AT83C5135

Features • 80C52X2 Core (6 Clocks per Instruction) – Maximum Core Frequency 48 MHz in X1 Mode, 24 MHz in X2 Mode – Dual Data Pointer – Full-duplex Enhanced UART (EUART), TxD and Rxd are 5 Volt Tolerant – Three 16-bit Timer/Counters: T0, T1 and T2 – 256 Bytes of Scratchpad RAM 8/16/32-Kbyte On-chip ROM 512 byte or 32-Kbyte EEPROM(1) On-chip Expanded RAM (ERAM): 1024 Bytes Integrated Power Monitor (POR/PFD) to Supervise Internal Power Supply USB 2.0 Full Speed Compliant Module with Interrupt on Transfer Completion (12Mbps) – Endpoint 0 for Control Transfers: 32-byte FIFO – 6 Programmable Endpoints with In or Out Directions and with Bulk, Interrupt or Isochronous Transfers • Endpoint 1, 2, 3: 32-byte FIFO • Endpoint 4, 5: 2 x 64-byte FIFO with Double Buffering (Ping-pong Mode) – Suspend/Resume Interrupts – Power-on Reset and USB Bus Reset – 48 MHz DPLL for Full-speed Bus Operation – USB Bus Disconnection on Microcontroller Request 5 Channels Programmable Counter Array (PCA) with 16-bit Counter, High-speed Output, Compare/Capture, PWM and Watchdog Timer Capabilities Programmable Hardware Watchdog Timer (One-time Enabled with Reset-out): 50 ms to 6s at 4 MHz Keyboard Interrupt Interface on Port P1 (8 Bits) TWI (Two Wire Interface) 400Kbit/s SPI Interface (Master/Slave Mode) MISO,MOSI,SCK and SS are 5 Volt Tolerant 34 I/O Pins 4 Direct-drive LED Outputs with Programmable Current Sources: 2-6-10 mA Typical 4-level Priority Interrupt System (11 sources) Idle and Power-down Modes 0 to 32 MHz On-chip Oscillator with Analog PLL for 48 MHz Synthesis Industrial Temperature Range Low Voltage Range Supply: 2.7V to 3.6V Packages: Die SO28, QFN32, MLF48, TQFP64 • • • • • 8-bit Microcontroller with Full Speed USB Device AT83C5134 AT83C5135 AT83C5136 • • • • • • • • • • • • • Notes: 1. EEPROM only available on MLF48 Rev. 7683B–USB–03/07 Description AT83C5134/35/36 are high performance ROM versions of the 80C51 single-chip 8-bit microcontrollers with full speed USB functions. AT83C5134/35 is pin compatible with AT89C5130A 16-Kbytes In-System Programmable Flash microcontrollers. This allows to use AT89C5130A for development, preproduction and flexibility, while using AT83C5134/35 for cost reduction in mass production. Similarly AT83C5136 is pin compatible with AT89C5131A 32-Kbytes Flash microcontroller. AT83C5134/35/36 features a full-speed USB module compatible with the USB specifications Version 2.0. This module integrates the USB transceivers and the Serial Interface Engine (SIE) with Digital Phase Locked Loop and 48 MHz clock recovery. USB Event detection logic (Reset and Suspend/Resume) and FIFO buffers supporting the mandatory control Endpoint (EP0) and 5 versatile Endpoints (EP1/EP2/EP3/EP4/EP5) with minimum software overhead are also part of the USB module. AT83C5134/35/36 retains the features of the Atmel 80C52 with extended ROM cpacity (8/16/32 Kbytes), 256 bytes of internal RAM, a 4-level interrupt system, two 16-bit timer/counters (T0/T1), a full duplex enhanced UART (EUART) and an on-chip oscillator. In addition, AT83C5134/35/36 has an on-chip expanded RAM of 1024 bytes (ERAM), a dual- data pointer, a 16-bit up/down Timer (T2), a Programmable Counter Array (PCA), up to 4 programmable LED current sources, a programmable hardware watchdog and a power-on reset. AT83C5134/35/36 has two software-selectable modes of reduced activity for further reduction in power consumption. In the idle mode the CPU is frozen while the timers, the serial ports and the interrupt system are still operating. In the power-down mode the RAM is saved, the peripheral clock is frozen, but the device has full wake-up capability through USB events or external interrupts. 2 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Block Diagram SDA MISO MOSI D+ VSS T2EX VDD CEX SCK SS RxD TxD ECI T2 SCL EEPROM* 1Kx8 TWI interface (2) (2) XTAL1 XTAL2 ERAM RAM 256x8 (1) (1) (1) (1) (1) (1) (1) (1) EUART + BRG 32Kx8 ROM 1Kx8 PCA Timer2 TWI SPI ALE PSEN CPU EA RD WR (2) (2) C51 CORE Timer 0 Timer 1 INT Ctrl Parallel I/O Ports & Ext. Bus Port 0 Port 1 Port 2 Port 3 Port 4 Key Watch USB Board Dog (2) (2) RST T0 T1 (2) (2) P1 P2 P0 P3 INT0 INT1 P4 KIN * EEPROM only available in MLF48 Notes: 1. Alternate function of Port 1 2. Alternate function of Port 3 3. Alternate function of Port 4 D- 3 7683B–USB–03/07 Pinout Description Pinout Figure 1. AT83C5134/35/36 64-pin VQFP Pinout P4.1/SDA P4.0/SCL P1.7/CEX4/KIN7/MOSI P1.5/CEX2/KIN5/MISO P1.6/CEX3/KIN6/SCK P1.1/T2EX/KIN1/SS P1.4/CEX1/KIN4 P1.3/CEX0/KIN3 P1.2/ECI/KIN2 P1.0/T2/KIN0 P0.0/AD0 P2.2/A10 P2.1/A9 P2.0/A8 NC 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 NC P2.3/A11 P2.4/A12 P2.5/A13 XTAL2 XTAL1 P2.6/A14 P2.7/A15 VDD AVDD NC 1 2 3 4 5 6 7 8 9 10 48 47 46 45 44 43 42 NC NC P0.1/AD1 P0.2/AD2 RST P0.3/AD3 VSS NC 41 40 39 38 37 36 35 VQFP64 NC P0.4/AD4 P3.7/RD/LED3 P0.5/AD5 P0.6/AD6 P0.7/AD7 11 AVSS 12 NC 13 P3.0/RxD NC NC 14 15 16 P3.6/WR/LED2 34 NC 33 NC 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3132 P3.3/INT1/LED0 P3.5/T1/LED1 NC NC NC VREF NC ALE PSEN P3.1/TxD P3.2/INT0 P3.4/T0 PLLF 4 AT83C5134/35/36 7683B–USB–03/07 D+ EA D- AT83C5134/35/36 Figure 2. AT83C5134/35/36 48-pin MLF Pinout P1.7/CEX4/KIN7/MOSI P1.5/CEX2/KIN5/MISO P1.6/CEX3/KIN6/SCK P1.1/T2EX/KIN1/SS P1.0/T2/KIN0 P0.1/AD1 P0.2/AD2 RST P0.3/AD3 VSS P1.4/CEX1/KIN4 P1.3/CEX0/KIN3 P4.1/SDA P2.3/A11 P2.4/A12 P2.5/A13 XTAL2 XTAL1 P2.6/A14 P2.7/A15 VDD AVDD 48 47 46 45 44 43 42 41 40 39 38 37 36 2 35 3 34 1 4 5 6 7 8 9 10 33 32 31 30 29 28 27 P1.2/ECI/KIN2 P4.0/SCL P2.2/A10 P2.1/A9 P0.0/AD0 P2.0/A8 MLF48 P0.4/AD4 P3.7/RD/LED3 P0.5/AD5 P0.6/AD6 P0.7/AD7 P3.6/WR/LED2 AVSS 11 26 P3.0/RxD 12 25 13 14 15 16 17 18 19 20 21 22 23 24 P3.3/INT1/LED0 P3.5/T1/LED1 VREF EA ALE PSEN P3.1/TxD P3.2/INT0 DP3.4/T0 PLLF Figure 3. AT83C5134/35/36 28-pin SO Pinout P1.5/CEX2/KIN5/MISO 1 P1.6/CEX3/KIN6/SCK 2 P1.7/CEX4/KIN7/MOSI 3 P4.0/SCL 4 P4.1/SDA 5 XTAL2 6 XTAL1 7 VDD 8 AVSS 9 P3.0/RxD 10 11 PLLF D- 12 D+ VREF D+ 28 27 26 25 P1.4/CEX1/KIN4 P1.3/CEX0/KIN3 P1.2/ECI/KIN2 P1.1/T2EX/KIN1/SS P1.0/T2/KIN0 RST VSS SO28 24 23 22 21 20 19 18 17 16 15 P3.7/RD/LED3 P3.6/WR/LED2 P3.5/T1/LED1 P3.4/T0 P3.3/INT1/LED0 P3.2/INT0 P3.1/TxD 13 14 5 7683B–USB–03/07 Figure 4. AT83C5134/35/36 32-pin QFN Pinout P1.7/CEX4/KIN7/MOSI P1.5/CEX2/KIN5/MISO P1.6/CEX3/KIN6/SCK P1.1/T2EX/KIN1/SS 24 23 22 21 20 19 18 17 9 10 11 12 13 14 15 16 D+ VREF UVSS DP3.2/INT0 P3.1/TxD P3.3/INT1/LED0 P3.4/T0 P1.4/CEX1/KIN4 P1.3/CEX0/KIN3 32 31 30 29 28 27 26 25 P4.1/SDA XTAL2 XTAL1 VDD AVDD AVSS P3.0/RxD PLLF 1 2 3 4 5 6 7 8 P1.0/T2/KIN0 RST NC VSS VSS QFN32 P1.2/ECI/KIN2 P4.0/SCL P3.7/RD/LED3 P3.6/WR/LED2 P3.5/T1/LED1 Note : The metal plate can be connected to Vss 6 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Signals All the AT83C5134/35/36 signals are detailed by functionality on Table 1 through Table 12. Table 1. Keypad Interface Signal Description Signal Name Type Description Keypad Input Lines Holding one of these pins high or low for 24 oscillator periods triggers a keypad interrupt if enabled. Held line is reported in the KBCON register. Alternate Function KIN[7:0) I P1[7:0] Table 2. Programmable Counter Array Signal Description Signal Name ECI Type I Description External Clock Input Capture External Input CEX[4:0] I/O Compare External Output Alternate Function P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 Table 3. Serial I/O Signal Description Signal Name RxD Type I Description Serial Input The serial input for Extended UART. This I/O is 5 Volt Tolerant. Serial Output The serial output for Extended UART. This I/O is 5 Volt Tolerant. Alternate Function P3.0 TxD O P3.1 Table 4. Timer 0, Timer 1 and Timer 2 Signal Description Signal Name Type Description Timer 0 Gate Input INT0 serves as external run control for timer 0, when selected by GATE0 bit in TCON register. INT0 I External Interrupt 0 INT0 input set IE0 in the TCON register. If bit IT0 in this register is set, bits IE0 are set by a falling edge on INT0. If bit IT0 is cleared, bits IE0 is set by a low level on INT0. Timer 1 Gate Input INT1 serves as external run control for Timer 1, when selected by GATE1 bit in TCON register. INT1 I External Interrupt 1 INT1 input set IE1 in the TCON register. If bit IT1 in this register is set, bits IE1 are set by a falling edge on INT1. If bit IT1 is cleared, bits IE1 is set by a low level on INT1. P3.3 P3.2 Alternate Function 7 7683B–USB–03/07 Table 4. Timer 0, Timer 1 and Timer 2 Signal Description (Continued) Signal Name Type Description Timer Counter 0 External Clock Input When Timer 0 operates as a counter, a falling edge on the T0 pin increments the count. Timer/Counter 1 External Clock Input When Timer 1 operates as a counter, a falling edge on the T1 pin increments the count. Timer/Counter 2 External Clock Input Timer/Counter 2 Clock Output Timer/Counter 2 Reload/Capture/Direction Control Input Alternate Function T0 I P3.4 T1 I P3.5 T2 T2EX I O I P1.0 P1.1 Table 5. LED Signal Description Signal Name Type Description Direct Drive LED Output These pins can be directly connected to the Cathode of standard LEDs without external current limiting resistors. The typical current of each output can be programmed by software to 2, 6 or 10 mA. Several outputs can be connected together to get higher drive capabilities. Alternate Function P3.3 P3.5 P3.6 P3.7 LED[3:0] O Table 6. TWI Signal Description Signal Name Type Description SCL: TWI Serial Clock SCL output the serial clock to slave peripherals. SCL input the serial clock from master. SDA: TWI Serial Data SCL is the bidirectional TWI data line. Alternate Function SCL I/O P4.0 SDA I/O P4.1 Table 7. SPI Signal Description Signal Name SS Type I/O Description SS: SPI Slave Select . This I/O is 5 Volt tolerant MISO: SPI Master Input Slave Output line MISO I/O When SPI is in master mode, MISO receives data from the slave peripheral. When SPI is in slave mode, MISO outputs data to the master controller. This I/O is 5 Volt tolerant SCK: SPI Serial Clock SCK I/O SCK outputs clock to the slave peripheral or receive clock from the master. This I/O is 5 Volt tolerant. MOSI: SPI Master Output Slave Input line MOSI I/O When SPI is in master mode, MOSI outputs data to the slave peripheral. When SPI is in slave mode, MOSI receives data from the master controller. This I/O is 5 Volt tolerant. P1.7 P1.6 P1.5 Alternate Function P1.1 8 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 8. Ports Signal Description Signal Name Type Description Port 0 P0 is an 8-bit open-drain bidirectional I/O port. Port 0 pins that have 1s written to them float and can be used as high impedance inputs. To avoid any parasitic current consumption, Floating P0 inputs must be pulled to VDD or VSS. Alternate Function P0[7:0] I/O AD[7:0] P1[7:0] I/O Port 1 P1 is an 8-bit bidirectional I/O port with internal pull-ups. KIN[7:0] T2 T2EX ECI CEX[4:0] P2[7:0] I/O Port 2 P2 is an 8-bit bidirectional I/O port with internal pull-ups. A[15:8] LED[3:0] RxD TxD P3[7:0] I/O Port 3 P3 is an 8-bit bidirectional I/O port with internal pull-ups. INT0 INT1 T0 T1 WR RD SCL SDA P4[1:0] I/O Port 4 P4 is an 2-bit open port. Table 9. Clock Signal Description Signal Name Type Description Input to the on-chip inverting oscillator amplifier To use the internal oscillator, a crystal/resonator circuit is connected to this pin. If an external oscillator is used, its output is connected to this pin. Output of the on-chip inverting oscillator amplifier To use the internal oscillator, a crystal/resonator circuit is connected to this pin. If an external oscillator is used, leave XTAL2 unconnected. PLL Low Pass Filter input Receives the RC network of the PLL low pass filter (See Figure 5 on page 12 ). Alternate Function XTAL1 I - XTAL2 O - PLLF I - 9 7683B–USB–03/07 Table 10. USB Signal Description Signal Name D+ Type I/O Description USB Data + signal Set to high level under reset. USB Data - signal Set to low level under reset. USB Reference Voltage Connect this pin to D+ using a 1.5 kΩ resistor to use the Detach function. Alternate Function - D- I/O - VREF O - Table 11. System Signal Description Signal Name AD[7:0] Type I/O Description Multiplexed Address/Data LSB for external access Data LSB for Slave port access (used for 8-bit and 16-bit modes) Address Bus MSB for external access Data MSB for Slave port access (used for 16-bit mode only) Read Signal Read signal asserted during external data memory read operation. Control input for slave port read access cycles. Write Signal Write signal asserted during external data memory write operation. Control input for slave write access cycles. Reset Holding this pin low for 64 oscillator periods while the oscillator is running resets the device. The Port pins are driven to their reset conditions when a voltage lower than VIL is applied, whether or not the oscillator is running. This pin has an internal pull-up resistor which allows the device to be reset by connecting a capacitor between this pin and VSS. Asserting RST when the chip is in Idle mode or Power-down mode returns the chip to normal operation. This pin is set to 0 for at least 12 oscillator periods when an internal reset occurs (hardware watchdog or Power monitor). Address Latch Enable Output The falling edge of ALE strobes the address into external latch. This signal is active only when reading or writing external memory using MOVX instructions. Program Strobe Enable / Hardware conditions Input for ISP PSEN O Used as input under reset to detect external hardware conditions of ISP mode External Access Enable EA I This pin must be held low to force the device to fetch code from external program memory starting at address 0000h. It is latched during reset and cannot be dynamically changed during operation. Alternate Function P0[7:0] A[15:8] I/O P2[7:0] RD I/O P3.7 WR I/O P3.6 RST I/O - ALE O - 10 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 12. Power Signal Description Signal Name AVSS Type GND Description Alternate Ground AVSS is used to supply the on-chip PLL and the USB PAD. Alternate Supply Voltage AVDD is used to supply the on-chip PLL and the USB PAD. Digital Ground VSS is used to supply the buffer ring and the digital core. Digital Supply Voltage VDD is used to supply the buffer ring on all versions of the device. It is also used to power the on-chip voltage regulator of the Standard versions or the digital core of the Low Power versions. USB pull-up Controlled Output VREF O VREF is used to control the USB D+ 1.5 kΩ pull up. The Vref output is in high impedance when the bit DETACH is set in the USBCON register. Alternate Function - AVDD PWR - VSS GND - VDD PWR - 11 7683B–USB–03/07 Typical Application Recommended External components All the external components described in the figure below must be implemented as close as possible from the microcontroller package. The following figure represents the typical wiring schematic. Figure 5. Typical Application VDD 100nF VSS 4.7µF VSS VSS 100nF VDD AVDD USB VBUS D+ DGND VSS 1.5K VRef AT83C5134/35/3 27R 27R D+ XTAL1 DQ 22pF 22pF XTAL2 VSS PLLF 150pF 560 820pF VSS VSS 12 AT83C5134/35/36 7683B–USB–03/07 VSS VSS AVSS AT83C5134/35/36 PCB Recommandations Figure 6. USB Pads Components must be close to the microcontroller Wires must be routed in Parallel and must be as short as possible VRef D+ DUSB Connector If possible, isolate D+ and D- signals from other signals with ground wires Note: No sharp angle in above drawing. Figure 7. USB PLL AVss PLLF Components must be C1 microcontroller Isolate filter components with a ground wire R C2 close to the 13 7683B–USB–03/07 Clock Controller Introduction The AT83C5134/35/36 clock controller is based on an on-chip oscillator feeding an onchip Phase Lock Loop (PLL). All the internal clocks to the peripherals and CPU core are generated by this controller. The AT83C5134/35/36 X1 and X2 pins are the input and the output of a single-stage onchip inverter (see Figure 8) that can be configured with off-chip components as a Pierce oscillator (see Figure 9). Value of capacitors and crystal characteristics are detailed in the section “DC Characteristics”. The X1 pin can also be used as input for an external 48 MHz clock. The clock controller outputs three different clocks as shown in Figure 8: • • • a clock for the CPU core a clock for the peripherals which is used to generate the Timers, PCA, WD, and Port sampling clocks a clock for the USB controller These clocks are enabled or disabled depending on the power reduction mode as detailed in Section “Power Management”, page 138. Figure 8. Oscillator Block Diagram ÷2 0 1 Peripheral Clock CPU Core Clock X2 CKCON.0 IDL PCON.0 X1 PLL 0 1 USB Clock X2 EXT48 PLLCON.2 PD PCON.1 Oscillator Two clock sources are available for CPU: • • Crystal oscillator on X1 and X2 pins: Up to 32 MHz External 48 MHz clock on X1 pin In order to optimize the power consumption, the oscillator inverter is inactive when the PLL output is not selected for the USB device. 