt Controller Block Diagram Operation Master Interrupt Enable The master interrupt enable bit (IRQE) in the Interrupt Control register globally enables and disables interrupts. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 58 Interrupts are globally enabled by any of the following actions: • • • Execution of an EI (Enable Interrupt) instruction Execution of an IRET (Return from Interrupt) instruction Writing a 1 to the IRQE bit in the Interrupt Control register Interrupts are globally disabled by any of the following actions: • • Execution of a DI (Disable Interrupt) instruction • • • • • • Writing a 0 to the IRQE bit in the Interrupt Control register eZ8 CPU acknowledgement of an interrupt service request from the interrupt controller Reset Execution of a Trap instruction Illegal Instruction Trap Primary Oscillator Fail Trap Watchdog Oscillator Fail Trap Interrupt Vectors and Priority The interrupt controller supports three levels of interrupt priority. Level 3 is the highest priority, Level 2 is the second highest priority, and Level 1 is the lowest priority. If all of the interrupts are enabled with identical interrupt priority (all as Level 2 interrupts, for example), the interrupt priority is assigned from highest to lowest as specified in Table 32 on page 56. Level 3 interrupts are always assigned higher priority than Level 2 interrupts which, in turn, always are assigned higher priority than Level 1 interrupts. Within each interrupt priority level (Level 1, Level 2, or Level 3), priority is assigned as specified in Table 32, above. Reset, Watchdog Timer interrupt (if enabled), Primary Oscillator Fail Trap, Watchdog Oscillator Fail Trap, and Illegal Instruction Trap always have highest (level 3) priority. Interrupt Assertion Interrupt sources assert their interrupt requests for only a single system clock period (single pulse). When the interrupt request is acknowledged by the eZ8 CPU, the corresponding bit in the Interrupt Request register is cleared until the next interrupt occurs. Writing a 0 to the corresponding bit in the Interrupt Request register likewise clears the interrupt request. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 59 Caution: The following coding style that clears bits in the Interrupt Request registers is not recommended. All incoming interrupts received between execution of the first LDX command and the final LDX command are lost. Poor coding style that can result in lost interrupt requests: LDX r0, IRQ0 AND r0, MASK LDX IRQ0, r0 Caution: To avoid missing interrupts, use the following coding style to clear bits in the Interrupt Request 0 register: Good coding style that avoids lost interrupt requests: ANDX IRQ0, MASK Software Interrupt Assertion Program code can generate interrupts directly. Writing a 1 to the correct bit in the Interrupt Request register triggers an interrupt (assuming that interrupt is enabled). When the interrupt request is acknowledged by the eZ8 CPU, the bit in the Interrupt Request register is automatically cleared to 0. Caution: The following coding style used to generate software interrupts by setting bits in the Interrupt Request registers is not recommended. All incoming interrupts received between execution of the first LDX command and the final LDX command are lost. Poor coding style that can result in lost interrupt requests: LDX r0, IRQ0 OR r0, MASK LDX IRQ0, r0 Caution: To avoid missing interrupts, use the following coding style to set bits in the Interrupt Request registers: Good coding style that avoids lost interrupt requests: ORX IRQ0, MASK Watchdog Timer Interrupt Assertion The Watchdog Timer interrupt behavior is different from interrupts generated by other sources. The Watchdog Timer continues to assert an interrupt as long as the timeout condition continues. As it operates on a different (and usually slower) clock domain than the rest of the device, the Watchdog Timer continues to assert this interrupt for many system clocks until the counter rolls over. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 60 Caution: To avoid re-triggerings of the Watchdog Timer interrupt after exiting the associated interrupt service routine, it is recommended that the service routine continues to read from the RSTSTAT register until the WDT bit is cleared as given in the following coding sample: CLEARWDT: LDX r0, RSTSTAT ; read reset status register to clear wdt bit BTJNZ 5, r0, CLEARWDT ; loop until bit is cleared Interrupt Control Register Definitions For all interrupts other than the Watchdog Timer interrupt, the Primary Oscillator Fail Trap, and the Watchdog Oscillator Fail Trap, the interrupt control registers enable individual interrupts, set interrupt priorities, and indicate interrupt requests. Interrupt Request 0 Register The Interrupt Request 0 (IRQ0) register (Table 33) stores the interrupt requests for both vectored and polled interrupts. When a request is presented to the interrupt controller, the corresponding bit in the IRQ0 register becomes 1. If interrupts are globally enabled (vectored interrupts), the interrupt controller passes an interrupt request to the eZ8 CPU. If interrupts are globally disabled (polled interrupts), the eZ8 CPU can read the Interrupt Request 0 register to determine if any interrupt requests are pending. Table 33. Interrupt Request 0 Register (IRQ0) BITS 7 6 5 4 3 2 1 0 FIELD Reserved T1I T0I U0RXI U0TXI Reserved Reserved ADCI RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W FC0H ADDR Reserved—Must be 0. T1I—Timer 1 Interrupt Request 0 = No interrupt request is pending for Timer 1. 1 = An interrupt request from Timer 1 is awaiting service. T0I—Timer 0 Interrupt Request 0 = No interrupt request is pending for Timer 0. 1 = An interrupt request from Timer 0 is awaiting service. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 61 U0RXI—UART 0 Receiver Interrupt Request 0 = No interrupt request is pending for the UART 0 receiver. 1 = An interrupt request from the UART 0 receiver is awaiting service. U0TXI—UART 0 Transmitter Interrupt Request 0 = No interrupt request is pending for the UART 0 transmitter. 1 = An interrupt request from the UART 0 transmitter is awaiting service. ADCI—ADC Interrupt Request 0 = No interrupt request is pending for the analog-to-digital Converter. 1 = An interrupt request from the Analog-to-Digital Converter is awaiting service. Interrupt Request 1 Register The Interrupt Request 1 (IRQ1) register (Table 34) stores interrupt requests for both vectored and polled interrupts. When a request is presented to the interrupt controller, the corresponding bit in the IRQ1 register becomes 1. If interrupts are globally enabled (vectored interrupts), the interrupt controller passes an interrupt request to the eZ8 CPU. If interrupts are globally disabled (polled interrupts), the eZ8 CPU can read the Interrupt Request 1 register to determine if any interrupt requests are pending. Table 34. Interrupt Request 1 Register (IRQ1) BITS 7 6 5 4 3 2 1 0 FIELD PA7VI PA6CI PA5I PA4I PA3I PA2I PA1I PA0I RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W ADDR FC3H PA7VI—Port A Pin 7 or LVD Interrupt Request 0 = No interrupt request is pending for GPIO Port A or LVD. 1 = An interrupt request from GPIO Port A or LVD. PA6CI—Port A Pin 6 or Comparator Interrupt Request 0 = No interrupt request is pending for GPIO Port A or Comparator. 1 = An interrupt request from GPIO Port A or Comparator. PAxI—Port A Pin x Interrupt Request 0 = No interrupt request is pending for GPIO Port A pin x. 1 = An interrupt request from GPIO Port A pin x is awaiting service. where x indicates the specific GPIO Port pin number (0–5). PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 62 Interrupt Request 2 Register The Interrupt Request 2 (IRQ2) register (Table 35) stores interrupt requests for both vectored and polled interrupts. When a request is presented to the interrupt controller, the corresponding bit in the IRQ2 register becomes 1. If interrupts are globally enabled (vectored interrupts), the interrupt controller passes an interrupt request to the eZ8 CPU. If interrupts are globally disabled (polled interrupts), the eZ8 CPU can read the Interrupt Request 2 register to determine if any interrupt requests are pending. Table 35. Interrupt Request 2 Register (IRQ2) BITS 7 6 4 Reserved FIELD 3 2 1 0 PC3I PC2I PC1I PC0I 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 5 FC6H ADDR Reserved—Must be 0. PCxI—Port C Pin x Interrupt Request 0 = No interrupt request is pending for GPIO Port C pin x. 1 = An interrupt request from GPIO Port C pin x is awaiting service. where x indicates the specific GPIO Port C pin number (0–3). IRQ0 Enable High and Low Bit Registers Table 36 describes the priority control for IRQ0. The IRQ0 Enable High and Low Bit registers (Table 37 and Table 38) form a priority encoded enabling for interrupts in the Interrupt Request 0 register. Table 36. IRQ0 Enable and Priority Encoding IRQ0ENH[x] IRQ0ENL[x] Priority Description 0 0 Disabled Disabled 0 1 Level 1 Low 1 0 Level 2 Medium 1 1 Level 3 High where x indicates the register bits from 0–7. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 63 Table 37. IRQ0 Enable High Bit Register (IRQ0ENH) BITS 7 6 5 4 3 2 1 0 FIELD Reserved T1ENH T0ENH U0RENH U0TENH Reserved Reserved ADCENH RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W FC1H ADDR Reserved—Must be 0. T1ENH—Timer 1 Interrupt Request Enable High Bit T0ENH—Timer 0 Interrupt Request Enable High Bit U0RENH—UART 0 Receive Interrupt Request Enable High Bit U0TENH—UART 0 Transmit Interrupt Request Enable High Bit ADCENH—ADC Interrupt Request Enable High Bit Table 38. IRQ0 Enable Low Bit Register (IRQ0ENL) BITS 7 6 5 4 3 2 1 0 FIELD Reserved T1ENL T0ENL U0RENL U0TENL Reserved Reserved ADCENL RESET 0 0 0 0 0 0 0 0 R/W R R/W R/W R/W R/W R R R/W FC2H ADDR Reserved—Must be 0. T1ENL—Timer 1 Interrupt Request Enable Low Bit T0ENL—Timer 0 Interrupt Request Enable Low Bit U0RENL—UART 0 Receive Interrupt Request Enable Low Bit U0TENL—UART 0 Transmit Interrupt Request Enable Low Bit ADCENL—ADC Interrupt Request Enable Low Bit IRQ1 Enable High and Low Bit Registers Table 39 describes the priority control for IRQ1. The IRQ1 Enable High and Low Bit registers (Table 40 and Table 41) form a priority encoded enabling for interrupts in the Interrupt Request 1 register. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 64 Table 39. IRQ1 Enable and Priority Encoding IRQ1ENH[x] IRQ1ENL[x] Priority Description 0 0 Disabled Disabled 0 1 Level 1 Low 1 0 Level 2 Medium 1 1 Level 3 High where x indicates the register bits from 0–7. Table 40. IRQ1 Enable High Bit Register (IRQ1ENH) BITS FIELD 7 PA7VENH PA6CENH 5 4 3 2 1 0 PA5ENH PA4ENH PA3ENH PA2ENH PA1ENH PA0ENH 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 6 FC4H ADDR PA7VENH—Port A Bit[7] or LVD Interrupt Request Enable High Bit PA6CENH—Port A Bit[7] or Comparator Interrupt Request Enable High Bit PAxENH—Port A Bit[x] Interrupt Request Enable High Bit See Shared Interrupt Select (IRQSS) register for selection of either the LVD or the comparator as the interrupt source. Table 41. IRQ1 Enable Low Bit Register (IRQ1ENL) BITS FIELD 7 PA7VENL PA6CENL 5 4 3 2 1 0 PA5ENL PA4ENL PA3ENL PA2ENL PA1ENL PA0ENL 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 6 ADDR FC5H PA7VENL—Port A Bit[7] or LVD Interrupt Request Enable Low Bit PA6CENL—Port A Bit[6] or Comparator Interrupt Request Enable Low Bit PAxENL—Port A Bit[x] Interrupt Request Enable Low Bit PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 65 IRQ2 Enable High and Low Bit Registers Table 42 describes the priority control for IRQ2. The IRQ2 Enable High and Low Bit registers (Table 43 and Table 44) form a priority encoded enabling for interrupts in the Interrupt Request 2 register. Table 42. IRQ2 Enable and Priority Encoding IRQ2ENH[x] IRQ2ENL[x] Priority Description 0 0 Disabled Disabled 0 1 Level 1 Low 1 0 Level 2 Medium 1 1 Level 3 High where x indicates the register bits from 0–7. Table 43. IRQ2 Enable High Bit Register (IRQ2ENH) BITS 7 6 5 4 Reserved FIELD 2 1 0 C3ENH C2ENH C1ENH C0ENH 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 3 FC7H ADDR Reserved—Must be 0. C3ENH—Port C3 Interrupt Request Enable High Bit C2ENH—Port C2 Interrupt Request Enable High Bit C1ENH—Port C1 Interrupt Request Enable High Bit C0ENH—Port C0 Interrupt Request Enable High Bit Table 44. IRQ2 Enable Low Bit Register (IRQ2ENL) BITS 7 6 5 3 Reserved FIELD 2 1 0 C3ENL C2ENL C1ENL C0ENL 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 4 ADDR PS022825-0908 FC8H Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 66 Reserved—Must be 0. C3ENL—Port C3 Interrupt Request Enable Low Bit C2ENL—Port C2 Interrupt Request Enable Low Bit C1ENL—Port C1 Interrupt Request Enable Low Bit C0ENL—Port C0 Interrupt Request Enable Low Bit Interrupt Edge Select Register The Interrupt Edge Select (IRQES) register (Table 45) determines whether an interrupt is generated for the rising edge or falling edge on the selected GPIO Port A input pin. Table 45. Interrupt Edge Select Register (IRQES) BITS 7 6 5 4 3 2 1 0 FIELD IES7 IES6 IES5 IES4 IES3 IES2 IES1 IES0 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W FCDH ADDR IESx—Interrupt Edge Select x 0 = An interrupt request is generated on the falling edge of the PAx input. 1 = An interrupt request is generated on the rising edge of the PAx input. where x indicates the specific GPIO Port pin number (0 through 7). Shared Interrupt Select Register The Shared Interrupt Select (IRQSS) register (Table 46) determines the source of the PADxS interrupts. The Shared Interrupt Select register selects between Port A and alternate sources for the individual interrupts. Because these shared interrupts are edge-triggered, it is possible to generate an interrupt just by switching from one shared source to another. For this reason, an interrupt must be disabled before switching between sources. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 67 Table 46. Shared Interrupt Select Register (IRQSS) BITS 7 6 FIELD PA7VS PA6CS RESET 0 0 0 0 R/W R/W R/W R/W R/W 5 4 3 2 1 0 0 0 0 0 R/W R/W R/W R/W Reserved FCEH ADDR PA7VS—PA7/LVD Selection 0 = PA7 is used for the interrupt for PA7VS interrupt request. 1 = The LVD is used for the interrupt for PA7VS interrupt request. PA6CS—PA6/Comparator Selection 0 = PA6 is used for the interrupt for PA6CS interrupt request. 1 = The Comparator is used for the interrupt for PA6CS interrupt request. Reserved—Must be 0. Interrupt Control Register The Interrupt Control (IRQCTL) register (Table 47) contains the master enable bit for all interrupts. Table 47. Interrupt Control Register (IRQCTL) BITS 7 6 5 4 3 2 1 0 FIELD IRQE RESET 0 0 0 0 0 0 0 0 R/W R R R R R R R R/W Reserved FCFH ADDR IRQE—Interrupt Request Enable This bit is set to 1 by executing an EI (Enable Interrupts) or IRET (Interrupt Return) instruction, or by a direct register write of a 1 to this bit. It is reset to 0 by executing a DI instruction, eZ8 CPU acknowledgement of an interrupt request, Reset or by a direct register write of a 0 to this bit. 0 = Interrupts are disabled. 1 = Interrupts are enabled. Reserved—Must be 0. PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 68 PS022825-0908 Interrupt Controller Z8 Encore! XP® F082A Series Product Specification 69 Timers These Z8 Encore! XP® F082A Series products contain two 16-bit reloadable timers that can be used for timing, event counting, or generation of pulse-width modulated (PWM) signals. The timers’ feature include: • • • • • 16-bit reload counter. • • Timer output pin. Programmable prescaler with prescale values from 1 to 128. PWM output generation. Capture and compare capability. External input pin for timer input, clock gating, or capture signal. External input pin signal frequency is limited to a maximum of one-fourth the system clock frequency. Timer interrupt. In addition to the timers described in this chapter, the Baud Rate Generator of the UART (if unused) may also provide basic timing functionality. For information on using the Baud Rate Generator as an additional timer, see Universal Asynchronous Receiver/Transmitter on page 97. Architecture Figure 9 on page 70 displays the architecture of the timers. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 70 Timer Block Block Control 16-Bit Reload Register System Clock Compare Timer Control Data Bus Timer Input Gate Input 16-Bit PWM/Compare Capture Input Compare 16-Bit Counter with Prescaler Interrupt, PWM, and Timer Output Control Timer Interrupt Timer Output Timer Output Complement Figure 9. Timer Block Diagram Operation The timers are 16-bit up-counters. Minimum time-out delay is set by loading the value 0001H into the Timer Reload High and Low Byte registers and setting the prescale value to 1. Maximum time-out delay is set by loading the value 0000H into the Timer Reload High and Low Byte registers and setting the prescale value to 128. If the Timer reaches FFFFH, the timer rolls over to 0000H and continues counting. Timer Operating Modes The timers can be configured to operate in the following modes: ONE-SHOT Mode In ONE-SHOT mode, the timer counts up to the 16-bit Reload value stored in the Timer Reload High and Low byte registers. The timer input is the system clock. Upon reaching the Reload value, the timer generates an interrupt and the count value in the Timer High and Low Byte registers is reset to 0001H. The timer is automatically disabled and stops counting. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 71 Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state for one system clock cycle (from Low to High or from High to Low) upon timer Reload. If it is appropriate to have the Timer Output make a state change at a One-Shot time-out (rather than a single cycle pulse), first set the TPOL bit in the Timer Control Register to the start value before enabling ONE-SHOT mode. After starting the timer, set TPOL to the opposite bit value. Follow the steps below for configuring a timer for ONE-SHOT mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer – Configure the timer for ONE-SHOT mode. – Set the prescale value. – Set the initial output level (High or Low) if using the Timer Output alternate function. 2. Write to the Timer High and Low Byte registers to set the starting count value. 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing to the relevant interrupt registers. 5. If using the Timer Output function, configure the associated GPIO port pin for the Timer Output alternate function. 6. Write to the Timer Control register to enable the timer and initiate counting. In ONE-SHOT mode, the system clock always provides the timer input. The timer period is given by the following equation: Reload Value – Start Value × Prescale ONE-SHOT Mode Time-Out Period ( s ) = -----------------------------------------------------------------------------------------------------------------System Clock Frequency ( Hz ) CONTINUOUS Mode In CONTINUOUS mode, the timer counts up to the 16-bit Reload value stored in the Timer Reload High and Low Byte registers. The timer input is the system clock. Upon reaching the Reload value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state (from Low to High or from High to Low) at timer Reload. Follow the steps below for configuring a timer for CONTINUOUS mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer – Configure the timer for CONTINUOUS mode. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 72 – – Set the prescale value. If using the Timer Output alternate function, set the initial output level (High or Low). 2. Write to the Timer High and Low Byte registers to set the starting count value (usually 0001H). This action only affects the first pass in CONTINUOUS mode. After the first timer Reload in CONTINUOUS mode, counting always begins at the reset value of 0001H. 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. Enable the timer interrupt (if appropriate) and set the timer interrupt priority by writing to the relevant interrupt registers. 5. Configure the associated GPIO port pin (if using the Timer Output function) for the Timer Output alternate function. 