STC12C2052-35I-DIP20

www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 . d e STC12C2052AD series MCU t i m i L STC12LE2052AD series MCU U C Data M Sheet C T S STC MCU Limited www.STCMCU.com Update date: 2011-7-15 STC MCU Limited. website：www.STCMCU.com  CONTENTS Chapter 1. Introduction.................................................................7 1.1 Features.................................................................................................. 7 1.2 Block diagram........................................................................................ 8 1.3 Pin Configurations . ............................................................................... 9 1.4 STC12C2052AD series Selection Table.............................................. 10 1.5 STC12C2052AD series Minimum Application System........................11 1.6 STC12C2052AD series MCU Typical Application Circuit for ISP..... 12 1.7 Pin Descriptions................................................................................... 14 1.8 Package Dimension Drawings.............................................................. 16 1.9 STC12C2052AD series MCU naming rules........................................ 18 1.10 Global Unique Identification Number (ID)........................................ 19 d e t i im L Chapter 2. Clock, Power Management and Reset....................22 U C M 2.1 Clock.................................................................................................... 22 2.1.1 2.1.2 2.1.3 2.1.4 On-Chip R/C Clock and External Crystal/Clcok are Optional in STC-ISP.exe 22 Divider for System Clock ................................................................................... 23 How to Know Internal RC Oscillator frequency(Internal clock frequency) ...... 24 Programmable Clock Output............................................................................... 27 C T S 2.1.4.1 Timer 0 Programmable Clock-out on P1.0........................................................................ 28 2.1.4.2 Timer 1 Programmable Clock-out on P1.1........................................................................ 29 2.2 Power Management Modes.................................................................. 30 2.2.1 Slow Down Mode................................................................................................ 31 2.2.2 Idle Mode............................................................................................................. 32 2.2.3 Stop / Power Down (PD) Mode and Demo Program (C and ASM).................... 33 2.3 RESET Sources.................................................................................... 39 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.3.7 RESET Pin........................................................................................................... 39 Software RESET.................................................................................................. 39 Power-On Reset (POR)........................................................................................ 40 MAX810 power-on-Reset delay.......................................................................... 40 Internal Low Voltage Detection Reset................................................................. 41 Watch-Dog-Timer................................................................................................ 44 Warm Boot and Cold Boot Reset......................................................................... 48 Chapter 3. Memory Organization..............................................49 3.1 Program Memory................................................................................. 49 3.2 Data Memory(SRAM).......................................................................... 50 3.3 Special Function Registers................................................................... 53 3.3.1 Special Function Registers Address Map............................................................ 53 3.3.2 Special Function Registers Bits Description....................................................... 54 Chapter 4. Configurable I/O Ports of STC12C2052AD series 58 4.1 I/O Ports Configurations...................................................................... 58 4.2 I/O ports Modes.................................................................................... 60 4.2.1 4.2.2 4.2.3 4.2.4 d e t i im Quasi-bidirectional I/O........................................................................................ 60 Push-pull Output.................................................................................................. 61 Input-only (High-Impedance) Mode................................................................... 61 Open-drain Output............................................................................................... 61 U C M L 4.3 I/O port application notes..................................................................... 62 4.4 Typical transistor control circuit........................................................... 62 4.5 Typical diode control circuit................................................................. 62 4.6 3V/5V hybrid system............................................................................ 63 4.7 How to make I/O port low after MCU reset......................................... 64 4.8 I/O status while PWM outputing.......................................................... 64 4.9 I/O drive LED application circuit......................................................... 65 4.10 I/O immediately drive LCD application circuit................................. 66 4.11 Using A/D Conversion to scan key application circuit....................... 67 C T S Chapter 5. Instruction System....................................................68 5.1 Addressing Modes................................................................................ 68 5.2 Instruction Set Summary...................................................................... 69 5.3 Instruction Definitions.......................................................................... 74 Chapter 6. Interrupt System..................................................... 111 6.1 6.2 6.3 6.4 6.5 6.6 Interrupt Structure...............................................................................113 Interrupt Register.................................................................................115 Interrupt Priorities.............................................................................. 125 How Interrupts Are Handled.............................................................. 126 External Interrupts............................................................................. 127 Response Time.................................................................................. 131 6.7 Demo Programs about Interrupts (C and ASM)................................. 132 6.7.1 6.7.2 6.7.3 6.7.4 6.7.5 6.7.6 External Interrupt 0 (INT0 ) Demo Programs (C and ASM)............................ 132 External Interrupt 1 (INT1 ) Demo Programs (C and ASM)............................ 136 Programs of P3.4/T0 Interrupt(falling edge) used to wake up PD mode.......... 140 Programs of P3.5/T1 Interrupt(falling edge) used to wake up PD mode.......... 142 Program of P3.0/RxD Interrupt(falling edge) used to wake up PD mode......... 144 Program of PCA Interrupt used to wake up Power Down mode....................... 147 Chapter 7. Timer/Counter 0/1..................................................151 7.1 Special Function Registers about Timer/Counter............................... 151 7.2 Timer/Counter 0 Mode of Operation (Compatible with traditional 8051 MCU).........155 7.2.1 7.2.2 7.2.3 7.2.4 d e t imi Mode 0 (13-bit Timer/Counter)......................................................................................155 Mode 1 (16-bit Timer/Counter) and Demo Programs (C and ASM).............................. 156 Mode 2 (8-bit Auto-Reload Mode) and Demo Programs (C and ASM)......................... 160 Mode 3 (Two 8-bit Timers/Couters)............................................................................... 163 U C M L 7.3 Timer/Counter 1 Mode of Operation.................................................. 164 7.3.1 Mode 0 (13-bit Timer/Counter)......................................................................................164 7.3.2 Mode 1 (16-bit Timer/Counter) and Demo Programs (C and ASM).............................. 165 7.3.3 Mode 2 (8-bit Auto-Reload Mode) and Demo Programs (C and ASM)......................... 169 C T S 7.4 Programmable Clock Output and Demo Programs (C and ASM)..... 172 7.4.1 Timer 0 Programmable Clock-out on P1.0 and Demo Program(C and ASM).. 174 7.4.2 Timer 1 Programmable Clock-out on P1.1 and Demo Program(C and ASM).. 177 7.5 Application note for Timer in practice............................................... 180 Chapter 8. UART with Enhanced Function............................181 8.1 Special Function Registers about UART............................................ 181 8.2 UART Operation Modes ................................................................... 185 8.2.1 8.2.2 8.2.3 8.2.4 8.3 8.4 8.5 8.6 8.7 Mode 0: 8-Bit Shift Register............................................................................. 185 Mode 1: 8-Bit UART with Variable Baud Rate................................................. 187 Mode 2: 9-Bit UART with Fixed Baud Rate..................................................... 189 Mode 3: 9-Bit UART with Variable Baud Rate................................................. 191 Frame Error Detection........................................................................ 193 Multiprocessor Communications....................................................... 193 Automatic Address Recognition......................................................... 194 Buad Rates.......................................................................................... 196 Demo Programs about UART (C and ASM)...................................... 197 Chapter 9. Analog to Digital Converter...................................203 9.1 9.2 9.3 9.4 9.5 9.6 9.7 A/D Converter Structure..................................................................... 203 Registers for ADC.............................................................................. 205 Application Circuit of A/D Converter ............................................... 208 ADC Application Circuit for Key Scan.............................................. 209 A/D reference voltage source............................................................. 210 Program using interrupts to demostrate A/D Conversion ..................211 Program using polling to demostrate A/D Conversion ..................... 217 d e t imi Chapter 10. Programmable Counter Array(PCA).................223 10.1 SFRs related with PCA..................................................................... 223 10.2 PCA/PWM Structure........................................................................ 228 10.3 PCA Modules Operation Mode....................................................... 230 10.3.1 10.3.2 10.3.3 10.3.4 10.4 10.5 10.6 10.7 10.8 10.9 U C M L PCA Capture Mode.......................................................................................... 230 16-bit Software Timer Mode........................................................................... 231 High Speed Output Mode................................................................................ 232 Pulse Width Modulator Mode (PWM mode).................................................. 233 C T S Programs for PCA module extended external interrupt .................. 234 Demo Programs for PCA module acted as 16-bit Timer . ............... 238 Programs for PCA module as 16-bit High Speed Output................. 242 Demo Programs for PCA module as PWM Output . ....................... 246 Demo Program for PCA clock base on Timer 1 overflow rate....... 250 Using PWM achieve D/A Conversion function reference circuit.... 254 Chapter 11. Serial Peripheral Interface (SPI).........................255 11.1 Special Function Registers related with SPI..................................... 255 11.2 SPI Structure..................................................................................... 258 11.3 SPI Data Communication................................................................. 259 11.3.1 SPI Configuration............................................................................................ 259 11.3.2 SPI Data Communication Modes.................................................................... 260 11.3.3 SPI Data Modes............................................................................................... 262 11.4 SPI Function Demo Programs (Single Master — Single Slave)...... 264 11.4.1 SPI Function Demo Programs using Interrupts (C and ASM)......................... 264 11.4.2 SPI Function Demo Programs using Polling (C and ASM)............................. 270 11.5 SPI Function Demo Programs (Each other as the Master-Slave)..... 276 11.5.1 SPI Function Demo Programs using Interrupts (C and ASM)......................... 276 11.5.2 SPI Function Demo Programs using Polling................................................... 282 Chapter 12. IAP / EEPROM.....................................................288 12.1 12.2 12.3 12.4 IAP / EEPROM Special Function Registers.................................... 289 STC12C2052AD series Internal EEPROM Allocation Table.......... 292 IAP/EEPROM Assembly Language Program Introduction............. 293 EEPROM Demo Program (C and ASM).......................................... 296 13.1 13.2 13.3 13.4 13.5 In-System-Programming (ISP) principle.......................................... 304 STC12C2052AD series Typical Application Circuit for ISP........... 305 PC side application usage................................................................. 307 Compiler / Assembler Programmer and Emulator........................... 309 Self-Defined ISP download Demo.................................................. 309 Chapter 13. STC12 series Development/Programming Tool 304 Appendix A: Assembly Language Programming....................313 Appendix B: 8051 C Programming..........................................335 Appendix C: STC12C2052AD series Electrical Characteristics ...............................................................................345 Appendix D: Program for indirect addressing inner 256B RAM ...............................................................................347 Appendix E: Using Serial port expand I/O interface.............348 Appendix F: Use STC MCU common I/O driving LCD Display ...............................................................................350 Appendix G: LED driven by an I/O port and Key Scan.........357 Appendix H: How to reduce the Length of Code through Keil C ...............................................................................358 Appendix I: Notes of STC12C2052AD series Application.....359 Appendix J: Notes of STC12 series Replaced Traditional 8051.. ...............................................................................360 www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Chapter 1. Introduction STC12C2052AD is a single-chip microcontroller based on a high performance 1T architecture 8051 CPU, which is produced by STC MCU Limited. With the enhanced kernel, STC12C2052AD executes instructions in 1~6 clock cycles (about 8~12 times the rate of a standard 8051 device), and has a fully compatible instruction set with industrial-standard 8051 series microcontroller. In-System-Programming (ISP) and In-Application-Programming (IAP) support the users to upgrade the program and data in system. ISP allows the user to download new code without removing the microcontroller from the actual end product; IAP means that the device can write nonvalatile data in Flash memory while the application program is running. The STC12C2052AD retains all features of the standard 80C51. In addition, the STC12C2052AD has a 9-sources, 4-priority-level interrupt structure, 8-bit ADC (100 thousands times per second), on-chip crystal oscillator, MAX810 special reset circuit, 2-channel PCA and PWM, SPI, a one-time enabled Watchdog Timer and so on. 1.1 Features • • • • • • • • • • • • • • • • • • • • . d e mit Enhanced 8051 Central Processing Unit ,1T per machine cycle, faster 8~12 times than the rate of a standard 8051. Operating voltage range: 5.5V ~ 3.5V or 2.2V ~ 3.6V (STC12LE2052AD). Operating frequency range: 0- 35MHz, is equivalent to standard 8051:0~420MHz On-chip 1K/2K/3K/4K/5K... FLASH program memory with flexible ISP/IAP capability On-chip 256 byte RAM Power control: idle mode(can be waked up by any interrupt) and power-down mode(can be waked up by external interrupts). Code protection for flash memory access Excellent noise immunity, very low power consumption Four 16-bit timer/counter, be compatible with Timer0/Timer1 of standard 8051, 2-channel PCA can be available as two timers. 9 vector-address, 4 level priority interrupt capability One enhanced UART with hardware address-recognition and frame-error detection function One 15 bits Watch-Dog-Timer with 8-bit pre-scaler (one-time-enabled) SPI Master/Slave communication interface Two channel Programmable Counter Array (PCA) 8-bit, 8-channel high-speed Analog-to-Digital Converter (ADC), up to 100 thousands times per second Simple internal RC oscillator and external crystal clock Three power management modes: idle mode, slow down mode and power-down mode Power down mode can be woken-up by P3.2/INT0, P3.3/INT1, P3.4/T0, P3.5/T1, P3.0/RxD, P3.7/PCA0, and P3.5/PCA1 Operation Temperature: -40 ~ + 85℃ (industrial) / 0 ~ 75℃ (Commercial) 15 common programmable I/O ports are available C T S U C M Li • Programmable clock output Function. T0 output the clock on P1.0, T1 output the clock on P1.1. • Five package type : SOP-20, DIP-20, LSSOP-20. STC MCU Limited. website：www.STCMCU.com  www.STCMCU.com Mobile:(86)13922809991 Fax:86-755-82905966 Tel:086-755-82948412 1.2 Block diagram The CPU kernel of STC12C2052AD is fully compatible to the standard 8051 microcontroller, maintains all instruction mnemonics and binary compatibility. With some great architecture enhancements, STC12C2052AD executes the fastest instructions per clock cycle. Improvement of individual programs depends on the actual instructions used. RAM 256B B Register . d e t i m Stack Pointer ACC TMP2 Li TMP1 CU M ALU C T S LVD/LVR Control Unit RESET Timer 0/1 Enhanced UART WDT PSW ISP/IAP Address Generator Program Counter PCA (2-channel) Port 3 Latch Port1 Latch FLASH SPI ADC XTAL1 XTAL2 Port 1 Driver 8 P1.0 ~ P1.7 P1.0 ~ P1.7 Port 3 Driver P3 STC12C2052AD Block Diagram  STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 1.3 Pin Configurations All packages meet the European Union RoHS standards. LQFP-32 also conform to the Green standard. Packages such as SOP-20 are strongly recommended though the traditional DIP packages are steady supplied. 