14 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 9. Crystal Connection X1 C1 Q C2 VSS X2 PLL PLL Description The AT83C5134/35/36 PLL is used to generate internal high frequency clock (the USB Clock) synchronized with an external low-frequency (the Peripheral Clock). The PLL clock is used to generate the USB interface clock. Figure 10 shows the internal structure of the PLL. The PFLD block is the Phase Frequency Comparator and Lock Detector. This block makes the comparison between the reference clock coming from the N divider and the reverse clock coming from the R divider and generates some pulses on the Up or Down signal depending on the edge position of the reverse clock. The PLLEN bit in PLLCON register is used to enable the clock generation. When the PLL is locked, the bit PLOCK in PLLCON register (see Figure 10) is set. The CHP block is the Charge Pump that generates the voltage reference for the VCO by injecting or extracting charges from the external filter connected on PLLF pin (see Figure 11). Value of the filter components are detailed in the Section “DC Characteristics”. The VCO block is the Voltage Controlled Oscillator controlled by the voltage VREF produced by the charge pump. It generates a square wave signal: the PLL clock. Figure 10. PLL Block Diagram and Symbol PLLCON.1 PLLF PLLEN N divider OSC CLOCK N3:0 Up PFLD Down PLOCK PLLCON.0 CHP Vref VCO USB Clock R divider R3:0 USB CLOCK OSC clk × ( R + 1 ) USBclk = ---------------------------------------------N+1 Figure 11. PLL Filter Connection PLLF R C1 VSS VSS USB Clock Symbol C2 The typical values are: R = 560 Ω, C1 = 820 pf, C2 = 150 pF. 15 7683B–USB–03/07 PLL Programming The PLL is programmed using the flow shown in Figure 12. As soon as clock generation is enabled user must wait until the lock indicator is set to ensure the clock output is stable. Figure 12. PLL Programming Flow PLL Programming Configure Dividers N3:0 = xxxxb R3:0 = xxxxb Enable PLL PLLEN = 1 PLL Locked? LOCK = 1? Divider Values To generate a 48 MHz clock using the PLL, the divider values have to be configured following the oscillator frequency. The typical divider values are shown in Table 13. Table 13. Typical Divider Values Oscillator Frequency 3 MHz 6 MHz 8 MHz 12 MHz 16 MHz 18 MHz 20 MHz 24 MHz 32 MHz 40 MHz R+1 16 8 6 4 3 8 12 2 3 12 N+1 1 1 1 1 1 3 5 1 2 10 PLLDIV F0h 70h 50h 30h 20h 72h B4h 10h 21h B9h 16 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Registers Table 14. CKCON0 (S:8Fh) Clock Control Register 0 7 TWIX2 6 WDX2 5 PCAX2 4 SIX2 3 T2X2 2 T1X2 1 T0X2 0 X2 Bit Bit Number Mnemonic Description TWI Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Watchdog Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Programmable Counter Array Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Enhanced UART Clock (Mode 0 and 2) This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Timer2 Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Timer1 Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. Timer0 Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. System Clock Control bit Clear to select 12 clock periods per machine cycle (STD mode, FCPU = FPER = FOSC/2). Set to select 6 clock periods per machine cycle (X2 mode, FCPU = FPER = FOSC). 7 TWIX2 6 WDX2 5 PCAX2 4 SIX2 3 T2X2 2 T1X2 1 T0X2 0 X2 Reset Value = 0000 0000b 17 7683B–USB–03/07 Table 15. CKCON1 (S:AFh) Clock Control Register 1 7 6 5 4 3 2 1 0 SPIX2 Bit Bit Number Mnemonic Description 7-1 Reserved The value read from this bit is always 0. Do not set this bit. SPI Clock This control bit is validated when the CPU clock X2 is set. When X2 is low, this bit has no effect. Clear to select 6 clock periods per peripheral clock cycle. Set to select 12 clock periods per peripheral clock cycle. 0 SPIX2 Reset Value = 0000 0000b Table 16. PLLCON (S:A3h) PLL Control Register 7 6 5 4 3 2 EXT48 1 PLLEN 0 PLOCK Bit Bit Number Mnemonic Description 7-3 Reserved The value read from this bit is always 0. Do not set this bit. External 48 MHz Enable Bit Set this bit to bypass the PLL and disable the crystal oscillator. Clear this bit to select the PLL output as USB clock and to enable the crystal oscillator. PLL Enable Bit Set to enable the PLL. Clear to disable the PLL. PLL Lock Indicator Set by hardware when PLL is locked. Clear by hardware when PLL is unlocked. 2 EXT48 1 PLLEN 0 PLOCK Reset Value = 0000 0000b Table 17. PLLDIV (S:A4h) PLL Divider Register 7 R3 6 R2 5 R1 4 R0 3 N3 2 N2 1 N1 0 N0 Bit Bit Number Mnemonic Description 7-4 3-0 R3:0 N3:0 PLL R Divider Bits PLL N Divider Bits Reset Value = 0000 0000 18 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 SFR Mapping The Special Function Registers (SFRs) of the AT83C5134/35/36 fall into the following categories: • • • • • • • • • • • • • • • • C51 core registers: ACC, B, DPH, DPL, PSW, SP I/O port registers: P0, P1, P2, P3, P4 Timer registers: T2CON, T2MOD, TCON, TH0, TH1, TH2, TMOD, TL0, TL1, TL2, RCAP2L, RCAP2H Serial I/O port registers: SADDR, SADEN, SBUF, SCON PCA (Programmable Counter Array) registers: CCON, CMOD, CCAPMx, CL, CH, CCAPxH, CCAPxL (x: 0 to 4) Power and clock control registers: PCON Hardware Watchdog Timer registers: WDTRST, WDTPRG Interrupt system registers: IEN0, IPL0, IPH0, IEN1, IPL1, IPH1 Keyboard Interface registers: KBE, KBF, KBLS LED register: LEDCON Two Wire Interface (TWI) registers: SSCON, SSCS, SSDAT, SSADR Serial Port Interface (SPI) registers: SPCON, SPSTA, SPDAT USB registers: Uxxx (17 registers) PLL registers: PLLCON, PLLDIV BRG (Baud Rate Generator) registers: BRL, BDRCON Others: AUXR, AUXR1, CKCON0, CKCON1 19 7683B–USB–03/07 The table below shows all SFRs with their address and their reset value. Table 18. SFR Descriptions Bit Addressable 0/8 F8h UEPINT 0000 0000 B 0000 0000 1/9 CH 0000 0000 LEDCON 0000 0000 CL 0000 0000 ACC 0000 0000 CCON 00X0 0000 PSW 0000 0000 T2CON 0000 0000 P4 XXXX 1111 IPL0 X000 000 P3 1111 1111 IEN0 0000 0000 P2 1111 1111 SCON 0000 0000 P1 1111 1111 TCON 0000 0000 P0 1111 1111 0/8 TMOD 0000 0000 SP 0000 0111 1/9 TL0 0000 0000 DPL 0000 0000 2/A SBUF XXXX XXXX SADEN 0000 0000 IEN1 X0XX X000 SADDR 0000 0000 AUXR1 XXXX X0X0 BRL 0000 0000 PLLCON XXXX XX00 BDRCON XXX0 0000 SSCON 0000 0000 TL1 0000 0000 DPH 0000 0000 3/B 4/C 5/D 6/E PLLDIV 0000 0000 KBLS 0000 0000 SSCS 1111 1000 TH0 0000 0000 KBE 0000 0000 SSDAT 1111 1111 TH1 0000 0000 WDTRST XXXX XXXX KBF 0000 0000 SSADR 1111 1110 AUXR XX0X 0000 CKCON0 0000 0000 PCON 00X1 0000 7/F T2MOD XXXX XX00 RCAP2L 0000 0000 UEPIEN 0000 0000 UFNUML 0000 0000 IPL1 X0XX X000 RCAP2H 0000 0000 SPCON 0001 0100 UFNUMH 0000 0000 IPH1 X0XX X000 CMOD 00XX X000 CCAP0L XXXX XXXX UBYCTLX 0000 0000 CCAPM0 X000 0000 CCAP1L XXXX XXXX UBYCTHX 0000 0000 CCAPM1 X000 0000 CCAPM2 X000 0000 UEPCONX 1000 0000 TL2 0000 0000 SPSTA 0000 0000 USBCON 0000 0000 CCAPM3 X000 0000 UEPRST 0000 0000 TH2 0000 0000 SPDAT XXXX XXXX USBINT 0000 0000 UEPSTAX 0000 0000 USBADDR 1000 0000 USBIEN 0000 0000 IPH0 X000 0000 CKCON1 0000 0000 WDTPRG XXXX X000 UEPDATX 0000 0000 UEPNUM 0000 0000 CCAPM4 X000 0000 CCAP2L XXXX XXXX CCAP3L XXXX XXXX CCAP4L XXXX XXXX 2/A CCAP0H XXXX XXXX 3/B CCAP1H XXXX XXXX Non-Bit Addressable 4/C CCAP2H XXXX XXXX 5/D CCAP3H XXXX XXXX 6/E CCAP4H XXXX XXXX 7/F FFh F0h F7h E8h EFh E0h E7h D8h DFh D0h D7h C8h CFh C0h C7h B8h BFh B0h B7h A8h AFh A0h A7h 98h 9Fh 90h 97h 88h 8Fh 80h 87h Note: 1. FCON access is reserved for the Flash API and ISP software. Reserved 20 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 The Special Function Registers (SFRs) of the AT89C5131 fall into the following categories: Table 19. C51 Core SFRs Mnemonic ACC B PSW Add E0h F0h D0h Name Accumulator B Register Program Status Word Stack Pointer LSB of SPX Data Pointer Low byte LSB of DPTR Data Pointer High byte MSB of DPTR 7 6 5 4 3 2 1 0 SP 81h DPL 82h DPH 83h Table 20. I/O Port SFRs Mnemonic P0 P1 P2 P3 P4 Add 80h 90h A0h B0h C0h Name Port 0 Port 1 Port 2 Port 3 Port 4 (2bits) 7 6 5 4 3 2 1 0 21 7683B–USB–03/07 Table 21. Timer SFR’s Mnemonic TH0 TL0 TH1 TL1 TH2 TL2 TCON Add 8Ch 8Ah 8Dh 8Bh CDh CCh 88h Name Timer/Counter 0 High byte Timer/Counter 0 Low byte Timer/Counter 1 High byte Timer/Counter 1 Low byte Timer/Counter 2 High byte Timer/Counter 2 Low byte Timer/Counter 0 and 1 control Timer/Counter 0 and 1 Modes Timer/Counter 2 control Timer/Counter 2 Mode Timer/Counter 2 Reload/Capture High byte Timer/Counter 2 Reload/Capture Low byte WatchDog Timer Reset WatchDog Timer Program S2 S1 S0 TF1 TR1 TF0 TR0 IE1 IT1 IE0 IT0 7 6 5 4 3 2 1 0 TMOD T2CON T2MOD RCAP2H 89h C8h C9h CBh GATE1 TF2 C/T1# EXF2 M11 RCLK M01 TCLK GATE0 EXEN2 C/T0# TR2 M10 C/T2# T2OE M00 CP/RL2# DCEN RCAP2L WDTRST WDTPRG CAh A6h A7h Table 22. Serial I/O Port SFR’s Mnemonic SCON SBUF SADEN SADDR Add 98h 99h B9h A9h Name Serial Control Serial Data Buffer Slave Address Mask Slave Address 7 FE/SM0 6 SM1 5 SM2 4 REN 3 TB8 2 RB8 1 TI 0 RI Table 23. Baud Rate Generator SFR’s Mnemonic BRL BDRCON Add 9Ah 9Bh Name Baud Rate Reload Baud Rate Control BRR TBCK RBCK SPD SRC 7 6 5 4 3 2 1 0 22 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 24. PCA SFR’s Mnemonic Add CCON CMOD CL CH CCAPM0 CCAPM1 CCAPM2 CCAPM3 CCAPM4 CCAP0H CCAP1H CCAP2H CCAP3H CCAP4H CCAP0L CCAP1L CCAP2L CCAP3L CCAP4L D8h D9h E9h F9h DAh DBh DCh DDh DEh FAh FBh FCh FDh FEh EAh EBh ECh EDh EEh Name PCA Timer/Counter Control PCA Timer/Counter Mode PCA Timer/Counter Low byte PCA Timer/Counter High byte PCA Timer/Counter Mode 0 PCA Timer/Counter Mode 1 PCA Timer/Counter Mode 2 PCA Timer/Counter Mode 3 PCA Timer/Counter Mode 4 PCA Compare Capture Module 0 H PCA Compare Capture Module 1 H PCA Compare Capture Module 2 H PCA Compare Capture Module 3 H PCA Compare Capture Module 4 H PCA Compare Capture Module 0 L PCA Compare Capture Module 1 L PCA Compare Capture Module 2 L PCA Compare Capture Module 3 L PCA Compare Capture Module 4 L 7 CF CIDL 6 CR WDTE 5 4 CCF4 3 CCF3 2 CCF2 CPS1 1 CCF1 CPS0 0 CCF0 ECF ECOM0 ECOM1 ECOM2 ECOM3 ECOM4 CCAP0H7 CCAP1H7 CCAP2H7 CCAP3H7 CCAP4H7 CCAP0L7 CCAP1L7 CCAP2L7 CCAP3L7 CCAP4L7 CCAP0H6 CCAP1H6 CCAP2H6 CCAP3H6 CCAP4H6 CCAP0L6 CCAP1L6 CCAP2L6 CCAP3L6 CCAP4L6 CAPP0 CAPP1 CAPP2 CAPP3 CAPP4 CCAP0H5 CCAP1H5 CCAP2H5 CCAP3H5 CCAP4H5 CCAP0L5 CCAP1L5 CCAP2L5 CCAP3L5 CCAP4L5 CAPN0 CAPN1 CAPN2 CAPN3 CAPN4 CCAP0H4 CCAP1H4 CCAP2H4 CCAP3H4 CCAP4H4 CCAP0L4 CCAP1L4 CCAP2L4 CCAP3L4 CCAP4L4 MAT0 MAT1 MAT2 MAT3 MAT4 CCAP0H3 CCAP1H3 CCAP2H3 CCAP3H3 CCAP4H3 CCAP0L3 CCAP1L3 CCAP2L3 CCAP3L3 CCAP4L3 TOG0 TOG1 TOG2 TOG3 TOG4 CCAP0H2 CCAP1H2 CCAP2H2 CCAP3H2 CCAP4H2 CCAP0L2 CCAP1L2 CCAP2L2 CCAP3L2 CCAP4L2 PWM0 PWM1 PWM2 PWM3 PWM4 CCAP0H1 CCAP1H1 CCAP2H1 CCAP3H1 CCAP4H1 CCAP0L1 CCAP1L1 CCAP2L1 CCAP3L1 CCAP4L1 ECCF0 ECCF1 ECCF2 ECCF3 ECCF4 CCAP0H0 CCAP1H0 CCAP2H0 CCAP3H0 CCAP4H0 CCAP0L0 CCAP1L0 CCAP2L0 CCAP3L0 CCAP4L0 Table 25. Interrupt SFR’s Mnemonic Add IEN0 IEN1 IPL0 IPH0 IPL1 IPH1 A8h B1h B8h B7h B2h B3h Name Interrupt Enable Control 0 Interrupt Enable Control 1 Interrupt Priority Control Low 0 Interrupt Priority Control High 0 Interrupt Priority Control Low 1 Interrupt Priority Control High 1 7 EA 6 EC EUSB PPCL PPCH PUSBL PUSBH PT2L PT2H PSL PSH PT1L PT1H 5 ET2 4 ES 3 ET1 2 EX1 ESPI PX1L PX1H PSPIL PSPIH 1 ET0 ETWI PT0L PT0H PTWIL PTWIH 0 EX0 EKB PX0L PX0H PKBL PKBH Table 26. PLL SFRs Mnemonic PLLCON PLLDIV Add A3h A4h Name PLL Control PLL Divider R3 R2 R1 R0 N3 7 6 5 4 3 2 EXT48 N2 1 PLLEN N1 0 PLOCK N0 23 7683B–USB–03/07 Table 27. Keyboard SFRs Mnemonic KBF Add 9Eh Name Keyboard Flag Register Keyboard Input Enable Register Keyboard Level Selector Register 7 KBF7 6 KBF6 5 KBF5 4 KBF4 3 KBF3 2 KBF2 1 KBF1 0 KBF0 KBE 9Dh KBE7 KBE6 KBE5 KBE4 KBE3 KBE2 KBE1 KBE0 KBLS 9Ch KBLS7 KBLS6 KBLS5 KBLS4 KBLS3 KBLS2 KBLS1 KBLS0 Table 28. TWI SFRs Mnemonic SSCON Add 93h Name Synchronous Serial Control Synchronous Serial Control-Status Synchronous Serial Data Synchronous Serial Address 7 CR2 6 SSIE 5 STA 4 STO 3 SI 2 AA 1 CR1 0 CR0 SSCS 94h SC4 SC3 SC2 SC1 SC0 - - - SSDAT 95h SD7 SD6 SD5 SD4 SD3 SD2 SD1 SD0 SSADR 96h A7 A6 A5 A4 A3 A2 A1 A0 Table 29. SPI SFRs Mnemonic SPCON Add C3h Name Serial Peripheral Control Serial Peripheral Status-Control Serial Peripheral Data 7 SPR2 6 SPEN 5 SSDIS 4 MSTR 3 CPOL 2 CPHA 1 SPR1 0 SPR0 SPSTA SPDAT C4h C5h SPIF R7 WCOL R6 SSERR R5 MODF R4 R3 R2 R1 R0 Table 30. USB SFR’s Mnemonic USBCON USBADDR USBINT USBIEN UEPNUM UEPCONX UEPSTAX UEPRST UEPINT Add BCh C6h BDh BEh C7h D4h CEh D5h F8h Name USB Global Control USB Address USB Global Interrupt USB Global Interrupt Enable USB Endpoint Number USB Endpoint X Control USB Endpoint X Status USB Endpoint Reset USB Endpoint Interrupt 7 USBE FEN EPEN DIR - 6 SUSPCLK UADD6 RXOUTB1 - 5 SDRMWUP UADD5 WUPCPU EWUPCPU STALLRQ EP5RST EP5INT 4 DETACH UADD4 EORINT EEORINT TXRDY EP4RST EP4INT 3 UPRSM UADD3 SOFINT ESOFINT EPNUM3 DTGL STLCRC EP3RST EP3INT 2 RMWUPE UADD2 EPNUM2 EPDIR RXSETUP EP2RST EP2INT 1 CONFG UADD1 EPNUM1 EPTYPE1 RXOUTB0 EP1RST EP1INT 0 FADDEN UADD0 SPINT ESPINT EPNUM0 EPTYPE0 TXCMP EP0RST EP0INT 24 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 30. USB SFR’s Mnemonic UEPIEN UEPDATX UBYCTLX Add C2h CFh E2h Name USB Endpoint Interrupt Enable USB Endpoint X FIFO Data USB Byte Counter Low (EP X) USB Byte Counter High (EP X) USB Frame Number Low USB Frame Number High 7 FDAT7 BYCT7 6 FDAT6 BYCT6 5 EP5INTE FDAT5 BYCT5 4 EP4INTE FDAT4 BYCT4 3 EP3INTE FDAT3 BYCT3 2 EP2INTE FDAT2 BYCT2 1 EP1INTE FDAT1 BYCT1 0 EP0INTE FDAT0 BYCT0 UBYCTHX UFNUML UFNUMH E3h BAh BBh FNUM7 - FNUM6 - FNUM5 CRCOK FNUM4 CRCERR FNUM3 - BYCT10 FNUM2 FNUM10 BYCT9 FNUM1 FNUM9 BYCT8 FNUM0 FNUM8 Table 31. Other SFR’s Mnemonic PCON AUXR AUXR1 CKCON0 CKCON1 LEDCON Add 87h 8Eh A2h 8Fh AFh F1h Name Power Control Auxiliary Register 0 Auxiliary Register 1 Clock Control 0 Clock Control 1 LED Control 7 SMOD1 DPU TWIX2 LED3 6 SMOD0 WDX2 5 M0 ENBOOT PCAX2 LED2 4 POF SIX2 3 GF1 XRS1 GF3 T2X2 LED1 2 GF0 XRS2 T1X2 1 PD EXTRAM T0X2 LED0 0 IDL A0 DPS X2 SPIX2 25 7683B–USB–03/07 Program/Code Memory The AT83C5134/35/36 implement 16 or 32 Kbytes of on-chip program/code memory. Figure 13 shows the split of internal and external program/code memory spaces depending on the product. Figure 13. Program/Code Memory Organization FFFFh FFFFh 32 Kbytes External Code 48 Kbytes External Code 8000h 7FFFh 4000h 3FFFh 16 Kbytes ROM 0000h AT83C5135 0000h 32 Kbytes ROM AT83C5136 Note: If the program executes exclusively from on-chip code memory (not from external memory), beware of executing code from the upper byte of on-chip memory and thereby disrupting I/O Ports 0 and 2 due to external prefetch. Fetching code constant from this location does not affect Ports 0 and 2. External Code Memory Access Memory Interface The external memory interface comprises the external bus (Port 0 and Port 2) as well as the bus control signals (PSEN, and ALE). Figure 14 shows the structure of the external address bus. P0 carries address A7:0 while P2 carries address A15:8. Data D7:0 is multiplexed with A7:0 on P0. Table 32 describes the external memory interface signals. Figure 14. External Code Memory Interface Structure AT89C5131 P2 ALE P0 AD7:0 Latch A7:0 A7:0 D7:0 PSEN OE A15:8 Flash EPROM A15:8 26 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 32. External Data Memory Interface Signals Signal Name A15:8 Type O Description Address Lines Upper address lines for the external bus. Address/Data Lines Multiplexed lower address lines and data for the external memory. Address Latch Enable ALE signals indicates that valid address information are available on lines AD7:0. Program Store Enable Output This signal is active low during external code fetch or external code read (MOVC instruction). Alternate Function P2.7:0 AD7:0 I/O P0.7:0 ALE O - PSEN O - External Bus Cycles This section describes the bus cycles the AT83C5134/35/36 executes to fetch code (see Figure 15) in the external program/code memory. External memory cycle takes 6 CPU clock periods. This is equivalent to 12 oscillator clock periods in standard mode or 6 oscillator clock periods in X2 mode. For further information on X2 mode (see the clock Section). For simplicity, the accompanying figure depicts the bus cycle waveforms in idealized form and do not provide precise timing information. Figure 15. External Code Fetch Waveforms CPU Clock ALE PSEN P0 D7:0 P2 PCH PCL D7:0 PCL D7:0 PCH PCH 27 7683B–USB–03/07 AT89C5131 ROM ROM Structure The AT89C5131 ROM memory is divided in two different arrays: • • Hardware Configuration Byte the code array: 16-32 Kbytes. the configuration byte:1 byte. The configuration byte sets the starting microcontroller options and the security levels. The starting default options are X1 mode, Oscillator A. Table 33. Hardware Security Byte (HSB) HSB (S:EFh) Power configuration Register 7 Bit Number 7 6 6 Bit Mnemonic Description Reserved Reserved Oscillator Control Bits These two bits are used to control the oscillator in order to reduce consumption. 