6. Write to the Timer Control register to enable the timer and initiate counting. In CONTINUOUS mode, the system clock always provides the timer input. The timer period is given by the following equation: Reload Value × Prescale CONTINUOUS Mode Time-Out Period (s) = -----------------------------------------------------------------------System Clock Frequency (Hz) If an initial starting value other than 0001H is loaded into the Timer High and Low Byte registers, use the ONE-SHOT mode equation to determine the first time-out period. COUNTER Mode In COUNTER mode, the timer counts input transitions from a GPIO port pin. The timer input is taken from the GPIO Port pin Timer Input alternate function. The TPOL bit in the Timer Control Register selects whether the count occurs on the rising edge or the falling edge of the Timer Input signal. In COUNTER mode, the prescaler is disabled. Caution: The input frequency of the Timer Input signal must not exceed one-fourth the system clock frequency. Further, the high or low state of the input signal pulse must be no less than twice the system clock period. A shorter pulse may not be captured. Upon reaching the Reload value stored in the Timer Reload High and Low Byte registers, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state (from Low to High or from High to Low) at timer Reload. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 73 Follow the steps below for configuring a timer for COUNTER mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for COUNTER mode. – Select either the rising edge or falling edge of the Timer Input signal for the count. This selection also sets the initial logic level (High or Low) for the Timer Output alternate function. However, the Timer Output function is not required to be enabled. 2. Write to the Timer High and Low Byte registers to set the starting count value. This only affects the first pass in COUNTER mode. After the first timer Reload in COUNTER mode, counting always begins at the reset value of 0001H. In COUNTER mode the Timer High and Low Byte registers must be written with the value 0001H. 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing to the relevant interrupt registers. 5. Configure the associated GPIO port pin for the Timer Input alternate function. 6. If using the Timer Output function, configure the associated GPIO port pin for the Timer Output alternate function. 7. Write to the Timer Control register to enable the timer. In COUNTER mode, the number of Timer Input transitions since the timer start is given by the following equation: COUNTER Mode Timer Input Transitions = Current Count Value - Start Value COMPARATOR COUNTER Mode In COMPARATOR COUNTER mode, the timer counts input transitions from the analog comparator output. The TPOL bit in the Timer Control Register selects whether the count occurs on the rising edge or the falling edge of the comparator output signal. In COMPARATOR COUNTER mode, the prescaler is disabled. Caution: The frequency of the comparator output signal must not exceed one-fourth the system clock frequency. Further, the high or low state of the comparator output signal pulse must be no less than twice the system clock period. A shorter pulse may not be captured. After reaching the Reload value stored in the Timer Reload High and Low Byte registers, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state (from Low to High or from High to Low) at timer Reload. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 74 Follow the steps below for configuring a timer for COMPARATOR COUNTER mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for COMPARATOR COUNTER mode. – Select either the rising edge or falling edge of the comparator output signal for the count. This also sets the initial logic level (High or Low) for the Timer Output alternate function. However, the Timer Output function is not required to be enabled. 2. Write to the Timer High and Low Byte registers to set the starting count value. This action only affects the first pass in COMPARATOR COUNTER mode. After the first timer Reload in COMPARATOR COUNTER mode, counting always begins at the reset value of 0001H. Generally, in COMPARATOR COUNTER mode the Timer High and Low Byte registers must be written with the value 0001H. 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing to the relevant interrupt registers. 5. If using the Timer Output function, configure the associated GPIO port pin for the Timer Output alternate function. 6. Write to the Timer Control register to enable the timer. In COMPARATOR COUNTER mode, the number of comparator output transitions since the timer start is given by the following equation: Comparator Output Transitions = Current Count Value – Start Value PWM SINGLE OUTPUT Mode In PWM SINGLE OUTPUT mode, the timer outputs a Pulse-Width Modulator (PWM) output signal through a GPIO Port pin. The timer input is the system clock. The timer first counts up to the 16-bit PWM match value stored in the Timer PWM High and Low Byte registers. When the timer count value matches the PWM value, the Timer Output toggles. The timer continues counting until it reaches the Reload value stored in the Timer Reload High and Low Byte registers. Upon reaching the Reload value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. If the TPOL bit in the Timer Control register is set to 1, the Timer Output signal begins as a High (1) and transitions to a Low (0) when the timer value matches the PWM value. The Timer Output signal returns to a High (1) after the timer reaches the Reload value and is reset to 0001H. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 75 If the TPOL bit in the Timer Control register is set to 0, the Timer Output signal begins as a Low (0) and transitions to a High (1) when the timer value matches the PWM value. The Timer Output signal returns to a Low (0) after the timer reaches the Reload value and is reset to 0001H. Follow the steps below for configuring a timer for PWM SINGLE OUTPUT mode and initiating the PWM operation: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for PWM SINGLE OUTPUT mode. – Set the prescale value. – Set the initial logic level (High or Low) and PWM High/Low transition for the Timer Output alternate function. 2. Write to the Timer High and Low Byte registers to set the starting count value (typically 0001H). This only affects the first pass in PWM mode. After the first timer reset in PWM mode, counting always begins at the reset value of 0001H. 3. Write to the PWM High and Low Byte registers to set the PWM value. 4. Write to the Timer Reload High and Low Byte registers to set the Reload value (PWM period). The Reload value must be greater than the PWM value. 5. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing to the relevant interrupt registers. 6. Configure the associated GPIO port pin for the Timer Output alternate function. 7. Write to the Timer Control register to enable the timer and initiate counting. The PWM period is represented by the following equation: Reload Value × Prescale PWM Period (s) = -----------------------------------------------------------------------System Clock Frequency (Hz) If an initial starting value other than 0001H is loaded into the Timer High and Low Byte registers, use the ONE-SHOT mode equation to determine the first PWM time-out period. If TPOL is set to 0, the ratio of the PWM output High time to the total period is represented by: Reload Value – PWM Value PWM Output High Time Ratio (%) = ------------------------------------------------------------------ × 100 Reload Value If TPOL is set to 1, the ratio of the PWM output High time to the total period is represented by: PWM Value PWM Output High Time Ratio (%) = -------------------------------- × 100 Reload Value PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 76 PWM DUAL OUTPUT Mode In PWM DUAL OUTPUT mode, the timer outputs a Pulse-Width Modulated (PWM) output signal pair (basic PWM signal and its complement) through two GPIO Port pins. The timer input is the system clock. The timer first counts up to the 16-bit PWM match value stored in the Timer PWM High and Low Byte registers. When the timer count value matches the PWM value, the Timer Output toggles. The timer continues counting until it reaches the Reload value stored in the Timer Reload High and Low Byte registers. Upon reaching the Reload value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. If the TPOL bit in the Timer Control register is set to 1, the Timer Output signal begins as a High (1) and transitions to a Low (0) when the timer value matches the PWM value. The Timer Output signal returns to a High (1) after the timer reaches the Reload value and is reset to 0001H. If the TPOL bit in the Timer Control register is set to 0, the Timer Output signal begins as a Low (0) and transitions to a High (1) when the timer value matches the PWM value. The Timer Output signal returns to a Low (0) after the timer reaches the Reload value and is reset to 0001H. The timer also generates a second PWM output signal Timer Output Complement. The Timer Output Complement is the complement of the Timer Output PWM signal. A programmable deadband delay can be configured to time delay (0 to 128 system clock cycles) PWM output transitions on these two pins from a low to a high (inactive to active). This ensures a time gap between the deassertion of one PWM output to the assertion of its complement. Follow the steps below for configuring a timer for PWM DUAL OUTPUT mode and initiating the PWM operation: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for PWM DUAL OUTPUT mode by writing the TMODE bits in the TxCTL1 register and the TMODEHI bit in TxCTL0 register. – Set the prescale value. – Set the initial logic level (High or Low) and PWM High/Low transition for the Timer Output alternate function. 2. Write to the Timer High and Low Byte registers to set the starting count value (typically 0001H). This only affects the first pass in PWM mode. After the first timer reset in PWM mode, counting always begins at the reset value of 0001H. 3. Write to the PWM High and Low Byte registers to set the PWM value. 4. Write to the PWM Control register to set the PWM dead band delay value. The deadband delay must be less than the duration of the positive phase of the PWM signal (as defined by the PWM high and low byte registers). It must also be less than the PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 77 duration of the negative phase of the PWM signal (as defined by the difference between the PWM registers and the Timer Reload registers). 5. Write to the Timer Reload High and Low Byte registers to set the Reload value (PWM period). The Reload value must be greater than the PWM value. 6. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing to the relevant interrupt registers. 7. Configure the associated GPIO port pin for the Timer Output and Timer Output Complement alternate functions. The Timer Output Complement function is shared with the Timer Input function for both timers. Setting the timer mode to Dual PWM automatically switches the function from Timer In to Timer Out Complement. 8. Write to the Timer Control register to enable the timer and initiate counting. The PWM period is represented by the following equation: Reload Value xPrescale PWM Period (s) = -----------------------------------------------------------------------------System Clock Frequency (Hz) If an initial starting value other than 0001H is loaded into the Timer High and Low Byte registers, the ONE-SHOT mode equation determines the first PWM time-out period. If TPOL is set to 0, the ratio of the PWM output High time to the total period is represented by: Reload Value – PWM Value PWM Output High Time Ratio (%) = ------------------------------------------------------------------- × 100 Reload Value If TPOL is set to 1, the ratio of the PWM output High time to the total period is represented by: PWM Value PWM Output High Time Ratio (%) = -------------------------------- × 100 Reload Value CAPTURE Mode In CAPTURE mode, the current timer count value is recorded when the appropriate external Timer Input transition occurs. The Capture count value is written to the Timer PWM High and Low Byte Registers. The timer input is the system clock. The TPOL bit in the Timer Control register determines if the Capture occurs on a rising edge or a falling edge of the Timer Input signal. When the Capture event occurs, an interrupt is generated and the timer continues counting. The INPCAP bit in TxCTL0 register is set to indicate the timer interrupt is because of an input capture event. The timer continues counting up to the 16-bit Reload value stored in the Timer Reload High and Low Byte registers. Upon reaching the Reload value, the timer generates an interrupt and continues counting. The INPCAP bit in TxCTL0 register clears indicating the timer interrupt is not because of an input capture event. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 78 Follow the steps below for configuring a timer for CAPTURE mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for CAPTURE mode. – Set the prescale value. – Set the Capture edge (rising or falling) for the Timer Input. 2. Write to the Timer High and Low Byte registers to set the starting count value (typically 0001H). 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. Clear the Timer PWM High and Low Byte registers to 0000H. Clearing these registers allows the software to determine if interrupts were generated by either a capture event or a reload. If the PWM High and Low Byte registers still contain 0000H after the interrupt, the interrupt was generated by a Reload. 5. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing to the relevant interrupt registers. By default, the timer interrupt is generated for both input capture and reload events. If appropriate, configure the timer interrupt to be generated only at the input capture event or the reload event by setting TICONFIG field of the TxCTL0 register. 6. Configure the associated GPIO port pin for the Timer Input alternate function. 7. Write to the Timer Control register to enable the timer and initiate counting. In CAPTURE mode, the elapsed time from timer start to Capture event can be calculated using the following equation: ( Capture Value – Start Value ) × Prescale Capture Elapsed Time (s) = --------------------------------------------------------------------------------------------------System Clock Frequency (Hz) CAPTURE RESTART Mode In CAPTURE RESTART mode, the current timer count value is recorded when the acceptable external Timer Input transition occurs. The Capture count value is written to the Timer PWM High and Low Byte Registers. The timer input is the system clock. The TPOL bit in the Timer Control register determines if the Capture occurs on a rising edge or a falling edge of the Timer Input signal. When the Capture event occurs, an interrupt is generated and the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. The INPCAP bit in TxCTL0 register is set to indicate the timer interrupt is because of an input capture event. If no Capture event occurs, the timer counts up to the 16-bit Compare value stored in the Timer Reload High and Low Byte registers. Upon reaching the Reload value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 79 0001H and counting resumes. The INPCAP bit in TxCTL0 register is cleared to indicate the timer interrupt is not caused by an input capture event. Follow the steps below for configuring a timer for CAPTURE RESTART mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for CAPTURE RESTART mode by writing the TMODE bits in the TxCTL1 register and the TMODEHI bit in TxCTL0 register. – Set the prescale value. – Set the Capture edge (rising or falling) for the Timer Input. 2. Write to the Timer High and Low Byte registers to set the starting count value (typically 0001H). 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. Clear the Timer PWM High and Low Byte registers to 0000H. This allows the software to determine if interrupts were generated by either a capture event or a reload. If the PWM High and Low Byte registers still contain 0000H after the interrupt, the interrupt was generated by a Reload. 5. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing to the relevant interrupt registers. By default, the timer interrupt is generated for both input capture and reload events. If appropriate, configure the timer interrupt to be generated only at the input capture event or the reload event by setting TICONFIG field of the TxCTL0 register. 6. Configure the associated GPIO port pin for the Timer Input alternate function. 7. Write to the Timer Control register to enable the timer and initiate counting. In CAPTURE mode, the elapsed time from timer start to Capture event can be calculated using the following equation: ( Capture Value – Start Value ) × Prescale Capture Elapsed Time (s) = --------------------------------------------------------------------------------------------------System Clock Frequency (Hz) COMPARE Mode In COMPARE mode, the timer counts up to the 16-bit maximum Compare value stored in the Timer Reload High and Low Byte registers. The timer input is the system clock. Upon reaching the Compare value, the timer generates an interrupt and counting continues (the timer value is not reset to 0001H). Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state (from Low to High or from High to Low) upon Compare. If the Timer reaches FFFFH, the timer rolls over to 0000H and continue counting. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 80 Follow the steps below for configuring a timer for COMPARE mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for COMPARE mode. – Set the prescale value. – Set the initial logic level (High or Low) for the Timer Output alternate function, if appropriate. 2. Write to the Timer High and Low Byte registers to set the starting count value. 3. Write to the Timer Reload High and Low Byte registers to set the Compare value. 4. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing to the relevant interrupt registers. 5. If using the Timer Output function, configure the associated GPIO port pin for the Timer Output alternate function. 6. Write to the Timer Control register to enable the timer and initiate counting. In COMPARE mode, the system clock always provides the timer input. The Compare time can be calculated by the following equation: ( Compare Value – Start Value ) × Prescale COMPARE Mode Time (s) = ----------------------------------------------------------------------------------------------------System Clock Frequency (Hz) GATED Mode In GATED mode, the timer counts only when the Timer Input signal is in its active state (asserted), as determined by the TPOL bit in the Timer Control register. When the Timer Input signal is asserted, counting begins. A timer interrupt is generated when the Timer Input signal is deasserted or a timer reload occurs. To determine if a Timer Input signal deassertion generated the interrupt, read the associated GPIO input value and compare to the value stored in the TPOL bit. The timer counts up to the 16-bit Reload value stored in the Timer Reload High and Low Byte registers. The timer input is the system clock. When reaching the Reload value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes (assuming the Timer Input signal remains asserted). Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state (from Low to High or from High to Low) at timer reset. Follow the steps below for configuring a timer for GATED mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for GATED mode. – Set the prescale value. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 81 2. Write to the Timer High and Low Byte registers to set the starting count value. Writing these registers only affects the first pass in GATED mode. After the first timer reset in GATED mode, counting always begins at the reset value of 0001H. 3. Write to the Timer Reload High and Low Byte registers to set the Reload value. 4. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing to the relevant interrupt registers. By default, the timer interrupt is generated for both input deassertion and reload events. If appropriate, configure the timer interrupt to be generated only at the input deassertion event or the reload event by setting TICONFIG field of the TxCTL0 register. 