20 VCC RST 1 20 VCC 2 19 P1.7/SCLK/ADC7 RxD/P3.0 2 19 P1.7/SCLK TxD/P3.1 3 18 P1.6/MISO/ADC6 TxD/P3.1 3 18 P1.6/MISO XTAL2 4 17 P1.5/MOSI/ADC5 XTAL2 4 17 P1.5/MOSI XTAL1 5 16 P1.4/SS/ADC4 XTAL1 5 16 P1.4/SS INT0/P3.2 6 15 P1.3/ADC3 15 P1.3 INT1/P3.3 7 14 P1.2/ADC2 14 P1.2 ECI/T0/P3.4 8 13 13 P1.1/CLKOUT1 PWM1/PCA1/T1/P3.5 9 10 Gnd INT0/P3.2 6 INT1/P3.3 7 P1.1/ADC1/CLKOUT1 ECI/T0/P3.4 8 12 P1.0/ADC0/CLKOUT0 PWM/PCA1/T1/P3.5 9 12 P1.0/CLKOUT0 11 P3.7/PCA0/PWM0 10 11 P3.7/PCA0/PWM0 15 I/O ports STC12C2052AD series (with A/D Converter)，20-Pin U C M Super small package : TSSOP-20, 6.4mm×6.4mm C T S STC MCU Limited. SOP-20 / DIP-20 TSSOP-20 1 SOP-20 / DIP-20 TSSOP-20 RST RxD/P3.0 Li . d e mit Gnd STC12C2052 series (without A/D Converter)，20-Pin website：www.STCMCU.com  www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 1.4 STC12C2052AD series Selection Table Type 1T 8051 MCU 16-bit U Operation PCA/ W Flash SRAM Timer PCA Programmable A EEP 8-bit A/D D Built-in SPI Voltage (Byte) (Byte) T0&T1 Timer Clock Output R ROM 8-ch Reset (V) PWM T T D/A Package of 20-Pin (15 I/O ports) STC12C2052AD series Selection Table STC12C1052 5.5-3.5 1K 256 Y 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP STC12C1052AD 5.5-3.5 1K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP STC12C2052 5.5-3.5 2K 256 Y 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP STC12C2052AD 5.5-3.5 2K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP STC12C3052 5.5-3.5 3K 256 Y 2 Y Y IAP 2-ch Y Y Y SOP/LSSOP/DIP STC12C3052AD 5.5-3.5 3K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP STC12C4052 5.5-3.5 4K 256 Y 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP STC12C4052AD 5.5-3.5 4K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP STC12C5052 5.5-3.5 5K 256 Y 2 Y Y 2-ch Y Y STC12C5052AD 5.5-3.5 6K 256 Y 2 Y Y 8-bit Y Y Y Application program can be modified in Y application program area (AP area) STC12LE1052 3.6-2.2 1K 256 Y STC12LE1052AD 3.6-2.2 1K 256 Y STC12LE2052 3.6-2.2 2K 256 Y STC12LE2052AD 3.6-2.2 2K 256 Y STC12LE3052 3.6-2.2 3K 256 STC12LE3052AD 3.6-2.2 3K STC12LE4052 3.6-2.2 STC12LE4052AD U C M i m i L Y Y . d e t 2-ch STC12LE2052AD series Selection Table 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP Y 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP 4K 256 Y 2 Y Y Y 2-ch Y Y Y SOP/LSSOP/DIP 3.6-2.2 4K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y SOP/LSSOP/DIP STC12LE5052 3.6-2.2 5K 256 Y 2 Y Y Y 2-ch Y Y STC12LE5052AD 3.6-2.2 5K 256 Y 2 Y Y Y 2-ch 8-bit Y Y Y Application program can be modified in Y application program area (AP area) 10 C T S STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 1.5 STC12C2052AD series Minimum Application System When the frequency of crystal oscillator is lower than 12MHz, it is suggested not to use C1 and R1 replaced by 1K resistor connect to ground. But R/C reset circuit is also suggest to reserve. 10μF + C1 1 RST 10K C2 1s ;work LED flash U C M . d e mit ;count-- Li website：www.STCMCU.com 159 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 7.2.3 Mode 2 (8-bit Auto-Reload Mode) and Demo Programs (C and ASM) Mode 2 configures the timer register as an 8-bit counter(TL0) with automatic reload. Overflow from TL0 not only set TF0, but also reload TL0 with the content of TH0, which is preset by software. The reload leaves TH0 unchanged. AUXR.7/T0x12=0 ÷12 Interrupt TF0 SYSclk ÷1 AUXR.7/T0x12=1 C/T=1 T0 Pin TR0 Toggle C/T=0 control GATE TL0 (8 Bits) CLKOUT0 P1.0 . d e t i m TH0 (8 Bits) INT0 T0CLKO Li Timer/Counter 0 Mode 2: 8-Bit Auto-Reload STC12C2052AD is able to generate a programmable clock output on P1.0. When T0CLKO/ WAKE_CLKO.0 bit in WAKE_CLKO SFR is set, T0 timer overflow pulse will toggle P1.0 latch to generate a 50% duty clock. The frequency of clock-out = T0 overflow rate/2. If C/T (TMOD.2) = 0, Timer/Counter 0 is set for Timer operation (input from internal system clock), the Frequency of clock-out is as following : (SYSclk) / (256 – TH0) / 2, when AUXR.7 / T0x12=1 or (SYSclk / 12) / (256 – TH0) / 2 , when AUXR.7 / T0x12=0 C T S U C M If C/T (TMOD.2) = 1, Timer/Counter 0 is set for Conter operation (input from external P3.4/T0 pin), the Frequency of clock-out is as following : T0_Pin_CLK / (256-TH0) / 2 160 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;T0 Interrupt (falling edge) Demo programs, where T0 operated in Mode 2 (8-bit auto-relaod mode) ; The Timer Interrupt can not wake up MCU from Power-Down mode in the following programs 1. C program /*----------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -------------------------------------*/ /* --- STC 1T Series MCU T0 (Falling edge) Demo ---------------------*/ /* --- Mobile: (86)13922809991 --------------------------------------------*/ /* --- Fax: 86-755-82905966 ------------------------------------------------*/ /* --- Tel: 86-755-82948412 -------------------------------------------------*/ /* --- Web: www.STCMCU.com -------------------------------------------*/ /* If you want to use the program or the program referenced in the --*/ /* article, please specify in which data and procedures from STC ---*/ /*---------------------------------------------------------------------------------*/ #include "reg51.h" sfr AUXR = 0x8e; //T0 interrupt service routine void t0int( ) interrupt 1 { } C T S void main() { AUXR = 0x80; TMOD = 0x06; TL0 = TH0 = 0xff; TR0 = 1; ET0 = 1; EA = 1; Li //Auxiliary register U C M . d e mit //T0 interrupt (location at 000BH) //timer0 work in 1T mode //set timer0 as counter mode2 (8-bit auto-reload) //fill with 0xff to count one time //timer0 start run //enable T0 interrupt //open global interrupt switch while (1); } STC MCU Limited. website：www.STCMCU.com 161 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly program /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series MCU T0(Falling edge) Demo -------------------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*------------------------------------------------------------------------------*/ AUXR DATA 08EH ;----------------------------------------;interrupt vector table ORG 0000H LJMP MAIN ORG 000BH LJMP T0INT U C M ;---------------------------------------- MAIN: ORG C T S 0100H MOV SP, MOV AUXR, MOV TMOD, MOV A, MOV TL0, MOV TH0, SETB TR0 SETB ET0 SETB EA SJMP $ #7FH #80H #06H #0FFH A A . d e t i m ;Auxiliary register Li ;T0 interrupt (location at 000BH) ;initial SP ;timer0 work in 1T mode ;set timer0 as counter mode2 (8-bit auto-reload) ;fill with 0xff to count one time ;timer0 start run ;enable T0 interrupt ;open global interrupt switch ;----------------------------------------;T0 interrupt service routine T0INT: RETI ;---------------------------------------- 162 END STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 7.2.4 Mode 3 (Two 8-bit Timers/Couters) Timer 1 in Mode 3 simply holds its count, the effect is the same as setting TR1 = 0. Timer 0 in Mode 3 established TL0 and TH0 as two separate 8-bit counters. TL0 use the Timer 0 control bits: C/T,GATE,TR0, INT0 and TF0. TH0 is locked into a timer function (counting machine cycles) and takes over the use of TR1 from Tmer 1. Thus, TH0 now controls the “Timer 1” interrupt. Mode 3 is provided for applications requiring an extra 8-bit timer or counter. When Timer 0 is in Mode 3, Timer 1 can be turned on and off by switching it out of and into its own Mode 3, or can still be used by the serial port as a baud rate generator, or in fact, in any application not requiring an interrupt. AUXR.7/T0x12=0 ÷12 . d e mit SYSclk ÷1 AUXR.7/T0x12=1 C/T=0 C/T=1 T0 Pin control TR0 GATE INT0 ÷12 SYSclk C T S STC MCU Limited. ÷1 U C M AUXR.7/T0x12=0 AUXR.7/T0x12=0 control TL0 (8 bit) Li TH0 (8 Bits) Interrupt TF0 TF1 Interrupt TR1 Timer/Counter 0 Mode 3: Two 8-Bit Timers/Counters website：www.STCMCU.com 163 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 7.3 Timer/Counter 1 Mode of Operation Timer/Counter 1 can be configured for three modes by setting M1(TMOD.5) and M0(TMOD.4) in sepcial function register TMOD. 7.3.1 Mode 0 (13-bit Timer/Counter) In this mode, the timer register is configured as a 13-bit register. As the count rolls over from all 1s to all 0s, it sets the timer interrupt flag TF1. The counted input is enabled to the timer when TR1 = 1 and either GATE=0 or INT1= 1.(Setting GATE = 1 allows the Timer to be controlled by external input INT1, to facilitate pulse width measurements.) TR0 is a control bit in the Special Function Register TCON. GATE is in TMOD. The 13-Bit register consists of all 8 bits of TH1 and the lower 5 bits of TL1. The upper 3 bits of TL1 are indeterminate and should be ignored. Setting the run flag (TR1) does not clear the registers. . d e t i m Li AUXR.6/T1x12=0 ÷12 SYSclk ÷1 AUXR.6/T1x12=1 T1 Pin C T S GATE INT1 M CU TR1 C/T=0 C/T=1 control TL1 TH1 (5 Bits) (8 bits) TF1 Interrupt Timer/Counter 1 Mode 0: 13-Bit Timer/Counter 164 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 7.3.2 Mode 1 (16-bit Timer/Counter) and Demo Programs (C and ASM) In this mode, the timer register is configured as a 16-bit register. As the count rolls over from all 1s to all 0s, it sets the timer interrupt flag TF1. The counted input is enabled to the timer when TR1 = 1 and either GATE=0 or INT1 = 1.(Setting GATE = 1 allows the Timer to be controlled by external input INT1, to facilitate pulse width measurements.) TRl is a control bit in the Special Function Register TCON. GATE is in TMOD. The 16-Bit register consists of all 8 bits of THl and the lower 8 bits of TL1. Setting the run flag (TR1) does not clear the registers. Mode 1 is the same as Mode 0, except that the timer register is being run with all 16 bits. AUXR.6/T1x12=0 ÷12 . d e mit SYSclk ÷1 AUXR.6/T1x12=1 C/T=1 T1 Pin TR1 GATE INT1 C/T=0 U C M TL1 TH1 (8 Bits) (8 bits) Li control TF1 Interrupt Timer/Counter 1 Mode 1 : 16-Bit Timer/Counter C T S There are another two simple programs that demostrates Timer 1 as 16-bit Timer/Counter, one written in C language while other in Assembly language. 1. C Program /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series 16-bit Timer Demo --------------------------------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ #include "reg51.h" typedef unsigned char BYTE; typedef unsigned int WORD; STC MCU Limited. website：www.STCMCU.com 165 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 //----------------------------------------------/* define constants */ #define FOSC 18432000L #define MODE1T //Timer clock mode, comment this line is 12T mode, uncomment is 1T mode #ifdef MODE1T #define T1MS (65536-FOSC/1000) #else #define T1MS (65536-FOSC/12/1000) #endif /* define SFR */ sfr AUXR = 0x8e; sbit TEST_LED = P0^0; /* define variables */ WORD count; //1ms timer calculation method in 1T mode //1ms timer calculation method in 12T mode //Auxiliary register //work LED, flash once per second . d e t i m Li //1000 times counter //----------------------------------------------- U C M /* Timer0 interrupt routine */ void tm1_isr() interrupt 3 using 1 { TL1 = T1MS; //reload timer1 low byte TH1 = T1MS >> 8; //reload timer1 high byte if (count-- == 0) //1ms * 1000 -> 1s { count = 1000; //reset counter TEST_LED = ! TEST_LED; //work LED flash } } C T S //----------------------------------------------/* main program */ void main() { #ifdef MODE1T AUXR = 0x40; #endif TMOD = 0x10; TL1 = T1MS; TH1 = T1MS >> 8; TR1 = 1; ET1 = 1; EA = 1; count = 0; } 166 while (1); //timer1 work in 1T mode //set timer1 as mode1 (16-bit) //initial timer1 low byte //initial timer1 high byte //timer1 start running //enable timer1 interrupt //open global interrupt switch //initial counter //loop STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assembly Program ;/*---------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ------------------------------------*/ ;/* --- STC 1T Series 16-bit Timer Demo ----------------------------------*/ ;/* --- Mobile: (86)13922809991 -------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -----------------------------------------------*/ ;/* --- Tel: 86-755-82948412 -----------------------------------------------*/ ;/* --- Web: www.STCMCU.com ------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------*/ ;/* define constants */ #define MODE1T #ifdef MODE1T T1MS EQU #else T1MS EQU #endif ;Timer clock mode, comment this line is 12T mode, uncomment is 1T mode . d e mit 0B800H ;1ms timer calculation method in 1T mode is (65536-18432000/1000) 0FA00H ;1ms timer calculation method in 12T mode is (65536-18432000/12/1000) ;/* define SFR */ AUXR DATA TEST_LED BIT 8EH P1.0 C T S ;/* define variables */ COUNT DATA 20H M CU Li ;Auxiliary register ;work LED, flash once per second ;1000 times counter (2 bytes) ;---------------------------------------------- ORG LJMP ORG LJMP 0000H MAIN 001BH TM1_ISR ;----------------------------------------------;/* main program */ MAIN: #ifdef MODE1T MOV AUXR, #40H #endif MOV TMOD, #10H MOV TL1, #LOW T1MS MOV TH1, #HIGH T1MS SETB TR1 SETB ET1 SETB EA CLR A MOV COUNT, A MOV COUNT+1,A SJMP $ STC MCU Limited. ;timer1 work in 1T mode ;set timer1 as mode1 (16-bit) ;initial timer1 low byte ;initial timer1 high byte ;timer1 start running ;enable timer1 interrupt ;open global interrupt switch ;initial counter website：www.STCMCU.com 167 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 ;----------------------------------------------;/* Timer1 interrupt routine */ TM1_ISR: PUSH ACC PUSH PSW MOV TL1, #LOW T1MS MOV TH1, #HIGH T1MS MOV A, COUNT ORL A, COUNT+1 JNZ SKIP MOV COUNT, #LOW 1000 MOV COUNT+1,#HIGH 1000 CPL TEST_LED SKIP: CLR C MOV A, COUNT SUBB A, #1 MOV COUNT, A MOV A, COUNT+1 SUBB A, #0 MOV COUNT+1,A POP PSW POP ACC RETI C T S U C M ;reload timer1 low byte ;reload timer1 high byte ;check whether count(2byte) is equal to 0 ;1ms * 1000 -> 1s . d e t i m ;work LED flash Li ;count-- ;---------------------------------------------- 168 END STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 7.3.3 Mode 2 (8-bit Auto-Reload Mode) and Demo Programs (C and ASM) Mode 2 configures the timer register as an 8-bit counter(TL1) with automatic reload. Overflow from TL1 not only set TFx, but also reload TL1 with the content of TH1, which is preset by software. The reload leaves TH1 unchanged. AUXR.6/T1x12=0 ÷12 TF1 SYSclk ÷1 AUXR.6/T1x12=1 T1 Pin C/T=0 C/T=1 Interrupt Toggle control TL1 (8 Bits) CLKOUT1 P1.1 TR1 GATE TH1 (8 Bits) INT1 T1CLKO . d e mit Timer/Counter 1 Mode 2: 8-Bit Auto-Reload Li STC12C2052AD is able to generate a programmable clock output on P1.1. When T1CLKO/WAKE_CLKO.1 bit in WAKE_CLKO SFR is set, T1 timer overflow pulse will toggle P1.1 latch to generate a 50% duty clock. The frequency of clock-out = T1 overflow rate/2. U C M If C/T (TMOD.6) = 0, Timer/Counter 1 is set for Timer operation (input from internal system clock), the Frequency of clock-out is as following : (SYSclk) / (256 – TH1) / 2, when AUXR.6 / T0x12=1 or (SYSclk / 12) / (256 – TH1) / 2 , when AUXR.6 / T0x12=0 C T S If C/T (TMOD.6) = 1, Timer/Counter 1 is set for Conter operation (input from external P3.5/T1 pin), the Frequency of clock-out is as following : T1_Pin_CLK / (256-TH1) / 2 STC MCU Limited. website：www.STCMCU.com 169 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 ;T1 Interrupt (falling edge) Demo programs, where T1 operated in Mode 2 (8-bit auto-relaod mode) ; The Timer Interrupt can not wake up MCU from Power-Down mode in the following programs 1. C program /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series MCU T1(Falling edge) Demo -------------------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*------------------------------------------------------------------------------*/ #include "reg51.h" sfr AUXR = 0x8e; U C M //T1 interrupt service routine void t1int( ) interrupt 3 { } C T S void main() { AUXR = 0x40; TMOD = 0x60; TL1 = TH1 = 0xff; TR1 = 1; ET1 = 1; EA = 1; . d e t i m Li //Auxiliary register //T1 interrupt (location at 001BH) //timer1 work in 1T mode //set timer1 as counter mode2 (8-bit auto-reload) //fill with 0xff to count one time //timer1 start run //enable T1 interrupt //open global interrupt switch while (1); } 170 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assembly program /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series MCU T1(Falling edge) Demo -------------------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*------------------------------------------------------------------------------*/ AUXR DATA 08EH ;Auxiliary register ;----------------------------------------;interrupt vector table ORG 0000H LJMP MAIN ORG 001BH LJMP T1INT ;---------------------------------------- MAIN: ORG C T S 0100H MOV SP, MOV AUXR, MOV TMOD, MOV A, MOV TL1, MOV TH1, SETB TR1 SETB ET1 SETB EA SJMP $ #7FH #40H #60H #0FFH A A U C M . d e mit Li ;T1 interrupt (location at 001BH) ;initial SP ;timer1 work in 1T mode ;set timer1 as counter mode2 (8-bit auto-reload) ;fill with 0xff to count one time ;timer1 start run ;enable T1 interrupt ;open global interrupt switch ;----------------------------------------;T1 interrupt service routine T1INT: RETI ;---------------------------------------- END STC MCU Limited. website：www.STCMCU.com 171 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 7.4 Programmable Clock Output and Demo Programs (C and ASM) STC12C2052AD series MCU have two channel programmable clock outputs, they are Timer 0 programmable clock output CLKOUT0(P1.0) and Timer 1 programmable clock output CLKOUT1(P1.1). There are some SFRs about programmable clock output as shown below. Symbol Description Address AUXR Auxiliary register CLK_Output Power down WAKE_CLKO Wake-up control register 8EH MSB Bit Address and Symbol T0x12 T1x12 UART_M0x6 EADCI PCAWAKEUP RXD_PIN_IE T1_PIN_IE T0_PIN_IE Value after Power-on or Reset 0000 00xxB LSB ESPI ELVDI - - - - T1CLKO T0CLKO 8FH 0000 xx00B . d e t i m The satement (used in C language) of Special function registers AUXR/WAKE_CLKO: sfr AUXR = 0x8E; //The address statement of Special function register AUXR sfr WAKE_CLKO = 0x8F; //The address statement of SFR WAKE_CLKO Li The satement (used in Assembly language) of Special function registers AUXR/WAKE_CLKO: AUXR EQU 0x8E ;The address statement of Special function register AUXR WAKE_CLKO EQU 0x8F ;The address statement of SFR WAKE_CLKO U C M 1. AUXR: Auxiliary register (Non bit-addressable) SFR name AUXR C T S Address 8EH bit B7 B6 B5 B4 name T0x12 T1x12 UART_M0x6 EADCI B3 ESPI B2 ELVDI B1 - B0 - T0x12 : Timer 0 clock source bit. 0 : The clock source of Timer 0 is SYSclk/12. It will compatible to the traditional 80C51 MCU 1 : The clock source of Timer 0 is SYSclk/1. It will drive the T0 faster than a traditional 80C51 MCU T1x12 : Timer 1 clock source bit. 0 : The clock source of Timer 1 is SYSclk/12. It will compatible to the traditional 80C51 MCU 1 : The clock source of Timer 1 is SYSclk/1. It will drive the T0 faster than a traditional 80C51 MCU UART_M0x6 : Baud rate select bit of UART1 while it is working under Mode-0 0 : The baud-rate of UART in mode 0 is SYSclk/12. 