5-4 OSCON1-0 OSCON1 OSCON0 Description 1 1 The oscillator is configured to run from 0 to 32 MHz 1 0 The oscillator is configured to run from 0 to 16 MHz 0 1 The oscillator is configured to run from 0 to 8 MHz 0 0 This configuration shouldn’t be set Reserved Reserved User Program Lock Bits See Table 34 on page 29 5 OSCON1 4 OSCON0 3 2 1 LB1 0 LB0 3 2 1-0 LB1-0 HSB = xxxx xx11b 28 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 ROM Lock System Program ROM lock Bits The program Lock system, when programmed, protects the on-chip program against software piracy. The lock bits when programmed according to Table 34 will provide different level of protection for the on-chip code and data. Table 34. Program Lock bits Program Lock Bits Security level 1 3 LB1 U P LB0 U U No program lock feature enabled. Reading ROM data from programmer is disabled. Protection Description U: unprogrammed P: programmed 29 7683B–USB–03/07 Stacked EEPROM Overview The AT83C5134/35/36 features a stacked 2-wire serial data EEPROM. The data EEPROM allows to save from 512 Byte for AT24C04 version up to 32 Kbytes for AT24C256 version. The EEPROM is internally connected to the microcontroller on SDA and SCL pins. In order to access this memory, it is necessary to use software subroutines according to the AT24Cxx datasheet. Nevertheless, because the internal pull-up resistors of the AT83C5134/35/36 is quite high (around 100KΩ), the protocol should be slowed in order to be sure that the SDA pin can rise to the high level before reading it. Another solution to keep the access to the EEPROM in specification is to work with a software pull-up. Using a software pull-up, consists of forcing a low level at the output pin of the microcontroller before configuring it as an input (high level). The C51 the ports are “quasi-bidirectional” ports. It means that the ports can be configured as output low or as input high. In case a port is configured as an output low, it can sink a current and all internal pull-ups are disconnected. In case a port is configured as an input high, it is pulled up with a strong pull-up (a few hundreds Ohms resistor) for 2 clock periods. Then, if the port is externally connected to a low level, it is only kept high with a weak pull up (around 100KΩ), and if not, the high level is latched high thanks to a medium pull (around 10kΩ). Thus, when the port is configured as an input, and when this input has been read at a low level, there is a pull-up of around 100KΩ, which is quite high, to quickly load the SDA capacitance. So in order to help the reading of a high level just after the reading of a low level, it is possible to force a transition of the SDA port from an input state (1), to an output low state (0), followed by a new transition from this output low state to input state; In this case, the high pull-up has been replaced with a low pull-up which warranties a good reading of the data. Protocol 30 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 On-chip Expanded RAM (ERAM) The AT83C5134/35/36 provides additional Bytes of random access memory (RAM) space for increased data parameters handling and high level language usage. AT83C5134/35/36 devices have an expanded RAM in the external data space; maximum size and location are described in Table 35. Table 35. Description of Expanded RAM Address Part Number AT83C5134/35/ 36 ERAM Size 1024 Start 00h End 3FFh The AT83C5134/35/36 has on-chip data memory which is mapped into the following four separate segments. 1. The Lower 128 bytes of RAM (addresses 00h to 7Fh) are directly and indirectly addressable. 2. The Upper 128 bytes of RAM (addresses 80h to FFh) are indirectly addressable only. 3. The Special Function Registers, SFRs, (addresses 80h to FFh) are directly addressable only. 4. The expanded RAM bytes are indirectly accessed by MOVX instructions, and with the EXTRAM bit cleared in the AUXR register (see Table 35) The lower 128 bytes can be accessed by either direct or indirect addressing. The Upper 128 bytes can be accessed by indirect addressing only. The Upper 128 bytes occupy the same address space as the SFR. That means they have the same address, but are physically separate from SFR space. Figure 16. Internal and External Data Memory Address 0FFh or 3FFh(*) 0FFh Upper 128 bytes Internal RAM indirect accesses ERAM 80h 7Fh Lower 128 bytes Internal RAM direct or indirect accesses 00 00 80h 0FFh 0FFFFh Special Function Register direct accesses External Data Memory 00FFh up to 03FFh (*) 0000 (*) Depends on XRS1..0 31 7683B–USB–03/07 When an instruction accesses an internal location above address 7Fh, the CPU knows whether the access is to the upper 128 bytes of data RAM or to SFR space by the addressing mode used in the instruction. • • Instructions that use direct addressing access SFR space. For example: MOV 0A0H, # data, accesses the SFR at location 0A0h (which is P2). Instructions that use indirect addressing access the Upper 128 bytes of data RAM. For example: MOV atR0, # data where R0 contains 0A0h, accesses the data byte at address 0A0h, rather than P2 (whose address is 0A0h). The ERAM bytes can be accessed by indirect addressing, with EXTRAM bit cleared and MOVX instructions. This part of memory which is physically located on-chip, logically occupies the first bytes of external data memory. The bits XRS0 and XRS1 are used to hide a part of the available ERAM as explained in Table 35. This can be useful if external peripherals are mapped at addresses already used by the internal ERAM. With EXTRAM = 0, the ERAM is indirectly addressed, using the MOVX instruction in combination with any of the registers R0, R1 of the selected bank or DPTR. An access to ERAM will not affect ports P0, P2, P3.6 (WR) and P3.7 (RD). For example, with EXTRAM = 0, MOVX atR0, # data where R0 contains 0A0H, accesses the ERAM at address 0A0H rather than external memory. An access to external data memory locations higher than the accessible size of the ERAM will be performed with the MOVX DPTR instructions in the same way as in the standard 80C51, with P0 and P2 as data/address busses, and P3.6 and P3.7 as write and read timing signals. Accesses to ERAM above 0FFH can only be done by the use of DPTR. With EXTRAM = 1, MOVX @Ri and MOVX @DPTR will be similar to the standard 80C51. MOVX at Ri will provide an eight-bit address multiplexed with data on Port0 and any output port pins can be used to output higher order address bits. This is to provide the external paging capability. MOVX @DPTR will generate a sixteen-bit address. Port2 outputs the high-order eight address bits (the contents of DPH) while Port0 multiplexes the low-order eight address bits (DPL) with data. MOVX at Ri and MOVX @DPTR will generate either read or write signals on P3.6 (WR) and P3.7 (RD). • • • The stack pointer (SP) may be located anywhere in the 256 bytes RAM (lower and upper RAM) internal data memory. The stack may not be located in the ERAM. The M0 bit allows to stretch the ERAM timings; if M0 is set, the read and write pulses are extended from 6 to 30 clock periods. This is useful to access external slow peripherals. 32 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 36. AUXR Register AUXR - Auxiliary Register (8Eh) 7 DPU Bit Number 6 Bit Mnemonic Description Disable Weak Pull Up 7 DPU Cleared to enabled weak pull up on standard Ports. Set to disable weak pull up on standard Ports. Reserved The value read from this bit is indeterminate. Do not set this bit Pulse length 5 M0 Cleared to stretch MOVX control: the RD and the WR pulse length is 6 clock periods (default). Set to stretch MOVX control: the RD and the WR pulse length is 30 clock periods. 4 3 XRS1 Reserved The value read from this bit is indeterminate. Do not set this bit ERAM Size XRS1XRS0 0 0 2 XRS0 0 1 1 1 0 1 ERAM size 256 bytes 512 bytes 768 bytes 1024 bytes (default) 5 M0 4 3 XRS1 2 XRS0 1 EXTRAM 0 AO 6 - 1 EXTRAM EXTRAM bit Cleared to access internal ERAM using MOVX at Ri at DPTR. Set to access external memory. ALE Output bit Cleared, ALE is emitted at a constant rate of 1/6 the oscillator frequency (or 1/3 if X2 mode is used) (default). Set, ALE is active only when a MOVX or MOVC instruction is used. 0 AO Reset Value = 0X0X 1100b Not bit addressable 33 7683B–USB–03/07 Timer 2 The Timer 2 in the AT83C5134/35/36 is the standard C52 Timer 2. It is a 16-bit timer/counter: the count is maintained by two cascaded eight-bit timer registers, TH2 and TL2. It is controlled by T2CON (Table 37) and T2MOD (Table 38) registers. Timer 2 operation is similar to Timer 0 and Timer 1. C/T2 selects FOSC/12 (timer operation) or external pin T2 (counter operation) as the timer clock input. Setting TR2 allows TL2 to be incremented by the selected input. Timer 2 has 3 operating modes: capture, auto reload and Baud Rate Generator. These modes are selected by the combination of RCLK, TCLK and CP/RL2 (T2CON). Refer to the Atmel 8-bit microcontroller hardware documentation for the description of Capture and Baud Rate Generator Modes. Timer 2 includes the following enhancements: • • Auto-reload mode with up or down counter Programmable Clock-output Auto-reload Mode The Auto-reload mode configures Timer 2 as a 16-bit timer or event counter with automatic reload. If DCEN bit in T2MOD is cleared, Timer 2 behaves as in 80C52 (refer to the Atmel 8-bit microcontroller hardware description). If DCEN bit is set, Timer 2 acts as an Up/down timer/counter as shown in Figure 17. In this mode the T2EX pin controls the direction of count. When T2EX is high, Timer 2 counts up. Timer overflow occurs at FFFFh which sets the TF2 flag and generates an interrupt request. The overflow also causes the 16-bit value in RCAP2H and RCAP2L registers to be loaded into the timer registers TH2 and TL2. When T2EX is low, Timer 2 counts down. Timer underflow occurs when the count in the timer registers TH2 and TL2 equals the value stored in RCAP2H and RCAP2L registers. The underflow sets TF2 flag and reloads FFFFh into the timer registers. The EXF2 bit toggles when Timer 2 overflows or underflows according to the direction of the count. EXF2 does not generate any interrupt. This bit can be used to provide 17-bit resolution. 34 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 17. Auto-reload Mode Up/Down Counter (DCEN = 1) FCLK PERIPH :6 0 1 T2 C/T2 T2CON TR2 T2CON (DOWN COUNTING RELOAD VALUE) T2EX: FFh (8-bit) FFh (8-bit) if DCEN = 1, 1 = UP if DCEN = 1, 0 = DOWN if DCEN = 0, up counting TOGGLE T2CON EXF2 TL2 (8-bit) TH2 (8-bit) TF2 T2CON Timer 2 INTERRUPT RCAP2L (8-bit) RCAP2H (8-bit) (UP COUNTING RELOAD VALUE) Programmable Clock Output In the Clock-out mode, Timer 2 operates as a 50%-duty-cycle, programmable clock generator (See Figure 18). The input clock increments TL2 at frequency FCLK PERIPH/2. The timer repeatedly counts to overflow from a loaded value. At overflow, the contents of RCAP2H and RCAP2L registers are loaded into TH2 and TL2. In this mode, Timer 2 overflows do not generate interrupts. The following formula gives the Clock-out frequency as a function of the system oscillator frequency and the value in the RCAP2H and RCAP2L registers F CLKPERIPH C lock – OutFrequency = ---------------------------------------------------------------------------------------4 × ( 65536 – RCAP 2 H ⁄ RCAP 2 L ) For a 16 MHz system clock, Timer 2 has a programmable frequency range of 61 Hz (FCLK PERIPH/216) to 4 MHz (FCLK PERIPH/4). The generated clock signal is brought out to T2 pin (P1.0). Timer 2 is programmed for the Clock-out mode as follows: • • • • • Set T2OE bit in T2MOD register. Clear C/T2 bit in T2CON register. Determine the 16-bit reload value from the formula and enter it in RCAP2H/RCAP2L registers. Enter a 16-bit initial value in timer registers TH2/TL2. It can be the same as the reload value or a different one depending on the application. To start the timer, set TR2 run control bit in T2CON register. 35 7683B–USB–03/07 It is possible to use Timer 2 as a baud rate generator and a clock generator simultaneously. For this configuration, the baud rates and clock frequencies are not independent since both functions use the values in the RCAP2H and RCAP2L registers. Figure 18. Clock-out Mode C/T2 = 0 FCLK PERIPH :6 TR2 T2CON TL2 (8-bit) TH2 (8-bit) OVERFLOW RCAP2L (8-bit) Toggle T2 Q D RCAP2H (8-bit) T2OE T2MOD T2EX EXEN2 T2CON EXF2 T2CON Timer 2 INTERRUPT 36 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 37. T2CON Register T2CON - Timer 2 Control Register (C8h) 7 TF2 Bit Number 6 EXF2 Bit Mnemonic Description Timer 2 overflow Flag Must be cleared by software. Set by hardware on Timer 2 overflow, if RCLK = 0 and TCLK = 0. Timer 2 External Flag Set when a capture or a reload is caused by a negative transition on T2EX pin if EXEN2 = 1. When set, causes the CPU to vector to Timer 2 interrupt routine when Timer 2 interrupt is enabled. Must be cleared by software. EXF2 doesn’t cause an interrupt in Up/down counter mode (DCEN = 1). Receive Clock bit Cleared to use Timer 1 overflow as receive clock for serial port in mode 1 or 3. Set to use Timer 2 overflow as receive clock for serial port in mode 1 or 3. Transmit Clock bit Cleared to use Timer 1 overflow as transmit clock for serial port in mode 1 or 3. Set to use Timer 2 overflow as transmit clock for serial port in mode 1 or 3. Timer 2 External Enable bit Cleared to ignore events on T2EX pin for Timer 2 operation. Set to cause a capture or reload when a negative transition on T2EX pin is detected, if Timer 2 is not used to clock the serial port. Timer 2 Run control bit Cleared to turn off Timer 2. Set to turn on Timer 2. Timer/Counter 2 select bit Cleared for timer operation (input from internal clock system: FCLK PERIPH). Set for counter operation (input from T2 input pin, falling edge trigger). Must be 0 for clock out mode. Timer 2 Capture/Reload bit If RCLK = 1 or TCLK = 1, CP/RL2# is ignored and timer is forced to Auto-reload on Timer 2 overflow. Cleared to Auto-reload on Timer 2 overflows or negative transitions on T2EX pin if EXEN2 = 1. Set to capture on negative transitions on T2EX pin if EXEN2 = 1. 