5. Configure the associated GPIO port pin for the Timer Input alternate function. 6. Write to the Timer Control register to enable the timer. 7. Assert the Timer Input signal to initiate the counting. CAPTURE/COMPARE Mode In CAPTURE/COMPARE mode, the timer begins counting on the first external Timer Input transition. The acceptable transition (rising edge or falling edge) is set by the TPOL bit in the Timer Control Register. The timer input is the system clock. Every subsequent acceptable transition (after the first) of the Timer Input signal captures the current count value. The Capture value is written to the Timer PWM High and Low Byte Registers. When the Capture event occurs, an interrupt is generated, the count value in the Timer High and Low Byte registers is reset to 0001H, and counting resumes. The INPCAP bit in TxCTL0 register is set to indicate the timer interrupt is caused by an input capture event. If no Capture event occurs, the timer counts up to the 16-bit Compare value stored in the Timer Reload High and Low Byte registers. Upon reaching the Compare value, the timer generates an interrupt, the count value in the Timer High and Low Byte registers is reset to 0001H and counting resumes. The INPCAP bit in TxCTL0 register is cleared to indicate the timer interrupt is not because of an input capture event. Follow the steps below for configuring a timer for CAPTURE/COMPARE mode and initiating the count: 1. Write to the Timer Control register to: – Disable the timer. – Configure the timer for CAPTURE/COMPARE mode. – Set the prescale value. – Set the Capture edge (rising or falling) for the Timer Input. 2. Write to the Timer High and Low Byte registers to set the starting count value (typically 0001H). 3. Write to the Timer Reload High and Low Byte registers to set the Compare value. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 82 4. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing to the relevant interrupt registers.By default, the timer interrupt are generated for both input capture and reload events. If appropriate, configure the timer interrupt to be generated only at the input capture event or the reload event by setting TICONFIG field of the TxCTL0 register. 5. Configure the associated GPIO port pin for the Timer Input alternate function. 6. Write to the Timer Control register to enable the timer. 7. Counting begins on the first appropriate transition of the Timer Input signal. No interrupt is generated by this first edge. In CAPTURE/COMPARE mode, the elapsed time from timer start to Capture event can be calculated using the following equation: ( Capture Value – Start Value ) × Prescale Capture Elapsed Time (s) = ---------------------------------------------------------------------------------------------------------------------System Clock Frequency (Hz) Reading the Timer Count Values The current count value in the timers can be read while counting (enabled). This capability has no effect on timer operation. When the timer is enabled and the Timer High Byte register is read, the contents of the Timer Low Byte register are placed in a holding register. A subsequent read from the Timer Low Byte register returns the value in the holding register. This operation allows accurate reads of the full 16-bit timer count value while enabled. When the timers are not enabled, a read from the Timer Low Byte register returns the actual value in the counter. Timer Pin Signal Operation Timer Output is a GPIO Port pin alternate function. The Timer Output is toggled every time the counter is reloaded. The Timer Input can be used as a selectable counting source. It shares the same pin as the complementary timer output. When selected by the GPIO Alternate Function Registers, this pin functions as a timer input in all modes except for the DUAL PWM OUTPUT mode. For this mode, there is no timer input available. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 83 Timer Control Register Definitions Timer 0–1 Control Registers Time 0–1 Control Register 0 The Timer Control Register 0 (TxCTL0) and Timer Control Register 1 (TxCTL1) determine the timer operating mode (Table 48). It also includes a programmable PWM deadband delay, two bits to configure timer interrupt definition, and a status bit to identify if the most recent timer interrupt is caused by an input capture event. Table 48. Timer 0–1 Control Register 0 (TxCTL0) BITS 7 6 5 3 Reserved 2 1 PWMD 0 FIELD TMODEHI RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R R/W TICONFIG 4 INPCAP F06H, F0EH ADDR TMODEHI—Timer Mode High Bit This bit along with the TMODE field in TxCTL1 register determines the operating mode of the timer. This is the most significant bit of the Timer mode selection value. See the TxCTL1 register description for details of the full timer mode decoding. TICONFIG—Timer Interrupt Configuration This field configures timer interrupt definition. 0x = Timer Interrupt occurs on all defined Reload, Compare and Input Events 10 = Timer Interrupt only on defined Input Capture/Deassertion Events 11 = Timer Interrupt only on defined Reload/Compare Events Reserved—Must be 0. PWMD—PWM Delay value This field is a programmable delay to control the number of system clock cycles delay before the Timer Output and the Timer Output Complement are forced to their active state. 000 = No delay 001 = 2 cycles delay 010 = 4 cycles delay 011 = 8 cycles delay 100 = 16 cycles delay 101 = 32 cycles delay PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 84 110 = 64 cycles delay 111 = 128 cycles delay INPCAP—Input Capture Event This bit indicates if the most recent timer interrupt is caused by a Timer Input Capture Event. 0 = Previous timer interrupt is not a result of Timer Input Capture Event 1 = Previous timer interrupt is a result of Timer Input Capture Event Timer 0–1 Control Register 1 The Timer 0–1 Control (TxCTL1) registers enable/disable the timers, set the prescaler value, and determine the timer operating mode (Table 49). Table 49. Timer 0–1 Control Register 1 (TxCTL1) BITS 7 6 FIELD TEN TPOL RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W 5 4 3 2 PRES 1 0 TMODE F07H, F0FH ADDR TEN—Timer Enable 0 = Timer is disabled. 1 = Timer enabled to count. TPOL—Timer Input/Output Polarity Operation of this bit is a function of the current operating mode of the timer. ONE-SHOT mode When the timer is disabled, the Timer Output signal is set to the value of this bit. When the timer is enabled, the Timer Output signal is complemented upon timer Reload. CONTINUOUS mode When the timer is disabled, the Timer Output signal is set to the value of this bit. When the timer is enabled, the Timer Output signal is complemented upon timer Reload. COUNTER mode If the timer is enabled the Timer Output signal is complemented after timer reload. 0 = Count occurs on the rising edge of the Timer Input signal. 1 = Count occurs on the falling edge of the Timer Input signal. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 85 PWM SINGLE OUTPUT mode 0 = Timer Output is forced Low (0) when the timer is disabled. When enabled, the Timer Output is forced High (1) upon PWM count match and forced Low (0) upon Reload. 1 = Timer Output is forced High (1) when the timer is disabled. When enabled, the Timer Output is forced Low (0) upon PWM count match and forced High (1) upon Reload. CAPTURE mode 0 = Count is captured on the rising edge of the Timer Input signal. 1 = Count is captured on the falling edge of the Timer Input signal. COMPARE mode When the timer is disabled, the Timer Output signal is set to the value of this bit. When the timer is enabled, the Timer Output signal is complemented upon timer Reload. GATED mode 0 = Timer counts when the Timer Input signal is High (1) and interrupts are generated on the falling edge of the Timer Input. 1 = Timer counts when the Timer Input signal is Low (0) and interrupts are generated on the rising edge of the Timer Input. CAPTURE/COMPARE mode 0 = Counting is started on the first rising edge of the Timer Input signal. The current count is captured on subsequent rising edges of the Timer Input signal. 1 = Counting is started on the first falling edge of the Timer Input signal. The current count is captured on subsequent falling edges of the Timer Input signal. PWM DUAL OUTPUT mode 0 = Timer Output is forced Low (0) and Timer Output Complement is forced High (1) when the timer is disabled. When enabled, the Timer Output is forced High (1) upon PWM count match and forced Low (0) upon Reload. When enabled, the Timer Output Complement is forced Low (0) upon PWM count match and forced High (1) upon Reload. The PWMD field in TxCTL0 register is a programmable delay to control the number of cycles time delay before the Timer Output and the Timer Output Complement is forced to High (1). 1 = Timer Output is forced High (1) and Timer Output Complement is forced Low (0) when the timer is disabled. When enabled, the Timer Output is forced Low (0) upon PWM count match and forced High (1) upon Reload.When enabled, the Timer Output Complement is forced High (1) upon PWM count match and forced Low (0) upon Reload. The PWMD field in TxCTL0 register is a programmable delay to control the number of cycles time delay before the Timer Output and the Timer Output Complement is forced to Low (0). PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 86 CAPTURE RESTART mode 0 = Count is captured on the rising edge of the Timer Input signal. 1 = Count is captured on the falling edge of the Timer Input signal. COMPARATOR COUNTER mode When the timer is disabled, the Timer Output signal is set to the value of this bit. When the timer is enabled, the Timer Output signal is complemented upon timer Reload. Also: 0 = Count is captured on the rising edge of the comparator output. 1 = Count is captured on the falling edge of the comparator output. Caution: When the Timer Output alternate function TxOUT on a GPIO port pin is enabled, TxOUT changes to whatever state the TPOL bit is in.The timer does not need to be enabled for that to happen. Also, the Port data direction sub register is not needed to be set to output on TxOUT. Changing the TPOL bit with the timer enabled and running does not immediately change the TxOUT. PRES—Prescale value The timer input clock is divided by 2PRES, where PRES can be set from 0 to 7. The prescaler is reset each time the Timer is disabled. This reset ensures proper clock division each time the Timer is restarted. 000 = Divide by 1 001 = Divide by 2 010 = Divide by 4 011 = Divide by 8 100 = Divide by 16 101 = Divide by 32 110 = Divide by 64 111 = Divide by 128 TMODE—Timer mode This field along with the TMODEHI bit in TxCTL0 register determines the operating mode of the timer. TMODEHI is the most significant bit of the Timer mode selection value. The entire operating mode bits are expressed as {TMODEHI, TMODE[2:0]}. The TMODEHI is bit 7 of the TxCTL0 register while TMODE[2:0] is the lower 3 bits of the TxCTL1 register. 0000 = ONE-SHOT mode 0001 = CONTINUOUS mode 0010 = COUNTER mode 0011 = PWM SINGLE OUTPUT mode 0100 = CAPTURE mode 0101 = COMPARE mode 0110 = GATED mode 0111 = CAPTURE/COMPARE mode PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 87 1000 = PWM DUAL OUTPUT mode 1001 = CAPTURE RESTART mode 1010 = COMPARATOR COUNTER mode Timer 0–1 High and Low Byte Registers The Timer 0–1 High and Low Byte (TxH and TxL) registers (Table 50 and Table 51) contain the current 16-bit timer count value. When the timer is enabled, a read from TxH causes the value in TxL to be stored in a temporary holding register. A read from TxL always returns this temporary register when the timers are enabled. When the timer is disabled, reads from TxL read the register directly. Writing to the Timer High and Low Byte registers while the timer is enabled is not recommended. There are no temporary holding registers available for write operations, so simultaneous 16-bit writes are not possible. If either the Timer High or Low Byte registers are written during counting, the 8-bit written value is placed in the counter (High or Low Byte) at the next clock edge. The counter continues counting from the new value. Table 50. Timer 0–1 High Byte Register (TxH) BITS 7 6 5 4 2 1 0 TH FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W 3 2 1 0 RESET R/W 3 F00H, F08H ADDR Table 51. Timer 0–1 Low Byte Register (TxL) BITS 7 6 5 4 TL FIELD 0 0 0 0 0 0 0 1 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W F01H, F09H ADDR TH and TL—Timer High and Low Bytes These 2 bytes, {TH[7:0], TL[7:0]}, contain the current 16-bit timer count value. Timer Reload High and Low Byte Registers The Timer 0–1 Reload High and Low Byte (TxRH and TxRL) registers (Table 52 and Table 53) store a 16-bit reload value, {TRH[7:0], TRL[7:0]}. Values written to the Timer Reload High Byte register are stored in a temporary holding register. When a write to the PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 88 Timer Reload Low Byte register occurs, the temporary holding register value is written to the Timer High Byte register. This operation allows simultaneous updates of the 16-bit Timer Reload value. In COMPARE mode, the Timer Reload High and Low Byte registers store the 16-bit Compare value. Table 52. Timer 0–1 Reload High Byte Register (TxRH) BITS 7 6 5 4 2 1 0 TRH FIELD 1 1 1 1 1 1 1 1 R/W R/W R/W R/W R/W R/W R/W R/W 3 2 1 0 RESET R/W 3 F02H, F0AH ADDR Table 53. Timer 0–1 Reload Low Byte Register (TxRL) BITS 7 6 5 4 TRL FIELD 1 1 1 1 1 1 1 1 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W F03H, F0BH ADDR TRH and TRL—Timer Reload Register High and Low These two bytes form the 16-bit Reload value, {TRH[7:0], TRL[7:0]}. This value sets the maximum count value which initiates a timer reload to 0001H. In COMPARE mode, these two bytes form the 16-bit Compare value. Timer 0-1 PWM High and Low Byte Registers The Timer 0-1 PWM High and Low Byte (TxPWMH and TxPWML) registers (Table 54 and Table 55) control Pulse-Width Modulator (PWM) operations. These registers also store the Capture values for the CAPTURE and CAPTURE/COMPARE modes. Table 54. Timer 0–1 PWM High Byte Register (TxPWMH) BITS 7 6 5 4 2 1 0 PWMH FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 3 ADDR PS022825-0908 F04H, F0CH Timers Z8 Encore! XP® F082A Series Product Specification 89 Table 55. Timer 0–1 PWM Low Byte Register (TxPWML) BITS 7 6 5 4 2 1 0 PWML FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 3 ADDR F05H, F0DH PWMH and PWML—Pulse-Width Modulator High and Low Bytes These two bytes, {PWMH[7:0], PWML[7:0]}, form a 16-bit value that is compared to the current 16-bit timer count. When a match occurs, the PWM output changes state. The PWM output value is set by the TPOL bit in the Timer Control Register (TxCTL1) register. The TxPWMH and TxPWML registers also store the 16-bit captured timer value when operating in CAPTURE or CAPTURE/COMPARE modes. PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 90 PS022825-0908 Timers Z8 Encore! XP® F082A Series Product Specification 91 Watchdog Timer The Watchdog Timer (WDT) protects against corrupt or unreliable software, power faults, and other system-level problems which may place the Z8 Encore! XP® F082A Series devices into unsuitable operating states. The features of Watchdog Timer include: • • • On-chip RC oscillator. A selectable time-out response: reset or interrupt. 24-bit programmable time-out value. Operation The Watchdog Timer is a one-shot timer that resets or interrupts the Z8 Encore! XP F082A Series devices when the WDT reaches its terminal count. The Watchdog Timer uses a dedicated on-chip RC oscillator as its clock source. The Watchdog Timer operates in only two modes: ON and OFF. Once enabled, it always counts and must be refreshed to prevent a time-out. Perform an enable by executing the WDT instruction or by setting the WDT_AO Flash Option Bit. The WDT_AO bit forces the Watchdog Timer to operate immediately upon reset, even if a WDT instruction has not been executed. The Watchdog Timer is a 24-bit reloadable downcounter that uses three 8-bit registers in the eZ8 CPU register space to set the reload value. The nominal WDT time-out period is described by the following equation: WDT Time-out Period (ms) WDT Reload Value = -----------------------------------------10 where the WDT reload value is the decimal value of the 24-bit value given by {WDTU[7:0], WDTH[7:0], WDTL[7:0]} and the typical Watchdog Timer RC oscillator frequency is 10 kHz. The Watchdog Timer cannot be refreshed after it reaches 000002H. The WDT Reload Value must not be set to values below 000004H. Table 56 provides information about approximate time-out delays for the minimum and maximum WDT reload values. Table 56. Watchdog Timer Approximate Time-Out Delays WDT Reload Value (Hex) 000004 FFFFFF PS022825-0908 WDT Reload Value (Decimal) 4 16,777,215 Approximate Time-Out Delay (with 10 kHz typical WDT oscillator frequency) Typical Description 400 μs Minimum time-out delay 28 minutes Maximum time-out delay Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 92 Watchdog Timer Refresh When first enabled, the Watchdog Timer is loaded with the value in the Watchdog Timer Reload registers. The Watchdog Timer counts down to 000000H unless a WDT instruction is executed by the eZ8 CPU. Execution of the WDT instruction causes the downcounter to be reloaded with the WDT Reload value stored in the Watchdog Timer Reload registers. Counting resumes following the reload operation. When the Z8 Encore! XP® F082A Series devices are operating in DEBUG mode (using the on-chip debugger), the Watchdog Timer is continuously refreshed to prevent any Watchdog Timer time-outs. Watchdog Timer Time-Out Response The Watchdog Timer times out when the counter reaches 000000H. A time-out of the Watchdog Timer generates either an interrupt or a system reset. The WDT_RES Flash Option Bit determines the time-out response of the Watchdog Timer. For information on programming the WDT_RES Flash Option Bit, see Flash Option Bits on page 153. WDT Interrupt in Normal Operation If configured to generate an interrupt when a time-out occurs, the Watchdog Timer issues an interrupt request to the interrupt controller and sets the WDT status bit in the Reset Status (RSTSTAT) register (see Reset Status Register on page 30). If interrupts are enabled, the eZ8 CPU responds to the interrupt request by fetching the Watchdog Timer interrupt vector and executing code from the vector address. After time-out and interrupt generation, the Watchdog Timer counter rolls over to its maximum value of FFFFFH and continues counting. The Watchdog Timer counter is not automatically returned to its Reload Value. The Reset Status (RSTSTAT) register must be read before clearing the WDT interrupt. This read clears the WDT timeout Flag and prevents further WDT interrupts from immediately occurring. WDT Interrupt in STOP Mode If configured to generate an interrupt when a time-out occurs and the Z8 Encore! XP F082A Series devices are in STOP mode, the Watchdog Timer automatically initiates a Stop Mode Recovery and generates an interrupt request. Both the WDT status bit and the STOP bit in the Reset Status (RSTSTAT) register are set to 1 following a WDT time-out in STOP mode. For more information on Stop Mode Recovery, see Reset, Stop Mode Recovery, and Low Voltage Detection on page 23. If interrupts are enabled, following completion of the Stop Mode Recovery the eZ8 CPU responds to the interrupt request by fetching the Watchdog Timer interrupt vector and executing code from the vector address. PS022825-0908 Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 93 WDT Reset in Normal Operation If configured to generate a Reset when a time-out occurs, the Watchdog Timer forces the device into the System Reset state. The WDT status bit in the Reset Status (RSTSTAT) register is set to 1. For more information on system reset, see Reset, Stop Mode Recovery, and Low Voltage Detection on page 23. WDT Reset in STOP Mode If configured to generate a Reset when a time-out occurs and the device is in STOP mode, the Watchdog Timer initiates a Stop Mode Recovery. Both the WDT status bit and the STOP bit in the Reset Status (RSTSTAT) register are set to 1 following WDT time-out in STOP mode. Watchdog Timer Reload Unlock Sequence Writing the unlock sequence to the Watchdog Timer (WDTCTL) Control register address unlocks the three Watchdog Timer Reload Byte registers (WDTU, WDTH, and WDTL) to allow changes to the time-out period. These write operations to the WDTCTL register address produce no effect on the bits in the WDTCTL register. The locking mechanism prevents spurious writes to the Reload registers. Follow the steps below to unlock the Watchdog Timer Reload Byte registers (WDTU, WDTH, and WDTL) for write access. 