1 : The baud-rate of UART in mode 0 is SYSclk/2. UART_M0x6 : Baud rate select bit of UART1 while it is working under Mode-0 0 : The baud-rate of UART in mode 0 is SYSclk/12. 1 : The baud-rate of UART in mode 0 is SYSclk/2. EADCI : Enable/Disable interrupt from A/D converter 0 : (default) Inhibit the ADC functional block to generate interrupt to the MCU 1 : Enable the ADC functional block to generate interrupt to the MCU ESPI : Enable/Disable interrupt from Serial Peripheral Interface (SPI) 0 : (default)Inhibit the SPI functional block to generate interrupt to the MCU 1 : Enable the SPI functional block to generate interrupt to the MCU ELVDI : Enable/Disable interrupt from low-voltage sensor 0 : (default)Inhibit the low-voltage sensor functional block to generate interrupt to the MCU 1 : Enable the low-voltage sensor functional block to generate interrupt to the MCU 172 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. WAKE_CLKO: CLK_Output Power down Wake-up control register (Non bit-Addressable) SFR name Address WAKE_CLKO 8FH bit B7 B6 B5 B4 name PCAWAKEUP RXD_PIN_IE T1_PIN_IE T0_PIN_IE B3 B2 - - B1 B0 T1CLKO T0CLKO PCAWAKEUP: When set and the associated-PCA interrupt control registers is configured correctly, the CEXn pin of PCA function is enabled to wake up MCU from power-down state. RXD_PIN_IE: When set and the associated-UART interrupt control registers is configured correctly, the RXD pin (P3.0) is enabled to wake up MCU from power-down state. T1_PIN_IE : When set and the associated-Timer1 interrupt control registers is configured correctly, the T1 pin (P3.5) is enabled to wake up MCU from power-down state. T0_PIN_IE : When set and the associated-Timer0 interrupt control registers is configured correctly, the T1 pin (P3.4) is enabled to wake up MCU from power-down state. . d e mit LVD_WAKE: When set and the associated-LVD interrupt control registers is configured correctly, the CMPIN pin is enabled to wake up MCU from power-down state. Li T1CKLO : When set, P3.5 is enabled to be the clock output of Timer 1. The clock rate is Timer 1overflow rate divided by 2. T0CKLO : When set, P3.4 is enabled to be the clock output of Timer 0. The clock rate is Timer 0overflow rate divided by 2. C T S STC MCU Limited. U C M website：www.STCMCU.com 173 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 7.4.1 Timer 0 Programmable Clock-out on P1.0 and Demo Program(C and ASM) AUXR.7/T0x12=0 ÷12 Interrupt TF0 SYSclk ÷1 AUXR.7/T0x12=1 C/T=1 T0 Pin TR0 Toggle C/T=0 control GATE TL0 (8 Bits) CLKOUT0 P1.0 T0CLKO TH0 (8 Bits) INT0 . d e t i m Timer/Counter 0 Mode 2: 8-Bit Auto-Reload STC12C2052AD is able to generate a programmable clock output on P1.0. When T0CLKO/ WAKE_CLKO.0 bit in WAKE_CLKO SFR is set, T0 timer overflow pulse will toggle P1.0 latch to generate a 50% duty clock. The frequency of clock-out = T0 overflow rate/2. If C/T (TMOD.2) = 0, Timer/Counter 0 is set for Timer operation (input from internal system clock), the Frequency of clock-out is as following : (SYSclk) / (256 – TH0) / 2, when AUXR.7 / T0x12=1 or (SYSclk / 12) / (256 – TH0) / 2 , when AUXR.7 / T0x12=0 C T S U C M Li If C/T (TMOD.2) = 1, Timer/Counter 0 is set for Conter operation (input from external P3.4/T0 pin), the Frequency of clock-out is as following : T0_Pin_CLK / (256-TH0) / 2 The following programs demostrate Program Clock Output on P1.0 pin when Timer 0 operates as 8-bit autoreload Timer/Counter. 1. C Program: /*--------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------*/ /* --- STC 1T Series Programmable Clock Output Demo -------------*/ /* --- Mobile: (86)13922809991 -------------- ----------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ #include "reg51.h" //----------------------------------------------/* define constants */ #define FOSC 18432000L //#define MODE 1T //Timer clock mode, comment this line is 12T mode, uncomment is 1T mode 174 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com #ifdef MODE 1T #define F38_4KHz #else #define F38_4KHz #endif /* define SFR */ sfr AUXR sfr WAKE_CLKO sbit T0CLKO Mobile:(86)13922809991 (256-FOSC/2/38400) (256-FOSC/2/12/38400) = 0x8e; = 0x8f; = P1^0; C T S while (1); //38.4KHz frequency calculation method of 1T mode //38.4KHz frequency calculation method of 12T mode . d e mit Li //timer0 work in 1T mode U C M Fax:86-755-82905966 //Auxiliary register //wakeup and clock output control register //timer0 clock output pin //----------------------------------------------/* main program */ void main() { #ifdef MODE1T AUXR = 0x80; #endif TMOD = 0x02; TL0 = F38_4KHz; TH0 = F38_4KHz; TR0 = 1; WAKE_CLKO = 0x01; } Tel:86-755-82948412 //set timer0 as mode2 (8-bit auto-reload) //initial timer0 //initial timer0 //timer0 start running //enable timer0 clock output //loop 2. Assembly Program: ;/*--------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -----------------------------------*/ ;/* --- STC 1T Series Programmable Clock Output Demo -------------*/ ;/* --- Mobile: (86)13922809991 -------------- ----------------------------*/ ;/* --- Fax: 86-755-82905966 -----------------------------------------------*/ ;/* --- Tel: 86-755-82948412 -----------------------------------------------*/ ;/* --- Web: www.STCMCU.com ------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*-------------------------------------------------------------------------------*/ ;/* define constants */ #define MODE 1T STC MCU Limited. ;Timer clock mode, comment this line is 12T mode, uncomment is 1T mode website：www.STCMCU.com 175 www.STCMCU.com Mobile:(86)13922809991 #ifdef MODE 1T F38_4KHz EQU 010H #else F38_4KHz EQU 0ECH #endif Tel:086-755-82948412 ;38.4KHz frequency calculation method of 1T mode is (256-18432000/2/38400) ;38.4KHz frequency calculation method of 12T mode (256-18432000/2/12/38400) ;/* define SFR */ AUXR DATA 08EH WAKE_CLKO DATA 08FH T0CLKO BIT P1.0 ;Auxiliary register ;wakeup and clock output control register ;timer0 clock output pin ;---------------------------------------------- ORG 0000H LJMP MAIN ;----------------------------------------------;/* main program */ MAIN: #ifdef MODE1T MOV AUXR, #80H #endif MOV TMOD, #02H MOV TL0, #F38_4KHz MOV TH0, #F38_4KHz SETB TR0 MOV WAKE_CLKO, #01H C T S Fax:86-755-82905966 M CU . d e t i m Li ;timer0 work in 1T mode ;set timer0 as mode2 (8-bit auto-reload) ;initial timer0 ;initial timer0 ;enable timer0 clock output SJMP $ ;---------------------------------------------- 176 END STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 7.4.2 Timer 1 Programmable Clock-out on P1.1 and Demo Program(C and ASM) AUXR.6/T1x12=0 ÷12 TF1 SYSclk ÷1 AUXR.6/T1x12=1 T1 Pin C/T=0 C/T=1 Interrupt Toggle control TL1 (8 Bits) CLKOUT1 P1.1 TR1 GATE T1CLKO TH1 (8 Bits) INT1 Timer/Counter 1 Mode 2: 8-Bit Auto-Reload . d e mit STC12C2052AD is able to generate a programmable clock output on P1.1. When T1CLKO/WAKE_CLKO.1 bit in WAKE_CLKO SFR is set, T1 timer overflow pulse will toggle P1.1 latch to generate a 50% duty clock. The frequency of clock-out = T1 overflow rate/2. U C M Li If C/T (TMOD.6) = 0, Timer/Counter 1 is set for Timer operation (input from internal system clock), the Frequency of clock-out is as following : (SYSclk) / (256 – TH1) / 2, when AUXR.6 / T0x12=1 or (SYSclk / 12) / (256 – TH1) / 2 , when AUXR.6 / T0x12=0 C T S If C/T (TMOD.6) = 1, Timer/Counter 1 is set for Conter operation (input from external P3.5/T1 pin), the Frequency of clock-out is as following : T1_Pin_CLK / (256-TH1) / 2 The following programs demostrate Program Clock Output on Timer 1 pin when Timer 1 operates as 8-bit autoreload Timer/Counter. 1. C Program: /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series Programmable Clock Output Demo ------------*/ /* --- Mobile: (86)13922809991 -------------- ---------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ #include "reg51.h" //----------------------------------------------STC MCU Limited. website：www.STCMCU.com 177 www.STCMCU.com Mobile:(86)13922809991 /* define constants */ #define FOSC 18432000L //#define MODE 1T #ifdef MODE 1T #define F38_4KHz #else #define F38_4KHz #endif Tel:086-755-82948412 Fax:86-755-82905966 //Timer clock mode, comment this line is 12T mode, uncomment is 1T mode (256-FOSC/2/38400) (256-FOSC/2/12/38400) //38.4KHz frequency calculation method of 1T mode //38.4KHz frequency calculation method of 12T mode /* define SFR */ sfr AUXR = 0x8e; //Auxiliary register sfr WAKE_CLKO = 0x8f; //wakeup and clock output control register sbit T1CLKO = P1^1; //timer1 clock output pin //----------------------------------------------/* main program */ void main() { #ifdef MODE1T AUXR = #endif TMOD = TL1 = TH1 = TR1 = WAKE_CLKO = while (1); } 0x40; C T S 178 U C M 0x20; F38_4KHz; F38_4KHz; 1; 0x02; STC MCU Limited. . d e t i m Li //timer1 work in 1T mode //set timer1 as mode2 (8-bit auto-reload) //initial timer1 //initial timer1 //timer1 start running //enable timer1 clock output //loop website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assembly Program: ;/*---------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ------------------------------------*/ ;/* --- STC 1T Series Programmable Clock Output Demo --------------*/ ;/* --- Mobile: (86)13922809991 -------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -----------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*-------------------------------------------------------------------------------*/ ;/* define constants */ #define MODE 1T #ifdef MODE 1T F38_4KHz EQU 010H #else F38_4KHz EQU 0ECH #endif . d e mit ;Timer clock mode, comment this line is 12T mode, uncomment is 1T mode Li ;38.4KHz frequency calculation method of 1T mode is (256-18432000/2/38400) U C M ;38.4KHz frequency calculation method of 12T mode (256-18432000/2/12/38400) ;/* define SFR */ AUXR DATA 08EH WAKE_CLKO DATA 08FH T1CLKO BIT P1.1 C T S ;Auxiliary register ;wakeup and clock output control register ;timer1 clock output pin ;---------------------------------------------- ORG 0000H LJMP MAIN ;----------------------------------------------;/* main program */ MAIN: #ifdef MODE1T MOV AUXR, #40H #endif MOV TMOD, #20H MOV TL1, #F38_4KHz MOV TH1, #F38_4KHz SETB TR1 MOV WAKE_CLKO, #02H ;timer1 work in 1T mode ;set timer1 as mode2 (8-bit auto-reload) ;initial timer1 ;initial timer1 ;enable timer1 clock output SJMP $ ;---------------------------------------------- END STC MCU Limited. website：www.STCMCU.com 179 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 7.5 Application note for Timer in practice (1) Real-time Timer Timer/Counter start running, When the Timer/Counter is overflow, the interrupt request generated, this action handle by the hardware automatically, however, the process which from propose interrupt request to respond interrupt request requires a certain amount of time, and that the delay interrupt request on-site with the environment varies, it normally takes three machine cycles of delay, which will bring real-time processing bias. In most occasions, this error can be ignored, but for some real-time processing applications, which require compensation. Such as the interrupt response delay, for timer mode 0 and mode 1, there are two meanings: the first, because of the interrupt response time delay of real-time processing error; the second, if you require multiple consecutive timing, due to interruption response delay, resulting in the interrupt service program once again sets the count value is delayed by several count cycle. . d e t i m If you choose to use Timer/Counter mode 1 to set the system clock, these reasons will produce real-time error for this situation, you should use dynamic compensation approach to reducing error in the system clock, compensation method can refer to the following example program. … CLR EA ;disable interrupt MOV A, TLx ;read TLx ADD A, #LOW ;LOW is low byte of compensation value MOV TLx, A ;update TLx MOV A, THx ;read THx ADDC A, #HIGH ;HIGH is high byte of compensation value MOV THx, A ;update THx SETB EA ;enable interrupt … C T S U C M Li (2) Dynamic read counts When dynamic read running timer count value, if you do not pay attention to could be wrong, this is because it is not possible at the same time read the value of the TLx and THx. For example the first reading TLx then THx, because the timer is running, after reading TLx, TLx carry on the THx produced, resulting in error; Similarly, after the first reading of THx then TLx, also have the same problems. A kind of way avoid reading wrong is first reading THx then TLx and read THx once more, if the THx twice to read the same value, then the read value is correct, otherwise repeat the above process. Realization method reference to the following example code. … RDTM: MOV A, THx ;save THx to ACC MOV R0, TLx ;save TLx to R0 CJNE A, THx, RDTM ;read THx again and compare with the previous value MOV R1, A ;save THx to R1 … 180 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Chapter 8. UART with Enhanced Function The serial port is full duplex,meaning it can transmit and receive simultaneously. It is also receive-buffered, meaning it can commence reception of a second byte before a previously received byte has been read from the reeeive register. (However,if the first byte still hasn’t been read by the time reception of the second byte is complete, one of the bytes will be lost). The serial port receive and transmit share the same SFR – SBUF, but actually there is two SBUF in the chip, one is for transmit and the other is for receive. The serial port(UART) can be operated in 4 different modes: Mode 0 provides synchronous communication while Modes 1, 2, and 3 provide asynchronous communication. The asynchronous communication operates as a full-duplex Universal Asynchronous Receiver and Transmitter (UART), which can transmit and receive simultaneously and at different baud rates. Serial communiction involves the transimission of bits of data through only one communication line. The data are transimitted bit by bit in either synchronous or asynchronous format. Synchronous serial communication transmits ont whole block of characters in syschronization with a reference clock while asynchronous serial communication randomly transmits one character at any time, independent of any clock. Li 8.1 Special Function Registers about UART CU M Symbol Description AUXR Auxiliary register 8EH T0x12 T1x12 UART_M0x6 EADCI ESPI ELVDI SCON Serial Control 98H SM0/FE SBUF C T S Address . d e mit Bit Address and Symbol MSB SM1 SM2 REN TB8 RB8 POF GF1 Value after Power-on or LSB Reset - 0000 00xxB TI RI PD IDL 0000 0000B Serial Buffer 99H Power Control 87H SMOD SMOD0 LVDF IE Interrupt Enable A8H EA EPCA_LVD EADC_SPI ES ET1 EX1 ET0 EX0 0000 0000B IP Interrupt Priority Low B8H - IPH Interrupt Priority High B7H - PPCA_LVDH PADC_LVDH PSH PT1H PX1H PT0H PX0H SADEN Slave Address Mask B9H SADDR Slave Address A9H PCON CLK_Output Power down WAKE_CLKO Wake-up control register STC MCU Limited. 8FH xxxx xxxxB PPCA_LVD PADC_LVD PS PT1 GF0 0011 0000B PX1 PT0 PX0 x000 0000B x000 0000B 0000 0000B 0000 0000B PCAWAKEUP RxD_PIN_IE T1_PIN_IE T0_PIN_IE - - website：www.STCMCU.com T1CLKO T0CLKO 0000 xx00B 181 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 1. Serial Port 1 (UART1) Control Register: SCON and PCON Serial port 1 of STC12C2052AD series has two control registers: Serial port control register (SCON) and PCON which used to select Baud-Rate SCON: Serial port Control Register (Bit-Addressable) SFR name Address bit B7 B6 B5 B4 B3 B2 B1 B0 SCON 98H name SM0/FE SM1 SM2 REN TB8 RB8 TI RI FE: Framing Error bit. The SMOD0 bit must be set to enable access to the FE bit 0: The FE bit is not cleared by valid frames but should be cleared by software. 1: This bit set by the receiver when an invalid stop bit id detected. SM0,SM1 : Serial Port Mode Bit 0/1. SM0 SM1 Description 0 0 8-bit shift register 0 1 8-bit UART 1 0 9-bit UART 1 1 9-bit UART Baud rate SYSclk/12 variable SYSclk/64 or SYSclk/32(SMOD=1) variable U C M . d e t i m Li SM2 : Enable the automatic address recognition feature in mode 2 and 3. If SM2=1, RI will not be set unless the received 9th data bit is 1, indicating an address, and the received byte is a Given or Broadcast address. In mode1, if SM2=1 then RI will not be set unless a valid stop Bit was received, and the received byte is a Given or Broadcast address. In mode 0, SM2 should be 0. C T S REN : When set enables serial reception. TB8 : The 9th data bit which will be transmitted in mode 2 and 3. RB8 : In mode 2 and 3, the received 9th data bit will go into this bit. TI : Transmit interrupt flag. Set by hardware when a byte of data has been transmitted by UART0 (after the 8th bit in 8-bit UART Mode, or at the beginning of the STOP bit in 9-bit UART Mode). When the UART0 interrupt is enabled, setting this bit causes the CPU to vector to the UART0 interrupt service routine. This bit must be cleared manually by software. RI : Receive interrupt flag. Set to ‘1’ by hardware when a byte of data has been received by UART0 (set at the STOP bit sam-pling time). When the UART0 interrupt is enabled, setting this bit to ‘1’ causes the CPU to vector to the UART0 interrupt service routine. This bit must be cleared manually by software. SMOD/PCON.7 in PCON register can be used to set whether the baud rates of mode 1, mode2 and mode 3 are doubled or not. PCON: Power Control register (Non bit-addressable) SFR name PCON Address 87H bit name B7 SMOD B6 SMOD0 B5 LVDF B4 POF B3 GF1 B2 GF0 B1 PD B0 IDL SMOD: double Baud rate control bit. 0 : Disable double Baud rate of the UART. 1 : Enable double Baud rate of the UART in mode 1,2,or 3. SMOD0: Frame Error select. 0 : SCON.7 is SM0 function. 1 : SCON.7 is FE function. Note that FE will be set after a frame error regardless of the state of SMOD0. 182 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. SBUF: Serial port 1 Data Buffer register (Non bit-addressable) SFR name SBUF Address 99H bit name B7 B6 B5 B4 B3 B2 B1 B0 It is used as the buffer register in transmission and reception.The serial port buffer register (SBUF) is really two buffers. Writing to SBUF loads data to be transmitted, and reading SBUF accesses received data. These are two separate and distinct registers, the transimit write-only register, and the receive read-only register. 3. AUXR: Auxiliary register (Non bit-addressable) SFR name AUXR Address 8EH bit B7 B6 B5 B4 name T0x12 T1x12 UART_M0x6 EADCI B3 ESPI B2 ELVDI . d e mit B1 - B0 - T0x12 : Timer 0 clock source bit. 0 : The clock source of Timer 0 is SYSclk/12. It will compatible to the traditional 80C51 MCU 1 : The clock source of Timer 0 is SYSclk/1. It will drive the T0 faster than a traditional 80C51 MCU Li T1x12 : Timer 1 clock source bit. 0 : The clock source of Timer 1 is SYSclk/12. It will compatible to the traditional 80C51 MCU 1 : The clock source of Timer 1 is SYSclk/1. It will drive the T0 faster than a traditional 80C51 MCU U C M UART_M0x6 : Baud rate select bit of UART1 while it is working under Mode-0 0 : The baud-rate of UART in mode 0 is SYSclk/12. 