5 RCLK 4 TCLK 3 EXEN2 2 TR2 1 C/T2# 0 CP/RL2# 7 TF2 6 EXF2 5 RCLK 4 TCLK 3 EXEN2 2 TR2 1 C/T2# 0 CP/RL2# Reset Value = 0000 0000b Bit addressable 37 7683B–USB–03/07 Table 38. T2MOD Register T2MOD - Timer 2 Mode Control Register (C9h) 7 Bit Number 7 6 Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Timer 2 Output Enable bit Cleared to program P1.0/T2 as clock input or I/O port. Set to program P1.0/T2 as clock output. Down Counter Enable bit Cleared to disable Timer 2 as up/down counter. Set to enable Timer 2 as up/down counter. 5 4 3 2 1 T2OE 0 DCEN 6 - 5 - 4 - 3 - 2 - 1 T2OE 0 DCEN Reset Value = xxxx xx00b Not bit addressable 38 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Programmable Counter Array (PCA) The PCA provides more timing capabilities with less CPU intervention than the standard timer/counters. Its advantages include reduced software overhead and improved accuracy. The PCA consists of a dedicated timer/counter which serves as the time base for an array of five compare/capture modules. Its clock input can be programmed to count any one of the following signals: • • • • • • • • Peripheral clock frequency (FCLK PERIPH) Timer 0 overflow External input on ECI (P1.2) rising and/or falling edge capture, software timer high-speed output, or pulse width modulator ÷6 Peripheral clock frequency (FCLK PERIPH) ÷ 2 Each compare/capture modules can be programmed in any one of the following modes: Module 4 can also be programmed as a watchdog timer (see Section "PCA Watchdog Timer", page 49). When the compare/capture modules are programmed in the capture mode, software timer, or high speed output mode, an interrupt can be generated when the module executes its function. All five modules plus the PCA timer overflow share one interrupt vector. The PCA timer/counter and compare/capture modules share Port 1 for external I/O. These pins are listed below. If the port pin is not used for the PCA, it can still be used for standard I/O. PCA Component 16-bit Counter 16-bit Module 0 16-bit Module 1 16-bit Module 2 16-bit Module 3 16-bit Module 4 External I/O Pin P1.2/ECI P1.3/CEX0 P1.4/CEX1 P1.5/CEX2 P1.6/CEX3 P1.7/CEX4 The PCA timer is a common time base for all five modules (see Figure 19). The timer count source is determined from the CPS1 and CPS0 bits in the CMOD register (Table 39) and can be programmed to run at: • • • • 1/6 the peripheral clock frequency (FCLK PERIPH). 1/2 the peripheral clock frequency (FCLK PERIPH). The Timer 0 overflow The input on the ECI pin (P1.2) 39 7683B–USB–03/07 Figure 19. PCA Timer/Counter To PCA modules FCLK PERIPH/6 FCLK PERIPH/2 T0 OVF P1.2 overflow CH CL 16 Bit Up Counter It CIDL Idle WDTE CPS1 CPS0 ECF CMOD 0xD9 CF CR CCF4 CCF3 CCF2 CCF1 CCF0 CCON 0xD8 Table 39. CMOD Register CMOD - PCA Counter Mode Register (D9h) 7 CIDL Bit Number 6 WDTE Bit Mnemonic Description Counter Idle Control 7 CIDL Cleared to program the PCA Counter to continue functioning during idle Mode. Set to program PCA to be gated off during idle. Watchdog Timer Enable 6 WDTE Cleared to disable Watchdog Timer function on PCA Module 4. Set to enable Watchdog Timer function on PCA Module 4. 5 Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. PCA Count Pulse Select CPS1CPS0 0 0 1 CPS0 0 1 1 1 0 1 Selected PCA input Internal clock fCLK PERIPH/6 Internal clock fCLK PERIPH/2 Timer 0 Overflow External clock at ECI/P1.2 pin (max rate = fCLK PERIPH/ 4) 5 4 3 2 CPS1 1 CPS0 0 ECF 4 - 3 2 CPS1 0 ECF PCA Enable Counter Overflow Interrupt Cleared to disable CF bit in CCON to inhibit an interrupt. Set to enable CF bit in CCON to generate an interrupt. Reset Value = 00XX X000b Not bit addressable 40 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 The CMOD register includes three additional bits associated with the PCA (See Figure 19 and Table 39). • • • The CIDL bit allows the PCA to stop during idle mode. The WDTE bit enables or disables the watchdog function on module 4. The ECF bit when set causes an interrupt and the PCA overflow flag CF (in the CCON SFR) to be set when the PCA timer overflows. The CCON register contains the run control bit for the PCA and the flags for the PCA timer (CF) and each module (see Table 40). • • Bit CR (CCON.6) must be set by software to run the PCA. The PCA is shut off by clearing this bit. Bit CF: The CF bit (CCON.7) is set when the PCA counter overflows and an interrupt will be generated if the ECF bit in the CMOD register is set. The CF bit can only be cleared by software. Bits 0 through 4 are the flags for the modules (bit 0 for module 0, bit 1 for module 1, etc.) and are set by hardware when either a match or a capture occurs. These flags can only be cleared by software. • Table 40. CCON Register CCON - PCA Counter Control Register (D8h) 7 CF Bit Bit 6 CR 5 – 4 CCF4 3 CCF3 2 CCF2 1 CCF1 0 CCF0 Number Mnemonic Description PCA Counter Overflow flag 7 CF Set by hardware when the counter rolls over. CF flags an interrupt if bit ECF in CMOD is set. CF may be set by either hardware or software but can only be cleared by software. PCA Counter Run control bit 6 CR Must be cleared by software to turn the PCA counter off. Set by software to turn the PCA counter on. Reserved The value read from this bit is indeterminate. Do not set this bit. PCA Module 4 interrupt flag 4 CCF4 Must be cleared by software. Set by hardware when a match or capture occurs. PCA Module 3 interrupt flag 3 CCF3 Must be cleared by software. Set by hardware when a match or capture occurs. PCA Module 2 interrupt flag 2 CCF2 Must be cleared by software. Set by hardware when a match or capture occurs. PCA Module 1 Interrupt Flag 1 CCF1 Must be cleared by software. Set by hardware when a match or capture occurs. PCA Module 0 Interrupt Flag 0 CCF0 Must be cleared by software. Set by hardware when a match or capture occurs. 5 – Reset Value = 000X 0000b Not bit addressable 41 7683B–USB–03/07 The watchdog timer function is implemented in module 4 (See Figure 22). The PCA interrupt system is shown in Figure 20. Figure 20. PCA Interrupt System CF PCA Timer/Counter CR CCF4 CCF3 CCF2 CCF1 CCF0 CCON 0xD8 Module 0 Module 1 To Interrupt priority decoder Module 2 Module 3 Module 4 CMOD.0 ECF ECCFn CCAPMn.0 IE.6 EC IE.7 EA PCA Modules: each one of the five compare/capture modules has six possible functions. It can perform: • • • • • • 16-bit capture, positive-edge triggered 16-bit capture, negative-edge triggered 16-bit capture, both positive and negative-edge triggered 16-bit Software Timer 16-bit High-speed Output 8-bit Pulse Width Modulator In addition, module 4 can be used as a Watchdog Timer. Each module in the PCA has a special function register associated with it. These registers are: CCAPM0 for module 0, CCAPM1 for module 1, etc. (see Table 41). The registers contain the bits that control the mode that each module will operate in. • The ECCF bit (CCAPMn.0 where n = 0, 1, 2, 3, or 4 depending on the module) enables the CCF flag in the CCON SFR to generate an interrupt when a match or compare occurs in the associated module. PWM (CCAPMn.1) enables the pulse width modulation mode. The TOG bit (CCAPMn.2) when set causes the CEX output associated with the module to toggle when there is a match between the PCA counter and the module's capture/compare register. The match bit MAT (CCAPMn.3) when set will cause the CCFn bit in the CCON register to be set when there is a match between the PCA counter and the module's capture/compare register. The next two bits CAPN (CCAPMn.4) and CAPP (CCAPMn.5) determine the edge that a capture input will be active on. The CAPN bit enables the negative edge, and • • • • 42 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 the CAPP bit enables the positive edge. If both bits are set both edges will be enabled and a capture will occur for either transition. • The last bit in the register ECOM (CCAPMn.6) when set enables the comparator function. Table 42 shows the CCAPMn settings for the various PCA functions. Table 41. CCAPMn Registers (n = 0-4) CCAPM0 - PCA Module 0 Compare/Capture Control Register (0DAh) CCAPM1 - PCA Module 1 Compare/Capture Control Register (0DBh) CCAPM2 - PCA Module 2 Compare/Capture Control Register (0DCh) CCAPM3 - PCA Module 3 Compare/Capture Control Register (0DDh) CCAPM4 - PCA Module 4 Compare/Capture Control Register (0DEh) 7 Bit Number 7 6 ECOMn Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. Enable Comparator 6 ECOMn Cleared to disable the comparator function. Set to enable the comparator function. Capture Positive 5 CAPPn Cleared to disable positive edge capture. Set to enable positive edge capture. Capture Negative 4 CAPNn Cleared to disable negative edge capture. Set to enable negative edge capture. Match 3 MATn When MATn = 1, a match of the PCA counter with this module's compare/capture register causes the CCFn bit in CCON to be set, flagging an interrupt. Toggle 2 TOGn When TOGn = 1, a match of the PCA counter with this module's compare/capture register causes the CEXn pin to toggle. Pulse Width Modulation Mode 1 PWMn Cleared to disable the CEXn pin to be used as a pulse width modulated output. Set to enable the CEXn pin to be used as a pulse width modulated output. Enable CCF Interrupt 0 ECCFn Cleared to disable compare/capture flag CCFn in the CCON register to generate an interrupt. Set to enable compare/capture flag CCFn in the CCON register to generate an interrupt. 5 CAPPn 4 CAPNn 3 MATn 2 TOGn 1 PWMn 0 ECCFn Reset Value = X000 0000b Not bit addressable 43 7683B–USB–03/07 Table 42. PCA Module Modes (CCAPMn Registers) ECOMn 0 X CAPPn 0 1 CAPNn 0 0 MATn 0 0 TOGn 0 0 PWM m 0 0 ECCF n Module Function 0 X No Operation 16-bit capture by a positiveedge trigger on CEXn 16-bit capture by a negative trigger on CEXn 16-bit capture by a transition on CEXn 16-bit Software Timer/Compare mode. 16-bit High Speed Output 8-bit PWM Watchdog Timer (module 4 only) X 0 1 0 0 0 X X 1 1 0 0 0 X 1 1 1 1 0 0 0 0 0 0 0 0 1 1 0 1 0 1 0 X 0 0 1 0 X X 0 X There are two additional registers associated with each of the PCA modules. They are CCAPnH and CCAPnL and these are the registers that store the 16-bit count when a capture occurs or a compare should occur. When a module is used in the PWM mode these registers are used to control the duty cycle of the output (see Table 43 and Table 44) 44 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 43. CCAPnH Registers (n = 0-4) CCAP0H - PCA Module 0 Compare/Capture Control Register High (0FAh) CCAP1H - PCA Module 1 Compare/Capture Control Register High (0FBh) CCAP2H - PCA Module 2 Compare/Capture Control Register High (0FCh) CCAP3H - PCA Module 3 Compare/Capture Control Register High (0FDh) CCAP4H - PCA Module 4 Compare/Capture Control Register High (0FEh) 7 Bit Number 7-0 6 Bit Mnemonic Description PCA Module n Compare/Capture Control CCAPnH Value 5 4 3 2 1 0 - Reset Value = XXXX XXXXb Not bit addressable Table 44. CCAPnL Registers (n = 0-4) CCAP0L - PCA Module 0 Compare/Capture Control Register Low (0EAh) CCAP1L - PCA Module 1 Compare/Capture Control Register Low (0EBh) CCAP2L - PCA Module 2 Compare/Capture Control Register Low (0ECh) CCAP3L - PCA Module 3 Compare/Capture Control Register Low (0EDh) CCAP4L - PCA Module 4 Compare/Capture Control Register Low (0EEh) 7 Bit Number 7-0 6 Bit Mnemonic Description PCA Module n Compare/Capture Control CCAPnL Value 5 4 3 2 1 0 - Reset Value = XXXX XXXXb Not bit addressable Table 45. CH Register CH - PCA Counter Register High (0F9h) 7 Bit Number 7-0 6 Bit Mnemonic Description PCA counter CH Value 5 4 3 2 1 0 - Reset Value = 0000 0000b Not bit addressable 45 7683B–USB–03/07 Table 46. CL Register CL - PCA Counter Register Low (0E9h) 7 Bit Number 7-0 6 Bit Mnemonic Description PCA Counter CL Value 5 4 3 2 1 0 - Reset Value = 0000 0000b Not bit addressable PCA Capture Mode To use one of the PCA modules in the capture mode either one or both of the CCAPM bits CAPN and CAPP for that module must be set. The external CEX input for the module (on port 1) is sampled for a transition. When a valid transition occurs the PCA hardware loads the value of the PCA counter registers (CH and CL) into the module's capture registers (CCAPnL and CCAPnH). If the CCFn bit for the module in the CCON SFR and the ECCFn bit in the CCAPMn SFR are set then an interrupt will be generated (see Figure 21). Figure 21. PCA Capture Mode CF CR CCF4 CCF3 CCF2 CCF1 CCF0 CCON 0xD8 PCA IT PCA Counter/Timer Cex.n Capture CH CL CCAPnH CCAPnL ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn, n = 0 to 4 0xDA to 0xDE 16-bit Software Timer/Compare Mode The PCA modules can be used as software timers by setting both the ECOM and MAT bits in the modules CCAPMn register. The PCA timer will be compared to the module's capture registers and when a match occurs an interrupt will occur if the CCFn (CCON SFR) and the ECCFn (CCAPMn SFR) bits for the module are both set (see Figure 22). 46 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 22. PCA Compare Mode and PCA Watchdog Timer CCON CF Write to CCAPnL Write to CCAPnH 1 0 Enable 16-bit Comparator RESET(1) Reset PCA IT CCAPnH CCAPnL Match CR CCF4 CCF3 CCF2 CCF1 CCF0 0xD8 CH CL PCA Counter/Timer ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn, n = 0 to 4 0xDA to 0xDE CIDL WDTE CPS1 CPS0 ECF CMOD 0xD9 Note: 1. Only for Module 4 Before enabling ECOM bit, CCAPnL and CCAPnH should be set with a non zero value, otherwise an unwanted match could happen. Writing to CCAPnH will set the ECOM bit. Once ECOM set, writing CCAPnL will clear ECOM so that an unwanted match doesn’t occur while modifying the compare value. Writing to CCAPnH will set ECOM. For this reason, user software should write CCAPnL first, and then CCAPnH. Of course, the ECOM bit can still be controlled by accessing to CCAPMn register. High Speed Output Mode In this mode, the CEX output (on port 1) associated with the PCA module will toggle each time a match occurs between the PCA counter and the module's capture registers. To activate this mode the TOG, MAT, and ECOM bits in the module's CCAPMn SFR must be set (see Figure 23). A prior write must be done to CCAPnL and CCAPnH before writing the ECOMn bit. 47 7683B–USB–03/07 Figure 23. PCA High-speed Output Mode CCON CF CR CCF4 CCF3 CCF2 CCF1 CCF0 0xD8 Write to CCAPnL Reset PCA IT Write to CCAPnH 0 CCAPnH Enable 16-bit Comparator CCAPnL Match 1 CH CL CEXn PCA counter/timer CCAPMn, n = 0 to 4 0xDA to 0xDE ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn Before enabling ECOM bit, CCAPnL and CCAPnH should be set with a non zero value, otherwise an unwanted match could happen. Once ECOM set, writing CCAPnL will clear ECOM so that an unwanted match doesn’t occur while modifying the compare value. Writing to CCAPnH will set ECOM. For this reason, user software should write CCAPnL first, and then CCAPnH. Of course, the ECOM bit can still be controlled by accessing to CCAPMn register. Pulse Width Modulator Mode All of the PCA modules can be used as PWM outputs. Figure 24 shows the PWM function. The frequency of the output depends on the source for the PCA timer. All of the modules will have the same frequency of output because they all share the PCA timer. The duty cycle of each module is independently variable using the module's capture register CCAPLn. When the value of the PCA CL SFR is less than the value in