1. Write 55H to the Watchdog Timer Control register (WDTCTL). 2. Write AAH to the Watchdog Timer Control register (WDTCTL). 3. Write the Watchdog Timer Reload Upper Byte register (WDTU) with the desired time-out value. 4. Write the Watchdog Timer Reload High Byte register (WDTH) with the desired time-out value. 5. Write the Watchdog Timer Reload Low Byte register (WDTL) with the desired time-out value. All three Watchdog Timer Reload registers must be written in the order just listed. There must be no other register writes between each of these operations. If a register write occurs, the lock state machine resets and no further writes can occur unless the sequence is restarted. The value in the Watchdog Timer Reload registers is loaded into the counter when the Watchdog Timer is first enabled and every time a WDT instruction is executed. Watchdog Timer Calibration Due to its extremely low operating current, the Watchdog Timer oscillator is somewhat inaccurate. This variation can be corrected using the calibration data stored in the Flash Information Page (see Table 97 and Table 98 on page 165). Loading these values into the PS022825-0908 Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 94 Watchdog Timer Reload Registers results in a one-second timeout at room temperature and 3.3 V supply voltage. Timeouts other than one second may be obtained by scaling the calibration values up or down as required. Note: The Watchdog Timer accuracy still degrades as temperature and supply voltage vary. See Table 133 on page 230 for details. Watchdog Timer Control Register Definitions Watchdog Timer Control Register The Watchdog Timer Control (WDTCTL) register is a write-only control register. Writing the 55H, AAH unlock sequence to the WDTCTL register address unlocks the three Watchdog Timer Reload Byte registers (WDTU, WDTH, and WDTL) to allow changes to the time-out period. These write operations to the WDTCTL register address produce no effect on the bits in the WDTCTL register. The locking mechanism prevents spurious writes to the Reload registers. This register address is shared with the read-only Reset Status register. Table 57. Watchdog Timer Control Register (WDTCTL) BITS 7 6 5 4 3 2 1 0 WDTUNLK FIELD RESET X X X X X X X X R/W W W W W W W W W FF0H ADDR X = Undefined. WDTUNLK—Watchdog Timer Unlock The software must write the correct unlocking sequence to this register before it is allowed to modify the contents of the Watchdog Timer reload registers. Watchdog Timer Reload Upper, High and Low Byte Registers The Watchdog Timer Reload Upper, High and Low Byte (WDTU, WDTH, WDTL) registers (Table 58 through Table 60) form the 24-bit reload value that is loaded into the Watchdog Timer when a WDT instruction executes. The 24-bit reload value is {WDTU[7:0], WDTH[7:0], WDTL[7:0]}. Writing to these registers sets the appropriate Reload Value. Reading from these registers returns the current Watchdog Timer count value. PS022825-0908 Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 95 Caution: The 24-bit WDT Reload Value must not be set to a value less than 000004H. Table 58. Watchdog Timer Reload Upper Byte Register (WDTU) BITS 7 6 5 4 3 FIELD WDTU RESET 00H R/W R/W* ADDR FF1H 2 1 0 R/W* - Read returns the current WDT count value. Write sets the appropriate Reload Value. WDTU—WDT Reload Upper Byte Most-significant byte (MSB), Bits[23:16], of the 24-bit WDT reload value. Table 59. Watchdog Timer Reload High Byte Register (WDTH) BITS 7 6 5 4 3 FIELD WDTH RESET 04H R/W R/W* ADDR FF2H 2 1 0 R/W* - Read returns the current WDT count value. Write sets the appropriate Reload Value. WDTH—WDT Reload High Byte Middle byte, Bits[15:8], of the 24-bit WDT reload value. Table 60. Watchdog Timer Reload Low Byte Register (WDTL) BITS 7 6 5 4 3 FIELD WDTL RESET 00H R/W R/W* ADDR FF3H 2 1 0 R/W* - Read returns the current WDT count value. Write sets the appropriate Reload Value. WDTL—WDT Reload Low Least significant byte (LSB), Bits[7:0], of the 24-bit WDT reload value. PS022825-0908 Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 96 PS022825-0908 Watchdog Timer Z8 Encore! XP® F082A Series Product Specification 97 Universal Asynchronous Receiver/Transmitter The universal asynchronous receiver/transmitter (UART) is a full-duplex communication channel capable of handling asynchronous data transfers. The UART uses a single 8-bit data mode with selectable parity. Features of the UART include: • • • • • • • • 8-bit asynchronous data transfer. • • Baud rate generator (BRG) can be configured and used as a basic 16-bit timer. Selectable even- and odd-parity generation and checking. Option of one or two STOP bits. Separate transmit and receive interrupts. Framing, parity, overrun and break detection. Separate transmit and receive enables. 16-bit baud rate generator (BRG). Selectable MULTIPROCESSOR (9-bit) mode with three configurable interrupt schemes. Driver enable (DE) output for external bus transceivers. Architecture The UART consists of three primary functional blocks: transmitter, receiver, and baud rate generator. The UART’s transmitter and receiver function independently, but employ the same baud rate and data format. Figure 10 on page 98 displays the UART architecture. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 98 Parity Checker Receiver Control with Address Compare RXD Receive Shifter Receive Data Register Control Registers System Bus Transmit Data Register Status Register Baud Rate Generator Transmit Shift Register TXD Transmitter Control Parity Generator CTS DE Figure 10. UART Block Diagram Operation Data Format The UART always transmits and receives data in an 8-bit data format, least-significant bit first. An even or odd parity bit can be added to the data stream. Each character begins with an active Low START bit and ends with either 1 or 2 active High STOP bits. Figure 11 and Figure 12 display the asynchronous data format employed by the UART without parity and with parity, respectively. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 99 1 Data Field Idle State of Line Stop Bit(s) lsb Start msb Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 0 1 2 Figure 11. UART Asynchronous Data Format without Parity 1 Stop Bit(s) Data Field Idle State of Line lsb Start Bit0 msb Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Parity 0 1 2 Figure 12. UART Asynchronous Data Format with Parity Transmitting Data using the Polled Method Follow the steps below to transmit data using the polled method of operation: 1. Write to the UART Baud Rate High and Low Byte registers to set the required baud rate. 2. Enable the UART pin functions by configuring the associated GPIO Port pins for alternate function operation. 3. Write to the UART Control 1 register, if MULTIPROCESSOR mode is appropriate, to enable MULTIPROCESSOR (9-bit) mode functions. 4. Set the Multiprocessor Mode Select (MPEN) bit to enable MULTIPROCESSOR mode. 5. Write to the UART Control 0 register to: – Set the transmit enable bit (TEN) to enable the UART for data transmission. – Set the parity enable bit (PEN), if parity is appropriate and MULTIPROCESSOR mode is not enabled, and select either even or odd parity (PSEL). – Set or clear the CTSE bit to enable or disable control from the remote receiver using the CTS pin. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 100 6. Check the TDRE bit in the UART Status 0 register to determine if the Transmit Data register is empty (indicated by a 1). If empty, continue to Step 7. If the Transmit Data register is full (indicated by a 0), continue to monitor the TDRE bit until the Transmit Data register becomes available to receive new data. 7. Write the UART Control 1 register to select the outgoing address bit. 8. Set the Multiprocessor Bit Transmitter (MPBT) if sending an address byte, clear it if sending a data byte. 9. Write the data byte to the UART Transmit Data register. The transmitter automatically transfers the data to the Transmit Shift register and transmits the data. 10. Make any changes to the Multiprocessor Bit Transmitter (MPBT) value, if appropriate and MULTIPROCESSOR mode is enabled. 11. To transmit additional bytes, return to Step 5. Transmitting Data using the Interrupt-Driven Method The UART Transmitter interrupt indicates the availability of the Transmit Data register to accept new data for transmission. Follow the steps below to configure the UART for interrupt-driven data transmission: 1. Write to the UART Baud Rate High and Low Byte registers to set the appropriate baud rate. 2. Enable the UART pin functions by configuring the associated GPIO Port pins for alternate function operation. 3. Execute a DI instruction to disable interrupts. 4. Write to the Interrupt control registers to enable the UART Transmitter interrupt and set the acceptable priority. 5. Write to the UART Control 1 register to enable MULTIPROCESSOR (9-bit) mode functions, if MULTIPROCESSOR mode is appropriate. 6. Set the MULTIPROCESSOR Mode Select (MPEN) to Enable MULTIPROCESSOR mode. 7. Write to the UART Control 0 register to: – Set the transmit enable bit (TEN) to enable the UART for data transmission. – Enable parity, if appropriate and if MULTIPROCESSOR mode is not enabled, and select either even or odd parity. – Set or clear CTSE to enable or disable control from the remote receiver using the CTS pin. 8. Execute an EI instruction to enable interrupts. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 101 The UART is now configured for interrupt-driven data transmission. Because the UART Transmit Data register is empty, an interrupt is generated immediately. When the UART Transmit interrupt is detected, the associated interrupt service routine (ISR) performs the following: 1. Write the UART Control 1 register to select the multiprocessor bit for the byte to be transmitted: 2. Set the Multiprocessor Bit Transmitter (MPBT) if sending an address byte, clear it if sending a data byte. 3. Write the data byte to the UART Transmit Data register. The transmitter automatically transfers the data to the Transmit Shift register and transmits the data. 4. Clear the UART Transmit interrupt bit in the applicable Interrupt Request register. 5. Execute the IRET instruction to return from the interrupt-service routine and wait for the Transmit Data register to again become empty. Receiving Data using the Polled Method Follow the steps below to configure the UART for polled data reception: 1. Write to the UART Baud Rate High and Low Byte registers to set an acceptable baud rate for the incoming data stream. 2. Enable the UART pin functions by configuring the associated GPIO Port pins for alternate function operation. 3. Write to the UART Control 1 register to enable MULTIPROCESSOR mode functions, if appropriate. 4. Write to the UART Control 0 register to: – Set the receive enable bit (REN) to enable the UART for data reception – Enable parity, if appropriate and if Multiprocessor mode is not enabled, and select either even or odd parity. 5. Check the RDA bit in the UART Status 0 register to determine if the Receive Data register contains a valid data byte (indicated by a 1). If RDA is set to 1 to indicate available data, continue to Step 5. If the Receive Data register is empty (indicated by a 0), continue to monitor the RDA bit awaiting reception of the valid data. 6. Read data from the UART Receive Data register. If operating in MULTIPROCESSOR (9-bit) mode, further actions may be required depending on the MULTIPROCESSOR mode bits MPMD[1:0]. 7. Return to Step 4 to receive additional data. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 102 Receiving Data using the Interrupt-Driven Method The UART Receiver interrupt indicates the availability of new data (as well as error conditions). Follow the steps below to configure the UART receiver for interrupt-driven operation: 1. Write to the UART Baud Rate High and Low Byte registers to set the acceptable baud rate. 2. Enable the UART pin functions by configuring the associated GPIO Port pins for alternate function operation. 3. Execute a DI instruction to disable interrupts. 4. Write to the Interrupt control registers to enable the UART Receiver interrupt and set the acceptable priority. 5. Clear the UART Receiver interrupt in the applicable Interrupt Request register. 6. Write to the UART Control 1 Register to enable Multiprocessor (9-bit) mode functions, if appropriate. – Set the Multiprocessor Mode Select (MPEN) to Enable MULTIPROCESSOR mode. – Set the Multiprocessor Mode Bits, MPMD[1:0], to select the acceptable address matching scheme. – Configure the UART to interrupt on received data and errors or errors only (interrupt on errors only is unlikely to be useful for Z8 Encore!® devices without a DMA block) 7. Write the device address to the Address Compare Register (automatic MULTIPROCESSOR modes only). 8. Write to the UART Control 0 register to: – Set the receive enable bit (REN) to enable the UART for data reception – Enable parity, if appropriate and if multiprocessor mode is not enabled, and select either even or odd parity. 9. Execute an EI instruction to enable interrupts. The UART is now configured for interrupt-driven data reception. When the UART Receiver interrupt is detected, the associated interrupt service routine (ISR) performs the following: 1. Checks the UART Status 0 register to determine the source of the interrupt - error, break, or received data. 2. Reads the data from the UART Receive Data register if the interrupt was because of data available. If operating in MULTIPROCESSOR (9-bit) mode, further actions may be required depending on the MULTIPROCESSOR mode bits MPMD[1:0]. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 103 3. Clears the UART Receiver interrupt in the applicable Interrupt Request register. 4. Executes the IRET instruction to return from the interrupt-service routine and await more data. Clear To Send (CTS) Operation The CTS pin, if enabled by the CTSE bit of the UART Control 0 register, performs flow control on the outgoing transmit datastream. The Clear To Send (CTS) input pin is sampled one system clock before beginning any new character transmission. To delay transmission of the next data character, an external receiver must deassert CTS at least one system clock cycle before a new data transmission begins. For multiple character transmissions, this action is typically performed during Stop Bit transmission. If CTS deasserts in the middle of a character transmission, the current character is sent completely. MULTIPROCESSOR (9-bit) Mode The UART has a MULTIPROCESSOR (9-bit) mode that uses an extra (9th) bit for selective communication when a number of processors share a common UART bus. In MULTIPROCESSOR mode (also referred to as 9-bit mode), the multiprocessor bit (MP) is transmitted immediately following the 8-bits of data and immediately preceding the Stop bit(s) as displayed in Figure 13. The character format is: 1 Stop Bit(s) Data Field Idle State of Line lsb Start Bit0 msb Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 MP 0 1 2 Figure 13. UART Asynchronous MULTIPROCESSOR Mode Data Format In MULTIPROCESSOR (9-bit) mode, the Parity bit location (9th bit) becomes the Multiprocessor control bit. The UART Control 1 and Status 1 registers provide MULTIPROCESSOR (9-bit) mode control and status information. If an automatic address matching scheme is enabled, the UART Address Compare register holds the network address of the device. MULTIPROCESSOR (9-bit) Mode Receive Interrupts When MULTIPROCESSOR mode is enabled, the UART only processes frames addressed to it. The determination of whether a frame of data is addressed to the UART can be made in hardware, software or some combination of the two, depending on the multiprocessor PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 104 configuration bits. In general, the address compare feature reduces the load on the CPU, because it does not require access to the UART when it receives data directed to other devices on the multi-node network. The following three MULTIPROCESSOR modes are available in hardware: 1. Interrupt on all address bytes. 2. Interrupt on matched address bytes and correctly framed data bytes. 3. Interrupt only on correctly framed data bytes. These modes are selected with MPMD[1:0] in the UART Control 1 Register. For all multiprocessor modes, bit MPEN of the UART Control 1 Register must be set to 1. The first scheme is enabled by writing 01b to MPMD[1:0]. In this mode, all incoming address bytes cause an interrupt, while data bytes never cause an interrupt. The interrupt service routine must manually check the address byte that caused triggered the interrupt. If it matches the UART address, the software clears MPMD[0]. Each new incoming byte interrupts the CPU. The software is responsible for determining the end of the frame. It checks for the end-of-frame by reading the MPRX bit of the UART Status 1 Register for each incoming byte. If MPRX=1, a new frame has begun. If the address of this new frame is different from the UART’s address, MPMD[0] must be set to 1 causing the UART interrupts to go inactive until the next address byte. If the new frame’s address matches the UART’s, the data in the new frame is processed as well. The second scheme requires the following: set MPMD[1:0] to 10B and write the UART’s address into the UART Address Compare Register. This mode introduces additional hardware control, interrupting only on frames that match the UART’s address. When an incoming address byte does not match the UART’s address, it is ignored. All successive data bytes in this frame are also ignored. When a matching address byte occurs, an interrupt is issued and further interrupts now occur on each successive data byte. When the first data byte in the frame is read, the NEWFRM bit of the UART Status 1 Register is asserted. All successive data bytes have NEWFRM=0. When the next address byte occurs, the hardware compares it to the UART’s address. If there is a match, the interrupts continues and the NEWFRM bit is set for the first byte of the new frame. If there is no match, the UART ignores all incoming bytes until the next address match. The third scheme is enabled by setting MPMD[1:0] to 11b and by writing the UART’s address into the UART Address Compare Register. This mode is identical to the second scheme, except that there are no interrupts on address bytes. The first data byte of each frame remains accompanied by a NEWFRM assertion. External Driver Enable The UART provides a Driver Enable (DE) signal for off-chip bus transceivers. This feature reduces the software overhead associated with using a GPIO pin to control the transceiver when communicating on a multi-transceiver bus, such as RS-485. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 105 Driver Enable is an active High signal that envelopes the entire transmitted data frame including parity and Stop bits as displayed in Figure 14. The Driver Enable signal asserts when a byte is written to the UART Transmit Data register. The Driver Enable signal asserts at least one UART bit period and no greater than two UART bit periods before the Start bit is transmitted. This allows a setup time to enable the transceiver. The Driver Enable signal deasserts one system clock period after the final Stop bit is transmitted. This one system clock delay allows both time for data to clear the transceiver before disabling it, as well as the ability to determine if another character follows the current character. In the event of back to back characters (new data must be written to the Transmit Data Register before the previous character is completely transmitted) the DE signal is not deasserted between characters. The DEPOL bit in the UART Control Register 1 sets the polarity of the Driver Enable signal. 