1 : The baud-rate of UART in mode 0 is SYSclk/2. C T S EADCI : Enable/Disable interrupt from A/D converter 0 : (default) Inhibit the ADC functional block to generate interrupt to the MCU 1 : Enable the ADC functional block to generate interrupt to the MCU ESPI : Enable/Disable interrupt from Serial Peripheral Interface (SPI) 0 : (default)Inhibit the SPI functional block to generate interrupt to the MCU 1 : Enable the SPI functional block to generate interrupt to the MCU ELVDI : Enable/Disable interrupt from low-voltage sensor 0 : (default)Inhibit the low-voltage sensor functional block to generate interrupt to the MCU 1 : Enable the low-voltage sensor functional block to generate interrupt to the MCU 4. Slave Address Control registers SADEN and SADDR SADEN: Slave Address Mask register SADDR: Slave Address register SADDR register is combined with SADEN register to form Given/Broadcast Address for automatic address recognition. In fact, SADEN function as the "mask" register for SADDR register. The following is the example for it. SADDR = 1100 0000 SADEN = 1111 1101 Given = 1100 00x0 The Given slave address will be checked except bit 1 is treated as "don't care". The Broadcast Address for each slave is created by taking the logical OR of SADDR and SADEN. Zero in this result is considered as "don't care" and a Broad cast Address of all " don't care". This disables the automatic address detection feature. STC MCU Limited. website：www.STCMCU.com 183 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 5. Power down wake-up register: WAKE_CLKO (Non bit-Addressable) SFR name WAKE_CLKO Address bit 8FH name B7 B6 B5 B4 PCAWAKEUP RXD_PIN_IE T1_PIN_IE T0_PIN_IE B3 B2 - - B1 B0 T1CKLO T0CKLO PCAWAKEUP: When set and the associated-PCA interrupt control registers is configured correctly, the CEXn pin of PCA function is enabled to wake up MCU from power-down state. RXD_PIN_IE: When set and the associated-UART interrupt control registers is configured correctly, the RXD pin (P3.0) is enabled to wake up MCU from power-down state. T1_PIN_IE : When set and the associated-Timer1 interrupt control registers is configured correctly, the T1 pin (P3.5) is enabled to wake up MCU from power-down state. T0_PIN_IE : When set and the associated-Timer0 interrupt control registers is configured correctly, the T1 pin (P3.4) is enabled to wake up MCU from power-down state. . d e t i m T1CKLO : When set, P3.5 is enabled to be the clock output of Timer 1. The clock rate is Timer 1overflow rate divided by 2. T0CKLO : When set, P3.4 is enabled to be the clock output of Timer 0. The clock rate is Timer 0overflow rate divided by 2. U C M Li 6. Registers related with UART1 interrupt : IE, IP and IPH C T S IE: Interrupt Enable Rsgister (Bit-addressable) SFR name Address IE A8H bit B7 name EA B6 B5 EPCA_LVD EADC_SPI B4 B3 B2 B1 B0 ES ET1 EX1 ET0 EX0 EA : disables all interrupts. If EA = 0,no interrupt will be acknowledged. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. ES : Serial port 1(UART1) interrupt enable bit. If ES = 0, Serial port (UART) interrupt will be diabled. If ES = 1, Serial port (UART) interrupt is enabled.0 IPH: Interrupt Priority High Register (Non bit-addressable) SFR name Address IPH B7H bit B7 name - B6 B5 B4 B3 B2 B1 B0 PPCA_LVDH PADC_SPIH PSH PT1H PX1H PT0H PX0H IP: Interrupt Priority Register (Bit-addressable) SFR name Address IP PSH, PS: 184 B8H bit B7 name - B6 B5 PPCA_LVD PADC_SPI B4 B3 B2 B1 B0 PS PT1 PX1 PT0 PX0 Serial Port (UART) interrupt priority control bits. if PSH=0 and PS=0, UART interrupt is assigned lowest priority (priority 0). if PSH=0 and PS=1, UART interrupt is assigned lower priority (priority 1). if PSH=1 and PS=0, UART interrupt is assigned higher priority (priority 2). if PSH=1 and PS=1, UART interrupt is assigned highest priority (priority 3). STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.2 UART Operation Modes The serial port (UART) can be operated in 4 different modes which are configured by setting SM0 and SM1 in SFR SCON. Mode 1, Mode 2 and Mode 3 are asynchronous communication. In Mode 0, UART is used as a simple shift register. 8.2.1 Mode 0: 8-Bit Shift Register Mode 0, selected by writing 0s into bits SM1 and SM0 of SCON, puts the serial port into 8-bit shift register mode. Serial data enters and exits through RXD. TXD outputs the shift clock. Eight data bits are transmitted/received with the least-significant (LSB) first. The baud rate is fixed at 1/12 the System clock cycle in the default state. If AUXR.5(UART_M0x6) is set, the baud rate is 1/2 System clock cycle. . d e mit Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal also loads a “1” into the 9th position of the transmit shift register and tells the TX Control block to commence a transmission. The internal timing is such that one full system clock cycle will elapse between "write to SBUF," and activation of SEND. Li SEND transfers the output of the shift register to the alternate output function line of P3.0, and also transfers Shift Clock to the alternate output function line of P3.1. At the falling edge of the Shift Clock, the contents of the shift register are shifted one position to the right. U C M As data bits shift out to the right, “0” come in from the left. When the MSB of the data byte is at the output position of the shift register, then the “1” that was initially loaded into the 9th position is just to the left of the MSB, and all positions to the left of that contains zeroes. This condition flags the TX Control block to do one last shift and then deactivate SEND and set TI. Both of these actions occur after "write to SBUF". C T S Reception is initiated by the condition REN=1 and RI=0. After that, the RX Control unit writes the bits 11111110 to the receive shift register, and in the next clock phase activates RECEIVE. RECEIVE enables SHIFT CLOCK to the alternate output function line of P3.1.At RECEIVE is active, the contents of the receive shift register are shifted to the left one position. The value that comes in from the right is the value that was sampled at the P3.0 pin the rising edge of Shift clock. As data bits come in from the right, “1”s shift out to the left. When the “0” that was initially loaded into the rightmost position arrives at the left-most position in the shift register, it flags the RX Control block to do one last shift and load SBUF. Then RECEIVE is cleared and RI is set. STC MCU Limited. website：www.STCMCU.com 185 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 INTERNAL BUS WRITE TO SBUF DS Q CL RXD/P3.0 OUTPUT FUNCTION SBUF SHIFT ZERO DETECTOR SYSclk/12 0 SYSclk/2 1 START TX CONTROL SERIAL PORT INTERRUPT AUXR.5(UART_M0x6) REN RI TX CLOCK TI RX CLOCK RI SHIFT SEND RX CONTROL SHIFT START 1 1 1 1 1 1 1 0 INPUT SHIFT REG. U C M LOAD SBUF TXD/P3.1 OUTPUT FUNCTION SHIFT CLOCK RECEIVE . d e t i m Li SHIFT RXD/P3.0 INPUT FUNCTION SBUF C T S READ SBUF INTERNAL BUS WRITE TO SBUF SEND SHIFT RXD(DATA OUT) TRANSMIT D0 D1 D2 D3 D4 D5 D6 D7 TXD(SHIFT CLOCK) TI WRITE TO SCON(CLEAR RI) RI RECEIVE RECEIVE SHIFT D0 RXD(DATA IN) D1 D2 D3 D4 D5 D6 D7 TXD(SHIFT CLOCK) Serial Port Mode 0 186 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.2.2 Mode 1: 8-Bit UART with Variable Baud Rate 10 bits are transmitted through TXD or received through RXD. The frame data includes a start bit(0), 8 data bits and a stop bit(1). One receive, the stop bit goes into RB8 in SFR – SCON. The baud rate is determined by the Timer 1 or BRT overflow rate. Baud rate in mode 1 = (2SMOD /32 ) x Timer 1 overflow rate When T1x12=0, Timer 1 overflow rate = SYSclk/12/(256-TH1); When T1x12=1, Timer 1 overflow rate = SYSclk / (256-TH1); Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal also loads a “1” into the 9th bit position of the transmit shift register and flags the TX Control unit that a transmission is requested. Transmission actually happens at the next rollover of divided-by-16 counter. Thus the bit times are synchronized to the divided-by-16 counter, not to the “write to SBUF” signal. . d e mit The transmission begins with activation of SEND , which puts the start bit at TXD. One bit time later, DATA is activated, which enables the output bit of the transmit shift register to TXD. The first shift pulse occurs one bit time after that. Li As data bits shift out to the right, zeroes are clocked in from the left. When the MSB of the data byte is at the output position of the shift register, then the 1 that was initially loaded into the 9th position is just to the left of the MSB, and all positions to the left of that contain zeroes. This condition flags the TX Control unit to do one last shift and then deactivate SEND and set TI. This occurs at the 10th divide-by-16 rollover after “write to SBUF.” U C M Reception is initiated by a 1-to-0 transition detected at RXD. For this purpose, RXD is sampled at a rate of 16 times the established baud rate. When a transition is detected, the divided-by-16 counter is immediately reset, and 1FFH is written into the input shift register. Resetting the divided-by-16 counter aligns its roll-overs with the boundaries of the incoming bit times. C T S The 16 states of the counter divide each bit time into 16ths. At the 7th, 8th and 9th counter states of each bit time, the bit detector samples the value of RXD. The value accepted is the value that was seen in at least 2 of the 3 samples. This is done to reject noise. In order to reject false bits, if the value accepted during the first bit time is not a 0, the receive circuits are reset and the unit continues looking for another 1-to-0 transition. This is to provide rejection of false start bits. If the start bit is valid, it is shifted into the input shift register, and reception of the rest of the frame proceeds. As data bits come in from the right, “1”s shift out to the left. When the start bit arrives at the left most position in the shift register,(which is a 9-bit register in Mode 1), it flags the RX Control block to do one last shift, load SBUF and RB8, and set RI. The signal to load SBUF and RB8 and to set RI is generated if, and only if, the following conditions are met at the time the final shift pulse is generated. 1) RI=0 and 2) Either SM2=0, or the received stop bit = 1 If either of these two conditions is not met, the received frame is irretrievably lost. If both conditions are met, the stop bit goes into RB8, the 8 data bits go into SBUF, and RI is activated. At this time, whether or not the above conditions are met, the unit continues looking for a 1-to-0 transition in RXD. STC MCU Limited. website：www.STCMCU.com 187 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 INTERNAL BUS TB8 Timer 1 Overflow WRITE TO SBUF ÷2 DS Q CL TXD ZERO DETECTOR SMOD =1 SMOD =0 SBUF SHIFT START ÷16 TX CLOCK SERIAL PORT INTERRUPT SAMPLE . d e t i m ÷16 RI Li LOAD SBUF RX CONTROL SHIFT 1FFH U C M BIT DETECTOR C T S SEND TI RX CLOCK START 1-TO-0 TRANSITION DETECTOR RXD DATA TX CONTROL INPUT SHIFT REG. (9 BITS) SHIFT LOAD SBUF SBUF READ SBUF INTERNAL BUS TX CLOCK WRITE TO SBUF SEND TRANSMIT DATA SHIFT D0 TXD START BIT TI D1 D2 D3 D4 D5 D6 D7 START BIT D0 D1 D2 D3 D4 D5 STOP BIT RX CLOCK RXD RECEIVE BIT DETECTOR SAMPLE TIMES SHIFT D6 D7 STOP BIT RI Serial Port Mode 1 188 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.2.3 Mode 2: 9-Bit UART with Fixed Baud Rate 11 bits are transmitted through TXD or received through RXD. The frame data includes a start bit(0), 8 data bits, a programmable 9th data bit and a stop bit(1). On transmit, the 9th data bit comes from TB8 in SCON. On receive, the 9th data bit goes into RB8 in SCON. The baud rate is programmable to either 1/32 or 1/64 the System clock cycle. Baud rate in mode 2 = (2SMOD/64) x SYSclk Transmission is initiated by any instruction that uses SBUF as a destination register. The “write to SBUF” signal also loads TB8 into the 9th bit position of the transmit shift register and flags the TX Control unit that a transmission is requested. Transmission actually happens at the next rollover of divided-by-16 counter. Thus the bit times are synchronized to the divided-by-16 counter, not to the “write to SBUF” signal. . d e mit The transmission begins when /SEND is activated, which puts the start bit at TXD. One bit time later, DATA is activated, which enables the output bit of the transmit shift register to TXD. The first shift pulse occurs one bit time after that. The first shift clocks a “1”(the stop bit) into the 9th bit position on the shift register. Thereafter, only “0”s are clocked in. As data bits shift out to the right, “0”s are clocked in from the left. When TB8 of the data byte is at the output position of the shift register, then the stop bit is just to the left of TB8, and all positions to the left of that contains “0”s. This condition flags the TX Control unit to do one last shift, then deactivate /SEND and set TI. This occurs at the 11th divided-by-16 rollover after “write to SBUF”. U C M Li Reception is initiated by a 1-to-0 transition detected at RXD. For this purpose, RXD is sampled at a rate of 16 times whatever baud rate has been estabished. When a transition is detected, the divided-by-16 counter is immediately reset, and 1FFH is written into the input shift register. C T S At the 7th, 8th and 9th counter states of each bit time, the bit detector samples the value of RXD. The value accepted is the value that was seen in at least 2 of the 3 samples. This is done to reject noise. In order to reject false bits, if the value accepted during the first bit time is not a 0, the receive circuits are reset and the unit continues looking for another 1-to-0 transition. If the start bit is valid, it is shifted into the input shift register, and reception of the rest of the frame proceeds. As data bits come in from the right, “1”s shift out to the left. When the start bit arrives at the leftmost position in the shift register,(which is a 9-bit register in Mode-2 and 3), it flags the RX Control block to do one last shift, load SBUF and RB8, and set RI. The signal to load SBUF and RB8 and to set RI is generated if, and only if, the following conditions are met at the time the final shift pulse is generated.: 1) RI=0 and 2) Either SM2=0, or the received 9th data bit = 1 If either of these two conditions is not met, the received frame is irretrievably lost. If both conditions are met, the stop bit goes into RB8, the first 8 data bits go into SBUF, and RI is activated. At this time, whether or not the above conditions are met, the unit continues looking for a 1-to-0 transition at the RXD input. Note that the value of received stop bit is irrelevant to SBUF, RB8 or RI. STC MCU Limited. website：www.STCMCU.com 189 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 INTERNAL BUS TB8 WRITE TO SBUF DS Q CL SBUF TXD ZERO DETECTOR SYSclk/2 STOP BIT START GEN. MODE 2 ÷16 ÷2 TX CONTROL TX CLOCK TI SERIAL PORT INTERRUPT SMOD=1 SMOD=0 1-TO-0 TRANSITION DETECTOR START U C M RX RI CLOCK C T S SEND Li LOAD SBUF RX CONTROL SHIFT 1FFH BIT DETECTOR RXD DATA . d e t i m ÷16 SAMPLE (SMOD IS PCON.7) SHIFT INPUT SHIFT REG. (9 BITS) SHIFT LOAD SBUF SBUF READ SBUF INTERNAL BUS TX CLOCK WRITE TO SBUF SEND TRANSMIT DATA SHIFT D0 TXD START BIT TI D1 D2 D3 D4 D5 D6 D7 TB8 STOP BIT START BIT D0 D1 D2 D3 D4 D5 D6 D7 STOP BIT GEN RX CLOCK RECEIVE RXD RB8 STOP BIT BIT DETECTOR SAMPLE TIMES SHIFT RI Serial Port Mode 2 190 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.2.4 Mode 3: 9-Bit UART with Variable Baud Rate Mode 3 is the same as mode 2 except the baud rate is variable. Baud rate in mode 3 = (2SMOD /32 ) x Timer 1 overflow rate When T1x12=0, Timer 1 overflow rate = SYSclk/12/(256-TH1); When T1x12=1, Timer 1 overflow rate = SYSclk / (256-TH1); In all four modes, transmission is initiated by any instruction that use SBUF as a destination register. Reception is initiated in mode 0 by the condition RI = 0 and REN = 1. Reception is initiated in the other modes by the incoming start bit with 1-to-0 transition if REN=1. C T S STC MCU Limited. U C M . d e mit Li website：www.STCMCU.com 191 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 INTERNAL BUS TB8 TIMER 1 OVERFLOW WRITE TO SBUF DS Q CL ÷2 SBUF TXD ZERO DETECTOR SMOD =0 SMOD =1 SHIFT START TX CONTROL ÷16 TX CLOCK SERIAL PORT INTERRUPT SEND TI . d e t i m ÷16 SAMPLE 1-TO-0 TRANSITION DETECTOR Li RI RX CLOCK START LOAD SBUF RX CONTROL SHIFT 1FFH U C M BIT DETECTOR RXD C T S DATA INPUT SHIFT REG. (9 BITS) SHIFT LOAD SBUF SBUF READ SBUF INTERNAL BUS TX CLOCK WRITE TO SBUF SEND TRANSMIT DATA SHIFT D0 TXD START BIT TI D1 D2 D3 D4 D5 D6 D7 TB8 STOP BIT D1 D2 D3 D4 D5 D6 D7 STOP BIT GEN RECEIVE RX CLOCK ÷16 RESET RXD START BIT D0 RB8 STOP BIT BIT DETECTOR SAMPLE TIMES SHIFT RI Serial Port Mode 3 192 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.3 Frame Error Detection When used for frame error detect, the UART looks for missing stop bits in the communication. A missing bit will set the FE bit in the SCON register. The FE bit shares the SCON.7 bit with SM0 and the function of SCON.7 is determined by PCON.6(SMOD0). If SMOD0 is set then SCON.7 functions as FE. SCON.7 functions as SM0 when SMOD0 is cleared.When used as FE,SCON.7 can only be cleared by software.Refer to the following figure. 