the module's CCAPLn SFR the output will be low, when it is equal to or greater than the output will be high. When CL overflows from FF to 00, CCAPLn is reloaded with the value in CCAPHn. This allows updating the PWM without glitches. The PWM and ECOM bits in the module's CCAPMn register must be set to enable the PWM mode. 48 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 24. PCA PWM Mode CCAPnH Overflow CCAPnL “0” Enable 8-bit Comparator < ≥ “1” CEXn CL PCA Counter/Timer ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn, n = 0 to 4 0xDA to 0xDE PCA Watchdog Timer An on-board watchdog timer is available with the PCA to improve the reliability of the system without increasing chip count. Watchdog timers are useful for systems that are susceptible to noise, power glitches, or electrostatic discharge. Module 4 is the only PCA module that can be programmed as a watchdog. However, this module can still be used for other modes if the watchdog is not needed. Figure 22 shows a diagram of how the watchdog works. The user pre-loads a 16-bit value in the compare registers. Just like the other compare modes, this 16-bit value is compared to the PCA timer value. If a match is allowed to occur, an internal reset will be generated. This will not cause the RST pin to be driven low. In order to hold off the reset, the user has three options: 1. Periodically change the compare value so it will never match the PCA timer 2. Periodically change the PCA timer value so it will never match the compare values, or 3. Disable the watchdog by clearing the WDTE bit before a match occurs and then re-enable it The first two options are more reliable because the watchdog timer is never disabled as in option #3. If the program counter ever goes astray, a match will eventually occur and cause an internal reset. The second option is also not recommended if other PCA modules are being used. Remember, the PCA timer is the time base for all modules; changing the time base for other modules would not be a good idea. Thus, in most applications the first solution is the best option. This watchdog timer won’t generate a reset out on the reset pin. 49 7683B–USB–03/07 Serial I/O Port The serial I/O port in the AT83C5134/35/36 is compatible with the serial I/O port in the 80C52. It provides both synchronous and asynchronous communication modes. It operates as an Universal Asynchronous Receiver and Transmitter (UART) in three full-duplex modes (modes 1, 2 and 3). Asynchronous transmission and reception can occur simultaneously and at different baud rates. Serial I/O port includes the following enhancements: • • Framing error detection Automatic address recognition Framing Error Detection Framing bit error detection is provided for the three asynchronous modes (modes 1, 2 and 3). To enable the framing bit error detection feature, set SMOD0 bit in PCON register (see Figure 25). Figure 25. Framing Error Block Diagram SM0/FE SM1 SM2 REN TB8 RB8 TI RI SCON (98h) Set FE Bit if Stop Bit is 0 (framing error) (SMOD0 = 1) SM0 to UART Mode Control (SMOD0 = 0) SMOD1 SMOD0 POF GF1 GF0 PD IDL PCON (87h) To UART Framing Error Control When this feature is enabled, the receiver checks each incoming data frame for a valid stop bit. An invalid stop bit may result from noise on the serial lines or from simultaneous transmission by two CPUs. If a valid stop bit is not found, the Framing Error bit (FE) in SCON register (See Table 47) bit is set. Software may examine FE bit after each reception to check for data errors. Once set, only software or a reset can clear FE bit. Subsequently received frames with valid stop bits cannot clear FE bit. When FE feature is enabled, RI rises on stop bit instead of the last data bit (See Figure 26 and Figure 27). Figure 26. UART Timings in Mode 1 RXD Start Bit RI SMOD0 = X FE SMOD0 = 1 D0 D1 D2 D3 D4 D5 D6 D7 Stop Bit Data Byte 50 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 27. UART Timings in Modes 2 and 3 RXD Start Bit RI SMOD0 = 0 RI SMOD0 = 1 FE SMOD0 = 1 D0 D1 D2 D3 D4 D5 D6 D7 D8 Ninth Stop Bit Bit Data Byte Automatic Address Recognition The automatic address recognition feature is enabled when the multiprocessor communication feature is enabled (SM2 bit in SCON register is set). Implemented in hardware, automatic address recognition enhances the multiprocessor communication feature by allowing the serial port to examine the address of each incoming command frame. Only when the serial port recognizes its own address, the receiver sets RI bit in SCON register to generate an interrupt. This ensures that the CPU is not interrupted by command frames addressed to other devices. If desired, you may enable the automatic address recognition feature in mode 1. In this configuration, the stop bit takes the place of the ninth data bit. Bit RI is set only when the received command frame address matches the device’s address and is terminated by a valid stop bit. To support automatic address recognition, a device is identified by a given address and a broadcast address. Note: The multiprocessor communication and automatic address recognition features cannot be enabled in mode 0 (i.e., setting SM2 bit in SCON register in mode 0 has no effect). Given Address Each device has an individual address that is specified in SADDR register; the SADEN register is a mask byte that contains don’t care bits (defined by zeros) to form the device’s given address. The don’t care bits provide the flexibility to address one or more slaves at a time. The following example illustrates how a given address is formed. To address a device by its individual address, the SADEN mask byte must be 1111 1111b. For example: SADDR0101 0110b SADEN1111 1100b Given0101 01XXb The following is an example of how to use given addresses to address different slaves: Slave A:SADDR1111 0001b SADEN1111 1010b Given1111 0X0Xb Slave B:SADDR1111 0011b SADEN1111 1001b Given1111 0XX1b Slave C:SADDR1111 0011b SADEN1111 1101b Given1111 00X1b 51 7683B–USB–03/07 The SADEN byte is selected so that each slave may be addressed separately. For slave A, bit 0 (the LSB) is a don’t care bit; for slaves B and C, bit 0 is a 1. To communicate with slave A only, the master must send an address where bit 0 is clear (e.g. 1111 0000b). For slave A, bit 1 is a 1; for slaves B and C, bit 1 is a don’t care bit. To communicate with slaves B and C, but not slave A, the master must send an address with bits 0 and 1 both set (e.g. 1111 0011b). To communicate with slaves A, B and C, the master must send an address with bit 0 set, bit 1 clear, and bit 2 clear (e.g. 1111 0001b). Broadcast Address A broadcast address is formed from the logical OR of the SADDR and SADEN registers with zeros defined as don’t care bits, e.g.: SADDR0101 0110b SADEN1111 1100b Broadcast = SADDR OR SADEN1111 111Xb The use of don’t care bits provides flexibility in defining the broadcast address, in most applications, a broadcast address is FFh. The following is an example of using broadcast addresses: Slave A:SADDR1111 0001b SADEN1111 1010b Broadcast1111 1X11b, Slave B:SADDR1111 0011b SADEN1111 1001b Broadcast1111 1X11B, Slave C:SADDR = 1111 0011b SADEN1111 1101b Broadcast1111 1111b For slaves A and B, bit 2 is a don’t care bit; for slave C, bit 2 is set. To communicate with all of the slaves, the master must send an address FFh. To communicate with slaves A and B, but not slave C, the master can send and address FBh. Reset Addresses On reset, the SADDR and SADEN registers are initialized to 00h, i.e. the given and broadcast addresses are XXXX XXXXb (all don’t care bits). This ensures that the serial port will reply to any address, and so, that it is backwards compatible with the 80C51 microcontrollers that do not support automatic address recognition. SADEN - Slave Address Mask Register (B9h) 7 6 5 4 3 2 1 0 Reset Value = 0000 0000b Not bit addressable 52 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 SADDR - Slave Address Register (A9h) 7 6 5 4 3 2 1 0 Reset Value = 0000 0000b Not bit addressable Baud Rate Selection for UART for Mode 1 and 3 The Baud Rate Generator for transmit and receive clocks can be selected separately via the T2CON and BDRCON registers. Figure 28. Baud Rate Selection TIMER1 TIMER2 0 1 RCLK INT_BRG RBCK TIMER_BRG_RX 0 1 / 16 Rx Clock TIMER1 TIMER2 0 1 TCLK TIMER_BRG_TX 0 1 / 16 Tx Clock INT_BRG TBCK Baud Rate Selection Table for UART TCLK (T2CON) 0 1 0 1 X X 0 1 X RCLK (T2CON) 0 0 1 1 0 1 X X X TBCK (BDRCON) 0 0 0 0 1 1 0 0 1 RBCK (BDRCON) 0 0 0 0 0 0 1 1 1 Clock Source UART Tx Timer 1 Timer 2 Timer 1 Timer 2 INT_BRG INT_BRG Timer 1 Timer 2 INT_BRG Clock Source UART Rx Timer 1 Timer 1 Timer 2 Timer 2 Timer 1 Timer 2 INT_BRG INT_BRG INT_BRG Internal Baud Rate Generator (BRG) When the internal Baud Rate Generator is used, the Baud Rates are determined by the BRG overflow depending on the BRL reload value, the value of SPD bit (Speed Mode) in BDRCON register and the value of the SMOD1 bit in PCON register. 53 7683B–USB–03/07 Figure 29. Internal Baud Rate Peripheral Clock /6 0 1 SPD BRR BRL auto reload counter overflow BRG /2 0 1 SMOD1 INT_BRG • The baud rate for UART is token by formula: Baud_Rate = 2x6 2SMOD1 x FCLK PERIPH (1-SPD) x 16 x [256 - (BRL)] (BRL) = 256 2x6 2SMOD1 x FCLK PERIPH (1-SPD) x 16 x Baud_Rate 54 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 47. SCON Register – SCON Serial Control Register (98h) 7 FE/SM0 Bit Number 6 SM1 Bit Mnemonic Description Framing Error bit (SMOD0 = 1) Clear to reset the error state, not cleared by a valid stop bit. Set by hardware when an invalid stop bit is detected. SMOD0 must be set to enable access to the FE bit Serial port Mode bit 0 Refer to SM1 for serial port mode selection. SMOD0 must be cleared to enable access to the SM0 bit Serial port Mode bit 1 SM0SM1ModeDescriptionBaud Rate 0 0 0 Shift RegisterFCPU PERIPH/6 0 1 1 8-bit UARTVariable 1 0 2 9-bit UARTFCPU PERIPH/32 or/16 1 1 3 9-bit UART Variable 5 SM2 4 REN 3 TB8 2 RB8 1 TI 0 RI FE 7 SM0 6 SM1 5 SM2 Serial port Mode 2 bit/Multiprocessor Communication Enable bit Clear to disable multiprocessor communication feature. Set to enable multiprocessor communication feature in mode 2 and 3, and eventually mode 1. This bit should be cleared in mode 0. Reception Enable bit Clear to disable serial reception. Set to enable serial reception. Transmitter Bit 8/Ninth bit to Transmit in Modes 2 and 3 4 REN 3 TB8 Clear to transmit a logic 0 in the 9th bit. Set to transmit a logic 1 in the 9th bit. Receiver Bit 8/Ninth bit received in modes 2 and 3 Cleared by hardware if 9th bit received is a logic 0. Set by hardware if 9th bit received is a logic 1. In mode 1, if SM2 = 0, RB8 is the received stop bit. In mode 0 RB8 is not used. Transmit Interrupt flag Clear to acknowledge interrupt. Set by hardware at the end of the 8th bit time in mode 0 or at the beginning of the stop bit in the other modes. Receive Interrupt flag Clear to acknowledge interrupt. Set by hardware at the end of the 8th bit time in mode 0, see Figure 26. and Figure 27. in the other modes. 2 RB8 1 TI 0 RI Reset Value = 0000 0000b Bit addressable 55 7683B–USB–03/07 Example of computed value when X2 = 1, SMOD1 = 1, SPD = 1 Baud Rates FOSC = 16.384 MHz BRL 115200 57600 38400 28800 19200 9600 4800 247 238 229 220 203 149 43 Error (%) 1.23 1.23 1.23 1.23 0.63 0.31 1.23 BRL 243 230 217 204 178 100 FOSC = 24 MHz Error (%) 0.16 0.16 0.16 0.16 0.16 0.16 - Example of computed value when X2 = 0, SMOD1 = 0, SPD = 0 FOSC = 16.384 MHz Baud Rates 4800 2400 1200 600 BRL 247 238 220 185 Error (%) 1.23 1.23 1.23 0.16 BRL 243 230 202 152 FOSC = 24 MHz Error (%) 0.16 0.16 3.55 0.16 The baud rate generator can be used for mode 1 or 3 (refer to Figure 28.), but also for mode 0 for UART, thanks to the bit SRC located in BDRCON register (Table 50.) UART Registers SADEN - Slave Address Mask Register for UART (B9h) 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – Reset Value = 0000 0000b SADDR - Slave Address Register for UART (A9h) 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – Reset Value = 0000 0000b SBUF - Serial Buffer Register for UART (99h) 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – Reset Value = XXXX XXXXb 56 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 BRL - Baud Rate Reload Register for the internal baud rate generator, UART (9Ah) 7 – 6 – 5 – 4 – 3 – 2 – 1 – 0 – Reset Value = 0000 0000b Table 48. T2CON Register T2CON - Timer 2 Control Register (C8h) 7 TF2 Bit Number 6 EXF2 Bit Mnemonic Description Timer 2 overflow Flag Must be cleared by software. Set by hardware on Timer 2 overflow, if RCLK = 0 and TCLK = 0. Timer 2 External Flag Set when a capture or a reload is caused by a negative transition on T2EX pin if EXEN2 = 1. When set, causes the CPU to vector to Timer 2 interrupt routine when Timer 2 interrupt is enabled. Must be cleared by software. EXF2 doesn’t cause an interrupt in Up/down counter mode (DCEN = 1) Receive Clock bit for UART Cleared to use Timer 1 overflow as receive clock for serial port in mode 1 or 3. Set to use Timer 2 overflow as receive clock for serial port in mode 1 or 3. Transmit Clock bit for UART Cleared to use Timer 1 overflow as transmit clock for serial port in mode 1 or 3. Set to use Timer 2 overflow as transmit clock for serial port in mode 1 or 3. Timer 2 External Enable bit Cleared to ignore events on T2EX pin for Timer 2 operation. Set to cause a capture or reload when a negative transition on T2EX pin is detected, if Timer 2 is not used to clock the serial port. Timer 2 Run control bit Cleared to turn off Timer 2. Set to turn on Timer 2. Timer/Counter 2 select bit Cleared for timer operation (input from internal clock system: FCLK PERIPH). Set for counter operation (input from T2 input pin, falling edge trigger). Must be 0 for clock out mode. Timer 2 Capture/Reload bit If RCLK = 1 or TCLK = 1, CP/RL2# is ignored and timer is forced to Auto-reload on Timer 2 overflow. Cleared to Auto-reload on Timer 2 overflows or negative transitions on T2EX pin if EXEN2 = 1. Set to capture on negative transitions on T2EX pin if EXEN2 = 1. 