1 DE 0 1 Data Field Idle State of Line Stop Bit lsb Start Bit0 msb Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Parity 0 1 Figure 14. UART Driver Enable Signal Timing (shown with 1 Stop Bit and Parity) The Driver Enable to Start bit setup time is calculated as follows: 1 ⎛ ----------------------------------------⎞ ⎝ Baud Rate (Hz)⎠ 2 -⎞ ≤ DE to Start Bit Setup Time (s) ≤ ⎛⎝ ---------------------------------------⎠ Baud Rate (Hz) UART Interrupts The UART features separate interrupts for the transmitter and the receiver. In addition, when the UART primary functionality is disabled, the Baud Rate Generator can also function as a basic timer with interrupt capability. Transmitter Interrupts The transmitter generates a single interrupt when the Transmit Data Register Empty bit (TDRE) is set to 1. This indicates that the transmitter is ready to accept new data for transmission. The TDRE interrupt occurs after the Transmit shift register has shifted the first bit of data out. The Transmit Data register can now be written with the next character to PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 106 send. This action provides 7 bit periods of latency to load the Transmit Data register before the Transmit shift register completes shifting the current character. Writing to the UART Transmit Data register clears the TDRE bit to 0. Receiver Interrupts The receiver generates an interrupt when any of the following occurs: • A data byte is received and is available in the UART Receive Data register. This interrupt can be disabled independently of the other receiver interrupt sources. The received data interrupt occurs after the receive character has been received and placed in the Receive Data register. To avoid an overrun error, software must respond to this received data available condition before the next character is completely received. Note: In MULTIPROCESSOR mode (MPEN = 1), the receive data interrupts are dependent on the multiprocessor configuration and the most recent address byte. • • • A break is received. An overrun is detected. A data framing error is detected. UART Overrun Errors When an overrun error condition occurs the UART prevents overwriting of the valid data currently in the Receive Data register. The Break Detect and Overrun status bits are not displayed until after the valid data has been read. After the valid data has been read, the UART Status 0 register is updated to indicate the overrun condition (and Break Detect, if applicable). The RDA bit is set to 1 to indicate that the Receive Data register contains a data byte. However, because the overrun error occurred, this byte may not contain valid data and must be ignored. The BRKD bit indicates if the overrun was caused by a break condition on the line. After reading the status byte indicating an overrun error, the Receive Data register must be read again to clear the error bits is the UART Status 0 register. Updates to the Receive Data register occur only when the next data word is received. UART Data and Error Handling Procedure Figure 15 displays the recommended procedure for use in UART receiver interrupt service routines. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 107 Receiver Ready Receiver Interrupt Read Status No Errors? Yes Read Data which clears RDA bit and resets error bits Read Data Discard Data Figure 15. UART Receiver Interrupt Service Routine Flow Baud Rate Generator Interrupts If the baud rate generator (BRG) interrupt enable is set, the UART Receiver interrupt asserts when the UART Baud Rate Generator reloads. This condition allows the Baud Rate Generator to function as an additional counter if the UART functionality is not employed. UART Baud Rate Generator The UART Baud Rate Generator creates a lower frequency baud rate clock for data transmission. The input to the Baud Rate Generator is the system clock. The UART Baud Rate High and Low Byte registers combine to create a 16-bit baud rate divisor value PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 108 (BRG[15:0]) that sets the data transmission rate (baud rate) of the UART. The UART data rate is calculated using the following equation: UART Data Rate (bits/s) System Clock Frequency (Hz) = --------------------------------------------------------------------------------16 × UART Baud Rate Divisor Value When the UART is disabled, the Baud Rate Generator functions as a basic 16-bit timer with interrupt on time-out. Follow the steps below to configure the Baud Rate Generator as a timer with interrupt on time-out: 1. Disable the UART by clearing the REN and TEN bits in the UART Control 0 register to 0. 2. Load the acceptable 16-bit count value into the UART Baud Rate High and Low Byte registers. 3. Enable the Baud Rate Generator timer function and associated interrupt by setting the BRGCTL bit in the UART Control 1 register to 1. When configured as a general purpose timer, the interrupt interval is calculated using the following equation: Interrupt Interval ( s ) = System Clock Period (s) × BRG [ 15:0 ] UART Control Register Definitions The UART control registers support the UART and the associated Infrared Encoder/ Decoders. For more information on infrared operation, see Infrared Encoder/Decoder on page 117. UART Control 0 and Control 1 Registers The UART Control 0 (UxCTL0) and Control 1 (UxCTL1) registers (Table 61 and Table 62) configure the properties of the UART’s transmit and receive operations. The UART Control registers must not be written while the UART is enabled. Table 61. UART Control 0 Register (U0CTL0) BITS 7 6 5 4 3 2 1 0 FIELD TEN REN CTSE PEN PSEL SBRK STOP LBEN RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W ADDR F42H TEN—Transmit Enable This bit enables or disables the transmitter. The enable is also controlled by the CTS signal PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 109 and the CTSE bit. If the CTS signal is Low and the CTSE bit is 1, the transmitter is enabled. 0 = Transmitter disabled. 1 = Transmitter enabled. REN—Receive Enable This bit enables or disables the receiver. 0 = Receiver disabled. 1 = Receiver enabled. CTSE—CTS Enable 0 = The CTS signal has no effect on the transmitter. 1 = The UART recognizes the CTS signal as an enable control from the transmitter. PEN—Parity Enable This bit enables or disables parity. Even or odd is determined by the PSEL bit. 0 = Parity is disabled. 1 = The transmitter sends data with an additional parity bit and the receiver receives an additional parity bit. PSEL—Parity Select 0 = Even parity is transmitted and expected on all received data. 1 = Odd parity is transmitted and expected on all received data. SBRK—Send Break This bit pauses or breaks data transmission. Sending a break interrupts any transmission in progress, so ensure that the transmitter has finished sending data before setting this bit. 0 = No break is sent. 1 = Forces a break condition by setting the output of the transmitter to zero. STOP—Stop Bit Select 0 = The transmitter sends one stop bit. 1 = The transmitter sends two stop bits. LBEN—Loop Back Enable 0 = Normal operation. 1 = All transmitted data is looped back to the receiver. Table 62. UART Control 1 Register (U0CTL1) BITS 7 6 5 4 3 2 1 0 FIELD MPMD[1] MPEN MPMD[0] MPBT DEPOL BRGCTL RDAIRQ IREN RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W ADDR PS022825-0908 F43H Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 110 MPMD[1:0]—MULTIPROCESSOR Mode If MULTIPROCESSOR (9-bit) mode is enabled, 00 = The UART generates an interrupt request on all received bytes (data and address). 01 = The UART generates an interrupt request only on received address bytes. 10 = The UART generates an interrupt request when a received address byte matches the value stored in the Address Compare Register and on all successive data bytes until an address mismatch occurs. 11 = The UART generates an interrupt request on all received data bytes for which the most recent address byte matched the value in the Address Compare Register. MPEN—MULTIPROCESSOR (9-bit) Enable This bit is used to enable MULTIPROCESSOR (9-bit) mode. 0 = Disable MULTIPROCESSOR (9-bit) mode. 1 = Enable MULTIPROCESSOR (9-bit) mode. MPBT—Multiprocessor Bit Transmit This bit is applicable only when MULTIPROCESSOR (9-bit) mode is enabled. The 9th bit is used by the receiving device to determine if the data byte contains address or data information. 0 = Send a 0 in the multiprocessor bit location of the data stream (data byte). 1 = Send a 1 in the multiprocessor bit location of the data stream (address byte). DEPOL—Driver Enable Polarity 0 = DE signal is Active High. 1 = DE signal is Active Low. BRGCTL—Baud Rate Control This bit causes an alternate UART behavior depending on the value of the REN bit in the UART Control 0 Register. When the UART receiver is not enabled (REN=0), this bit determines whether the Baud Rate Generator issues interrupts. 0 = Reads from the Baud Rate High and Low Byte registers return the BRG Reload Value 1 = The Baud Rate Generator generates a receive interrupt when it counts down to 0. Reads from the Baud Rate High and Low Byte registers return the current BRG count value. When the UART receiver is enabled (REN=1), this bit allows reads from the Baud Rate Registers to return the BRG count value instead of the Reload Value. 0 = Reads from the Baud Rate High and Low Byte registers return the BRG Reload Value. 1 = Reads from the Baud Rate High and Low Byte registers return the current BRG count value. Unlike the Timers, there is no mechanism to latch the Low Byte when the High Byte is read. RDAIRQ—Receive Data Interrupt Enable 0 = Received data and receiver errors generates an interrupt request to the Interrupt Controller. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 111 1 = Received data does not generate an interrupt request to the Interrupt Controller. Only receiver errors generate an interrupt request. IREN—Infrared Encoder/Decoder Enable 0 = Infrared Encoder/Decoder is disabled. UART operates normally. 1 = Infrared Encoder/Decoder is enabled. The UART transmits and receives data through the Infrared Encoder/Decoder. UART Status 0 Register The UART Status 0 (UxSTAT0) and Status 1(UxSTAT1) registers (Table 63 and Table 64) identify the current UART operating configuration and status. Table 63. UART Status 0 Register (U0STAT0) BITS 7 6 5 4 3 2 1 0 FIELD RDA PE OE FE BRKD TDRE TXE CTS RESET 0 0 0 0 0 1 1 X R/W R R R R R R R R F41H ADDR RDA—Receive Data Available This bit indicates that the UART Receive Data register has received data. Reading the UART Receive Data register clears this bit. 0 = The UART Receive Data register is empty. 1 = There is a byte in the UART Receive Data register. PE—Parity Error This bit indicates that a parity error has occurred. Reading the UART Receive Data register clears this bit. 0 = No parity error has occurred. 1 = A parity error has occurred. OE—Overrun Error This bit indicates that an overrun error has occurred. An overrun occurs when new data is received and the UART Receive Data register has not been read. If the RDA bit is reset to 0, reading the UART Receive Data register clears this bit. 0 = No overrun error occurred. 1 = An overrun error occurred. FE—Framing Error This bit indicates that a framing error (no Stop bit following data reception) was detected. Reading the UART Receive Data register clears this bit. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 112 0 = No framing error occurred. 1 = A framing error occurred. BRKD—Break Detect This bit indicates that a break occurred. If the data bits, parity/multiprocessor bit, and Stop bit(s) are all 0s this bit is set to 1. Reading the UART Receive Data register clears this bit. 0 = No break occurred. 1 = A break occurred. TDRE—Transmitter Data Register Empty This bit indicates that the UART Transmit Data register is empty and ready for additional data. Writing to the UART Transmit Data register resets this bit. 0 = Do not write to the UART Transmit Data register. 1 = The UART Transmit Data register is ready to receive an additional byte to be transmitted. TXE—Transmitter Empty This bit indicates that the transmit shift register is empty and character transmission is finished. 0 = Data is currently transmitting. 1 = Transmission is complete. CTS—CTS signal When this bit is read it returns the level of the CTS signal. This signal is active Low. UART Status 1 Register This register contains multiprocessor control and status bits. Table 64. UART Status 1 Register (U0STAT1) BITS 7 6 5 4 3 2 Reserved FIELD 1 0 NEWFRM MPRX RESET 0 0 0 0 0 0 0 0 R/W R R R R R/W R/W R R F44H ADDR Reserved—Must be 0. NEWFRM—Status bit denoting the start of a new frame. Reading the UART Receive Data register resets this bit to 0. 0 = The current byte is not the first data byte of a new frame. 1 = The current byte is the first data byte of a new frame. PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 113 MPRX—Multiprocessor Receive Returns the value of the most recent multiprocessor bit received. Reading from the UART Receive Data register resets this bit to 0. UART Transmit Data Register Data bytes written to the UART Transmit Data (UxTXD) register (Table 65) are shifted out on the TXDx pin. The Write-only UART Transmit Data register shares a Register File address with the read-only UART Receive Data register. Table 65. UART Transmit Data Register (U0TXD) BITS 7 6 5 4 3 2 1 0 TXD FIELD RESET X X X X X X X X R/W W W W W W W W W F40H ADDR TXD—Transmit Data UART transmitter data byte to be shifted out through the TXDx pin. UART Receive Data Register Data bytes received through the RXDx pin are stored in the UART Receive Data (UxRXD) register (Table 66). The read-only UART Receive Data register shares a Register File address with the Write-only UART Transmit Data register. Table 66. UART Receive Data Register (U0RXD) BITS 7 6 5 4 3 2 1 0 RXD FIELD RESET X X X X X X X X R/W R R R R R R R R ADDR F40H X = Undefined. RXD—Receive Data UART receiver data byte from the RXDx pin PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 114 UART Address Compare Register The UART Address Compare (UxADDR) register stores the multi-node network address of the UART (see Table 67). When the MPMD[1] bit of UART Control Register 0 is set, all incoming address bytes are compared to the value stored in the Address Compare register. Receive interrupts and RDA assertions only occur in the event of a match. Table 67. UART Address Compare Register (U0ADDR) BITS 7 6 5 3 2 1 0 COMP_ADDR FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 4 F45H ADDR COMP_ADDR—Compare Address This 8-bit value is compared to incoming address bytes. UART Baud Rate High and Low Byte Registers The UART Baud Rate High (UxBRH) and Low Byte (UxBRL) registers (Table 68 and Table 69) combine to create a 16-bit baud rate divisor value (BRG[15:0]) that sets the data transmission rate (baud rate) of the UART. Table 68. UART Baud Rate High Byte Register (U0BRH) BITS 7 6 5 4 2 1 0 BRH FIELD 1 1 1 1 1 1 1 1 R/W R/W R/W R/W R/W R/W R/W R/W 3 2 1 0 RESET R/W 3 F46H ADDR Table 69. UART Baud Rate Low Byte Register (U0BRL) BITS 7 6 5 4 BRL FIELD 1 1 1 1 1 1 1 1 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W ADDR PS022825-0908 F47H Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 115 The UART data rate is calculated using the following equation: System Clock Frequency (Hz) UART Baud Rate (bits/s) = -----------------------------------------------------------------------------------------------16 × UART Baud Rate Divisor Value For a given UART data rate, calculate the integer baud rate divisor value using the following equation: System Clock Frequency (Hz) UART Baud Rate Divisor Value (BRG) = Round ⎛ -------------------------------------------------------------------------------⎞ ⎝ 16 × UART Data Rate (bits/s) ⎠ The baud rate error relative to the acceptable baud rate is calculated using the following equation: Actual Data Rate – Desired Data Rate UART Baud Rate Error (%) = 100 × ⎛ ----------------------------------------------------------------------------------------------------⎞ ⎝ ⎠ Desired Data Rate For reliable communication, the UART baud rate error must never exceed 5 percent. Table 70 provides information on the data rate errors for popular baud rates and commonly used crystal oscillator frequencies. Table 70. UART Baud Rates 10.0 MHz System Clock 5.5296 MHz System Clock Acceptable BRG Divisor Actual Rate Rate (kHz) (Decimal) (kHz) Error (%) Acceptable BRG Divisor Actual Rate Rate (kHz) (Decimal) (kHz) Error (%) 1250.0 N/A N/A N/A 1250.0 N/A N/A N/A 625.0 1 625.0 0.00 625.0 N/A N/A N/A 250.0 3 208.33 -16.67 250.0 1 345.6 38.24 115.2 5 125.0 8.51 115.2 3 115.2 0.00 57.6 11 56.8 -1.36 57.6 6 57.6 0.00 38.4 16 39.1 1.73 38.4 9 38.4 0.00 19.2 33 18.9 0.16 19.2 18 19.2 0.00 9.60 65 9.62 0.16 9.60 36 9.60 0.00 4.80 130 4.81 0.16 4.80 72 4.80 0.00 2.40 260 2.40 -0.03 2.40 144 2.40 0.00 1.20 521 1.20 -0.03 1.20 288 1.20 0.00 0.60 1042 0.60 -0.03 0.60 576 0.60 0.00 0.30 2083 0.30 0.2 0.30 1152 0.30 0.00 PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 116 Table 70. UART Baud Rates (Continued) 3.579545 MHz System Clock 1.8432 MHz System Clock Acceptable BRG Divisor Actual Rate Rate (kHz) (Decimal) (kHz) Error (%) Acceptable BRG Divisor Actual Rate Rate (kHz) (Decimal) (kHz) Error (%) 1250.0 N/A N/A N/A 1250.0 N/A N/A N/A 625.0 N/A N/A N/A 625.0 N/A N/A N/A 250.0 1 223.72 -10.51 250.0 N/A N/A N/A 115.2 2 111.9 -2.90 115.2 1 115.2 0.00 57.6 4 55.9 -2.90 57.6 2 57.6 0.00 38.4 6 37.3 -2.90 38.4 3 38.4 0.00 19.2 12 18.6 -2.90 19.2 6 19.2 0.00 9.60 23 9.73 1.32 9.60 12 9.60 0.00 4.80 47 4.76 -0.83 4.80 24 4.80 0.00 2.40 93 2.41 0.23 2.40 48 2.40 0.00 1.20 186 1.20 0.23 1.20 96 1.20 0.00 0.60 373 0.60 -0.04 0.60 192 0.60 0.00 0.30 746 0.30 -0.04 0.30 384 0.30 0.00 PS022825-0908 Universal Asynchronous Receiver/Transmitter Z8 Encore! XP® F082A Series Product Specification 117 Infrared Encoder/Decoder The Z8 Encore! XP® F082A Series products contain a fully-functional, high-performance UART to Infrared Encoder/Decoder (Endec). The Infrared Endec is integrated with an on-chip UART to allow easy communication between the Z8 Encore! and IrDA Physical Layer Specification, Version 1.3-compliant infrared transceivers. Infrared communication provides secure, reliable, low-cost, point-to-point communication between PCs, PDAs, cell phones, printers, and other infrared enabled devices. Architecture Figure 16 displays the architecture of the Infrared Endec. System Clock Infrared Transceiver RxD TxD UART Interrupt I/O Signal Address Baud Rate Clock RXD Infrared Encoder/Decoder (Endec) TXD RXD TXD Data Figure 16. Infrared Data Communication System Block Diagram Operation When the Infrared Endec is enabled, the transmit data from the associated on-chip UART is encoded as digital signals in accordance with the IrDA standard and output to the infrared transceiver through the TXD pin. Likewise, data received from the infrared transceiver is passed to the Infrared Endec through the RXD pin, decoded by the Infrared PS022825-0908 Infrared Encoder/Decoder Z8 Encore! XP® F082A Series Product Specification 118 Endec, and passed to the UART. Communication is half-duplex, which means simultaneous data transmission and reception is not allowed. The baud rate is set by the UART’s Baud Rate Generator and supports IrDA standard baud rates from 9600 baud to 115.2 kbaud. Higher baud rates are possible, but do not meet IrDA specifications. The UART must be enabled to use the Infrared Endec. The Infrared Endec data rate is calculated using the following equation: Infrared Data Rate (bits/s) System Clock Frequency (Hz) = --------------------------------------------------------------------------------16 × UART Baud Rate Divisor Value Transmitting IrDA Data The data to be transmitted using the infrared transceiver is first sent to the UART. The UART’s transmit signal (TXD) and baud rate clock are used by the IrDA to generate the modulation signal (IR_TXD) that drives the infrared transceiver. Each UART/Infrared data bit is 16 clocks