9-bit data START BIT D0 D1 D2 D3 D4 D5 D6 D7 D8 STOP BIT SET FE bit if STOP=0 SM0 to UART mode control PCON.SMOD0 SCON SM0/FE SM1 SM2 REN TB8 . d e mit RB8 TI RI UART Frame Error Detection 8.4 Multiprocessor Communications U C M Li Modes 2 and 3 have a special provision for multiproceasor communications. In these modes 9 data bits are received.The 9th one goes into RB8. Then comes a stop bit. The port can be programmed such that when the stop bit is received,the serial port interrupt will be activated only if RB8 = 1. This feature is enabled by setting bit SM2 in SCON. A way to use this feature in multiprocessor systems is as follows. C T S When the master processor wants to transmit a block of data to one of several slaves, it first sends out an address byte which identifies the target slave.An address byte differs from a data byte in that the 9th bit is 1 in an address byte and 0 in a data byte.With SM2 = 1, no slave will be interrupted by a data byte. An address byte, however,will interrupt all slaves, so that each slave can examine the received byte and see if it is being addressed.The addressed slave will clear its SM2 bit and prepare to receive the data bytes that will be coming. The slaves that weren’t being addressed leave their SM2s set and go on about their business, ignoring the coming data bytes. SM2 has no effect in Mode 0,and in Mode 1 can be used to check the validity of the stop bit. In a Mode 1 reception, if SM2 = 1, the receive interrupt will not be activated unless a vatid stop bit is received. STC MCU Limited. website：www.STCMCU.com 193 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 8.5 Automatic Address Recognition Automatic Address Recognition is a future which allows the UART to recognize certain addresses in the serial bit stream by using hardware to make the comparisons. This feature saves a great deal of software overhead by eliminating the need for the software to examine every serial address which passes by the serial port. This feature is enabled by setting the SM2 bit in SCON. In the 9-bit UART modes, Mode 2 and Mode 3, the Receive interrupt flag(RI) will be automatically set when the received byte contains either the “Given” address or the “Broadcast” address. The 9-bit mode requires that the 9th information bit is a “1” to indicate that the received information is an address and not data. The 8-bit mode is called Mode 1. In this mode the RI flag will be set if SM2 is enabled and the information received has a valid stop bit following the 8 address bits and the information is either a Given or Broadcast address. Mode 0 is the Shift Register mode and SM2 is ignored. . d e t i m Using the Automatic Address Recognition feature allows a master to selectively communicate with one or more slaves by invoking the given slave address or addresses. All of the slaves may be contacted by using the broadcast address. Two special function registers are used to define the slave’s address, SADDR, and the address mask, SADEN. SADEN is used to define which bits in the SADDR are to be used and which bits are “don’t care”. The SADEN mask can be logically ANDed with the SADDR to create the “Given” address which the master will use for addressing each of the slaves. Use of the Given address allows multiple slaves to be recognized which excluding others. The following examples will help to show the versatility of this scheme : Slave 0 SADDR = 1100 0000 SADEN = 1111 1101 GIVEN = 1100 00x0 Slave 1 SADDR = 1100 0000 SADEN = 1111 1110 GIVEN = 1100 000x C T S U C M Li In the previous example SADDR is the same and the SADEN data is used to differentiate between the two slaves. Slave 0 requires a “0” in bit 0 and it ignores bit 1. Slave 1 requires a “0” in bit 1 and bit 0 is ignored. A unique address for slave 0 would be 11000010 since slave 1 requires a “0” in bit 1. A unique address for slave 1 would be 11000001 since a “1” in bit 0 will exclude slave 0. Both slaves can be selected at the same time by an address which has bit 0=0 (for slave 0) and bit 1 =0 (for salve 1). Thus, both could be addressed with 11000000. In a more complex system the following could be used to select slaves 1 and 2 while excluding slave 0: Slave 0 SADDR = 1100 0000 SADEN = 1111 1001 GIVEN = 1100 0xx0 Slave 1 SADDR = 1110 0000 SADEN = 1111 1010 GIVEN = 1110 0x0x Slave 2 SADDR = 1110 0000 SADEN = 1111 1100 GIVEN = 1110 00xx 194 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 In the above example the differentiation among the 3 slaves is in the lower 3 address bits.Slave 0 requires that bit0 = 0 and it can be uniquely addressed by 11100110. Slave 1 requires that bit 1=0 and it can be uniquely addressed by 11100101. Slave 2 requires that bit 2=0 and its unique address is 11100011. To select Salve 0 and 1 and exclude Slave 2, use address 11100100, since it is necessary to make bit2=1 to exclude Slave 2. The Broadcast Address for each slave is created by taking the logic OR of SADDR and SADEN. Zeros in this result are trended as don’t cares. In most cares, interpreting the don’t cares as ones, the broadcast address will be FF hexadecimal. Upon reset SADDR and SADEN are loaded with “0”s. This produces a given address of all “don’t cares as well as a Broadcast address of all “don’t cares”. This effectively disables the Automatic Addressing mode and allows the microcontroller to use standard 80C51-type UART drivers which do not make use of this feature. . d e mit Example: write an program that continually transmits characters from a transmit buffer. If incoming characters are detected on the serial port, store them in the receive buffer starting at internal RAM location 50H. Assume that the STC12C2052AD series MCU serial port has already been initialized in mode 1. Solution: Li ORG 0030H MOV R0, #30H ;pointer for tx buffer MOV R1, #50H ;pointer for rx buffer LOOP: JB RI, RECEIVE ;character received? ;yes: process it JB TI, TX ;previous character transmitted ? ;yes: process it SJMP LOOP ;no: continue checking TX: MOV A, @R0 ;get character from tx buffer MOV C, P ;put parity bit in C CPL C ;change to odd parity MOV ACC.7, C ;add to character code CLR TI ;clear transmit flag MOV SBUF, A ;send character CLR ACC.7 ;strip off parity bit INC R0 ;point to next character in buffer CJNE R0, #50H, LOOP ;end of buffer? ;no: continue MOV R0, #30H ;yes: recycle SJMP LOOP ;continue checking RX: CLR RI ;clear receive flag MOV A, SBUF ;read character into A MOV C, P ;for odd parity in A, P should be set CPL C ;complementing correctly indicates "error" CLR ACC.7 ;strip off parity MOV @R1, A ;store received character in buffer INC R1 ;point to next location in buffer SJMP LOOP ;continue checking END C T S STC MCU Limited. U C M website：www.STCMCU.com 195 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 8.6 Buad Rates The baud rate in Mode 0 is fixed: Mode 0 Baud Rate = or = SYSclk 12 SYSclk 2 when AUXR.5/UART_M0x6 =0 when AUXR.5/UART_M0x6 =1 The baud rate in Mode 2 depends on the value of bit SMOD in Special Function Register PCON. If SMOD =0 (which is the value on reset), the baud rate 1/64 the System clock cycle. If SMOD = 1, the baud rate is 1/32 the System clock cycle . 2SMOD (SYSclk) ×�������� Mode 2 Baud Rate = 64 . d e t i m In the STC12C2052AD, the baud rates in Modes 1 and 3 are determined by Timer 1 overflow rate. The baud rate in Mode 1 and 3 are fixed: Mode 1,3 Baud rate = (2SMOD /32 ) x timer 1 overflow rate Li Timer 1 overflow rate = (SYSclk/12)/(256 - TH1); U C M When Timer 1 is used as the baud rate generator, the Timer 1 interrupt should be disabled in this application. The Timer itself can be configured for either “timer” or “cormter” operation, and in any of its 3 running modes. In the most typcial applications, it is configured for “timer” operation, in the auto-reload mode (high nibble of TMOD = 0010B). One can achieve very low baud rate with Timer 1 by leaving the Timer 1 interrupt enabled, and configuring the Timer to run as a 16-bit timer (high nibble of TMOD = 0001B), and using the Timer 1 interrupt to do a l6-bit software reload. C T S The following figure lists various commonly used baud rates and how they can be obtained from Timer 1. Baud Rate fOSC SMOD Mode 0 MAX:1MHZ Mode 2 MAX:375K Mode 1,3:62.5K 19.2K 9.6K 4.8K 2.4K 1.2K 137.5 110 110 12MHZ 12MHZ 12MHZ 11.059MHZ 11.059MHZ 11.059MHZ 11.059MHZ 11.059MHZ 11.986MHZ 6MHZ 12MHZ X 1 1 1 0 0 0 0 0 0 0 Timer 1 Reload C/T Mode Value X X X X X X 0 2 FFH 0 2 FDH 0 2 FDH 0 2 FAH 0 2 F4H 0 2 E8H 0 2 1DH 0 2 72H 0 1 FEEBH Timer 1 Generated Commonly Used Baud Rates 196 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 8.7 Demo Programs about UART (C and ASM) 1. C program: /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------*/ /* --- STC12C5Axx Series MCU UART (8-bit/9-bit)Demo ----------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" typedef unsigned char typedef unsigned int BYTE; WORD; U C M . d e mit Li #define FOSC 18432000L #define BAUD 9600 //System frequency //UART baudrate /*Define UART parity mode*/ #define NONE_PARITY 0 #define ODD_PARITY 1 #define EVEN_PARITY 2 #define MARK_PARITY 3 #define SPACE_PARITY 4 //None parity //Odd parity //Even parity //Mark parity //Space parity C T S #define PARITYBIT sbit bit bit9 = P2^2; busy; EVEN_PARITY //Testing even parity //P2.2 show UART data bit9 void SendData(BYTE dat); void SendString(char *s); void main() { #if (PARITYBIT == NONE_PARITY) SCON = 0x50; //8-bit variable UART #elif (PARITYBIT == ODD_PARITY) || (PARITYBIT == EVEN_PARITY) || (PARITYBIT == MARK_PARITY) SCON = 0xda; //9-bit variable UART, parity bit initial to 1 #elif (PARITYBIT == SPACE_PARITY) SCON = 0xd2; //9-bit variable UART, parity bit initial to 0 #endif STC MCU Limited. website：www.STCMCU.com 197 www.STCMCU.com Mobile:(86)13922809991 TMOD TH1 TR1 ES EA SendString("STC12C2052AD\r\nUart Test !\r\n"); while(1); = 0x20; = TL1 = -(FOSC/12/32/BAUD); = 1; = 1; = 1; Tel:086-755-82948412 Fax:86-755-82905966 //Set Timer1 as 8-bit auto reload mode //Set auto-reload vaule //Timer1 start run //Enable UART interrupt //Open master interrupt switch } /*---------------------------UART interrupt service routine ----------------------------*/ void Uart_Isr() interrupt 4 using 1 { if (RI) { RI = 0; P0 = SBUF; bit9 = RB8; } if (TI) { TI = 0; busy = 0; } } /*---------------------------Send a byte data to UART Input: dat (data to be sent) Output:None ----------------------------*/ void SendData(BYTE dat) { while (busy); ACC = dat; if (P) { #if (PARITYBIT == ODD_PARITY) TB8 = 0; #elif (PARITYBIT == EVEN_PARITY) TB8 = 1; #endif } C T S 198 STC MCU Limited. U C M . d e t i m Li //Clear receive interrupt flag //P0 show UART data //P2.2 show parity bit //Clear transmit interrupt flag //Clear transmit busy flag //Wait for the completion of the previous data is sent //Calculate the even parity bit P (PSW.0) //Set the parity bit according to P //Set parity bit to 0 //Set parity bit to 1 website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 else { #if (PARITYBIT == ODD_PARITY) TB8 = 1; #elif (PARITYBIT == EVEN_PARITY) TB8 = 0; #endif } busy = 1; SBUF = ACC; } Fax:86-755-82905966 /*---------------------------Send a string to UART Input: s (address of string) Output:None ----------------------------*/ void SendString(char *s) { while (*s) { SendData(*s++); } } C T S STC MCU Limited. U C M //Set parity bit to 1 //Set parity bit to 0 //Send data to UART buffer . d e mit Li //Check the end of the string //Send current char and increment string ptr website：www.STCMCU.com 199 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly program: /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------*/ /* --- STC12C5Axx Series MCU UART (8-bit/9-bit)Demo ----------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ ;/*Define UART parity mode*/ #define NONE_PARITY 0 #define ODD_PARITY 1 #define EVEN_PARITY 2 #define MARK_PARITY 3 #define SPACE_PARITY 4 M CU #define PARITYBIT EVEN_PARITY ;----------------------------------------BUSY BIT 20H.0 ;---------------------------------------- ORG 0000H LJMP MAIN C T S . d e t i m //None parity //Odd parity //Even parity //Mark parity //Space parity Li //Testing even parity ;transmit busy flag ORG 0023H LJMP UART_ISR ;---------------------------------------- ORG 0100H MAIN: CLR BUSY CLR EA MOV SP, #3FH #if (PARITYBIT == NONE_PARITY) MOV SCON, #50H ;8-bit variable UART #elif (PARITYBIT == ODD_PARITY) || (PARITYBIT == EVEN_PARITY) || (PARITYBIT == MARK_PARITY) MOV SCON, #0DAH ;9-bit variable UART, parity bit initial to 1 #elif (PARITYBIT == SPACE_PARITY) MOV SCON, #0D2H ;9-bit variable UART, parity bit initial to 0 #endif ;------------------------------- 200 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 MOV TMOD, #20H MOV A, #0FBH MOV TH1, A MOV TL1, A SETB TR1 SETB ES SETB EA ;------------------------------ MOV DPTR, #TESTSTR LCALL SENDSTRING ;------------------------------ SJMP $ ;----------------------------------------TESTSTR: ;Test string DB "STC12C2052AD Uart Test !", ;/*---------------------------;UART2 interrupt service routine ;----------------------------*/ UART_ISR: PUSH ACC PUSH PSW JNB RI, CHECKTI CLR RI MOV P0, SBUF MOV C, RB8 MOV P2.2, C CHECKTI: JNB TI, ISR_EXIT CLR TI CLR BUSY ISR_EXIT: POP PSW POP ACC RETI C T S U C M ;/*---------------------------;Send a byte data to UART ;Input: ACC (data to be sent) ;Output:None ;----------------------------*/ SENDDATA: JB BUSY, $ MOV ACC, A JNB P, EVEN1INACC STC MCU Limited. Tel:86-755-82948412 Fax:86-755-82905966 ;Set Timer1 as 8-bit auto reload mode ;256-18432000/12/32/9600 ;Set auto-reload vaule ;Timer1 start run ;Enable UART interrupt ;Open master interrupt switch ;Load string address to DPTR ;Send string . d e mit 0DH,0AH,0 Li ;Check RI bit ;Clear RI bit ;P0 show UART data ;P2.2 show parity bit ;Check S2TI bit ;Clear S2TI bit ;Clear transmit busy flag ;Wait for the completion of the previous data is sent ;Calculate the even parity bit P (PSW.0) ;Set the parity bit according to P website：www.STCMCU.com 201 www.STCMCU.com Mobile:(86)13922809991 ODD1INACC: #if (PARITYBIT == ODD_PARITY) CLR TB8 #elif (PARITYBIT == EVEN_PARITY) SETB TB8 #endif SJMP PARITYBITOK EVEN1INACC: #if (PARITYBIT == ODD_PARITY) SETB TB8 #elif (PARITYBIT == EVEN_PARITY) CLR TB8 #endif PARITYBITOK: SETB BUSY MOV SBUF, A RET U C M ;/*---------------------------;Send a string to UART ;Input: DPTR (address of string) ;Output:None ;----------------------------*/ SENDSTRING: CLR A MOVC A, @A+DPTR JZ STRINGEND INC DPTR LCALL SENDDATA SJMP SENDSTRING STRINGEND: RET ;---------------------------------------- END C T S 202 STC MCU Limited. Tel:086-755-82948412 Fax:86-755-82905966 ;Set parity bit to 0 ;Set parity bit to 1 ;Set parity bit to 1 ;Set parity bit to 0 . d e t i m ;Parity bit set completed Li ;Send data to UART buffer ;Get current char ;Check the end of the string ;increment string ptr ;Send current char ;Check next website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Chapter 9. Analog to Digital Converter 9.1 A/D Converter Structure STC12C2052AD series MCU with A/D conversion function have 8-channel and 8-bit high-speed A/D converter whose speed is up to 100KHz (100 thousand times per second). the 8-channel ADC, which are on P1 port (P1.0-P1.7) , can be used as temperature detection, battery voltage detection, key scan, spectrum detection, etc. After power on reset, P1 ports are in weak pull-up mode. Users can set any one of 8 channels as A/D conversion through software. And those I/O ports not as ADC function can continue to be used as I/O ports. STC12C2052AD series MCU ADC (A/D converter) structure is shown below. ADC_CONTR Register ADC_POWER SPEED1 Analog input Signal channel Select switch CHS2/CHS1/CHS0 ADC7/P1.7 ADC6/P1.6 ADC5/P1.5 ADC4/P1.4 ADC3/P1.3 ADC2/P1.2 ADC1/P1.1 C T S SPEED0 ADC_FLAG . d e mit ADC_START CHS2 CHS1 CHS0 Li U C M ADC result Register : ADC_ DATA Successive Approximation Register + - Comparator ADC0/P1.0 8-bit DAC ADC_DATA[7:0] ADC_B9 ADC_B8 ADC_B7 ADC_B6 ADC_B5 ADC_B4 ADC_B3 ADC_B2 The ADC on STC12C2052AD is an 8-bit resolution, successive-approximation approach, medium-speed A/D converter. VREFP/VREFM is the positive/negative reference voltage input for internal voltage-scaling DAC use, the typical sink current on it is 600uA ~ 1mA. For STC12C2052AD, these two references are internally tied to VCC and GND separately. STC MCU Limited. website：www.STCMCU.com 203 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 Conversion is invoked since ADC_STRAT(ADC_CONTR.3) bit is set. Before invoking conversion, ADC_POWER/ADC_CONTR.7 bit should be set first in order to turn on the power of analog front-end in ADC circuitry. Prior to ADC conversion, the desired I/O ports for analog inputs should be configured as inputonly or open-drain mode first. The converter takes around a fourth cycles to sample analog input data and other three fourths cycles in successive-approximation steps. Total conversion time is controlled by two register bits – SPEED1 and SPEED0. Eight analog channels are available on P1 and only one of them is connected to to the comparator depending on the selection bits {CHS2,CHS1,CHS0}. When conversion is completed, the result will be saved onto ADC_DATA register. After the result are completed and saved, ADC_FLAG is also set. ADC_FLAG should be cleared in software. The ADC interrupt service routine vectors to 2Bh . When the chip enters idle mode or power-down mode, the power of ADC is gated off by hardware. Calculating the result according to the following formula: . d e t i m 8-bit A/D Conversion Result:(ADC_DATA[7:0]) = 256 x Li Vin Vcc In the above formula, Vin stand for analog input channel voltage, Vcc stand for actual operation voltage C T S 204 STC MCU Limited. U C M website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 9.2 Registers for ADC Mnemonic Description Address P1M0 P1M1 P1 Configuration 0 P1 Configuration 1 91H 92H ADC_CONTR ADC Control Register C5H ADC_DATA ADC Result Register IE Interrupt Enable Interrupt Priority IP Low Interrupt Priority IPH High AUXR Auxiliary register C6H A8H MSB bit address and Symbol LSB Reset value 0000 0000B 0000 0000B ADC_POWER SPEED1 SPEED0 ADC_FLAG ADC_START CHS2 CHS1 CHS0 EA EPCA_LVD EADC_SPI ES ET1 EX1 ET0 EX0 0000 0000B 0000 0000B 0000 0000B B8H - PPCA_LVD PADC_SPI PS PT1 PX1 PT0 PX0 x000 0000B B7H - A2H . d e t PPCA_LVDH PADC_SPIH PSH PT1H PX1H PT0H PX0H i m i L T0x12 T1x12 UART_M0x12 EADCI ESPI ELVDI 1. P1 Analog Function Configure register: P1M0 and P1M1 U C M - - x000 0000B 0000 00xxB Those P1 ports which need to be used as A/D converter should be first set in open-drain or high-impedance (input-only) mode through registers P1M0 and P1M1. P1 Configure (P1�������� address：90H�) C T S P1M0[7 : 0] P1M1 [7 : 0] 0 0 0 1 1 0 1 1 I/O ports Mode quasi_bidirectional(standard 8051 I/O port output） , Sink Current up to 20mA , pull-up Current is 230μA , Because of manufactured error, the actual pull-up current is 250uA ~ 150uA push-pull output(strong pull-up output，current can be up to 20mA, resistors need to be added to restrict current input-only (high-impedance ). If any P1 port need to be used as ADC, its mode is optional between inputonly (high-impedance ) and open-drain mode. Open Drain，internal pull-up resistors should be disabled and external pull-up resistors need to join. If any P1 port need to be used as ADC, its mode is optional between inputonly (high-impedance ) and open-drain mode. Example: MOV P1M0, #10100000B MOV P1M1, #11000000B ;P1.7 in Open Drain mode, P1.6 in strong push-pull output, P1.5 in high-impedance input, P1.4/P1.3/P1.2/ P1.1/P1.0 in quasi_bidirectional������������� /weak pull-up STC MCU Limited. website：www.STCMCU.com 205 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. ADC control register: ADC_CONTR (Non bit-addressable) SFR name Address ADC_CONTR C5H bit B7 B6 B5 B4 B3 B2 B1 B0 name ADC_POWER SPEED1 SPEED0 ADC_FLAG ADC_START CHS2 CHS1 CHS0 When operating to ADC_CONTR register, "MOV" should be used, while "AND" and "OR" don not be recommended to use ADC_POWER : When clear shut down the power of ADC block. When set turn on the power of ADC block. SPEED1, SPEED0 : Conversion speed selection. SPEED1 SPEED0 Times needed by an A/D Coversion 0 0 1080 clock cycles are needed for a conversion. 0 1 810 clock cycles are needed for a conversion. 