5 RCLK 4 TCLK 3 EXEN2 2 TR2 1 C/T2# 0 CP/RL2# 7 TF2 6 EXF2 5 RCLK 4 TCLK 3 EXEN2 2 TR2 1 C/T2# 0 CP/RL2# Reset Value = 0000 0000b Bit addressable 57 7683B–USB–03/07 Table 49. PCON Register PCON - Power Control Register (87h) 7 SMOD1 Bit Number 7 6 SMOD0 Bit Mnemonic SMOD1 Description Serial port Mode bit 1 for UART Set to select double baud rate in mode 1, 2 or 3. Serial port Mode bit 0 for UART 6 SMOD0 Cleared to select SM0 bit in SCON register. Set to select FE bit in SCON register. Reserved The value read from this bit is indeterminate. Do not set this bit. Power-Off Flag Cleared to recognize next reset type. Set by hardware when VCC rises from 0 to its nominal voltage. Can also be set by software. General-purpose Flag Cleared by user for general-purpose usage. Set by user for general-purpose usage. General-purpose Flag Cleared by user for general-purpose usage. Set by user for general-purpose usage. Power-down Mode Bit Cleared by hardware when reset occurs. Set to enter power-down mode. Idle Mode Bit Cleared by hardware when interrupt or reset occurs. Set to enter idle mode. 5 4 POF 3 GF1 2 GF0 1 PD 0 IDL 5 - 4 POF 3 GF1 2 GF0 1 PD 0 IDL Reset Value = 00x1 0000b Not bit addressable Power-off flag reset value will be 1 only after a power on (cold reset). A warm reset doesn’t affect the value of this bit. 58 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 50. BDRCON Register BDRCON - Baud Rate Control Register (9Bh) 7 Bit Number 7 6 Bit Mnemonic 5 4 BRR 3 TBCK 2 RBCK 1 SPD 0 SRC Description Reserved The value read from this bit is indeterminate. Do not set this bit Reserved The value read from this bit is indeterminate. Do not set this bit Reserved The value read from this bit is indeterminate. Do not set this bit. Baud Rate Run Control bit Cleared to stop the internal Baud Rate Generator. Set to start the internal Baud Rate Generator. Transmission Baud rate Generator Selection bit for UART Cleared to select Timer 1 or Timer 2 for the Baud Rate Generator. Set to select internal Baud Rate Generator. Reception Baud Rate Generator Selection bit for UART Cleared to select Timer 1 or Timer 2 for the Baud Rate Generator. Set to select internal Baud Rate Generator. Baud Rate Speed Control bit for UART Cleared to select the SLOW Baud Rate Generator. Set to select the FAST Baud Rate Generator. Baud Rate Source select bit in Mode 0 for UART 6 - 5 - 4 BRR 3 TBCK 2 RBCK 1 SPD 0 SRC Cleared to select FOSC/12 as the Baud Rate Generator (FCLK PERIPH/6 in X2 mode). Set to select the internal Baud Rate Generator for UARTs in mode 0. Reset Value = xxx0 0000b Not bit addressable 59 7683B–USB–03/07 Dual Data Pointer Register The additional data pointer can be used to speed up code execution and reduce code size. The dual DPTR structure is a way by which the chip will specify the address of an external data memory location. There are two 16-bit DPTR registers that address the external memory, and a single bit called DPS = AUXR1.0 (see Table 51) that allows the program code to switch between them (see Figure 30). Figure 30. Use of Dual Pointer External Data Memory 7 0 DPS DPTR1 DPTR0 AUXR1(A2H) DPH(83H) DPL(82H) Table 51. AUXR1 Register AUXR1- Auxiliary Register 1(0A2h) 7 Bit Number 7 6 Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. This bit is a general-purpose user flag. Always cleared. Reserved The value read from this bit is indeterminate. Do not set this bit. Data Pointer Selection Cleared to select DPTR0. Set to select DPTR1. 5 4 3 GF3 2 0 1 0 DPS 6 - 5 - 4 3 2 1 GF3 0 - 0 DPS Reset Value = xxxx x0x0b Not bit addressable a. Bit 2 stuck at 0; this allows to use INC AUXR1 to toggle DPS without changing GF3. 60 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 ASSEMBLY LANGUAGE ; Block move using dual data pointers ; Modifies DPTR0, DPTR1, A and PSW ; note: DPS exits opposite of entry state ; unless an extra INC AUXR1 is added ; 00A2 AUXR1 EQU 0A2H ; 0000 909000MOV DPTR,#SOURCE ; address of SOURCE 0003 05A2 INC AUXR1 ; switch data pointers 0005 90A000 MOV DPTR,#DEST ; address of DEST 0008 LOOP: 0008 05A2 INC AUXR1 ; switch data pointers 000A E0 MOVX A,@DPTR ; get a byte from SOURCE 000B A3 INC DPTR ; increment SOURCE address 000C 05A2 INC AUXR1 ; switch data pointers 000E F0 MOVX @DPTR,A ; write the byte to DEST 000F A3 INC DPTR ; increment DEST address 0010 70F6JNZ LOOP ; check for 0 terminator 0012 05A2 INC AUXR1 ; (optional) restore DPS INC is a short (2 bytes) and fast (12 clocks) way to manipulate the DPS bit in the AUXR1 SFR. However, note that the INC instruction does not directly force the DPS bit to a particular state, but simply toggles it. In simple routines, such as the block move example, only the fact that DPS is toggled in the proper sequence matters, not its actual value. In other words, the block move routine works the same whether DPS is '0' or '1' on entry. Observe that without the last instruction (INC AUXR1), the routine will exit with DPS in the opposite state. 61 7683B–USB–03/07 Interrupt System Overview The AT83C5134/35/36 has a total of 11 interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (timers 0, 1 and 2), the serial port interrupt, SPI interrupt, Keyboard interrupt, USB interrupt and the PCA global interrupt. These interrupts are shown in Figure 31. Figure 31. Interrupt Control System TCON.0 IPH, IPL 0 IE0 0 1 3 3 High priority interrupt IT0 INT0 TF0 TCON.2 IT1 INT1 0 0 IE1 0 1 3 3 Interrupt Polling Sequence, Decreasing From High-to-Low Priority TF1 0 3 PCA IT 0 RI TI 3 0 3 0 3 KBD IT 0 3 TWI IT SPI IT 0 USBINT UEPINT 3 0 0 3 TF2 EXF2 Individual Enable Global Disable Low Priority Interrupt 62 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Each of the interrupt sources can be individually enabled or disabled by setting or clearing a bit in the Interrupt Enable register (Table 53). This register also contains a global disable bit, which must be cleared to disable all interrupts at once. Each interrupt source can also be individually programmed to one out of four priority levels by setting or clearing a bit in the Interrupt Priority register (Table 54.) and in the Interrupt Priority High register (Table 55). Table 52. shows the bit values and priority levels associated with each combination. Registers The PCA interrupt vector is located at address 0033H, the SPI interrupt vector is located at address 004BH and Keyboard interrupt vector is located at address 003BH. All other vectors addresses are the same as standard C52 devices. Table 52. Priority Level Bit Values IPH.x 0 0 1 1 IPL.x 0 1 0 1 Interrupt Level Priority 0 (Lowest) 1 2 3 (Highest) A low-priority interrupt can be interrupted by a high priority interrupt, but not by another low-priority interrupt. A high-priority interrupt can’t be interrupted by any other interrupt source. If two interrupt requests of different priority levels are received simultaneously, the request of higher priority level is serviced. If interrupt requests of the same priority level are received simultaneously, an internal polling sequence determines which request is serviced. Thus within each priority level there is a second priority structure determined by the polling sequence. 63 7683B–USB–03/07 Table 53. IEN0 Register IEN0 - Interrupt Enable Register (A8h) 7 EA Bit Number 6 EC Bit Mnemonic Description Enable All interrupt bit Cleared to disable all interrupts. Set to enable all interrupts. PCA interrupt enable bit Cleared to disable. Set to enable. Timer 2 overflow interrupt Enable bit Cleared to disable Timer 2 overflow interrupt. Set to enable Timer 2 overflow interrupt. Serial port Enable bit Cleared to disable serial port interrupt. Set to enable serial port interrupt. Timer 1 overflow interrupt Enable bit Cleared to disable Timer 1 overflow interrupt. Set to enable Timer 1 overflow interrupt. External interrupt 1 Enable bit Cleared to disable external interrupt 1. Set to enable external interrupt 1. Timer 0 overflow interrupt Enable bit Cleared to disable timer 0 overflow interrupt. Set to enable timer 0 overflow interrupt. External interrupt 0 Enable bit Cleared to disable external interrupt 0. Set to enable external interrupt 0. 5 ET2 4 ES 3 ET1 2 EX1 1 ET0 0 EX0 7 EA 6 EC 5 ET2 4 ES 3 ET1 2 EX1 1 ET0 0 EX0 Reset Value = 0000 0000b Bit addressable 64 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 54. IPL0 Register IPL0 - Interrupt Priority Register (B8h) 7 Bit Number 7 6 PPCL Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. PCA interrupt Priority bit Refer to PPCH for priority level. Timer 2 overflow interrupt Priority bit Refer to PT2H for priority level. Serial port Priority bit Refer to PSH for priority level. Timer 1 overflow interrupt Priority bit Refer to PT1H for priority level. External interrupt 1 Priority bit Refer to PX1H for priority level. Timer 0 overflow interrupt Priority bit Refer to PT0H for priority level. External interrupt 0 Priority bit Refer to PX0H for priority level. 5 PT2L 4 PSL 3 PT1L 2 PX1L 1 PT0L 0 PX0L 6 PPCL 5 PT2L 4 PSL 3 PT1L 2 PX1L 1 PT0L 0 PX0L Reset Value = x000 0000b Bit addressable 65 7683B–USB–03/07 Table 55. IPH0 Register IPH0 - Interrupt Priority High Register (B7h) 7 Bit Number 7 6 PPCH Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. PCA interrupt Priority high bit. PPCHPPCLPriority Level 0 0Lowest 01 10 1 1Highest Timer 2 overflow interrupt Priority High bit PT2HPT2LPriority Level 0 0Lowest 01 10 1 1Highest Serial port Priority High bit PSHPSLPriority Level 0 0Lowest 01 10 1 1Highest Timer 1 overflow interrupt Priority High bit PT1HPT1LPriority Level 0 0Lowest 01 10 1 1Highest External interrupt 1 Priority High bit PX1HPX1LPriority Level 0 0Lowest 01 10 1 1Highest Timer 0 overflow interrupt Priority High bit PT0HPT0LPriority Level 0 0Lowest 01 10 1 1Highest External interrupt 0 Priority High bit PX0HPX0LPriority Level 0 0Lowest 01 10 1 1Highest 5 PT2H 4 PSH 3 PT1H 2 PX1H 1 PT0H 0 PX0H 6 PPCH 5 PT2H 4 PSH 3 PT1H 2 PX1H 1 PT0H 0 PX0H Reset Value = x000 0000b Not bit addressable 66 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 56. IEN1 Register IEN1 - Interrupt Enable Register (B1h) 7 Bit Number 7 6 EUSB Bit Mnemonic Description Reserved USB Interrupt Enable bit 6 EUSB Cleared to disable USB interrupt. Set to enable USB interrupt. Reserved Reserved Reserved SPI interrupt Enable bit Cleared to disable SPI interrupt. Set to enable SPI interrupt. TWI interrupt Enable bit Cleared to disable TWI interrupt. Set to enable TWI interrupt. Keyboard interrupt Enable bit Cleared to disable keyboard interrupt. Set to enable keyboard interrupt. 5 4 3 2 ESPI 1 ETWI 0 EKB 5 4 3 - 2 ESPI 1 ETWI 0 EKB Reset Value = x0xx x000b Not bit addressable 67 7683B–USB–03/07 Table 57. IPL1 Register IPL1 - Interrupt Priority Register (B2h) 7 Bit Number 7 6 PUSBL Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. USB Interrupt Priority bit Refer to PUSBH for priority level. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. SPI Interrupt Priority bit Refer to PSPIH for priority level. TWI Interrupt Priority bit Refer to PTWIH for priority level. Keyboard Interrupt Priority bit Refer to PKBH for priority level. 5 4 3 2 PSPIL 1 PTWIL 0 PKBDL 6 PUSBL 5 - 4 - 3 - 2 PSPIL 1 PTWIL 0 PKBL Reset Value = X0XX X000b Not bit addressable 68 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 58. IPH1 Register IPH1 - Interrupt Priority High Register (B3h) 7 Bit Number 7 6 PUSBH Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit. USB Interrupt Priority High bit PUSBHPUSBLPriority Level 0 0Lowest 01 10 1 1Highest Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. SPI Interrupt Priority High bit PSPIHPSPILPriority Level 0 0Lowest 01 10 1 1Highest TWI Interrupt Priority High bit PTWIHPTWILPriority Level 0 0Lowest 01 10 1 1Highest Keyboard Interrupt Priority High bit PKBHPKBLPriority Level 0 0Lowest 01 10 1 1Highest 5 4 3 2 PSPIH 1 PTWIH 0 PKBH 6 PUSBH 5 - 4 - 3 - 2 PSPIH 1 PTWIH 0 PKBH Reset Value = X0XX X000b Not bit addressable 69 7683B–USB–03/07 Interrupt Sources and Vector Addresses Table 59. Vector Table Number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Polling Priority 0 1 2 3 4 6 7 5 8 9 10 11 12 13 14 15 USB UEPINT + USBINT Interrupt Source Reset INT0 Timer 0 INT1 Timer 1 UART Timer 2 PCA Keyboard TWI SPI IE0 TF0 IE1 IF1 RI+TI TF2+EXF2 CF + CCFn (n = 0-4) KBDIT TWIIT SPIIT Interrupt Request Vector Address 0000h 0003h 000Bh 0013h 001Bh 0023h 002Bh 0033h 003Bh 0043h 004Bh 0053h 005Bh 0063h 006Bh 0073h 70 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Keyboard Interface Introduction The AT83C5134/35/36 implements a keyboard interface allowing the connection of a 8 x n matrix keyboard. It is based on 8 inputs with programmable interrupt capability on both high or low level. These inputs are available as an alternate function of P1 and allow to exit from idle and power down modes. The keyboard interface communicates with the C51 core through 3 special function registers: KBLS, the Keyboard Level Selection register (Table 62), KBE, The Keyboard interrupt Enable register (Table 61), and KBF, the Keyboard Flag register (Table 60). The keyboard inputs are considered as 8 independent interrupt sources sharing the same interrupt vector. An interrupt enable bit (KBD in IE1) allows global enable or disable of the keyboard interrupt (see Figure 32). As detailed in Figure 33 each keyboard input has the capability to detect a programmable level according to KBLS.x bit value. Level detection is then reported in interrupt flags KBF.x that can be masked by software using KBE.x bits. This structure allow keyboard arrangement from 1 by n to 8 by n matrix and allow usage of P1 inputs for other purpose. Figure 32. Keyboard Interface Block Diagram P1.0 P1.1 P1.2 P1.3 P1.4 P1.5 P1.6 P1.7 Input Circuitry Input Circuitry Input Circuitry Input Circuitry KBDIT Input Circuitry Input Circuitry Input Circuitry Input Circuitry KBD IE1.0 Description Interrupt Keyboard Interface Interrupt Request Figure 33. Keyboard Input Circuitry Vcc 0 P1:x 1 Internal Pull-up KBF.x KBE.x KBLS.x 71 7683B–USB–03/07 Power Reduction Mode P1 inputs allow exit from idle and power down modes as detailed in section “Powerdown Mode”. Table 60. KBF Register KBF - Keyboard Flag Register (9Eh) 7 KBF7 Bit Number 6 KBF6 5 KBF5 4 KBF4 3 KBF3 2 KBF2 1 KBF1 0 KBF0 Registers Bit Mnemonic Description Keyboard line 7 flag Set by hardware when the Port line 7 detects a programmed level. It generates a Keyboard interrupt request if the KBKBIE.7 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 6 flag Set by hardware when the Port line 6 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.6 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 5 flag Set by hardware when the Port line 5 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.5 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 4 flag Set by hardware when the Port line 4 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.4 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 3 flag Set by hardware when the Port line 3 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.3 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 2 flag Set by hardware when the Port line 2 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.2 bit in KBIE register is set. Must be cleared by software. Keyboard line 1 flag Set by hardware when the Port line 1 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.1 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. Keyboard line 0 flag Set by hardware when the Port line 0 detects a programmed level. It generates a Keyboard interrupt request if the KBIE.0 bit in KBIE register is set. Cleared by hardware when reading KBF SFR by software. 7 KBF7 6 KBF6 5 KBF5 4 KBF4 3 KBF3 2 KBF2 1 KBF1 0 KBF0 Reset Value = 0000 0000b 72 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Table 61. KBE Register KBE - Keyboard Input Enable Register (9Dh) 7 KBE7 Bit Number 6 KBE6 5 KBE5 4 KBE4 3 KBE3 2 KBE2 1 KBE1 0 KBE0 Bit Mnemonic Description Keyboard line 7 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.7 bit in KBF register to generate an interrupt request. Keyboard line 6 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.6 bit in KBF register to generate an interrupt request. Keyboard line 5 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.5 bit in KBF register to generate an interrupt request. Keyboard line 4 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.4 bit in KBF register to generate an interrupt request. Keyboard line 3 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.3 bit in KBF register to generate an interrupt request. Keyboard line 2 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.2 bit in KBF register to generate an interrupt request. Keyboard line 1 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.1 bit in KBF register to generate an interrupt request. Keyboard line 0 Enable bit Cleared to enable standard I/O pin. Set to enable KBF.0 bit in KBF register to generate an interrupt request. 