wide. If the data to be transmitted is 1, the IR_TXD signal remains low for the full 16 clock period. If the data to be transmitted is 0, the transmitter first outputs a 7 clock low period, followed by a 3 clock high pulse. Finally, a 6 clock low pulse is output to complete the full 16 clock data period. Figure 17 displays IrDA data transmission. When the Infrared Endec is enabled, the UART’s TXD signal is internal to the Z8 Encore! XP® F082A Series products while the IR_TXD signal is output through the TXD pin. 16 clock period Baud Rate Clock UART’s TXD Start Bit = 0 Data Bit 0 = 1 Data Bit 1 = 0 Data Bit 2 = 1 Data Bit 3 = 1 3 clock pulse IR_TXD 7-clock delay Figure 17. Infrared Data Transmission PS022825-0908 Infrared Encoder/Decoder Z8 Encore! XP® F082A Series Product Specification 119 Receiving IrDA Data Data received from the infrared transceiver using the IR_RXD signal through the RXD pin is decoded by the Infrared Endec and passed to the UART. The UART’s baud rate clock is used by the Infrared Endec to generate the demodulated signal (RXD) that drives the UART. Each UART/Infrared data bit is 16-clocks wide. Figure 18 displays data reception. When the Infrared Endec is enabled, the UART’s RXD signal is internal to the Z8 Encore! XP® F082A Series products while the IR_RXD signal is received through the RXD pin. 16 clock period Baud Rate Clock Start Bit = 0 Data Bit 0 = 1 Data Bit 1 = 0 Data Bit 2 = 1 Data Bit 3 = 1 IR_RXD min. 1.4 μs pulse UART’s RXD Start Bit = 0 8 clock delay 16 clock period Data Bit 0 = 1 16 clock period Data Bit 1 = 0 16 clock period Data Bit 2 = 1 Data Bit 3 = 1 16 clock period Figure 18. IrDA Data Reception Infrared Data Reception Caution: The system clock frequency must be at least 1.0 MHz to ensure proper reception of the 1.4 μs minimum width pulses allowed by the IrDA standard. Endec Receiver Synchronization The IrDA receiver uses a local baud rate clock counter (0 to 15 clock periods) to generate an input stream for the UART and to create a sampling window for detection of incoming pulses. The generated UART input (UART RXD) is delayed by 8 baud rate clock periods with respect to the incoming IrDA data stream. When a falling edge in the input data stream is detected, the Endec counter is reset. When the count reaches a value of 8, the UART RXD value is updated to reflect the value of the decoded data. When the count reaches 12 baud clock periods, the sampling window for the next incoming pulse opens. The window remains open until the count again reaches 8 (that is, 24 baud clock periods since the previous pulse was detected), giving the Endec a sampling window of minus four PS022825-0908 Infrared Encoder/Decoder Z8 Encore! XP® F082A Series Product Specification 120 baud rate clocks to plus eight baud rate clocks around the expected time of an incoming pulse. If an incoming pulse is detected inside this window this process is repeated. If the incoming data is a logical 1 (no pulse), the Endec returns to the initial state and waits for the next falling edge. As each falling edge is detected, the Endec clock counter is reset, resynchronizing the Endec to the incoming signal, allowing the Endec to tolerate jitter and baud rate errors in the incoming datastream. Resynchronizing the Endec does not alter the operation of the UART, which ultimately receives the data. The UART is only synchronized to the incoming data stream when a Start bit is received. Infrared Encoder/Decoder Control Register Definitions All Infrared Endec configuration and status information is set by the UART control registers as defined in Universal Asynchronous Receiver/Transmitter on page 97. Caution: To prevent spurious signals during IrDA data transmission, set the IREN bit in the UART Control 1 register to 1 to enable the Infrared Encoder/Decoder before enabling the GPIO Port alternate function for the corresponding pin. PS022825-0908 Infrared Encoder/Decoder Z8 Encore! XP® F082A Series Product Specification 121 Analog-to-Digital Converter The analog-to-digital converter (ADC) converts an analog input signal to its digital representation. The features of this sigma-delta ADC include: • • • 11-bit resolution in DIFFERENTIAL mode. • • • • • • • 9th analog input obtained from temperature sensor peripheral. 10-bit resolution in SINGLE-ENDED mode. Eight single-ended analog input sources are multiplexed with general-purpose I/O ports. 11 pairs of differential inputs also multiplexed with general-purpose I/O ports. Low-power operational amplifier (LPO). Interrupt on conversion complete. Bandgap generated internal voltage reference with two selectable levels. Manual in-circuit calibration is possible employing user code (offset calibration). Factory calibrated for in-circuit error compensation. Architecture Figure 19 displays the major functional blocks of the ADC. An analog multiplexer network selects the ADC input from the available analog pins, ANA0 through ANA7. The input stage of the ADC allows both differential gain and buffering. The following input options are available: • • • PS022825-0908 Unbuffered input (SINGLE-ENDED and DIFFERENTIAL modes). Buffered input with unity gain (SINGLE-ENDED and DIFFERENTIAL modes). LPO output with full pin access to the feedback path. Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 122 2 Vrefsel Internal Voltage Reference Generator VREF pin Analog Input Multiplexer VREFEXT ADC 13 Data ANA0 ANA1 ANA2 ANA3 ANA4 ANA5 Ref Input 13 bit Sigma-Delta ADC Buffer Amplifier 4 Analog In - - Analog In + + Analog Input Multiplexer ANA0 ANA1 ANA2 ANA3 ANA4 ANA5 ANA6 ANA7 ADC IRQ for offset calibration ANAIN BUFFMODE Amplifier tristates when disabled + Low-Power Operational Amplifier Temp Sensor Figure 19. Analog-to-Digital Converter Block Diagram Operation Data Format In both SINGLE-ENDED and DIFFERENTIAL modes, the effective output of the ADC is an 11-bit, signed, two’s complement digital value. In DIFFERENTIAL mode, the ADC PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 123 can output values across the entire 11-bit range, from -1024 to +1023. In SINGLE-ENDED mode, the output generally ranges from 0 to +1023, but offset errors can cause small negative values. The ADC registers actually return 13 bits of data, but the two LSBs are intended for compensation use only. When the software compensation routine is performed on the 13 bit raw ADC value, two bits of resolution are lost because of a rounding error. As a result, the final value is an 11-bit number. Hardware Overflow When the hardware overflow bit (OVF) is set in ADC Data Low Byte (ADCD_L) register, all other data bits are invalid. The hardware overflow bit is set for values greater than Vref and less than -Vref (DIFFERENTIAL mode). Automatic Powerdown If the ADC is idle (no conversions in progress) for 160 consecutive system clock cycles, portions of the ADC are automatically powered down. From this powerdown state, the ADC requires 40 system clock cycles to power up. The ADC powers up when a conversion is requested by the ADC Control register. Single-Shot Conversion When configured for single-shot conversion, the ADC performs a single analog-to-digital conversion on the selected analog input channel. After completion of the conversion, the ADC shuts down. Follow the steps below for setting up the ADC and initiating a singleshot conversion: 1. Enable the desired analog inputs by configuring the general-purpose I/O pins for alternate analog function. This configuration disables the digital input and output drivers. 2. Write the ADC Control/Status Register 1 to configure the ADC. – Write to BUFMODE[2:0] to select SINGLE-ENDED or DIFFERENTIAL mode, as well as unbuffered or buffered mode. – Write the REFSELH bit of the pair {REFSELH, REFSELL} to select the internal voltage reference level or to disable the internal reference. The REFSELL bit is. contained in the ADC Control Register 0. 3. Write to the ADC Control Register 0 to configure the ADC and begin the conversion. The bit fields in the ADC Control register can be written simultaneously (the ADC can be configured and enabled with the same write instruction): – Write to the ANAIN[3:0] field to select from the available analog input sources (different input pins available depending on the device). – Clear CONT to 0 to select a single-shot conversion. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 124 – – – If the internal voltage reference must be output to a pin, set the REFEXT bit to 1. The internal voltage reference must be enabled in this case. Write the REFSELL bit of the pair {REFSELH, REFSELL} to select the internal voltage reference level or to disable the internal reference. The REFSELH bit is contained in the ADC Control/Status Register 1. Set CEN to 1 to start the conversion. 4. CEN remains 1 while the conversion is in progress. A single-shot conversion requires 5129 system clock cycles to complete. If a single-shot conversion is requested from an ADC powered-down state, the ADC uses 40 additional clock cycles to power up before beginning the 5129 cycle conversion. 5. When the conversion is complete, the ADC control logic performs the following operations: – 13-bit two’s-complement result written to {ADCD_H[7:0], ADCD_L[7:3]}. – Sends an interrupt request to the Interrupt Controller denoting conversion complete. – CEN resets to 0 to indicate the conversion is complete. 6. If the ADC remains idle for 160 consecutive system clock cycles, it is automatically powered-down. Continuous Conversion When configured for continuous conversion, the ADC continuously performs an analog-to-digital conversion on the selected analog input. Each new data value over-writes the previous value stored in the ADC Data registers. An interrupt is generated after each conversion. Caution: In CONTINUOUS mode, ADC updates are limited by the input signal bandwidth of the ADC and the latency of the ADC and its digital filter. Step changes at the input are not immediately detected at the next output from the ADC. The response of the ADC (in all modes) is limited by the input signal bandwidth and the latency. Follow the steps below for setting up the ADC and initiating continuous conversion: 1. Enable the desired analog input by configuring the general-purpose I/O pins for alternate function. This action disables the digital input and output driver. 2. Write the ADC Control/Status Register 1 to configure the ADC. – Write to BUFMODE[2:0] to select SINGLE-ENDED or DIFFERENTIAL mode, as well as unbuffered or buffered mode. – Write the REFSELH bit of the pair {REFSELH, REFSELL} to select the internal voltage reference level or to disable the internal reference. The REFSELL bit is contained in the ADC Control Register 0. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 125 3. Write to the ADC Control Register 0 to configure the ADC for continuous conversion. The bit fields in the ADC Control register may be written simultaneously: – Write to the ANAIN[3:0] field to select from the available analog input sources (different input pins available depending on the device). – Set CONT to 1 to select continuous conversion. – If the internal VREF must be output to a pin, set the REFEXT bit to 1. The internal voltage reference must be enabled in this case. – Write the REFSELL bit of the pair {REFSELH, REFSELL} to select the internal voltage reference level or to disable the internal reference. The REFSELH bit is contained in ADC Control/Status Register 1. – Set CEN to 1 to start the conversions. 4. When the first conversion in continuous operation is complete (after 5129 system clock cycles, plus the 40 cycles for power-up, if necessary), the ADC control logic performs the following operations: – CEN resets to 0 to indicate the first conversion is complete. CEN remains 0 for all subsequent conversions in continuous operation. – An interrupt request is sent to the Interrupt Controller to indicate the conversion is complete. 5. The ADC writes a new data result every 256 system clock cycles. For each completed conversion, the ADC control logic performs the following operations: – Writes the 13-bit two’s complement result to {ADCD_H[7:0], ADCD_L[7:3]}. – Sends an interrupt request to the Interrupt Controller denoting conversion complete. 6. To disable continuous conversion, clear the CONT bit in the ADC Control Register to 0. Interrupts The ADC is able to interrupt the CPU when a conversion has been completed. When the ADC is disabled, no new interrupts are asserted; however, an interrupt pending when the ADC is disabled is not cleared. Calibration and Compensation The Z8 Encore! XP® F082A Series ADC is factory calibrated for offset error and gain error, with the compensation data stored in Flash memory. Alternatively, you can perform your own calibration, storing the values into Flash themselves. Thirdly, the user code can perform a manual offset calibration during DIFFERENTIAL mode operation. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 126 Factory Calibration Devices that have been factory calibrated contain 30 bytes of calibration data in the Flash option bit space. This data consists of 3 bytes for each input mode, one for offset and two for gain correction. For a list of input modes for which calibration data exists, see Zilog Calibration Data on page 161. User Calibration If you have precision references available, its own external calibration can be performed using any input modes. This calibration data takes into account buffer offset and non-linearity, so it is recommended that this calibration be performed separately for each of the ADC input modes planned for use. Manual Offset Calibration When uncalibrated, the ADC has significant offset (see Table 135 on page 231). Subsequently, manual offset calibration capability is built into the block. When the ADC Control Register 0 sets the input mode (ANAIN[2:0]) to MANUAL OFFSET CALIBRATION mode, the differential inputs to the ADC are shorted together by an internal switch. Reading the ADC value at this point produces 0 in an ideal system. The value actually read is the ADC offset. This value can be stored in non-volatile memory (see Non-Volatile Data Storage on page 169) and accessed by user code to compensate for the input offset error. There is no provision for manual gain calibration. Software Compensation Procedure Using Factory Calibration Data The value read from the ADC high and low byte registers is uncompensated. The user mode software must apply gain and offset correction to this uncompensated value for maximum accuracy. The following equation yields the compensated value: ADC comp = ( ADC uncomp – OFFCAL ) + ( ( ADC uncomp – OFFCAL ) × GAINCAL ) ⁄ 2 16 where GAINCAL is the gain calibration value, OFFCAL is the offset calibration value and ADCuncomp is the uncompensated value read from the ADC. All values are in two’s complement format. Note: The offset compensation is performed first, followed by the gain compensation. One bit of resolution is lost because of rounding on both the offset and gain computations. As a result the ADC registers read back 13 bits: 1 sign bit, two calibration bits lost to rounding and 10 data bits. Also note that in the second term, the multiplication must be performed before the division by 216. Otherwise, the second term incorrectly evaluates to zero. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 127 Caution: Although the ADC can be used without the gain and offset compensation, it does exhibit non-unity gain. Designing the ADC with sub-unity gain reduces noise across the ADC range but requires the ADC results to be scaled by a factor of 8/7. ADC Compensation Details High efficiency assembly code that performs this compensation is available for download on www.zilog.com. The following is a bit-specific description of the ADC compensation process used by this code. The following data bit definitions are used: 0-9, a-f = bit indices in hexadecimal s = sign bit v = overflow bit - = unused Input Data MSB s b a 9 8 7 6 5 s s s s s 7 6 5 LSB 4 3 2 1 0 - - v (ADC) ADC Output Word; if v = 1, the data is invalid s 6 5 4 3 2 1 0 Offset Correction Byte 4 3 2 1 0 0 0 0 (Offset) Offset Byte shifted to align with ADC data s e d c b a 9 8 PS022825-0908 7 6 5 4 3 2 1 0 (Gain) Gain Correction Word Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 128 Compensation Steps: 1. Correct for Offset ADC MSB ADC LSB Offset MSB Offset LSB #1 MSB #1 LSB = 2. Take absolute value of the offset corrected ADC value if negative—the gain correction factor is computed assuming positive numbers, with sign restoration afterward. #2 MSB #2 LSB Also take absolute value of the gain correction word if negative. AGain MSB AGain LSB 3. Multiply by Gain Correction Word. If in DIFFERENTIAL mode, there are two gain correction values: one for positive ADC values, another for negative ADC values. Based on the sign of #2, use the appropriate Gain Correction Word. #2 MSB #2 LSB AGain MSB AGain LSB #3 #3 * = #3 #3 4. Round the result and discard the least significant two bytes (this is equivalent to dividing by 216). #3 #3 #3 #3 0x00 0x00 0x80 0x00 #4 MSB #4 LSB = 5. Determine sign of the gain correction factor using the sign bits from Step 2. If the offset corrected ADC value AND the gain correction word have the same sign, then the factor is positive and is left unchanged. If they have differing signs, then the factor is negative and must be multiplied by -1. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 129 #5 MSB #5 LSB 6. Add the gain correction factor to the original offset corrected value. #5 MSB #5 LSB #1 MSB #1 LSB #6 MSB #6 LSB + = 7. Shift the result to the right, using the sign bit determined in Step 1. This allows for the detection of computational overflow. S-> #6 MSB #6 LSB Output Data The following is the output format of the corrected ADC value. MSB s v b a 9 8 7 6 LSB 5 4 3 2 1 0 - - The overflow bit in the corrected output indicates that the computed value was greater than the maximum logical value (+1023) or less than the minimum logical value (-1024). Unlike the hardware overflow bit, this is not a simple binary Flag. For a normal sample (non-overflow), the sign and the overflow bit matches. If the sign bit and overflow bit do not match, a computational overflow has occurred. Input Buffer Stage Many applications require the measurement of an input voltage source with a high output impedance. This ADC provides a buffered input for such situations. The drawback of the buffered input is a limitation of the input range. When using unity gain buffered mode, the input signal must be prevented from coming too close to either VSS or VDD. See Table 135 on page 231 for details. This condition applies only to the input voltage level (with respect to ground) of each differential input signal. The actual differential input voltage magnitude may be less than 300 mV. The input range of the unbuffered ADC swings from VSS to VDD. Input signals smaller than 300 mV must use the unbuffered input mode. If these signals do not contain low output impedances, they might require off-chip buffering. Signals outside the allowable input range can be used without instability or device damage. Any ADC readings made outside the input range are subject to greater inaccuracy than specified. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 130 ADC Control Register Definitions ADC Control Register 0 The ADC Control Register 0 (ADCCTL0) selects the analog input channel and initiates the analog-to-digital conversion. It also selects the voltage reference configuration. Table 71. ADC Control Register 0 (ADCCTL0) BITS 7 6 5 4 FIELD CEN REFSELL REFOUT CONT RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W 3 2 1 0 ANAIN[3:0] F70H ADDR CEN—Conversion Enable 0 = Conversion is complete. Writing a 0 produces no effect. The ADC automatically clears this bit to 0 when a conversion is complete. 1 = Begin conversion. Writing a 1 to this bit starts a conversion. If a conversion is already in progress, the conversion restarts. This bit remains 1 until the conversion is complete. REFSELL—Voltage Reference Level Select Low Bit; in conjunction with the High bit (REFSELH) in ADC Control/Status Register 1, this determines the level of the internal voltage reference; the following details the effects of {REFSELH, REFSELL}; note that this reference is independent of the Comparator reference. 