1 0 540 clock cycles are needed for a conversion. 1 1 270 clock cycles are needed for a conversion. When the CPU operation frequency is 27MHz, the speed of ADC is about 100KHz. . d e t i m Li The clock source used by ADC block of STC12C2052AD series MCU is On-chip R/C clock which is not divided by Clock divider register CLK_DIV. U C M ADC_FLAG : ADC interrupt flag.It will be set by the device after the device has finished a conversion, and should be cleared by the user's software. ADC_STRAT : ADC start bit, which enable ADC conversion.It will automatically cleared by the device after the device has finished the conversion. C T S CHS2 ~ CHS0 : Used to select one analog input source from 8 channels. CHS2 CHS1 CHS0 Source 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 P1.0 (default) as the A/D channel input P1.1 as the A/D channel input P1.2 as the A/D channel input P1.3 as the A/D channel input P1.4 as the A/D channel input P1.5 as the A/D channel input P1.6 as the A/D channel input P1.7 as the A/D channel input Note : The corresponding bits in P1ASF should be configured correctly before starting A/D conversion. The sepecific P1ASF bits should be set corresponding with the desired channels. Because it will by delayed 4 CPU clocks after the instruction which set ADC_CONTR register has been executed, Four "NOP" instructions should be added after setting ADC_CONTR register. See the following code: MOV ADC_CONTR, #DATA NOP NOP NOP NOP MOV A, ADC_CONTR ;Only delayed 4 clocks, can the ADC_CONTR be read correctly. 206 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 3. ADC result register: ADC_DATA ADC_DATA is used to save the ADC result, their format as shown below: Mnemonic Add ADC_DATA C6h Name B7 B6 B5 B4 B3 B2 B1 B0 ADC result register high Calculating the result according to the following formula: 8-bit A/D Conversion Result:(ADC_DATA[7:0]) = 256 x Vin Vcc . d e mit In the above formula, Vin stand for analog input channel voltage, Vcc stand for actual operation voltage Li 4. Registers related with UART1 interrupt : IE, AUXR, IP and IPH CU IE: Interrupt Enable Rsgister (Bit-addressable) SFR name Address IE A8H bit B7 name EA C T S EA : disables all interrupts. M B6 B5 EPCA_LVD EADC_SPI B4 B3 B2 B1 B0 ES ET1 EX1 ET0 EX0 If EA = 0,no interrupt will be acknowledged. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. EADC_SPI : Interrupt controller of Serial Peripheral Interface (SPI) and A/D Converter (ADC). If EADC_SPI = 0, Disable the interrupt of Serial Peripheral Interface (SPI) and A/D Converter (ADC). If EADC_SPI = 1, Enable the interrupt of Serial Peripheral Interface (SPI) and A/D Converter (ADC). AUXR: Auxiliary register (Non bit-addressable) SFR name AUXR Address 8EH bit B7 B6 B5 B4 name T0x12 T1x12 UART_M0x6 EADCI B3 ESPI B2 ELVDI B1 - B0 - EADCI : Enable/Disable interrupt from A/D converter 0 : (default) Inhibit the ADC functional block to generate interrupt to the MCU 1 : Enable the ADC functional block to generate interrupt to the MCU STC MCU Limited. website：www.STCMCU.com 207 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 IPH: Interrupt Priority High Register (Non bit-addressable) SFR name Address IPH B7H bit B7 name - B6 B5 PPCA_LVDH PADC_SPIH B4 B3 B2 B1 B0 PSH PT1H PX1H PT0H PX0H IP: Interrupt Priority Register (Bit-addressable) SFR name Address IP B8H bit B7 name - B6 B5 PPCA_LVD PADC_SPI B4 B3 B2 B1 B0 PS PT1 PX1 PT0 PX0 PADC_SPIH, PADC_SPI : Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt priority control bits. if PADC_SPIH=0 and PADC_SPI=0, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 0). if PADC_SPIH=0 and PADC_SPI=1, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 1). if PADC_SPIH=1 and PADC_SPI=0, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 2). if PADC_SPIH=1 and PADC_SPI=1, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 3). . d e t i m Li U C M C T S 9.3 Application Circuit of A/D Converter 1 28 Vcc P2.3 2 27 P2.1 RST 3 26 P2.0/PCA2/PWM2 RxD/P3.0 4 25 P1.7/ADC7 24 P1.6/ADC6 23 P1.5/ADC5 22 P1.4/ADC4 21 P1.3/ADC3 20 P1.2/ADC2 19 P1.1/ADC1/CLKOUT1 TxD/P3.1 5 XTAL2 6 XTAL1 7 INT0/P3.2 8 INT1/P3.3 9 ECI/T0/P3.4 10 PWM1/PCA1/T1/P3.5 11 PWM3/PCA3/P2.4 SOP-28/SKDIP-28 P2.2 more than 47pF 1K 18 P1.0/ADC0/CLKOUT0 12 17 P3.7/PCA0/PWM0 P2.5 13 16 P2.7 Gnd 14 15 P2.6 Signal source ADC function in P1 port, P1.0 - P1.7 in all 8 channels 208 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 9.4 ADC Application Circuit for Key Scan P2.2 1 28 Vcc P2.3 2 27 P2.1 Vcc 3 26 P2.0/PCA2/PWM2 4 25 P1.7/ADC7 TxD/P3.1 5 24 P1.6/ADC6 XTAL2 6 23 P1.5/ADC5 XTAL1 7 22 P1.4/ADC4 INT0/P3.2 8 21 P1.3/ADC3 INT1/P3.3 9 20 P1.2/ADC2 19 P1.1/ADC1/CLKOUT1 18 P1.0/ADC0/CLKOUT0 SOP-28/SKDIP-28 RST RxD/P3.0 10K more than 47pF 1K 0V 10K 1/2 Vcc 10K 2/3 Vcc 10K ECI/T0/P3.4 10 PWM1/PCA1/T1/P3.5 11 PWM3/PCA3/P2.4 12 17 P3.7/PCA0/PWM0 P2.5 13 16 P2.7 Gnd 14 15 P2.6 3/4 Vcc 10K . d e mit 4/5 Vcc Li ADC function in P1 port, P1.0 - P1.7 in all 8 channels CU +5V M 1 28 Vcc P2.3 2 27 P2.1 RST 3 26 P2.0/PCA2/PWM2 RxD/P3.0 4 25 P1.7/ADC7 TxD/P3.1 5 24 P1.6/ADC6 XTAL2 6 23 P1.5/ADC5 22 P1.4/ADC4 21 P1.3/ADC3 20 P1.2/ADC2 19 P1.1/ADC1/CLKOUT1 18 P1.0/ADC0/CLKOUT0 C T S XTAL1 7 INT0/P3.2 8 INT1/P3.3 9 SOP-28/SKDIP-28 P2.2 47pF sw1 ECI/T0/P3.4 10 PWM1/PCA1/T1/P3.5 11 PWM3/PCA3/P2.4 12 17 P3.7/PCA0/PWM0 P2.5 13 16 P2.7 Gnd 14 15 P2.6 +5V R0 ADCx 10KΩ sw1 R2 520Ω R3 1.8KΩ R4 R5 R6 3.3KΩ 5.4KΩ 8.2KΩ sw2 sw3 sw4 0`0.5 0 0.5`1 1`1.5 sw5 sw6 1.5`2.0 2.0`2.5 This curcuit can realize the single key scan and assembling key scan detection function, but the value of resistors should be adjusted according to the actual demand. 10 keys are used to divide the voltage in the below curcuit, what the error of each key float between -0.25V and +0.25V can effectively avoid that resistance error or temprature difit lead to disable key detection. R1 520Ω 47pF R1 10KΩ ADCx R2 1.2KΩ sw2 R3 1.6KΩ sw3 R4 1.8KΩ sw4 R5 3KΩ sw5 R6 4KΩ sw6 R7 6.5Ω sw7 R8 10KΩ sw8 R9 30KΩ sw9 R10 100KΩ sw10 sw11 0 STC MCU Limited. website：www.STCMCU.com 209 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 9.5 A/D reference voltage source STC12C2052AD series ADC reference voltage is from MCU power supply voltage directly, so it can work without an external reference voltage source. If the required precision is relatively high, then you maybe using a stable reference voltage source, in order to calculate the operating voltage VCC, then calculate the ADC exact value. For example, you can connect a 1.25V(or 1.00V, ect. …) to ADC channel 7, according to the conversion result, you can get the actual VCC voltage, thus you can calculate other 7 channels ADC results. (Vcc is constant in short time) C T S 210 STC MCU Limited. U C M . d e t i m Li website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 9.6 Program using interrupts to demostrate A/D Conversion There are two example procedures using interrupts to demostrate A/D conversion, one written in C langugage and the other in assembly language. 1. C language code listing: /*---------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ------------------------------------*/ /* --- STC 1T Series MCU A/D Conversion Demo ----------------------*/ /* --- Mobile: (86)13922809991 --------------------------------------------*/ /* --- Fax: 86-755-82905966 ------------------------------------------------*/ /* --- Tel: 86-755-82948412 -------------------------------------------------*/ /* --- Web: www.STCMCU.com --------------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*---------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" #define FOSC 18432000L #define BAUD 9600 typedef unsigned char typedef unsigned int BYTE; WORD; C T S U C M /*Declare SFR associated with the ADC */ sfr AUXR = 0x8e; sfr ADC_CONTR = 0xC5; sfr ADC_DATA = 0xC6; sfr ADC_LOW2 = 0xBE; sfr P1M0 = 0x91; sfr P1M1 = 0x92; . d e mit Li //ADC control register //ADC high 8-bit result register //ADC low 2-bit result register //P1 mode control register0 //P1 mode control register1 /*Define ADC operation const for ADC_CONTR*/ #define ADC_POWER 0x80 //ADC power control bit #define ADC_FLAG 0x10 //ADC complete flag #define ADC_START 0x08 //ADC start control bit #define ADC_SPEEDLL 0x00 //1080 clocks #define ADC_SPEEDL 0x20 //810 clocks #define ADC_SPEEDH 0x40 //540 clocks #define ADC_SPEEDHH 0x60 //270 clocks void InitUart(); void SendData(BYTE dat); void Delay(WORD n); void InitADC(); STC MCU Limited. website：www.STCMCU.com 211 www.STCMCU.com Mobile:(86)13922809991 BYTE ch = 0; void main() { InitUart(); InitADC(); AUXR |= 0x10; IE = 0xa0; while (1); } Fax:86-755-82905966 //ADC channel NO. //Init UART, use to show ADC result //Init ADC sfr //set EADCI //Enable ADC interrupt and Open master interrupt switch //Start A/D conversion /*---------------------------ADC interrupt service routine ----------------------------*/ void adc_isr() interrupt 5 using 1 { ADC_CONTR &= !ADC_FLAG; Tel:086-755-82948412 M CU SendData(ch); SendData(ADC_DATA); C T S . d e t i m Li //Clear ADC interrupt flag //Show Channel NO. //Get ADC high 8-bit result and Send to UART //if you want show 10-bit result, uncomment next line // SendData(ADC_LOW2); //Show ADC low 2-bit result if (++ch > 7) ch = 0; //switch to next channel ADC_CONTR = ADC_POWER | ADC_SPEEDLL | ADC_START | ch; } /*---------------------------Initial ADC sfr ----------------------------*/ void InitADC() { P1 = P1M0 = P1M1 = 0xff; //Set all P1 as Open-Drain mode ADC_DATA = 0; //Clear previous result ADC_CONTR = ADC_POWER | ADC_SPEEDLL | ADC_START | ch; Delay(2); //ADC power-on delay and Start A/D conversion } /*---------------------------Initial UART ----------------------------*/ 212 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 void InitUart() { SCON = 0x5a; TMOD = 0x20; TH1 = TL1 = -(FOSC/12/32/BAUD); TR1 = 1; } /*---------------------------Send one byte data to PC Input: dat (UART data) Output:----------------------------*/ void SendData(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } /*---------------------------Software delay function ----------------------------*/ void Delay(WORD n) { WORD x; } C T S U C M Tel:86-755-82948412 Fax:86-755-82905966 //8 bit data ,no parity bit //T1 as 8-bit auto reload //Set Uart baudrate //T1 start running . d e mit //Wait for the previous data is sent //Clear TI flag //Send current data Li while (n--) { x = 5000; while (x--); } STC MCU Limited. website：www.STCMCU.com 213 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly language code listing: ;/*----------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -------------------------------------*/ ;/* --- STC 1T Series MCU A/D Conversion Demo -----------------------*/ ;/* --- Mobile: (86)13922809991 ---------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 --------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ---------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*-----------------------------------------------------------------------------------*/ ;/*Declare SFR associated with the ADC */ AUXR EQU 8EH ADC_CONTR EQU 0C5H ADC_DATA EQU 0C6H ADC_LOW2 EQU 0BEH P1M0 EQU 091H P1M1 EQU 092H . d e t i m ;ADC control register ;ADC high 8-bit result register ;ADC low 2-bit result register ;P1 mode control register0 ;P1 mode control register1 U C M Li ;/*Define ADC operation const for ADC_CONTR*/ ADC_POWER EQU 80H ;ADC power control bit ADC_FLAG EQU 10H ;ADC complete flag ADC_START EQU 08H ;ADC start control bit ADC_SPEEDLL EQU 00H ;1080 clocks ADC_SPEEDL EQU 20H ;810 clocks ADC_SPEEDH EQU 40H ;540 clocks ADC_SPEEDHH EQU 60H ;270 clocks C T S ADCCH DATA 20H ;ADC channel NO. ;---------------------------------------- ORG 0000H LJMP MAIN ORG 002BH LJMP ADC_ISR ;---------------------------------------- ORG 0100H MAIN: MOV SP, MOV ADCCH, #0 LCALL INIT_UART LCALL INIT_ADC ORL AUXR, #10H MOV IE, #0A0H SJMP $ 214 STC MCU Limited. #3FH ;Init UART, use to show ADC result ;Init ADC sfr ;set EADCI ;Enable ADC interrupt and Open master interrupt switch website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;/*---------------------------;ADC interrupt service routine ;----------------------------*/ ADC_ISR: PUSH ACC PUSH PSW ANL MOV LCALL MOV LCALL ADC_CONTR, #NOT ADC_FLAG A, ADCCH SEND_DATA A, ADC_DATA SEND_DATA ;//if you want show 10-bit result, uncomment next 2 lines ; MOV A, ADC_LOW2 ; LCALL SEND_DATA INC MOV ANL MOV ORL MOV POP POP RETI ;Clear ADC interrupt flag ;Send channel NO. ;Get ADC high 8-bit result ;Send to UART . d e mit ;Get ADC low 2-bit result ;Send to UART Li ADCCH A, ADCCH A, #07H ADCCH, A A, #ADC_POWER | ADC_SPEEDLL | ADC_START ADC_CONTR,A ;ADC power-on delay and re-start A/D conversion PSW ACC C T S U C M ;/*---------------------------;Initial ADC sfr ;----------------------------*/ INIT_ADC: MOV A, #0FFH MOV P1, A MOV P1M0, A MOV P1M1, A ;Set all P1 as Open-Drain mode MOV ADC_DATA, #0 ;Clear previous result MOV A, ADCCH ORL A, #ADC_POWER | ADC_SPEEDLL | ADC_START MOV ADC_CONTR, A ;ADC power-on delay and Start A/D conversion MOV A,#2 LCALL DELAY RET STC MCU Limited. website：www.STCMCU.com 215 www.STCMCU.com Mobile:(86)13922809991 ;/*---------------------------;Initial UART ;----------------------------*/ INIT_UART: MOV SCON, MOV TMOD, MOV A, MOV TH1, MOV TL1, SETB TR1 RET ;/*---------------------------;Send one byte data to PC ;Input: ACC (UART data) ;Output:;----------------------------*/ SEND_DATA: JNB TI, CLR TI MOV SBUF, RET #5AH #20H #-5 A A $ A C T S ;/*---------------------------;Software delay function ;----------------------------*/ DELAY: MOV R2, CLR A MOV R0, MOV R1, DELAY1: DJNZ R0, DJNZ R1, DJNZ R2, RET 216 U C M Tel:086-755-82948412 Fax:86-755-82905966 ;8 bit data ,no parity bit ;T1 as 8-bit auto reload ;Set Uart baudrate -(18432000/12/32/9600) ;Set T1 reload value ;T1 start running . d e t i m Li ;Wait for the previous data is sent ;Clear TI flag ;Send current data A A A DELAY1 DELAY1 DELAY1 END STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 9.7 Program using polling to demostrate A/D Conversion There are two example procedures using inquiry to demostrate A/D conversion, one written in C langugage and the other in assembly language. 1. C language code listing: /*--------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------*/ /* --- STC 1T Series MCU A/D Conversion Demo ---------------------*/ /* --- Mobile: (86)13922809991 ------------------------------------------*/ /* --- Fax: 86-755-82905966 ----------------------------------------------*/ /* --- Tel: 86-755-82948412 -----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" #define FOSC 18432000L #define BAUD 9600 typedef unsigned char typedef unsigned int BYTE; WORD; C T S U C M /*Declare SFR associated with the ADC */ sfr ADC_CONTR = 0xC5; sfr ADC_DATA = 0xC6; sfr ADC_LOW2 = 0xBE; sfr P1M0 = 0x91; sfr P1M1 = 0x92; /*Define ADC operation const for ADC_CONTR*/ #define ADC_POWER 0x80 #define ADC_FLAG 0x10 #define ADC_START 0x08 #define ADC_SPEEDLL 0x00 #define ADC_SPEEDL 0x20 #define ADC_SPEEDH 0x40 #define ADC_SPEEDHH 0x60 . d e mit Li //ADC control register //ADC high 8-bit result register //ADC low 2-bit result register //P1 mode control register0 //P1 mode control register1 //ADC power control bit //ADC complete flag //ADC start control bit //1080 clocks //810 clocks //540 clocks //270 clocks void InitUart(); void InitADC(); void SendData(BYTE dat); BYTE GetADCResult(BYTE ch); void Delay(WORD n); void ShowResult(BYTE ch); STC MCU Limited. website：www.STCMCU.com 217 www.STCMCU.com Mobile:(86)13922809991 void main() { InitUart(); InitADC(); while (1) { ShowResult(0); ShowResult(1); ShowResult(2); ShowResult(3); ShowResult(4); ShowResult(5); ShowResult(6); ShowResult(7); } } /*---------------------------Send ADC result to UART ----------------------------*/ void ShowResult(BYTE ch) { SendData(ch); SendData(GetADCResult(ch)); C T S U C M //if you want show 10-bit result, uncomment next line // SendData(ADC_LOW2); } Tel:086-755-82948412 Fax:86-755-82905966 //Init UART, use to show ADC result //Init ADC sfr //Show Channel0 //Show Channel1 //Show Channel2 //Show Channel3 //Show Channel4 //Show Channel5 //Show Channel6 //Show Channel7 . d e t i m Li //Show Channel NO. //Show ADC high 8-bit result //Show ADC low 2-bit result /*---------------------------Get ADC result ----------------------------*/ BYTE GetADCResult(BYTE ch) { ADC_CONTR = ADC_POWER | ADC_SPEEDLL | ch | ADC_START; _nop_(); //Must wait before inquiry _nop_(); _nop_(); _nop_(); while (!