7 KBE7 6 KBE6 5 KBE5 4 KBE4 3 KBE3 2 KBE2 1 KBE1 0 KBE0 Reset Value = 0000 0000b 73 7683B–USB–03/07 Table 62. KBLS Register KBLS-Keyboard Level Selector Register (9Ch) 7 KBLS7 Bit Number 6 KBLS6 5 KBLS5 4 KBLS4 3 KBLS3 2 KBLS2 1 KBLS1 0 KBLS0 Bit Mnemonic Description Keyboard line 7 Level Selection bit Cleared to enable a low level detection on Port line 7. Set to enable a high level detection on Port line 7. Keyboard line 6 Level Selection bit Cleared to enable a low level detection on Port line 6. Set to enable a high level detection on Port line 6. Keyboard line 5 Level Selection bit Cleared to enable a low level detection on Port line 5. Set to enable a high level detection on Port line 5. Keyboard line 4 Level Selection bit Cleared to enable a low level detection on Port line 4. Set to enable a high level detection on Port line 4. Keyboard line 3 Level Selection bit Cleared to enable a low level detection on Port line 3. Set to enable a high level detection on Port line 3. Keyboard line 2 Level Selection bit Cleared to enable a low level detection on Port line 2. Set to enable a high level detection on Port line 2. Keyboard line 1 Level Selection bit Cleared to enable a low level detection on Port line 1. Set to enable a high level detection on Port line 1. Keyboard line 0 Level Selection bit Cleared to enable a low level detection on Port line 0. Set to enable a high level detection on Port line 0. 7 KBLS7 6 KBLS6 5 KBLS5 4 KBLS4 3 KBLS3 2 KBLS2 1 KBLS1 0 KBLS0 Reset Value = 0000 0000b 74 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Programmable LED AT83C5134/35/36 have up to 4 programmable LED current sources, configured by the register LEDCON. Table 63. LEDCON Register LEDCON (S:F1h) LED Control Register 7 LED3 Bit Number Bit Mnemonic 6 5 LED2 4 3 LED1 2 1 LED0 0 Description PortLED3Configuration 0 0Standard C51 Port 0 12 mA current source when P3.7 is low 1 04 mA current source when P3.7 is low 1 110 mA current source when P3.7 is low Port/LED2Configuration 0 0Standard C51 Port 0 12 mA current source when P3.6 is low 1 04 mA current source when P3.6 is low 1 110 mA current source when P3.6 is low Port/LED1Configuration 0 0Standard C51 Port 0 12 mA current source when P3.5 is low 1 04 mA current source when P3.5 is low 1 110 mA current source when P3.5 is low Port/LED0Configuration 0 0Standard C51 Port 0 12 mA current source when P3.3 is low 1 04 mA current source when P3.3 is low 1 110 mA current source when P3.3 is low 7:6 LED3 5:4 LED2 3:2 LED1 1:0 LED0 Reset Value = 00h 75 7683B–USB–03/07 Serial Peripheral Interface (SPI) Features The Serial Peripheral Interface module (SPI) allows full-duplex, synchronous, serial communication between the MCU and peripheral devices, including other MCUs. Features of the SPI module include the following: • • • • • • Full-duplex, three-wire synchronous transfers Master or Slave operation Eight programmable Master clock rates Serial clock with programmable polarity and phase Master mode fault error flag with MCU interrupt capability Write collision flag protection Signal Description Figure 34 shows a typical SPI bus configuration using one Master controller and many Slave peripherals. The bus is made of three wires connecting all the devices: Figure 34. SPI Master/Slaves Interconnection MISO MOSI SCK SS Slave 1 MISO MOSI SCK SS VDD Master 0 1 2 3 PORT MISO MOSI SCK SS Slave 4 Slave 3 MISO MOSI SCK SS Slave 2 The Master device selects the individual Slave devices by using four pins of a parallel port to control the four SS pins of the Slave devices. Master Output Slave Input (MOSI) This 1-bit signal is directly connected between the Master Device and a Slave Device. The MOSI line is used to transfer data in series from the Master to the Slave. Therefore, it is an output signal from the Master, and an input signal to a Slave. A byte (8-bit word) is transmitted most significant bit (MSB) first, least significant bit (LSB) last. This 1-bit signal is directly connected between the Slave Device and a Master Device. The MISO line is used to transfer data in series from the Slave to the Master. Therefore, it is an output signal from the Slave, and an input signal to the Master. A byte (8-bit word) is transmitted most significant bit (MSB) first, least significant bit (LSB) last. This signal is used to synchronize the data movement both in and out the devices through their MOSI and MISO lines. It is driven by the Master for eight clock cycles which allows to exchange one byte on the serial lines. Each Slave peripheral is selected by one Slave Select pin (SS). This signal must stay low for any message for a Slave. It is obvious that only one Master (SS high level) can drive the network. The Master may select each Slave device by software through port Master Input Slave Output (MISO) SPI Serial Clock (SCK) Slave Select (SS) 76 AT83C5134/35/36 7683B–USB–03/07 MISO MOSI SCK SS AT83C5134/35/36 pins (Figure 34). To prevent bus conflicts on the MISO line, only one slave should be selected at a time by the Master for a transmission. In a Master configuration, the SS line can be used in conjunction with the MODF flag in the SPI Status register (SPSTA) to prevent multiple masters from driving MOSI and SCK (see Section “Error Conditions”, page 81). A high level on the SS pin puts the MISO line of a Slave SPI in a high-impedance state. The SS pin could be used as a general-purpose if the following conditions are met: • The device is configured as a Master and the SSDIS control bit in SPCON is set. This kind of configuration can be found when only one Master is driving the network and there is no way that the SS pin could be pulled low. Therefore, the MODF flag in the SPSTA will never be set(1). The Device is configured as a Slave with CPHA and SSDIS control bits set(2) This kind of configuration can happen when the system comprises one Master and one Slave only. Therefore, the device should always be selected and there is no reason that the Master uses the SS pin to select the communicating Slave device. 1. Clearing SSDIS control bit does not clear MODF. 2. Special care should be taken not to set SSDIS control bit when CPHA =’0’ because in this mode, the SS is used to start the transmission. • Notes: Baud Rate In Master mode, the baud rate can be selected from a baud rate generator which is controlled by three bits in the SPCON register: SPR2, SPR1 and SPR0. The Master clock is chosen from one of seven clock rates resulting from the division of the internal clock by 2, 4, 8, 16, 32, 64 or 128. Table 64 gives the different clock rates selected by SPR2:SPR1:SPR0: Table 64. SPI Master Baud Rate Selection SPR2 0 0 0 0 1 1 1 1 SPR1 0 0 1 1 0 0 1 1 SPR0 0 1 0 1 0 1 0 1 Clock Rate Don’t Use FCLK PERIPH/4 FCLK PERIPH/8 FCLK PERIPH/16 FCLK PERIPH/32 FCLK PERIPH/64 FCLK PERIPH/128 Don’t Use Baud Rate Divisor (BD) No BRG 4 8 16 32 64 128 No BRG 77 7683B–USB–03/07 Functional Description Figure 35 shows a detailed structure of the SPI module. Figure 35. SPI Module Block Diagram Internal Bus SPDAT FCLK PERIPH Shift Register 7 6 5 4 3 2 1 0 Clock Divider /4 /8 /16 /32 /64 /128 Receive Data Register Pin Control Logic MOSI MISO Clock Logic Clock Select M S SCK SS SPR2 SPEN SSDIS MSTR CPOL CPHA SPR1 SPR0 SPCON SPI Control 8-bit bus 1-bit signal SPI Interrupt Request SPSTA SPIF WCOL SSERR MODF - Operating Modes The Serial Peripheral Interface can be configured as one of the two modes: Master mode or Slave mode. The configuration and initialization of the SPI module is made through one register: • • • • The Serial Peripheral CONtrol register (SPCON) SPCON The Serial Peripheral STAtus register (SPSTA) The Serial Peripheral DATa register (SPDAT) Once the SPI is configured, the data exchange is made using: During an SPI transmission, data is simultaneously transmitted (shifted out serially) and received (shifted in serially). A serial clock line (SCK) synchronizes shifting and sampling on the two serial data lines (MOSI and MISO). A Slave Select line (SS) allows individual selection of a Slave SPI device; Slave devices that are not selected do not interfere with SPI bus activities. When the Master device transmits data to the Slave device via the MOSI line, the Slave device responds by sending data to the Master device via the MISO line. This implies full-duplex transmission with both data out and data in synchronized with the same clock (Figure 36). 78 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Figure 36. Full-duplex Master/Slave Interconnection MISO MOSI SPI Clock Generator SCK SS VDD MISO MOSI SCK SS VSS 8-bit Shift Register 8-bit Shift Register Master MCU Slave MCU Master Mode The SPI operates in Master mode when the Master bit, MSTR (1), in the SPCON register is set. Only one Master SPI device can initiate transmissions. Software begins the transmission from a Master SPI module by writing to the Serial Peripheral Data Register (SPDAT). If the shift register is empty, the byte is immediately transferred to the shift register. The byte begins shifting out on MOSI pin under the control of the serial clock, SCK. Simultaneously, another byte shifts in from the Slave on the Master’s MISO pin. The transmission ends when the Serial Peripheral transfer data flag, SPIF, in SPSTA becomes set. At the same time that SPIF becomes set, the received byte from the Slave is transferred to the receive data register in SPDAT. Software clears SPIF by reading the Serial Peripheral Status register (SPSTA) with the SPIF bit set, and then reading the SPDAT. The SPI operates in Slave mode when the Master bit, MSTR (2), in the SPCON register is cleared. Before a data transmission occurs, the Slave Select pin, SS , of the Slave device must be set to’0’. SS must remain low until the transmission is complete. In a Slave SPI module, data enters the shift register under the control of the SCK from the Master SPI module. After a byte enters the shift register, it is immediately transferred to the receive data register in SPDAT, and the SPIF bit is set. To prevent an overflow condition, Slave software must then read the SPDAT before another byte enters the shift register (3). A Slave SPI must complete the write to the SPDAT (shift register) at least one bus cycle before the Master SPI starts a transmission. If the write to the data register is late, the SPI transmits the data already in the shift register from the previous transmission. Slave Mode Transmission Formats Software can select any of four combinations of serial clock (SCK) phase and polarity using two bits in the SPCON: the Clock POLarity (CPOL ( 4) ) and the Clock PHAse (CPHA4). CPOL defines the default SCK line level in idle state. It has no significant effect on the transmission format. CPHA defines the edges on which the input data are sampled and the edges on which the output data are shifted (Figure 37 and Figure 38). The clock phase and polarity should be identical for the Master SPI device and the communicating Slave device. 1. 2. 3. 4. The SPI module should be configured as a Master before it is enabled (SPEN set). Also the Master SPI should be configured before the Slave SPI. The SPI module should be configured as a Slave before it is enabled (SPEN set). The maximum frequency of the SCK for an SPI configured as a Slave is the bus clock speed. Before writing to the CPOL and CPHA bits, the SPI should be disabled (SPEN =’0’). 79 7683B–USB–03/07 Figure 37. Data Transmission Format (CPHA = 0) SCK cycle number SPEN (internal) 1 2 3 4 5 6 7 8 SCK (CPOL = 0) SCK (CPOL = 1) MOSI (from Master) MISO (from Slave) SS (to Slave) Capture point MSB MSB bit6 bit6 bit5 bit5 bit4 bit4 bit3 bit3 bit2 bit2 bit1 bit1 LSB LSB Figure 38. Data Transmission Format (CPHA = 1) SCK cycle number SPEN (internal) SCK (CPOL = 0) SCK (CPOL = 1) MOSI (from Master) MISO (from Slave) SS (to Slave) Capture point MSB MSB bit6 bit6 bit5 bit5 bit4 bit4 bit3 bit3 bit2 bit2 bit1 bit1 LSB LSB 1 2 3 4 5 6 7 8 Figure 39. CPHA/SS Timing MISO/MOSI Master SS Slave SS (CPHA = 0) Slave SS (CPHA = 1) Byte 1 Byte 2 Byte 3 As shown in Figure 38, the first SCK edge is the MSB capture strobe. Therefore the Slave must begin driving its data before the first SCK edge, and a falling edge on the SS pin is used to start the transmission. The SS pin must be toggled high and then low between each byte transmitted (Figure 35). Figure 39 shows an SPI transmission in which CPHA is’1’. In this case, the Master begins driving its MOSI pin on the first SCK edge. Therefore the Slave uses the first SCK edge as a start transmission signal. The SS pin can remain low between transmissions (Figure 34). This format may be preferable in systems having only one Master and only one Slave driving the MISO data line. 80 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Error Conditions Mode Fault (MODF) The following flags in the SPSTA signal SPI error conditions: Mode Fault error in Master mode SPI indicates that the level on the Slave Select (SS) pin is inconsistent with the actual mode of the device. MODF is set to warn that there may have a multi-master conflict for system control. In this case, the SPI system is affected in the following ways: • • • An SPI receiver/error CPU interrupt request is generated, The SPEN bit in SPCON is cleared. This disable the SPI, The MSTR bit in SPCON is cleared When SS DISable (SSDIS) bit in the SPCON register is cleared, the MODF flag is set when the SS signal becomes “0”. However, as stated before, for a system with one Master, if the SS pin of the Master device is pulled low, there is no way that another Master attempt to drive the network. In this case, to prevent the MODF flag from being set, software can set the SSDIS bit in the SPCON register and therefore making the SS pin as a general-purpose I/O pin. Clearing the MODF bit is accomplished by a read of SPSTA register with MODF bit set, followed by a write to the SPCON register. SPEN Control bit may be restored to its original set state after the MODF bit has been cleared. Write Collision (WCOL) A Write Collision (WCOL) flag in the SPSTA is set when a write to the SPDAT register is done during a transmit sequence. WCOL does not cause an interruption, and the transfer continues uninterrupted. Clearing the WCOL bit is done through a software sequence of an access to SPSTA and an access to SPDAT. Overrun Condition An overrun condition occurs when the Master device tries to send several data bytes and the Slave devise has not cleared the SPIF bit issuing from the previous data byte transmitted. In this case, the receiver buffer contains the byte sent after the SPIF bit was last cleared. A read of the SPDAT returns this byte. All others bytes are lost. This condition is not detected by the SPI peripheral. Interrupts Two SPI status flags can generate a CPU interrupt requests: Table 65. SPI Interrupts Flag SPIF (SP Data Transfer) MODF (Mode Fault) Request SPI Transmitter Interrupt request SPI Receiver/Error Interrupt Request (if SSDIS = “0”) Serial Peripheral data transfer flag, SPIF: This bit is set by hardware when a transfer has been completed. SPIF bit generates transmitter CPU interrupt requests. Mode Fault flag, MODF: This bit becomes set to indicate that the level on the SS is inconsistent with the mode of the SPI. MODF with SSDIS reset, generates receiver/error CPU interrupt requests. Figure 40 gives a logical view of the above statements. 81 7683B–USB–03/07 Figure 40. SPI Interrupt Requests Generation SPIF SPI Transmitter CPU Interrupt Request SPI Receiver/Error CPU Interrupt Request SSDIS SPI CPU Interrupt Request MODF Registers There are three registers in the module that provide control, status and data storage functions. These registers are describes in the following paragraphs. • The Serial Peripheral Control Register does the following: – – – – – Selects one of the Master clock rates Configure the SPI module as Master or Slave Selects serial clock polarity and phase Enables the SPI module Frees the SS pin for a general-purpose Serial Peripheral Control Register (SPCON) Table 66 describes this register and explains the use of each bit. Table 66. SPCON Register 7 SPR2 Bit Number 7 6 SPEN 5 SSDIS 4 MSTR 3 CPOL 2 CPHA 1 SPR1 0 SPR0 Bit Mnemonic Description SPR2 Serial Peripheral Rate 2 Bit with SPR1 and SPR0 define the clock rate. Serial Peripheral Enable 6 SPEN Cleared to disable the SPI interface. Set to enable the SPI interface. SS Disable 5 SSDIS Cleared to enable SS in both Master and Slave modes. Set to disable SS in both Master and Slave modes. In Slave mode, this bit has no effect if CPHA = “0”. Serial Peripheral Master 5 MSTR Cleared to configure the SPI as a Slave. Set to configure the SPI as a Master. Clock Polarity 4 CPOL Cleared to have the SCK set to “0” in idle state. Set to have the SCK set to “1” in idle state. Clock Phase 3 CPHA Cleared to have the data sampled when the SCK leaves the idle state (see CPOL). Set to have the data sampled when the SCK returns to idle state (see CPOL). 