00= Internal Reference Disabled, reference comes from external pin 01= Internal Reference set to 1.0 V 10= Internal Reference set to 2.0 V (default) 11= Reserved REFOUT—Internal Reference Output Enable 0 = Reference buffer is disabled; Vref pin is available for GPIO or analog functions 1 = The internal ADC reference is buffered and driven out to the Vref pin Warning: When the ADC is used with an external reference ({REFSELH,REFSELL}=00), the REFOUT bit must be set to 0. CONT 0 = Single-shot conversion. ADC data is output once at completion of the 5129 system clock cycles (measurements of the internal temperature sensor take twice as long) 1 = Continuous conversion. ADC data updated every 256 system clock cycles after an initial 5129 clock conversion (measurements of the internal temperature sensor take twice as long) PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 131 ANAIN[3:0]—Analog Input Select These bits select the analog input for conversion. Not all Port pins in this list are available in all packages for the Z8 Encore! XP® F082A Series. For information on port pins available with each package style, see Pin Description on page 9. Do not enable unavailable analog inputs. Usage of these bits changes depending on the buffer mode selected in ADC Control/Status Register 1. For the reserved values, all input switches are disabled to avoid leakage or other undesirable operation. ADC samples taken with reserved bit settings are undefined. SINGLE-ENDED: 0000 = ANA0 (transimpedance amp output when enabled) 0001 = ANA1 (transimpedance amp inverting input) 0010 = ANA2 (transimpedance amp non-inverting input) 0011 = ANA3 0100 = ANA4 0101 = ANA5 0110 = ANA6 0111 = ANA7 1000 = Reserved 1001 = Reserved 1010 = Reserved 1011 = Reserved 1100 = Hold transimpedance input nodes (ANA1 and ANA2) to ground. 1101 = Reserved 1110 = Temperature Sensor. 1111 = Reserved. DIFFERENTIAL (non-inverting input and inverting input respectively): 0000 = ANA0 and ANA1 0001 = ANA2 and ANA3 0010 = ANA4 and ANA5 0011 = ANA1 and ANA0 0100 = ANA3 and ANA2 0101 = ANA5 and ANA4 0110 = ANA6 and ANA5 0111 = ANA0 and ANA2 1000 = ANA0 and ANA3 1001 = ANA0 and ANA4 1010 = ANA0 and ANA5 1011 = Reserved 1100 = Reserved 1101 = Reserved 1110 = Reserved 1111 = Manual Offset Calibration Mode PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 132 ADC Control/Status Register 1 The ADC Control/Status Register 1 (ADCCTL1) configures the input buffer stage, enables the threshold interrupts and contains the status of both threshold triggers. It is also used to select the voltage reference configuration. Table 72. ADC Control/Status Register 1 (ADCCTL1) BITS 7 6 5 4 3 2 0 FIELD REFSELH RESET 1 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W Reserved 1 BUFMODE[2:0] F71H ADDR REFSELH—Voltage Reference Level Select High Bit; in conjunction with the Low bit (REFSELL) in ADC Control Register 0, this determines the level of the internal voltage reference; the following details the effects of {REFSELH, REFSELL}; this reference is independent of the Comparator reference. 00= Internal Reference Disabled, reference comes from external pin 01= Internal Reference set to 1.0 V 10= Internal Reference set to 2.0 V (default) 11= Reserved BUFMODE[2:0] - Input Buffer Mode Select 000 = Single-ended, unbuffered input 001 = Single-ended, buffered input with unity gain 010 = Reserved 011 = Reserved 100 = Differential, unbuffered input 101 = Differential, buffered input with unity gain 110 = Reserved 111 = Reserved ADC Data High Byte Register The ADC Data High Byte (ADCD_H) register contains the upper eight bits of the ADC output. The output is an 13-bit two’s complement value. During a single-shot conversion, this value is invalid. Access to the ADC Data High Byte register is read-only. Reading the ADC Data High Byte register latches data in the ADC Low Bits register. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 133 Table 73. ADC Data High Byte Register (ADCD_H) BITS 7 6 5 4 3 2 1 0 ADCDH FIELD RESET X X X X X X X X R/W R R R R R R R R F72H ADDR X = Undefined. ADCDH—ADC Data High Byte This byte contains the upper eight bits of the ADC output. These bits are not valid during a single-shot conversion. During a continuous conversion, the most recent conversion output is held in this register. These bits are undefined after a Reset. ADC Data Low Byte Register The ADC Data Low Byte (ADCD_L) register contains the lower bits of the ADC output as well as an overflow status bit. The output is a 13-bit two’s complement value. During a single-shot conversion, this value is invalid. Access to the ADC Data Low Byte register is read-only. Reading the ADC Data High Byte register latches data in the ADC Low Bits register. Table 74. ADC Data Low Byte Register (ADCD_L) BITS 7 6 5 4 3 2 ADCDL FIELD 1 Reserved 0 OVF RESET X X X X X X X X R/W R R R R R R R R F73H ADDR X = Undefined. ADCDL—ADC Data Low Bits These bits are the least significant five bits of the 13-bits of the ADC output. These bits are undefined after a Reset. Reserved—Must be undefined. OVF—Overflow Status 0= A hardware overflow did not occur in the ADC for the current sample. 1= A hardware overflow did occur in the ADC for the current sample, therefore the current sample is invalid. PS022825-0908 Analog-to-Digital Converter Z8 Encore! XP® F082A Series Product Specification 134 Low Power Operational Amplifier Overview The LPO is a general-purpose low power operational amplifier. Each of the three ports of the amplifier is accessible from the package pins. The LPO contains only one pin configuration: ANA0 is the output/feedback node, ANA1 is the inverting input and ANA2 is the non-inverting input. Operation To use the LPO, it must be enabled in the Power Control Register 0 (PWRCTL0). The default state of the LPO is OFF. To use the LPO, the LPO bit must be cleared, turning it ON (Power Control Register 0 (PWRCTL0) on page 35). When making normal ADC measurements on ANA0 (measurements not involving the LPO output), the LPO bit must be OFF. Turning the LPO bit ON interferes with normal ADC measurements. The LPO bit enables the amplifier even in STOP mode. If the amplifier is not required Warning: in STOP mode, disable it. Failing to perform this results in STOP mode currents higher than necessary. As with other ADC measurements, any pins used for analog purposes must be configured as such in the GPIO registers (see Port A–D Alternate Function Sub-Registers on page 47). LPO output measurements are made on ANA0, as selected by the ANAIN[3:0] bits of ADC Control Register 0. It is also possible to make single-ended measurements on ANA1 and ANA2 while the amplifier is enabled, which is often useful for determining offset conditions. Differential measurements between ANA0 and ANA2 may be useful for noise cancellation purposes. If the LPO output is routed to the ADC, then the BUFFMODE[2:0] bits of ADC Control/Status Register 1 must also be configured for unity-gain buffered operation. Sampling the LPO in an unbuffered mode is not recommended. When either input is overdriven, the amplifier output saturates at the positive or negative supply voltage. No instability results. PS022825-0908 Low Power Operational Amplifier Z8 Encore! XP® F082A Series Product Specification 135 Comparator The Z8 Encore! XP® F082A Series devices feature a general purpose comparator that compares two analog input signals. These analog signals may be external stimulus from a pin (CINP and/or CINN) or internally generated signals. Both a programmable voltage reference and the temperature sensor output voltage are available internally. The output is available as an interrupt source or can be routed to an external pin. CINP Pin Temperature Sensor To COUT Pin INPSEL + REFLVL Comparator Internal Reference INNSEL To Interrupt Controller CINN Pin Figure 20. Comparator Block Diagram Operation When the positive comparator input exceeds the negative input by more than the specified hysteresis, the output is a logic HIGH. When the negative input exceeds the positive by more than the hysteresis, the output is a logic LOW. Otherwise, the comparator output retains its present value. See Table 137 on page 233 for details. The comparator may be powered down to reduce supply current. See Power Control Register 0 on page 34 for details. Caution: Because of the propagation delay of the comparator, it is not recommended to enable or reconfigure the comparator without first disabling interrupts and waiting for the comparator output to settle. Doing so can result in spurious interrupts. The following example describes how to safely enable the comparator: di ld cmp0, r0 ; load some new configuration nop PS022825-0908 Comparator Z8 Encore! XP® F082A Series Product Specification 136 nop ; wait for output to settle clr irq0 ; clear any spurious interrupts pending ei Comparator Control Register Definitions Comparator Control Register The Comparator Control Register (CMP0) configures the comparator inputs and sets the value of the internal voltage reference. Table 75. Comparator Control Register (CMP0) BITS 7 6 5 4 3 2 INPSEL INNSEL 0 0 0 1 0 1 0 0 R/W R/W R/W R/W R/W R/W R/W R/W REFLVL R/W 0 Reserved (20-/28-pin) REFLVL (8-pin) FIELD RESET 1 F90H ADDR INPSEL—Signal Select for Positive Input 0 = GPIO pin used as positive comparator input 1 = temperature sensor used as positive comparator input INNSEL—Signal Select for Negative Input 0 = internal reference disabled, GPIO pin used as negative comparator input 1 = internal reference enabled as negative comparator input REFLVL—Internal Reference Voltage Level (this reference is independent of the ADC voltage reference). Note that the 8-pin devices contain two additional LSBs for increased resolution. For 20-/28-pin devices: 0000 = 0.0 V 0001 = 0.2 V 0010 = 0.4 V 0011 = 0.6 V 0100 = 0.8 V 0101 = 1.0 V (Default) 0110 = 1.2 V 0111 = 1.4 V 1000 = 1.6 V PS022825-0908 Comparator Z8 Encore! XP® F082A Series Product Specification 137 1001 = 1.8 V 1010–1111 = Reserved For 8-pin devices: 000000 = 0.00 V 000001 = 0.05 V 000010 = 0.10 V 000011 = 0.15 V 000100 = 0.20 V 000101 = 0.25 V 000110 = 0.30 V 000111 = 0.35 V 001000 = 0.40 V 001001 = 0.45 V 001010 = 0.50 V 001011 = 0.55 V 001100 = 0.60 V 001101 = 0.65 V 001110 = 0.70 V 001111 = 0.75 V 010000 = 0.80 V 010001 = 0.85 V 010010 = 0.90 V 010011 = 0.95 V 010100 = 1.00 V (Default) 010101 = 1.05 V 010110 = 1.10 V 010111 = 1.15 V 011000 = 1.20 V 011001 = 1.25 V 011010 = 1.30 V 011011 = 1.35 V 011100 = 1.40 V 011101 = 1.45 V 011110 = 1.50 V 011111 = 1.55 V 100000 = 1.60 V 100001 = 1.65 V 100010 = 1.70 V 100011 = 1.75 V 100100 = 1.80 V PS022825-0908 Comparator Z8 Encore! XP® F082A Series Product Specification 138 PS022825-0908 Comparator Z8 Encore! XP® F082A Series Product Specification 139 Temperature Sensor The on-chip Temperature Sensor allows you to measure temperature on the die with either the on-board ADC or on-board comparator. This block is factory calibrated for in-circuit software correction. Uncalibrated accuracy is significantly worse, therefore the temperature sensor is not recommended for uncalibrated use. Temperature Sensor Operation The on-chip temperature sensor is a Proportional to Absolute Temperature (PTAT) topology. A pair of Flash option bytes contain the calibration data. The temperature sensor can be disabled by a bit in the Power Control Register 0 on page 34 to reduce power consumption. The temperature sensor can be directly read by the ADC to determine the absolute value of its output. The temperature sensor output is also available as an input to the comparator for threshold type measurement determination. The accuracy of the sensor when used with the comparator is substantially less than when measured by the ADC. If the temperature sensor is routed to the ADC, the ADC must be configured in unity-gain buffered mode (see Input Buffer Stage on page 129) The value read back from the ADC is a signed number, although it is always positive. The sensor is factory-trimmed through the ADC using the external 2.0 V reference. Unless the sensor is re-trimmed for use with a different reference, it is most accurate when used with the external 2.0 V reference. Because this sensor is an on-chip sensor it is recommended that the user account for the difference between ambient and die temperature when inferring ambient temperature conditions. During normal operation, the die undergoes heating that causes a mismatch between the ambient temperature and that measured by the sensor. For best results, the Z8 Encore! XP® device must be placed into STOP mode for sufficient time such that the die and ambient temperatures converge (this time is dependent on the thermal design of the system). The temperature sensor measurement must then be made immediately after recovery from STOP mode. The following equation defines the transfer function between the temperature sensor output voltage and the die temperature. This is needed for comparator threshold measurements. V = 0.01 × T + 0.65 where, T is the temperature in °C; V is the sensor output in volts. PS022825-0908 Temperature Sensor Z8 Encore! XP® F082A Series Product Specification 140 Assuming a compensated ADC measurement, the following equation defines the relationship between the ADC reading and the die temperature: T = ( 25 ⁄ 128 ) × ( ADC – TSCAL [ 11:2 ] ) + 30 where, T is the temperature in C; ADC is the 10-bit compensated ADC value; and TSCAL is the temperature sensor calibration value, ignoring the two least significant bits of the 12-bit value. See Temperature Sensor Calibration Data on page 164 for the location of TSCAL. Calibration The temperature sensor undergoes calibration during the manufacturing process and is maximally accurate at 30 °C. Accuracy decreases as measured temperatures move further from the calibration point. PS022825-0908 Temperature Sensor Z8 Encore! XP® F082A Series Product Specification 141 Flash Memory The products in the Z8 Encore! XP® F082A Series feature a non-volatile Flash memory of 8 KB (8192), 4 KB (4096), 2 KB (2048 bytes), or 1 KB (1024) with read/write/ erase capability. The Flash Memory can be programmed and erased in-circuit by user code or through the On-Chip Debugger. The features include: • • • User controlled read and write protect capability Sector-based write protection scheme Additional protection schemes against accidental program and erasure Architecture The Flash memory array is arranged in pages with 512 bytes per page. The 512 byte page is the minimum Flash block size that can be erased. Each page is divided into 8 rows of 64 bytes. For program or data protection, the Flash memory is also divided into sectors. In the Z8 Encore! XP F082A Series, these sectors are either 1024 bytes (in the 8 KB devices) or 512 bytes (all other memory sizes) in size. Page and sector sizes are not generally equal. The first 2 bytes of the Flash Program memory are used as Flash Option Bits. For more information about their operation, see Flash Option Bits on page 153. Table 76 describes the Flash memory configuration for each device in the Z8 Encore! XP F082A Series. Figure 21 displays the Flash memory arrangement. Table 76. Z8 Encore! XP F082A Series Flash Memory Configurations Flash Size KB (Bytes) Flash Pages Program Memory Addresses Flash Sector Size (Bytes) Z8F08xA 8 (8192) 16 0000H–1FFFH 1024 Z8F04xA 4 (4096) 8 0000H–0FFFH 512 Z8F02xA 2 (2048) 4 0000H–07FFH 512 Z8F01xA 1 (1024) 2 0000H–03FFH 512 Part Number PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 142 4 KB Flash Program Memory 8 KB Flash Program Memory Addresses (hex) 0FFF Addresses (hex) 1FFF Sector 7 Sector 7 0E00 1C00 0DFF 1BFF Sector 6 Sector 6 0C00 1800 0BFF 17FF Sector 5 Sector 5 1400 0A00 13FF 09FF 0800 1000 07FF 0FFF Sector 3 Sector 3 0600 0C00 0BFF Sector 2 05FF 0400 0800 03FF 07FF Sector 1 Sector 1 Sector 0 0000 Sector 4 Sector 4 Sector 2 2 KB Flash Program Memory Addresses (hex) 07FF Sector 3 0600 05FF Sector 2 0400 03FF Sector 1 0200 01FF Sector 0 0400 0200 03FF 01FF Sector 0 1 KB Flash Program Memory Addresses (hex) 03FF Sector 1 0200 01FF Sector 0 0000 0000 0000 Figure 21. Flash Memory Arrangement Flash Information Area The Flash information area is separate from Program Memory and is mapped to the address range FE00H to FFFFH. This area is readable but cannot be erased or overwritten. Factory trim values for the analog peripherals are stored here. Factory calibration data for the ADC is also stored here. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 143 Operation The Flash Controller programs and erases Flash memory. The Flash Controller provides the proper Flash controls and timing for Byte Programming, Page Erase, and Mass Erase of Flash memory. The Flash Controller contains several protection mechanisms to prevent accidental programming or erasure. These mechanism operate on the page, sector and full-memory levels. The Flow Chart in Figure 22 displays basic Flash Controller operation. The following subsections provide details about the various operations (Lock, Unlock, Byte Programming, Page Protect, Page Unprotect, Page Select, Page Erase, and Mass Erase) displayed in Figure 22. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 144 Reset Lock State 0 Write Page Select Register Write FCTL No 73H Yes Lock State 1 Write FCTL No Writes to Page Select Register in Lock State 1 result in a return to Lock State 0 8CH Yes Write Page Select Register No Page Select values match? Yes Yes Page in Protected Sector? No Page Unlocked Program/Erase Enabled Byte Program Write FCTL 95H Yes Page Erase No Figure 22. Flash Controller Operation Flow Chart PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 145 Flash Operation Timing Using the Flash Frequency Registers Before performing either a program or erase operation on Flash memory, you must first configure the Flash Frequency High and Low Byte registers. The Flash Frequency registers allow programming and erasing of the Flash with system clock frequencies ranging from 32 kHz (32768 Hz) through 20 MHz. The Flash Frequency High and Low Byte registers combine to form a 16-bit value, FFREQ, to control timing for Flash program and erase operations. The 16-bit binary Flash Frequency value must contain the system clock frequency (in kHz). This value is calculated using the following equation: FFREQ[15:0] System Clock Frequency (Hz) = -----------------------------------------------------------------1000 Caution: Flash programming and erasure are not supported for system clock frequencies below 32 kHz (32768 Hz) or above 20 MHz. The Flash Frequency High and Low Byte registers must be loaded with the correct value to ensure operation of the Z8 Encore! XP® F082A Series devices. Flash Code Protection Against External Access The user code contained within the Flash memory can be protected against external access by the on-chip debugger. Programming the FRP Flash Option Bit prevents reading of the user code with the On-Chip Debugger. See Flash Option Bits on page 153 and On-Chip Debugger on page 173 for more information. Flash Code Protection Against Accidental Program and Erasure The Z8 Encore! XP F082A Series provides several levels of protection against accidental program and erasure of the Flash memory contents. This protection is provided by a combination of the Flash Option bits, the register locking mechanism, the page select redundancy and the sector level protection control of the Flash Controller. Flash Code Protection Using the Flash Option Bits The FRP and FWP Flash Option Bits combine to provide three levels of Flash Program Memory protection as listed in Table 77. See Flash Option Bits on page 153 for more information. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 146 . Table 77. Flash Code Protection Using the Flash Option Bits FWP Flash Code Protection Description 0 Programming and erasing disabled for all of Flash Program Memory. In user code programming, Page Erase, and Mass Erase are all disabled. Mass Erase is available through the On-Chip Debugger. 