(ADC_CONTR & ADC_FLAG)); //Wait complete flag ADC_CONTR &= ~ADC_FLAG; //Close ADC return ADC_DATA; //Return ADC result } 218 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 /*---------------------------Initial UART ----------------------------*/ void InitUart() { SCON = 0x5a; TMOD = 0x20; TH1 = TL1 = -(FOSC/12/32/BAUD); TR1 = 1; } Tel:86-755-82948412 Fax:86-755-82905966 //8 bit data ,no parity bit //T1 as 8-bit auto reload //Set Uart baudrate //T1 start running /*---------------------------Initial ADC sfr ----------------------------*/ void InitADC() { P1 = P1M0 = P1M1 = 0xff; //Set all P1 as Open-Drain mode ADC_DATA = 0; //Clear previous result ADC_CONTR = ADC_POWER | ADC_SPEEDLL; Delay(2); //ADC power-on and delay } /*---------------------------Send one byte data to PC Input: dat (UART data) Output:----------------------------*/ void SendData(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } C T S U C M . d e mit Li //Wait for the previous data is sent //Clear TI flag //Send current data /*---------------------------Software delay function ----------------------------*/ void Delay(WORD n) { WORD x; while (n--) { x = 5000; while (x--); } } STC MCU Limited. website：www.STCMCU.com 219 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly language code listing: ;/*-------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ----------------------------------*/ ;/* --- STC 1T Series MCU A/D Conversion Demo --------------------*/ ;/* --- Mobile: (86)13922809991 ------------------------------------------*/ ;/* --- Fax: 86-755-82905966 ----------------------------------------------*/ ;/* --- Tel: 86-755-82948412 -----------------------------------------------*/ ;/* --- Web: www.STCMCU.com -----------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------*/ . d e t i m ;/*Declare SFR associated with the ADC */ ADC_CONTR EQU 0C5H ADC_DATA EQU 0C6H ADC_LOW2 EQU 0BEH P1M0 EQU 091H P1M1 EQU 092H ;ADC control register ;ADC high 8-bit result register ;ADC low 2-bit result register ;P1 mode control register0 ;P1 mode control register1 ;/*Define ADC operation const for ADC_CONTR*/ ADC_POWER EQU 80H ADC_FLAG EQU 10H ADC_START EQU 08H ADC_SPEEDLL EQU 00H ADC_SPEEDL EQU 20H ADC_SPEEDH EQU 40H ADC_SPEEDHH EQU 60H ;ADC power control bit ;ADC complete flag ;ADC start control bit ;1080 clocks ;810 clocks ;540 clocks ;270 clocks C T S U C M ;---------------------------------------- ORG 0000H LJMP MAIN ;---------------------------------------- ORG 0100H MAIN: LCALL INIT_UART LCALL INIT_ADC ;------------------------------NEXT: MOV A, #0 LCALL SHOW_RESULT MOV A, #1 LCALL SHOW_RESULT MOV A, #2 LCALL SHOW_RESULT 220 STC MCU Limited. Li ;Init UART, use to show ADC result ;Init ADC sfr ;Show channel0 result ;Show channel1 result ;Show channel2 result website：www.STCMCU.com www.STCMCU.com MOV LCALL MOV LCALL MOV LCALL MOV LCALL MOV LCALL Mobile:(86)13922809991 A, #3 SHOW_RESULT A, #4 SHOW_RESULT A, #5 SHOW_RESULT A, #6 SHOW_RESULT A, #7 SHOW_RESULT Tel:86-755-82948412 ;Show channel3 result ;Show channel4 result ;Show channel5 result ;Show channel6 result ;Show channel7 result Fax:86-755-82905966 SJMP NEXT ;/*---------------------------;Send ADC result to UART ;Input: ACC (ADC channel NO.) ;Output:;----------------------------*/ SHOW_RESULT: LCALL SEND_DATA LCALL GET_ADC_RESULT LCALL SEND_DATA C T S U C M ;//if you want show 10-bit result, uncomment next 2 lines ; MOV A, ADC_LOW2 ; LCALL SEND_DATA RET . d e mit Li ;Show Channel NO. ;Get high 8-bit ADC result ;Show result ;Get low 2-bit ADC result ;Show result ;/*---------------------------;Read ADC conversion result ;Input: ACC (ADC channel NO.) ;Output:ACC (ADC result) ;----------------------------*/ GET_ADC_RESULT: ORL A, #ADC_POWER | ADC_SPEEDLL | ADC_START MOV ADC_CONTR, A ;Start A/D conversion NOP ;Must wait before inquiry NOP NOP NOP WAIT: MOV A, ADC_CONTR ;Wait complete flag JNB ACC.4, WAIT ;ADC_FLAG(ADC_CONTR.4) ANL ADC_CONTR ,#NOT ADC_FLAG ;Clear ADC_FLAG MOV A, ADC_DATA ;Return ADC result RET STC MCU Limited. website：www.STCMCU.com 221 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 ;/*---------------------------;Initial ADC sfr ;----------------------------*/ INIT_ADC: MOV A, #0FFH MOV P1, A MOV P1M0, A MOV P1M1, A ;Set all P1 as Open-Drain mode MOV ADC_DATA,#0 ;Clear previous result MOV ADC_CONTR, #ADC_POWER | ADC_SPEEDLL MOV A, #2 ;ADC power-on and delay LCALL DELAY RET ;/*---------------------------;Initial UART ;----------------------------*/ INIT_UART: MOV SCON, #5AH ;8 bit data ,no parity bit MOV TMOD, #20H ;T1 as 8-bit auto reload MOV A, #-5 ;Set Uart baudrate -(18432000/12/32/9600) MOV TH1, A ;Set T1 reload value MOV TL1, A SETB TR1 ;T1 start running RET U C M C T S ;/*---------------------------;Send one byte data to PC ;Input: ACC (UART data) ;Output:;----------------------------*/ SEND_DATA: JNB TI,$ CLR TI MOV SBUF, RET ;/*---------------------------;Software delay function ;----------------------------*/ DELAY: MOV R2, CLR A MOV R0, MOV R1, DELAY1: DJNZ R0, DJNZ R1, DJNZ R2, RET 222 A . d e t i m Li ;Wait for the previous data is sent ;Clear TI flag ;Send current data A A A DELAY1 DELAY1 DELAY1 END STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Chapter 10. Programmable Counter Array(PCA) The Programmable Counter Array is a special 16-bit Timer that has four 16-bit capture/compare modules associated with it. Each of the modules can be programmed to operate in one of four modes: rising and/or falling edge capture (calculator of duty length for high/low pulse), software timer, high-speed output, or pulse width modulator. Module 0 is connected to pin P3.7, module 1 to pin P3.5, module 2 to pin P2.0, module 3 to pin P2.4 in STC12C2052AD series. The PCA timer is a common time base for all four modules and can be programmed to run at 1/12 the system clock, 1/2 the system clock, the Timer 0 overflow or the input on ECI pin(P3.4). The timer count source is determined from CPS1 and CPS0 bits in the CMOD SFR. 10.1 SFRs related with PCA . d e mit PCA/PWM SFRs table Mnemonic Description Add B7 B6 B5 CF CR - - - CU CCON PCA Control Register D8H CMOD PCA Mode Register D9H CIDL M CCAPM0 PCA Module 0 Mode Register DAH - CCAPM1 PCA Module 1 Mode Register DBH - C T S Li Bit address and Symbol B4 - B3 B2 B1 - - CCF1 - CPS1 CPS0 B0 Reset Value CCF0 00xx,xx00 ECF 0xxx,x000 ECOM0 CAPP0 CAPN0 MAT0 TOG0 PWM0 ECCF0 x000,0000 ECOM1 CAPP1 CAPN1 MAT1 TOG1 PWM1 ECCF1 x000,0000 CL PCA Base Timer Low E9H 0000,0000 CH PCA Base Timer High F9H 0000,0000 CCAP0L PCA Module-0 Capture Register Low EAH 0000,0000 CCAP0H PCA Module-0 Capture Register High FAH 0000,0000 CCAP1L PCA Module-1 Capture Register Low EBH 0000,0000 CCAP1H PCA Module-1 Capture Register High FBH 0000,0000 PCA_PWM0 PCA PWM Mode Auxiliary F2H Register 0 - - - - - - EPC0H EPC0L xxxx,xx00 PCA_PWM1 PCA PWM Mode Auxiliary F3H Register 1 - - - - - - EPC1H EPC1L xxxx,xx00 STC MCU Limited. website：www.STCMCU.com 223 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 1. PCA operation mode register: CMOD (Non bit-addressable) bit B7 B6 B5 B4 B3 B2 B1 B0 name CIDL - - - - CPS1 CPS0 ECF SFR name Address CMOD D9H CIDL : PCA Counter control bit in Idle mode. If CIDL=0, the PCA counter will continue functioning during idle mode. If CIDL=1, the PCA counter will be gated off during idle mode. CPS1, CPS0 : PCA Counter Pulse source Select bits. CPS1 CPS0 Select PCA/PWM clock source 0 0 0, System clock/12, SYSclk/12 0 1 1, System clock/2, SYSclk/2 1 0 2, Timer 0 overflow. PCA/PWM clock can up to SYSclk because Timer 0 can operate in 1T mode. Frequency-adjustable PWM output can be achieved by changing the Timer 0 overflow. 1 1 3, Exrenal clock from ECI/P3.4 pin (max speed = SYSclk/2) . d e t i m Li For example, If CPS1/CPS0=0/0, PCA/PWM clock source is SYSclk/12. If users need to select SYSclk/3 as PCA clock source, Timer 0 should be set to operate in 1T mode and generate an overflow every 3 counting pulse. C T S U C M ECF : PCA Counter Overflow interrupt Enable bit. ECF=0 disables CF bit in CCON to generate an interrupt. ECF=1 enables CF bit in CCON to generate an interrupt. 2. PCA control register : CCON (Non bit-addressable) SFR name Address bit B7 B6 B5 B4 B3 B2 B1 B0 CCON D8H name CF CR - - - - CCF1 CCF0 CF : PCA Counter overflow flag. 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. CR : PCA Counter Run control bit. Set by software to turn the PCA counter on. Must be cleared by software to turn the PCA counter off. CCF1 : PCA Module 1 interrupt flag. Set by hardware when a match or capture from module 1 occurs. Must be cleared by software. A match means the value of the PCA counter equals the value of the Capture/ Compare register in module 1. A capture means a specific edge from PCA1 happens, so the Capture/ Compare register latches the value of the PCA counter, and the CCF1 is set. CCF0 : PCA Module 0 interrupt flag. Set by hardware when a match or capture from module 0 occurs. Must be cleared by software. A match means the value of the PCA counter equals the value of the Capture/ Compare register in module 0. A capture means a specific edge from PCA0 happens, so the Capture/ Compare register latches the value of the PCA counter, and the CCF0 is set. 224 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 3. PCA capture/campare register CCAPM0 and CCAPM1 Each module in the PCA has a special function register associated with it. These registers are CCAPMn, n=0 and 1. CCAPM0 for module 0, CCAPM1 for module 1. The register contains the bits that control the mode in which each module will operate. The ECCFn bit enables the CCFn flag in the CCON SFR to generate an interrupt when a match or compare occurs in the associated module. PWMn enables the pulse width modulation mode. The TOGn bit when set causes the CCPn 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(MATn) 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 CAPNn and CAPPn determine the edge that a capture input will be active on. The CAPNn bit enables the negative edge, and the CAPPn bit enables the positive edge. If both bits are set, both edges will be enabled and a capture will occur for either transition. The bit ECOMn when set enables the comparator function. . d e mit Capture/Compare register of PCA module 0 : CCAPM0 (Non bit-addressable) SFR name Address CCAPM0 DAH bit B7 name - B6 B5 Li B4 ECOM0 CAPP0 CAPN0 U C M ECOM0 : Comparator Enable bit. ECOM0=0 disables the comparator function; ECOM0=1 enables the comparator function. B3 B2 MAT0 TOG0 B1 B0 PWM0 ECCF0 CAPP0 : Capture Positive control bit. CAPP0=1 enables positive edge capture. C T S CAPN0 : Capture Negative control bit. CAPN0=1 enables negative edge capture. MAT0 : Match control bit. When MAT0 = 1, a match of the PCA counter with this module’s compare/capture register causes the CCF0 bit in CCON to be set. TOG0 : Toggle control bit. When TOG0=1, a match of the PCA counter with this module’s compare/capture register causes the CCP0 pin to toggle. (PCA0/PWM0/P3.7) PWM0 : Pulse Width Modulation. PWM0=1 enables the CCP0 pin to be used as a pulse width modulated output. (PCA0/PWM0/P3.7) ECCF0 : Enable CCF0 interrupt. Enables compare/capture flag CCF0 in the CCON register to generate an interrupt. STC MCU Limited. website：www.STCMCU.com 225 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 Capture/Compare register of PCA module 1 : CCAPM1 (Non bit-addressable) SFR name Address CCAPM1 DBH bit B7 name - B6 B5 B4 ECOM1 CAPP1 CAPN1 B3 B2 MAT1 TOG1 B1 B0 PWM1 ECCF1 ECOM1 : Comparator Enable bit. ECOM1=0 disables the comparator function; ECOM1=1 enables the comparator function. CAPP1 : Capture Positive control bit. CAPP1=1 enables positive edge capture. CAPN1 : Capture Negative control bit. CAPN1=1 enables negative edge capture. MAT1 : Match control bit. When MAT1 = 1, a match of the PCA counter with this module’s compare/capture register causes the CCF1 bit in CCON to be set. TOG1 : Toggle control bit. When TOG1=1, a match of the PCA counter with this module’s compare/capture register causes the CCP1 pin to toggle. (PCA1/PWM1/P3.5) PWM1 : U C M . d e t i m Li Pulse Width Modulation. PWM1=1 enables the CEX1 pin to be used as a pulse width modulated output. (PCA1/PWM1/P3.5) ECCF1 : Enable CCF1 interrupt. Enables compare/capture flag CCF1 in the CCON register to generate an interrupt. C T S The operation mode of PCA modules set as shown in the below table. Setting the operation mode of PCA modules（CCAPMn register，n = 0,1） - ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn Function of PCA modules 0 0 0 0 0 0 0 No operation 1 0 0 0 0 1 0 8-bit PWM, no interrupt 8-bit PWM output, interrupt can be generated 1 1 0 0 0 1 1 on rising edge. 8-bit PWM output, interrupt can be generated 1 0 1 0 0 1 1 on falling edge. 8-bit PWM output, interrupt can be generated 1 1 1 0 0 1 1 on both rising and falling edges. 16-bit Capture Mode, caputre triggered by the X 1 0 0 0 0 X rising edge on CCPn/PCAn pin 16-bit Capture Mode, capture triggered by the X 0 1 0 0 0 X falling edge on CCPn/PCAn pin 16-bit Capture Mode, capture triggered by the X 1 1 0 0 0 X transition on CCPn/PCAn pin 1 0 0 1 0 0 X 16-bit software timer 1 0 0 1 1 0 X 16-bit high-speed output 226 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 4. PCA 16-bit Counter — low 8-bit CL and high 8-bit CH The addresses of CL and CH respectively are E9H and F9H, and their reset value both are 00H. CL and CH are used to save the PCA load value. 5. PCA Capture/Compare register — CCAPnL and CCAPnH When PCA is used to capture/compare, CCAPnL and CCAPnH are used to save the 16-bit capture value in corresponding block. When PCA is operated in PWM mode, CCAPnL and CCAPnH are used to control the duty cycle of PWM output signal. "n=0 or 1" respectively stand for module 0 and 1. Reset value of regsiters CCAPnL and CCAPnH are both 00H. Their addresses respectively are: CCAP0L — EAH, CCAP0H — FAH : Capture / Compare register of module 0 CCAP1L — EBH, CCAP1H — FBH : Capture / Compare register of module 1 . d e mit 6. PWM registers of PCA modules : PCA_PWM0 and PCA_PWM1 PCA_PWM0 : PWM register of PCA module 0 SFR name Address bit B7 PCA_PWM0 F2H name - B6 B5 U C M - - B4 - Li B3 B2 - - B1 B0 EPC0H EPC0L B7 ~ B2 : Reserved EPC0H : Associated with CCAP0H, it is used in PCA PWM mode. EPC0L : Associated with CCAP0L, it is used in PCA PWM mode. C T S PCA_PWM1 : PWM register of PCA module 1 SFR name Address bit B7 B6 B5 B4 B3 B2 PCA_PWM1 F3H name - - - - - - B1 B0 EPC1H EPC1L B7 ~ B2 : Reserved EPC1H : Associated with CCAP1H, it is used in PCA PWM mode. EPC1L : Associated with CCAP1L, it is used in PCA PWM mode. STC MCU Limited. website：www.STCMCU.com 227 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.2 PCA/PWM Structure There are 2 channels Programmable Counter Arrary PCA/PWM in STC12C2052AD series MCU. 16-bit PCA Timer/Counter Module 0 P3.7/CCP0/PCA0/PWM0 Module 1 P3.5/CCP1/PCA1/PWM1 Programmable Counter Arrary Structure . d e t i m Each PCA/PWM module can be operated in 4 modes : rising / falling capture mode, software timer, high-speed output mode and adjustable pulse output mode. STC12C2052AD series: module 0 connect to P3.7/PCA0/PWM0, module 1 connect to P3.5/PCA1/PWM1. SYSclk/1 SYSclk/2 C T S SYSclk/4 Li U C M To PCA Module SYSclk/6 CH CL 16-Bit counter SYSclk/8 PCA Interrput SYSclk/12 Timer 0 overflow External input ECI(P3.4) CMOD CIDL IDLE CF - CR - - - - - CPS1 CPS0 - - ECF CCF1 CCF0 CCON PCA Timer/Counter 228 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 In the CMOD SFR, there are two additional bits associated with the PCA. They are CIDL which allows the PCA to stop during idle mode, and ECF which 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 SFR contains the run control bit for PCA and the flags for the PCA timer and each module. To run the PCA the CR bit(CCON.6) must be set by software; oppositely clearing bit CR will shut off PCA is shut off PCA. The CF bit(CCON.7) is set when the PCA counter overflows and an interrupt will be generated if the ECF (CMOD.0) bit in the CMOD register is set. The CF bit can only be cleared by software. There are two bits named CCF0 and CCF1 in SFR CCON. The CCF0 and CCF1 are the flags for module 0 and module 1 respectively. They are set by hardware when either a match or a capture occurs. These flags also can only be cleared by software. Each module in the PCA has a special function register associated with it, CCAPM0 for module-0 and CCAPM1 for module-1. The register contains the bits that control the mode in which each module will operate. The ECCFn bit controls if to pass the interrupt from CCFn flag in the CCON SFR to the MCU when a match or compare occurs in the associated module. PWMn enables the pulse width modulation mode. The TOGn bit when set causes the pin CCPn 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 (MATn) 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. U C M . d e mit Li The next two bits CAPNn and CAPPn determine the edge type that a capture input will be active on. The CAPNn bit enables the negative edge, and the CAPPn bit enables the positive edge. If both bits are set, both edges will be enabled and a capture will occur for either transition. The bit ECOMn when set enables the comparator function. C T S STC MCU Limited. website：www.STCMCU.com 229 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.3 PCA Modules Operation Mode The operation mode of PCA modules set as shown in the below table. Setting the operation mode of PCA modules（CCAPMn register，n = 0,1） - ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn Function of PCA modules 0 0 0 0 0 0 0 No operation 1 0 0 0 0 1 0 8-bit PWM, no interrupt 8-bit PWM output, interrupt can be generated 1 1 0 0 0 1 1 on rising edge. 8-bit PWM output, interrupt can be generated 1 0 1 0 0 1 1 on falling edge. 8-bit PWM output, interrupt can be generated 1 1 1 0 0 1 1 on both rising and falling edges. 16-bit Capture Mode, caputre triggered by the X 1 0 0 0 0 X rising edge on CCPn/PCAn pin 16-bit Capture Mode, capture triggered by the X 0 1 0 0 0 X falling edge on CCPn/PCAn pin 16-bit Capture Mode, capture triggered by the X 1 1 0 0 0 X transition on CCPn/PCAn pin 1 0 0 1 0 0 X 16-bit software timer 1 0 0 1 1 0 X 16-bit high-speed output C T S 10.3.1 PCA Capture Mode . d e t i m Li U C M To use one of the PCA modules in the capture mode either one or both of the CCAPM bits – CAPPn and CAPNn, for the module must be set. The external CCPn input (CCP0/P3.7, CCP1/P3.5) for the module is sampled for a transition. When a valid transition occurs, the PCA hardware loads the value of the PCA counter register(CH and CL) into the module’s capture registers(CCAPnH and CCAPnL). 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. CF CR CCF1 CCF0 CCON (address:D8H) PCA interrupt Capture CCPn CH CL CCAPnH CCAPnL ECOMn CAPPn CAPNn MATn 0 0 CCAPMn, n=0,1 TOGn PWMn ECCFn Address: DAh, DBh 0 0 PCA Capture Mode 230 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 10.3.2 16-bit Software Timer Mode The PCA modules can be used as software timers by setting both the ECOMn and MATn 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 be generated if the CCFn and ECCFn bits for the module are both set. write first Write to CCAPnL write late Write to CCAPnH Stop comparing 0 CF CR CCF1 CCF0 CCON Renew comparing 1 CCAPnH CCAPnL PCA Interrupt . d e mit (To CCFn) Enable if ECOMn=0, Stop comparing if ECOMn=0, renew comparing CH - C T S STC MCU Limited. 16-Bit comparator U C M CL Match Li ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn 0 0 1 0 0 PCA Software Timer Mode website：www.STCMCU.com 231 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.3.3 High Speed Output Mode In this mode the CCPn output (port latch) 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 TOGn,MATn,and ECOMn bits in the module’s CCAPMn SFR must be set. write first Write to CCAPnL write late Write to CCAPnH Stop comparing 0 CF CR CCF1 CCF0 CCON Renew comparing 1 CCAPnH CCAPnL PCA Interrupt (To CCFn) Enable if ECOMn=0, Stop comparing if ECOMn=0, renew comparing CH - C T S 232 16-Bit comparator STC MCU Limited. CL U C M Match i m i . d e t L Toggle CCPn ECOMn CAPPn CAPNn MATn TOGn PWMn ECCFn CCAPMn 0 0 1 1 0 PCA High-Speed Output Mode website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 10.3.4 Pulse Width Modulator Mode (PWM mode) All of the PCA modules can be used as PWM outputs. 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 same PCA timer. The duty cycle of each module is independently variable using the module’ s capture register CCAPnL and EPCnL bit in PCAPWMn register. When the value of the PCA CL SFR is less than the value in the module’s {EPCnL,CCAPnL} SFR, the output will be low. When it is equal to or greater than , the output will be high. When CL overflows from FFH to 00H, {EPCnL,CCAPnL} is reloaded with the value in {EPCnH,CCAPnH}. That allows updating the PWM without glitches. The PWMn and ECOMn bits in the module’s CCAPMn register must be set to enable the PWM mode. . d e mit EPCnH CCAPnH Li U C M EPCnL CCAPnL C T S enable 9-BIT COMPARATOR output 0 (0,CL)=(EPCnL,CCPnL) PWMn CCPn output 1 0 CL CL overflow - ECOMn CAPPn 1 0 CAPNn MATn 0 0 TOGn 0 PWMn 1 ECCFn CCAPMn, n=0,1 0 PCA PWM mode STC MCU Limited. website：www.STCMCU.com 233 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.4 Programs for PCA module extended external interrupt (C and ASM) There are two programs for PCA module extended external interrupt demo, one wrriten in C language and the other in assembly language. 