82 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Bit Number Bit Mnemonic Description SPR2 SPR1 SPR0 Serial Peripheral Rate 2 SPR1 000Reserved 00 1FCLK PERIPH/4 010 FCLK PERIPH/8 011FCLK PERIPH/16 100FCLK PERIPH/32 1 SPR0 10 1FCLK PERIPH/64 110FCLK PERIPH/128 1 11Reserved Reset Value = 0001 0100b Not bit addressable Serial Peripheral Status Register (SPSTA) The Serial Peripheral Status Register contains flags to signal the following conditions: • • • Data transfer complete Write collision Inconsistent logic level on SS pin (mode fault error) Table 67 describes the SPSTA register and explains the use of every bit in the register. Table 67. SPSTA Register SPSTA - Serial Peripheral Status and Control register (0C4H) Table 1. 7 SPIF Bit Number 6 WCOL 5 SSERR 4 MODF 3 2 1 0 - Bit Mnemonic Description Serial Peripheral data transfer flag 7 SPIF Cleared by hardware to indicate data transfer is in progress or has been approved by a clearing sequence. Set by hardware to indicate that the data transfer has been completed. Write Collision flag 6 WCOL Cleared by hardware to indicate that no collision has occurred or has been approved by a clearing sequence. Set by hardware to indicate that a collision has been detected. Synchronous Serial Slave Error flag 5 SSERR Set by hardware when SS is deasserted before the end of a received data. Cleared by disabling the SPI (clearing SPEN bit in SPCON). Mode Fault 4 MODF Cleared by hardware to indicate that the SS pin is at appropriate logic level, or has been approved by a clearing sequence. Set by hardware to indicate that the SS pin is at inappropriate logic level. 3 - Reserved The value read from this bit is indeterminate. Do not set this bit 83 7683B–USB–03/07 Bit Number 2 Bit Mnemonic Description Reserved The value read from this bit is indeterminate. Do not set this bit Reserved The value read from this bit is indeterminate. Do not set this bit. Reserved The value read from this bit is indeterminate. Do not set this bit. 1 - 0 - Reset Value = 00X0 XXXXb Not Bit addressable Serial Peripheral Data Register (SPDAT) The Serial Peripheral Data Register (Table 68) is a read/write buffer for the receive data register. A write to SPDAT places data directly into the shift register. No transmit buffer is available in this model. A Read of the SPDAT returns the value located in the receive buffer and not the content of the shift register. Table 68. SPDAT Register SPDAT - Serial Peripheral Data Register (0C5H) Table 2. 7 R7 6 R6 5 R5 4 R4 3 R3 2 R2 1 R1 0 R0 Reset Value = Indeterminate R7:R0: Receive data bits SPCON, SPSTA and SPDAT registers may be read and written at any time while there is no on-going exchange. However, special care should be taken when writing to them while a transmission is on-going: • • • • • Do not change SPR2, SPR1 and SPR0 Do not change CPHA and CPOL Do not change MSTR Clearing SPEN would immediately disable the peripheral Writing to the SPDAT will cause an overflow 84 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 Two Wire Interface (TWI) This section describes the 2-wire interface. The 2-wire bus is a bi-directional 2-wire serial communication standard. It is designed primarily for simple but efficient integrated circuit (IC) control. The system is comprised of two lines, SCL (Serial Clock) and SDA (Serial Data) that carry information between the ICs connected to them. The serial data transfer is limited to 100 Kbit/s in standard mode. Various communication configuration can be designed using this bus. Figure 41 shows a typical 2-wire bus configuration. All the devices connected to the bus can be master and slave. Figure 41. 2-wire Bus Configuration device1 device2 device3 ... deviceN SCL SDA 85 7683B–USB–03/07 Figure 42. Block Diagram 8 SSADR Address Register Input Filter SDA Output Stage Comparator SSDAT Shift Register ACK 8 Input Filter SCL Output Stage Timer 1 overflow SSCON Arbitration & Sink Logic Timing & Control logic FCLK PERIPH/4 Serial clock generator Interrupt Control Register 7 Status Bits Status Decoder SSCS Status Register 8 86 AT83C5134/35/36 7683B–USB–03/07 Internal Bus AT83C5134/35/36 Description The CPU interfaces to the 2-wire logic via the following four 8-bit special function registers: the Synchronous Serial Control register (SSCON; Table 78), the Synchronous Serial Data register (SSDAT; Table 79), the Synchronous Serial Control and Status register (SSCS; Table 80) and the Synchronous Serial Address register (SSADR Table 81). SSCON is used to enable the TWI interface, to program the bit rate (see Table 71), to enable slave modes, to acknowledge or not a received data, to send a START or a STOP condition on the 2-wire bus, and to acknowledge a serial interrupt. A hardware reset disables the TWI module. SSCS contains a status code which reflects the status of the 2-wire logic and the 2-wire bus. The three least significant bits are always zero. The five most significant bits contains the status code. There are 26 possible status codes. When SSCS contains F8h, no relevant state information is available and no serial interrupt is requested. A valid status code is available in SSCS one machine cycle after SI is set by hardware and is still present one machine cycle after SI has been reset by software. to Table 77. give the status for the master modes and miscellaneous states. SSDAT contains a byte of serial data to be transmitted or a byte which has just been received. It is addressable while it is not in process of shifting a byte. This occurs when 2-wire logic is in a defined state and the serial interrupt flag is set. Data in SSDAT remains stable as long as SI is set. While data is being shifted out, data on the bus is simultaneously shifted in; SSDAT always contains the last byte present on the bus. SSADR may be loaded with the 7-bit slave address (7 most significant bits) to which the TWI module will respond when programmed as a slave transmitter or receiver. The LSB is used to enable general call address (00h) recognition. Figure 43 shows how a data transfer is accomplished on the 2-wire bus. Figure 43. Complete Data Transfer on 2-wire Bus SDA MSB acknowledgement signal from receiver SCL S start condition 1 2 7 8 9 ACK 1 2 3-8 acknowledgement signal from receiver 9 ACK clock line held low while interrupts are serviced P stop condition The four operating modes are: • • • • Master Transmitter Master Receiver Slave transmitter Slave receiver Data transfer in each mode of operation is shown in Table to Table 77 and Figure 44. to Figure 47.. These figures contain the following abbreviations: S : START condition R : Read bit (high level at SDA) W: Write bit (low level at SDA) 87 7683B–USB–03/07 A: Acknowledge bit (low level at SDA) A: Not acknowledge bit (high level at SDA) Data: 8-bit data byte P : STOP condition In Figure 44 to Figure 47, circles are used to indicate when the serial interrupt flag is set. The numbers in the circles show the status code held in SSCS. At these points, a service routine must be executed to continue or complete the serial transfer. These service routines are not critical since the serial transfer is suspended until the serial interrupt flag is cleared by software. When the serial interrupt routine is entered, the status code in SSCS is used to branch to the appropriate service routine. For each status code, the required software action and details of the following serial transfer are given in Table to Table 77. Master Transmitter Mode In the master transmitter mode, a number of data bytes are transmitted to a slave receiver (Figure 44). Before the master transmitter mode can be entered, SSCON must be initialised as follows: Table 69. SSCON Initialization CR2 bit rate SSIE 1 STA 0 STO 0 SI 0 AA X CR1 bit rate CR0 bit rate CR0, CR1 and CR2 define the internal serial bit rate if external bit rate generator is not used. SSIE must be set to enable TWI. STA, STO and SI must be cleared. The master transmitter mode may now be entered by setting the STA bit. The 2-wire logic will now test the 2-wire bus and generate a START condition as soon as the bus becomes free. When a START condition is transmitted, the serial interrupt flag (SI bit in SSCON) is set, and the status code in SSCS will be 08h. This status must be used to vector to an interrupt routine that loads SSDAT with the slave address and the data direction bit (SLA+W). When the slave address and the direction bit have been transmitted and an acknowledgement bit has been received, SI is set again and a number of status code in SSCS are possible. There are 18h, 20h or 38h for the master mode and also 68h, 78h or B0h if the slave mode was enabled (AA=logic 1). The appropriate action to be taken for each of these status code is detailed in Table . This scheme is repeated until a STOP condition is transmitted. SSIE, CR2, CR1 and CR0 are not affected by the serial transfer and are referred to Table 7 to Table 11. After a repeated START condition (state 10h) the TWI module may switch to the master receiver mode by loading SSDAT with SLA+R. Master Receiver Mode In the master receiver mode, a number of data bytes are received from a slave transmitter (Figure 45). The transfer is initialized as in the master transmitter mode. When the START condition has been transmitted, the interrupt routine must load SSDAT with the 7-bit slave address and the data direction bit (SLA+R). The serial interrupt flag SI must then be cleared before the serial transfer can continue. When the slave address and the direction bit have been transmitted and an acknowledgement bit has been received, the serial interrupt flag is set again and a number of 88 AT83C5134/35/36 7683B–USB–03/07 AT83C5134/35/36 status code in SSCS are possible. There are 40h, 48h or 38h for the master mode and also 68h, 78h or B0h if the slave mode was enabled (AA=logic 1). The appropriate action to be taken for each of these status code is detailed in Table . This scheme is repeated until a STOP condition is transmitted. SSIE, CR2, CR1 and CR0 are not affected by the serial transfer and are referred to Table 7 to Table 11. After a repeated START condition (state 10h) the TWI module may switch to the master transmitter mode by loading SSDAT with SLA+W. Slave Receiver Mode In the slave receiver mode, a number of data bytes are received from a master transmitter (Figure 46). To initiate the slave receiver mode, SSADR and SSCON must be loaded as follows: Table 70. SSADR: Slave Receiver Mode Initialization A6 A5 A4 A3 own slave address A2 A1 A0 GC The upper 7 bits are the address to which the TWI module will respond when addressed by a master. If the LSB (GC) is set the TWI module will respond to the general call address (00h); otherwise it ignores the general call address. Table 71. SSCON: Slave Receiver Mode Initialization CR2 bit rate SSIE 1 STA 0 STO 0 SI 0 AA 1 CR1 bit rate CR0 bit rate CR0, CR1 and CR2 have no effect in the slave mode. SSIE must be set to enable the TWI. The AA bit must be set to enable the own slave address or the general call address acknowledgement. STA, STO and SI must be cleared. When SSADR and SSCON have been initialised, the TWI module waits until it is addressed by its own slave address followed by the data direction bit which must be at logic 0 (W) for the TWI to operate in the slave receiver mode. After its own slave address and the W bit have been received, the serial interrupt flag is set and a valid status code can be read from SSCS. This status code is used to vector to an interrupt service routine.The appropriate action to be taken for each of these status code is detailed in Table . The slave receiver mode may also be entered if arbitration is lost while TWI is in the master mode (states 68h and 78h). If the AA bit is reset during a transfer, TWI module will return a not acknowledge (logic 1) to SDA after the next received data byte. While AA is reset, the TWI module does not respond to its own slave address. However, the 2-wire bus is still monitored and address recognition may be resume at any time by setting AA. This means that the AA bit may be used to temporarily isolate the module from the 2-wire bus. Slave Transmitter Mode In the slave transmitter mode, a number of data bytes are transmitted to a master receiver (Figure 47). Data transfer is initialized as in the slave receiver mode. When SSADR and SSCON have been initialized, the TWI module waits until it is addressed by its own slave address followed by the data direction bit which must be at logic 1 (R) for TWI to operate in the slave transmitter mode. After its own slave address and the R bit 89 7683B–USB–03/07 have been received, the serial interrupt flag is set and a valid status code can be read from SSCS. This status code is used to vector to an interrupt service routine. The appropriate action to be taken for each of these status code is detailed in Table . The slave transmitter mode may also be entered if arbitration is lost while the TWI module is in the master mode. If the AA bit is reset during a transfer, the TWI module will transmit the last byte of the transfer and enter state C0h or C8h. the TWI module is switched to the not addressed slave mode and will ignore the master receiver if it continues the transfer. Thus the master receiver receives all 1’s as serial data. While AA is reset, the TWI module does not respond to its own slave address. However, the 2-wire bus is still monitored and address recognition may be resume at any time by setting AA. This means that the AA bit may be used to temporarily isolate the TWI module from the 2-wire bus. Miscellaneous States There are two SSCS codes that do not correspond to a define TWI hardware state (Table 77 ). These codes are discuss hereafter. Status F8h indicates that no relevant information is available because the serial interrupt flag is not set yet. This occurs between other states and when the TWI module is not involved in a serial transfer. Status 00h indicates that a bus error has occurred during a TWI serial transfer. A bus error is caused when a START or a STOP condition occurs at an illegal position in the format frame. Examples of such illegal positions happen during the serial transfer of an address byte, a data byte, or an acknowledge bit. When a bus error occurs, SI is set. To recover from a bus error, the STO flag must be set and SI must be cleared. This causes the TWI module to enter the not addressed slave mode and to clear the STO flag (no other bits in SSCON are affected). The SDA and SCL lines are released and no STOP condition is transmitted. Notes the TWI module interfaces to the external 2-wire bus via two port pins: SCL (serial clock line) and SDA (serial data line). To avoid low level asserting on these lines when the TWI module is enabled, the output latches of SDA and SLC must be set to logic 1. Table 72. Bit Frequency Configuration Bit Frequency ( kHz) CR2 0 0 0 0 1 1 1 CR1 0 0 1 1 0 0 1 CR0 0 1 0 1 0 1 0 FOSCA= 12 MHz 47 53.5 62.5 75 100 200 FOSCA = 16 MHz 62.5 71.5 83 100 133.3 266.6 FOSCA divided by 256 224 192 160 Unused 120 60 Timer 1 in mode 2 can be used as TWI baudrate generator with the following formula: 96.(256-”Timer1 reload value”) 1 1 1 0.5