1 Programming, Page Erase, and Mass Erase are enabled for all of Flash Program Memory. Flash Code Protection Using the Flash Controller At Reset, the Flash Controller locks to prevent accidental program or erasure of the Flash memory. To program or erase the Flash memory, first write the Page Select Register with the target page. Unlock the Flash Controller by making two consecutive writes to the Flash Control register with the values 73H and 8CH, sequentially. The Page Select Register must be rewritten with the target page. If the two Page Select writes do not match, the controller reverts to a locked state. If the two writes match, the selected page becomes active. See Figure 22 on page 144 for details. After unlocking a specific page, you can enable either Page Program or Erase. Writing the value 95H causes a Page Erase only if the active page resides in a sector that is not protected. Any other value written to the Flash Control register locks the Flash Controller. Mass Erase is not allowed in the user code but only in through the Debug Port. After unlocking a specific page, you can also write to any byte on that page. After a byte is written, the page remains unlocked, allowing for subsequent writes to other bytes on the same page. Further writes to the Flash Control Register cause the active page to revert to a locked state. Sector Based Flash Protection The final protection mechanism is implemented on a per-sector basis. The Flash memories of Z8 Encore!® devices are divided into at most 8 sectors. A sector is 1/8 of the total size of the Flash memory, unless this value is smaller than the page size, in which case the sector and page sizes are equal. The Sector Protect register controls the protection state of each Flash sector. This register is shared with the Page Select Register. It is accessed by writing 73H followed by 5EH to the Flash controller. The next write to the Flash Control Register targets the Sector Protect Register. The Sector Protect Register is initialized to 0 on reset, putting each sector into an unprotected state. When a bit in the Sector Protect Register is written to 1, the corresponding sector is no longer written or erased by the CPU. External Flash programming through PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 147 the OCD or via the Flash Controller Bypass mode are unaffected. After a bit of the Sector Protect Register has been set, it cannot be cleared except by powering down the device. Byte Programming The Flash Memory is enabled for byte programming after unlocking the Flash Controller and successfully enabling either Mass Erase or Page Erase. When the Flash Controller is unlocked and Mass Erase is successfully completed, all Program Memory locations are available for byte programming. In contrast, when the Flash Controller is unlocked and Page Erase is successfully completed, only the locations of the selected page are available for byte programming. An erased Flash byte contains all 1’s (FFH). The programming operation can only be used to change bits from 1 to 0. To change a Flash bit (or multiple bits) from 0 to 1 requires execution of either the Page Erase or Mass Erase commands. Byte Programming can be accomplished using the On-Chip Debugger's Write Memory command or eZ8 CPU execution of the LDC or LDCI instructions. Refer to the eZ8 CPU User Manual (available for download at www.zilog.com) for a description of the LDC and LDCI instructions. While the Flash Controller programs the Flash memory, the eZ8 CPU idles but the system clock and on-chip peripherals continue to operate. To exit programming mode and lock the Flash, write any value to the Flash Control register, except the Mass Erase or Page Erase commands. Caution: The byte at each address of the Flash memory cannot be programmed (any bits written to 0) more than twice before an erase cycle occurs. Doing so may result in corrupted data at the target byte. Page Erase The Flash memory can be erased one page (512 bytes) at a time. Page Erasing the Flash memory sets all bytes in that page to the value FFH. The Flash Page Select register identifies the page to be erased. Only a page residing in an unprotected sector can be erased. With the Flash Controller unlocked and the active page set, writing the value 95h to the Flash Control register initiates the Page Erase operation. While the Flash Controller executes the Page Erase operation, the eZ8 CPU idles but the system clock and on-chip peripherals continue to operate. The eZ8 CPU resumes operation after the Page Erase operation completes. If the Page Erase operation is performed using the On-Chip Debugger, poll the Flash Status register to determine when the Page Erase operation is complete. When the Page Erase is complete, the Flash Controller returns to its locked state. Mass Erase The Flash memory can also be Mass Erased using the Flash Controller, but only by using the On-Chip Debugger. Mass Erasing the Flash memory sets all bytes to the value FFH. With the Flash Controller unlocked and the Mass Erase successfully enabled, writing the PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 148 value 63H to the Flash Control register initiates the Mass Erase operation. While the Flash Controller executes the Mass Erase operation, the eZ8 CPU idles but the system clock and on-chip peripherals continue to operate. Using the On-Chip Debugger, poll the Flash Status register to determine when the Mass Erase operation is complete. When the Mass Erase is complete, the Flash Controller returns to its locked state. Flash Controller Bypass The Flash Controller can be bypassed and the control signals for the Flash memory brought out to the GPIO pins. Bypassing the Flash Controller allows faster Row Programming algorithms by controlling the Flash programming signals directly. Row programming is recommended for gang programming applications and large volume customers who do not require in-circuit initial programming of the Flash memory. Page Erase operations are also supported when the Flash Controller is bypassed. For more information on bypassing the Flash Controller, refer to Third-Party Flash Programming Support for Z8 Encore!® MCU Application Note (AN0117) available for download at www.zilog.com. Flash Controller Behavior in DEBUG Mode The following changes in behavior of the Flash Controller occur when the Flash Controller is accessed using the On-Chip Debugger: • • The Flash Write Protect option bit is ignored. • Programming operations are not limited to the page selected in the Page Select register. • • Bits in the Flash Sector Protect register can be written to one or zero. • • The Page Select register can be written when the Flash Controller is unlocked. The Flash Sector Protect register is ignored for programming and erase operations. The second write of the Page Select register to unlock the Flash Controller is not necessary. The Mass Erase command is enabled through the Flash Control register. Caution: For security reasons, the Flash controller allows only a single page to be opened for write/erase. When writing multiple Flash pages, the flash controller must go through the unlock sequence again to select another page. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 149 Flash Control Register Definitions Flash Control Register The Flash Controller must be unlocked using the Flash Control (FCTL) register before programming or erasing the Flash memory. Writing the sequence 73H 8CH, sequentially, to the Flash Control register unlocks the Flash Controller. When the Flash Controller is unlocked, the Flash memory can be enabled for Mass Erase or Page Erase by writing the appropriate enable command to the FCTL. Page Erase applies only to the active page selected in Flash Page Select register. Mass Erase is enabled only through the On-Chip Debugger. Writing an invalid value or an invalid sequence returns the Flash Controller to its locked state. The Write-only Flash Control Register shares its Register File address with the read-only Flash Status Register. Table 78. Flash Control Register (FCTL) BITS 7 6 5 4 3 2 1 0 FCMD FIELD RESET 0 0 0 0 0 0 0 0 R/W W W W W W W W W FF8H ADDR FCMD—Flash Command 73H = First unlock command. 8CH = Second unlock command. 95H = Page Erase command (must be third command in sequence to initiate Page Erase). 63H = Mass Erase command (must be third command in sequence to initiate Mass Erase). 5EH = Enable Flash Sector Protect Register Access PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 150 Flash Status Register The Flash Status (FSTAT) register indicates the current state of the Flash Controller. This register can be read at any time. The read-only Flash Status register shares its Register File address with the Write-only Flash Control register. Table 79. Flash Status Register (FSTAT) BITS 7 6 5 4 3 Reserved FIELD 2 1 0 FSTAT RESET 0 0 0 0 0 0 0 0 R/W R R R R R R R R FF8H ADDR Reserved—Must be 0. FSTAT—Flash Controller Status 000000 = Flash Controller locked 000001 = First unlock command received (73H written) 000010 = Second unlock command received (8CH written) 000011 = Flash Controller unlocked 000100 = Sector protect register selected 001xxx = Program operation in progress 010xxx = Page erase operation in progress 100xxx = Mass erase operation in progress Flash Page Select Register The Flash Page Select (FPS) register shares address space with the Flash Sector Protect Register. Unless the Flash controller is unlocked and written with 5EH, writes to this address target the Flash Page Select Register. The register is used to select one of the available Flash memory pages to be programmed or erased. Each Flash Page contains 512 bytes of Flash memory. During a Page Erase operation, all Flash memory having addresses with the most significant 7 bits given by FPS[6:0] are chosen for program/erase operation. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 151 Table 80. Flash Page Select Register (FPS) BITS 7 6 5 4 3 2 1 0 FIELD INFO_EN RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W PAGE FF9H ADDR INFO_EN—Information Area Enable 0 = Information Area us not selected. 1 = Information Area is selected. The Information Area is mapped into the Program Memory address space at addresses FE00H through FFFFH. PAGE—Page Select This 7-bit field identifies the Flash memory page for Page Erase and page unlocking. Program Memory Address[15:9] = PAGE[6:0]. For the Z8F08xx devices, the upper 3 bits must be zero. For the Z8F04xx devices, the upper 4 bits must be zero. For Z8F02xx devices, the upper 5 bits must always be 0. For the Z8F01xx devices, the upper 6 bits must always be 0. Flash Sector Protect Register The Flash Sector Protect (FPROT) register is shared with the Flash Page Select Register. When the Flash Control Register is written with 73H followed by 5EH, the next write to this address targets the Flash Sector Protect Register. In all other cases, it targets the Flash Page Select Register. This register selects one of the 8 available Flash memory sectors to be protected. The reset state of each Sector Protect bit is an unprotected state. After a sector is protected by setting its corresponding register bit, it cannot be unprotected (the register bit cannot be cleared) without powering down the device. Table 81. Flash Sector Protect Register (FPROT) BITS 7 6 5 4 3 2 1 0 FIELD SPROT7 SPROT6 SPROT5 SPROT4 SPROT3 SPROT2 SPROT1 SPROT0 RESET 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W R/W ADDR PS022825-0908 FF9H Flash Memory Z8 Encore! XP® F082A Series Product Specification 152 SPROT7-SPROT0—Sector Protection Each bit corresponds to a 512 byte Flash sector. For the Z8F08xx devices, the upper 3 bits must be zero. For the Z8F04xx devices all bits are used. For the Z8F02xx devices, the upper 4 bits are unused. For the Z8F01xx devices, the upper 6 bits are unused. Flash Frequency High and Low Byte Registers The Flash Frequency High (FFREQH) and Low Byte (FFREQL) registers combine to form a 16-bit value, FFREQ, to control timing for Flash program and erase operations. The 16-bit binary Flash Frequency value must contain the system clock frequency (in kHz) and is calculated using the following equation: FFREQ[15:0] System Clock Frequency = { FFREQH[7:0],FFREQL[7:0] } = ------------------------------------------------------1000 Caution: The Flash Frequency High and Low Byte registers must be loaded with the correct value to ensure proper operation of the device. Also, Flash programming and erasure is not supported for system clock frequencies below 20 kHz or above 20 MHz. Table 82. Flash Frequency High Byte Register (FFREQH) BITS 7 6 5 4 2 1 0 FFREQH FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W 2 1 0 RESET R/W 3 FFAH ADDR FFREQH—Flash Frequency High Byte High byte of the 16-bit Flash Frequency value. Table 83. Flash Frequency Low Byte Register (FFREQL) BITS 7 6 5 4 3 FIELD FFREQL RESET 0 R/W ADDR R/W FFBH FFREQL—Flash Frequency Low Byte Low byte of the 16-bit Flash Frequency value. PS022825-0908 Flash Memory Z8 Encore! XP® F082A Series Product Specification 153 Flash Option Bits Programmable Flash option bits allow user configuration of certain aspects of Z8 Encore! XP® F082A Series operation. The feature configuration data is stored in the Flash program memory and loaded into holding registers during Reset. The features available for control through the Flash Option Bits include: • • • • Watchdog Timer time-out response selection–interrupt or system reset • Voltage Brownout configuration-always enabled or disabled during STOP mode to reduce STOP mode power consumption • Oscillator mode selection-for high, medium, and low power crystal oscillators, or external RC oscillator • Factory trimming information for the internal precision oscillator and low voltage detection • Factory calibration values for ADC, temperature sensor, and Watchdog Timer compensation • Factory serialization and randomized lot identifier (optional) Watchdog Timer always on (enabled at Reset) The ability to prevent unwanted read access to user code in Program Memory The ability to prevent accidental programming and erasure of all or a portion of the user code in Program Memory Operation Option Bit Configuration By Reset Each time the Flash Option Bits are programmed or erased, the device must be Reset for the change to take effect. During any reset operation (System Reset, Power-On Reset, or Stop Mode Recovery), the Flash Option Bits are automatically read from the Flash Program Memory and written to Option Configuration registers. The Option Configuration registers control operation of the devices within the Z8 Encore! XP F082A Series. Option Bit control is established before the device exits Reset and the eZ8 CPU begins code execution. The Option Configuration registers are not part of the Register File and are not accessible for read or write access. PS022825-0908 Flash Option Bits Z8 Encore! XP® F082A Series Product Specification 154 Option Bit Types User Option Bits The user option bits are contained in the first two bytes of program memory. User access to these bits has been provided because these locations contain application-specific device configurations. The information contained here is lost when page 0 of the program memory is erased. Trim Option Bits The trim option bits are contained in the information page of the Flash memory. These bits are factory programmed values required to optimize the operation of onboard analog circuitry and cannot be permanently altered. Program Memory may be erased without endangering these values. It is possible to alter working values of these bits by accessing the Trim Bit Address and Data Registers, but these working values are lost after a power loss or any other reset event. There are 32 bytes of trim data. To modify one of these values the user code must first write a value between 00H and 1FH into the Trim Bit Address Register. The next write to the Trim Bit Data register changes the working value of the target trim data byte. Reading the trim data requires the user code to write a value between 00H and 1FH into the Trim Bit Address Register. The next read from the Trim Bit Data register returns the working value of the target trim data byte. Note: The trim address range is from information address 20-3F only. The remainder of the information page is not accessible through the trim bit address and data registers. Calibration Option Bits The calibration option bits are also contained in the information page. These bits are factory programmed values intended for use in software correcting the device’s analog performance. To read these values, the user code must employ the LDC instruction to access the information area of the address space as defined in See Flash Information Area on page 17. Serialization Bits As an optional feature, Zilog® is able to provide factory-programmed serialization. For serialized products, the individual devices are programmed with unique serial numbers. These serial numbers are binary values, four bytes in length. The numbers increase in size with each device, but gaps in the serial sequence may exist. These serial numbers are stored in the Flash information page (see Reading the Flash Information Page on page 155 and Serialization Data on page 165 for more details) and are unaffected by mass erasure of the device's Flash memory. PS022825-0908 Flash Option Bits Z8 Encore! XP® F082A Series Product Specification 155 Randomized Lot Identification Bits As an optional feature, Zilog is able to provide a factory-programmed random lot identifier. With this feature, all devices in a given production lot are programmed with the same random number. This random number is uniquely regenerated for each successive production lot and is not likely to be repeated. The randomized lot identifier is a 32 byte binary value, stored in the Flash information page (see Reading the Flash Information Page on page 155 and Randomized Lot Identifier on page 166 for more details) and is unaffected by mass erasure of the device's Flash memory. Reading the Flash Information Page The following code example shows how to read data from the Flash information area. ; get value at info address 60 (FE60h) ldx FPS, #%80 ; enable access to flash info page ld R0, #%FE ld R1, #%60 ldc R2, @RR0 ; R2 now contains the calibration value Flash Option Bit Control Register Definitions Trim Bit Address Register The Trim Bit Address (TRMADR) register contains the target address for an access to the trim option bits (Table 84). Table 84. Trim Bit Address Register (TRMADR) BITS 7 6 4 3 2 1 0 TRMADR - Trim Bit Address (00H to 1FH) FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 5 ADDR PS022825-0908 FF6H Flash Option Bits Z8 Encore! XP® F082A Series Product Specification 156 Trim Bit Data Register The Trim Bid Data (TRMDR) register contains the read or write data for access to the trim option bits (Table 85). Table 85. Trim Bit Data Register (TRMDR) BITS 7 6 5 4 3 2 1 0 TRMDR - Trim Bit Data FIELD 0 0 0 0 0 0 0 0 R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W FF7H ADDR Flash Option Bit Address Space The first two bytes of Flash program memory at addresses 0000H and 0001H are reserved for the user-programmable Flash option bits. Flash Program Memory Address 0000H Table 86. Flash Option Bits at Program Memory Address 0000H BITS FIELD 7 WDT_RES WDT_AO 5 4 OSC_SEL[1:0] 3 2 1 0 VBO_AO FRP Reserved FWP U U U U U U U U R/W R/W R/W R/W R/W R/W R/W R/W RESET R/W 6 ADDR Program Memory 0000H Note: U = Unchanged by Reset. R/W = Read/Write. WDT_RES—Watchdog Timer Reset 0 = Watchdog Timer time-out generates an interrupt request. Interrupts must be globally enabled for the eZ8 CPU to acknowledge the interrupt request. 1 = Watchdog Timer time-out causes a system reset. This setting is the default for unprogrammed (erased) Flash. WDT_AO—Watchdog Timer Always On 0 = Watchdog Timer is automatically enabled upon application of system power. Watchdog Timer can not be disabled. PS022825-0908 Flash Option Bits Z8 Encore! XP® F082A Series Product Specification 157 1 = Watchdog Timer is enabled upon execution of the WDT instruction. Once enabled, the Watchdog Timer can only be disabled by a Reset or Stop Mode Recovery. This setting is the default for unprogrammed (erased) Flash. OSC_SEL[1:0]—Oscillator Mode Selection 00 = On-chip oscillator configured for use with external RC networks (