1. C code listing: /*-------------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------------*/ /* --- STC 1T Series MCU PCA module Extended external interrupt ----*/ /* --- Mobile: (86)13922809991 -----------------------------------------------*/ /* --- Fax: 86-755-82905966 ---------------------------------------------------*/ /* --- Tel: 86-755-82948412 ----------------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*------------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" typedef unsigned char BYTE; typedef unsigned int WORD; U C M /*Declare SFR associated with the PCA */ sbit EPCAI = IE^6; sfr CCON = 0xD8; sbit CCF0 = CCON^0; sbit CCF1 = CCON^1; sbit CR = CCON^6; sbit CF = CCON^7; sfr CMOD = 0xD9; sfr CL = 0xE9; sfr CH = 0xF9; sfr CCAPM0 = 0xDA; sfr CCAP0L = 0xEA; sfr CCAP0H = 0xFA; sfr CCAPM1 = 0xDB; sfr CCAP1L = 0xEB; sfr CCAP1H = 0xFB; sfr CCAPM2 = 0xDC; sfr CCAP2L = 0xEC; sfr CCAP2H = 0xFC; sfr CCAPM3 = 0xDD; sfr CCAP3L = 0xED; sfr CCAP3H = 0xFD; sfr PCAPWM0 = 0xF2; sfr PCAPWM1 = 0xF3; sfr PCAPWM2 = 0xF4; sfr PCAPWM3 = 0xF5; C T S 234 STC MCU Limited. . d e t i m Li //PCA control register //PCA module-0 interrupt flag //PCA module-1 interrupt flag //PCA timer run control bit //PCA timer overflow flag //PCA mode register //PCA base timer LOW //PCA base timer HIGH //PCA module-0 mode register //PCA module-0 capture register LOW //PCA module-0 capture register HIGH //PCA module-1 mode register //PCA module-1 capture register LOW //PCA module-1 capture register HIGH //PCA module-2 mode register //PCA module-2 capture register LOW //PCA module-2 capture register HIGH //PCA module-3 mode register //PCA module-3 capture register LOW //PCA module-3 capture register HIGH website：www.STCMCU.com www.STCMCU.com sbit PCA_LED Mobile:(86)13922809991 = P1^0; void PCA_isr() interrupt 7 using 1 { CCF0 = 0; PCA_LED = !PCA_LED; } void main() { CCON = 0; CL = 0; CH = 0; CMOD = 0x00; CCAPM0 = 0x11; // CCAPM0 = 0x21; // CCAPM0 = 0x31; C T S CR = 1; EPCAI = 1; EA = 1; Tel:86-755-82948412 Fax:86-755-82905966 //PCA test LED //Clear interrupt flag //toggle the test pin while CEX0(P1.3) have a falling edge //Initial PCA control register //PCA timer stop running //Clear CF flag //Clear all module interrupt flag //Reset PCA base timer . d e mit Li //Set PCA timer clock source as Fosc/12 //Disable PCA timer overflow interrupt //PCA module-0 capture by a negative tigger on CEX0(P1.3) //and enable PCA interrupt //PCA module-0 capture by a rising edge on CEX0(P1.3) //and enable PCA interrupt //PCA module-0 capture by a transition (falling/rising edge) //on CEX0(P1.3) and enable PCA interrupt U C M //PCA timer start run while (1); } STC MCU Limited. website：www.STCMCU.com 235 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly code listing: ;/*------------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ---------------------------------------------*/ ;/* --- STC 1T Series MCU PCA module Extended external interrupt ----------*/ ;/* --- Mobile: (86)13922809991 -----------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 ---------------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ----------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com -----------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*-------------------------------------------------------------------------------------------*/ . d e t i m ;/*Declare SFR associated with the PCA */ EPCAI BIT IE.6 CCON CCF0 CCF1 CR CF CMOD CL CH CCAPM0 CCAP0L CCAP0H CCAPM1 CCAP1L CCAP1H CCAPM2 CCAP2L CCAP2H CCAPM3 CCAP3L CCAP3H EQU BIT BIT BIT BIT EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU 0D8H CCON.0 CCON.1 CCON.6 CCON.7 0D9H 0E9H 0F9H 0DAH 0EAH 0FAH 0DBH 0EBH 0FBH 0DCH 0ECH 0FCH 0DDH 0EDH 0FDH PCA_LED BIT P1.0 C T S U C M Li ;PCA control register ;PCA module-0 interrupt flag ;PCA module-1 interrupt flag ;PCA timer run control bit ;PCA timer overflow flag ;PCA mode register ;PCA base timer LOW ;PCA base timer HIGH ;PCA module-0 mode register ;PCA module-0 capture register LOW ;PCA module-0 capture register HIGH ;PCA module-1 mode register ;PCA module-1 capture register LOW ;PCA module-1 capture register HIGH ;PCA module-2 mode register ;PCA module-2 capture register LOW ;PCA module-2 capture register HIGH ;PCA module-3 mode register ;PCA module-3 capture register LOW ;PCA module-3 capture register HIGH ;PCA test LED ;---------------------------------------- ORG 0000H LJMP MAIN 236 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 ORG 0033H PCA_ISR: CLR CCF0 CPL PCA_LED RETI ;---------------------------------------- ORG 0100H MAIN: MOV CCON, #0 CLR A MOV CL, A MOV CH, A MOV CMOD, #00H MOV CCAPM0,#11H ; MOV CCAPM0,#21H ; MOV CCAPM0,#31H ;------------------------------ SETB CR SETB EPCAI SETB EA C T S Tel:86-755-82948412 Fax:86-755-82905966 ;Clear interrupt flag ;toggle the test pin while CEX0(P1.3) have a falling edge ;Initial PCA control register ;PCA timer stop running ;Clear CF flag ;Clear all module interrupt flag ; ;Reset PCA base timer ; ;Set PCA timer clock source as Fosc/12 ;Disable PCA timer overflow interrupt ;PCA module-0 capture by a falling edge on CEX0(P1.3) ;and enable PCA interrupt ;PCA module-0 capture by a rising edge on CEX0(P1.3) ;and enable PCA interrupt ;PCA module-0 capture by a transition (falling/rising edge) ;on CEX0(P1.3) and enable PCA interrupt U C M . d e mit Li ;PCA timer start run SJMP $ ;---------------------------------------- END STC MCU Limited. website：www.STCMCU.com 237 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.5 Demo Programs for PCA module acted as 16-bit Timer (C and ASM) There are two programs for PCA module acted as 16-bit Timer demo, one wrriten in C language and the other in assembly language. 1. C code listing: ;/*------------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ---------------------------------------------*/ ;/* --- STC 1T Series MCU PCA module acted as 16-bit Timer Demo ---------*/ ;/* --- Mobile: (86)13922809991 -----------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 ---------------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ----------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com -----------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" #define FOSC 18432000L #define T100Hz (FOSC / 12 / 100) typedef unsigned char typedef unsigned int BYTE; WORD; C T S U C M /*Declare SFR associated with the PCA */ sbit EPCAI = IE^6; sfr CCON = 0xD8; sbit CCF0 = CCON^0; sbit CCF1 = CCON^1; sbit CR = CCON^6; sbit CF = CCON^7; sfr CMOD = 0xD9; sfr CL = 0xE9; sfr CH = 0xF9; sfr CCAPM0 = 0xDA; sfr CCAP0L = 0xEA; sfr CCAP0H = 0xFA; sfr CCAPM1 = 0xDB; sfr CCAP1L = 0xEB; sfr CCAP1H = 0xFB; sfr CCAPM2 = 0xDC; sfr CCAP2L = 0xEC; sfr CCAP2H = 0xFC; sfr CCAPM3 = 0xDD; sfr CCAP3L = 0xED; sfr CCAP3H = 0xFD; 238 STC MCU Limited. . d e t i m Li //PCA control register //PCA module-0 interrupt flag //PCA module-1 interrupt flag //PCA timer run control bit //PCA timer overflow flag //PCA mode register //PCA base timer LOW //PCA base timer HIGH //PCA module-0 mode register //PCA module-0 capture register LOW //PCA module-0 capture register HIGH //PCA module-1 mode register //PCA module-1 capture register LOW //PCA module-1 capture register HIGH //PCA module-2 mode register //PCA module-2 capture register LOW //PCA module-2 capture register HIGH //PCA module-3 mode register //PCA module-3 capture register LOW //PCA module-3 capture register HIGH website：www.STCMCU.com www.STCMCU.com sbit PCA_LED Mobile:(86)13922809991 = P1^0; Tel:86-755-82948412 Fax:86-755-82905966 //PCA test LED BYTE cnt; WORD value; void PCA_isr() interrupt 7 using 1 { CCF0 = 0; CCAP0L = value; CCAP0H = value >> 8; value += T100Hz; if (cnt-- == 0) { cnt = 100; PCA_LED = !PCA_LED; } } void main() { CCON = 0; U C M C T S CL = 0; CH = 0; CMOD = 0x00; value = T100Hz; CCAP0L = value; CCAP0H = value >> 8; value += T100Hz; CCAPM0 = 0x49; CR = 1; EPCAI = 1; EA = 1; cnt = 0; while (1); //Clear interrupt flag //Update compare value . d e mit //Count 100 times //Flash once per second Li //Initial PCA control register //PCA timer stop running //Clear CF flag //Clear all module interrupt flag //Reset PCA base timer //Set PCA timer clock source as Fosc/12 //Disable PCA timer overflow interrupt //Initial PCA module-0 //PCA module-0 work in 16-bit timer mode //and enable PCA interrupt //PCA timer start run } STC MCU Limited. website：www.STCMCU.com 239 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly code listing: ;/*------------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ---------------------------------------------*/ ;/* --- STC 1T Series MCU PCA module acted as 16-bit Timer Demo ---------*/ ;/* --- Mobile: (86)13922809991 -----------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 ---------------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ---------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ----------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*-----------------------------------------------------------------------------------------*/ T100Hz EQU 3C00H ;/*Declare SFR associated with the PCA */ EPCAI BIT IE.6 CCON CCF0 CCF1 CR CF CMOD CL CH CCAPM0 CCAP0L CCAP0H CCAPM1 CCAP1L CCAP1H CCAPM2 CCAP2L CCAP2H CCAPM3 CCAP3L CCAP3H PCA_LED EQU BIT BIT BIT BIT EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU EQU 0D8H CCON.0 CCON.1 CCON.6 CCON.7 0D9H 0E9H 0F9H 0DAH 0EAH 0FAH 0DBH 0EBH 0FBH 0DCH 0ECH 0FCH 0DDH 0EDH 0FDH BIT P1.0 C T S U C M . d e t i m ;(18432000 / 12 / 100) Li ;PCA control register ;PCA module-0 interrupt flag ;PCA module-1 interrupt flag ;PCA timer run control bit ;PCA timer overflow flag ;PCA mode register ;PCA base timer LOW ;PCA base timer HIGH ;PCA module-0 mode register ;PCA module-0 capture register LOW ;PCA module-0 capture register HIGH ;PCA module-1 mode register ;PCA module-1 capture register LOW ;PCA module-1 capture register HIGH ;PCA module-2 mode register ;PCA module-2 capture register LOW ;PCA module-2 capture register HIGH ;PCA module-3 mode register ;PCA module-3 capture register LOW ;PCA module-3 capture register HIGH ;PCA test LED CNT EQU 20H ;---------------------------------------- ORG 0000H LJMP MAIN 240 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ORG 0033H LJMP PCA_ISR ;---------------------------------------- ORG 0100H MAIN: MOV SP, #3FH ;Initial stack point MOV CCON, #0 ;Initial PCA control register ;PCA timer stop running ;Clear CF flag ;Clear all module interrupt flag CLR A ; MOV CL, A ;Reset PCA base timer MOV CH, A ; MOV CMOD, #00H ;Set PCA timer clock source as Fosc/12 ;Disable PCA timer overflow interrupt ;------------------------------ MOV CCAP0L, #LOW T100Hz ; MOV CCAP0H,#HIGH T100Hz ;Initial PCA module-0 MOV CCAPM0,#49H ;PCA module-0 work in 16-bit timer mode and enable PCA interrupt ;------------------------------ SETB CR ;PCA timer start run SETB EPCAI SETB EA MOV CNT, #100 C T S U C M SJMP $ ;----------------------------------------PCA_ISR: PUSH PSW PUSH ACC CLR CCF0 MOV A, CCAP0L ADD A, #LOW T100Hz MOV CCAP0L, A MOV A, CCAP0H ADDC A, #HIGH T100Hz MOV CCAP0H,A DJNZ CNT, PCA_ISR_EXIT MOV CNT, #100 CPL PCA_LED PCA_ISR_EXIT: POP ACC POP PSW RETI ;---------------------------------------- END STC MCU Limited. . d e mit Li ;Clear interrupt flag ;Update compare value ;count 100 times ;Flash once per second website：www.STCMCU.com 241 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.6 Programs for PCA module as 16-bit High Speed Output(C and ASM) There are two programs for PCA module as 16-bit High Speed Output, one wrriten in C language and the other in assembly language. 1. C code listing: ;/*--------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -----------------------------------------*/ ;/* --- STC 1T Series MCU PCA module as 16-bit High Speed Output ----*/ ;/* --- Mobile: (86)13922809991 -------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -----------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com -------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*---------------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" #define FOSC 18432000L #define T100KHz (FOSC / 4 / 100000) C T S typedef unsigned char typedef unsigned int BYTE; WORD; U C M . d e t i m Li /*Declare SFR associated with the PCA */ sbit EPCAI = IE^6; sfr sbit sbit sbit sbit sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr sfr 242 CCON CCF0 CCF1 CR CF CMOD CL CH CCAPM0 CCAP0L CCAP0H CCAPM1 CCAP1L CCAP1H CCAPM2 CCAP2L CCAP2H CCAPM3 CCAP3L CCAP3H = = = = = = = = = = = = = = = = = = = = 0xD8; CCON^0; CCON^1; CCON^6; CCON^7; 0xD9; 0xE9; 0xF9; 0xDA; 0xEA; 0xFA; 0xDB; 0xEB; 0xFB; 0xDC; 0xEC; 0xFC; 0xDD; 0xED; 0xFD; STC MCU Limited. //PCA control register //PCA module-0 interrupt flag //PCA module-1 interrupt flag //PCA timer run control bit //PCA timer overflow flag //PCA mode register //PCA base timer LOW //PCA base timer HIGH //PCA module-0 mode register //PCA module-0 capture register LOW //PCA module-0 capture register HIGH //PCA module-1 mode register //PCA module-1 capture register LOW //PCA module-1 capture register HIGH //PCA module-2 mode register //PCA module-2 capture register LOW //PCA module-2 capture register HIGH //PCA module-3 mode register //PCA module-3 capture register LOW //PCA module-3 capture register HIGH website：www.STCMCU.com www.STCMCU.com sbit PCA_LED Mobile:(86)13922809991 = P1^0; Tel:86-755-82948412 Fax:86-755-82905966 //PCA test LED BYTE cnt; WORD value; void PCA_isr( ) interrupt 7 using 1 { CCF0 = 0; CCAP0L = value; CCAP0H = value >> 8; value += T100KHz; } void main() { CCON = 0; //Clear interrupt flag //Update compare value U C M CL = 0; CH = 0; CMOD = 0x02; value = T100KHz; CCAP0L = value; CCAP0H = value >> 8; value += T100KHz; CCAPM0 = 0x4d; C T S CR = 1; EPCAI = 1; EA = 1; cnt = 0; while (1); . d e mit //Initial PCA control register //PCA timer stop running //Clear CF flag //Clear all module interrupt flag //Reset PCA base timer Li //Set PCA timer clock source as Fosc/2 //Disable PCA timer overflow interrupt //P1.3 output 100KHz square wave //Initial PCA module-0 //PCA module-0 work in 16-bit timer mode //and enable PCA interrupt, toggle the output pin CEX0(P1.3) //PCA timer start run } STC MCU Limited. website：www.STCMCU.com 243 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly code listing: ;/*--------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -----------------------------------------*/ ;/* --- STC 1T Series MCU PCA module as 16-bit High Speed Output ----*/ ;/* --- Mobile: (86)13922809991 -------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -----------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com -------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*---------------------------------------------------------------------------------------*/ T100KHz EQU 2EH ;/*Declare SFR associated with the PCA */ CCON EQU 0D8H CCF0 BIT CCON.0 CCF1 BIT CCON.1 CR BIT CCON.6 CF BIT CCON.7 CMOD EQU 0D9H CL EQU 0E9H CH EQU 0F9H CCAPM0 EQU 0DAH CCAP0L EQU 0EAH CCAP0H EQU 0FAH CCAPM1 EQU 0DBH CCAP1L EQU 0EBH CCAP1H EQU 0FBH CCAPM2 EQU 0DCH CCAP2L EQU 0ECH CCAP2H EQU 0FCH CCAPM3 EQU 0DDH CCAP3L EQU 0EDH CCAP3H EQU 0FDH ;---------------------------------------- ORG 0000H LJMP MAIN C T S ORG PCA_ISR: PUSH PUSH CLR 244 U C M . d e t i m ;(18432000 / 4 / 100000) Li ;PCA control register ;PCA module-0 interrupt flag ;PCA module-1 interrupt flag ;PCA timer run control bit ;PCA timer overflow flag ;PCA mode register ;PCA base timer LOW ;PCA base timer HIGH ;PCA module-0 mode register ;PCA module-0 capture register LOW ;PCA module-0 capture register HIGH ;PCA module-1 mode register ;PCA module-1 capture register LOW ;PCA module-1 capture register HIGH ;PCA module-2 mode register ;PCA module-2 capture register LOW ;PCA module-2 capture register HIGH ;PCA module-3 mode register ;PCA module-3 capture register LOW ;PCA module-3 capture register HIGH 0033H PSW ACC CCF0 STC MCU Limited. ;Clear interrupt flag website：www.STCMCU.com www.STCMCU.com MOV ADD MOV CLR ADDC MOV Mobile:(86)13922809991 A, CCAP0L A, #T100KHz CCAP0L, A A A, CCAP0H CCAP0H,A PCA_ISR_EXIT: POP ACC POP PSW RETI ;---------------------------------------- ORG 0100H MAIN: MOV CCON, #0 CLR A MOV CL, A MOV CH, A MOV CMOD, #02H ;------------------------------ MOV CCAP0L, #T100KHz MOV CCAP0H,#0 MOV CCAPM0,#4dH ;------------------------------ SETB CR SETB EA SJMP $ ;---------------------------------------- END C T S STC MCU Limited. Tel:86-755-82948412 Fax:86-755-82905966 ;Update compare value . d e mit ;Initial PCA control register ;PCA timer stop running ;Clear CF flag ;Clear all module interrupt flag ; ;Reset PCA base timer ; ;Set PCA timer clock source as Fosc/2 ;Disable PCA timer overflow interrupt U C M Li ;P1.3 output 100KHz square wave ;Initial PCA module-0 ;PCA module-0 work in 16-bit timer mode ;and enable PCA interrupt, toggle the output pin CEX0(P1.3) ;PCA timer start run website：www.STCMCU.com 245 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.7 Demo Programs for PCA module as PWM Output (C and ASM) 1. C code listing: *------------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited --------------------------------------------*/ ;/* --- STC 1T Series MCU PCA module output PWM wave Demo -----------*/ ;/* --- Mobile: (86)13922809991 ----------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 --------------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ---------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ----------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" #define FOSC 18432000L typedef unsigned char typedef unsigned int BYTE; WORD; U C M /*Declare SFR associated with the PCA */ sfr CCON = 0xD8; sbit CCF0 = CCON^0; sbit CCF1 = CCON^1; sbit CR = CCON^6; sbit CF = CCON^7; sfr CMOD = 0xD9; sfr CL = 0xE9; sfr CH = 0xF9; sfr CCAPM0 = 0xDA; sfr CCAP0L = 0xEA; sfr CCAP0H = 0xFA; sfr CCAPM1 = 0xDB; sfr CCAP1L = 0xEB; sfr CCAP1H = 0xFB; sfr CCAPM2 = 0xDC; sfr CCAP2L = 0xEC; sfr CCAP2H = 0xFC; sfr CCAPM3 = 0xDD; sfr CCAP3L = 0xED; sfr CCAP3H = 0xFD; sfr PCAPWM0 = 0xF2; sfr PCAPWM1 = 0xF3; sfr PCAPWM2 = 0xF4; sfr PCAPWM3 = 0xF5; C T S 246 STC MCU Limited. . d e t i m Li //PCA control register //PCA module-0 interrupt flag //PCA module-1 interrupt flag //PCA timer run control bit //PCA timer overflow flag //PCA mode register //PCA base timer LOW //PCA base timer HIGH //PCA module-0 mode register //PCA module-0 capture register LOW //PCA module-0 capture register HIGH //PCA module-1 mode register //PCA module-1 capture register LOW //PCA module-1 capture register HIGH //PCA module-2 mode register //PCA module-2 capture register LOW //PCA module-2 capture register HIGH //PCA module-3 mode register //PCA module-3 capture register LOW //PCA module-3 capture register HIGH website：www.STCMCU.com www.STCMCU.com void main() { CCON = 0; Mobile:(86)13922809991 } CR = 1; while (1); C T S STC MCU Limited. Fax:86-755-82905966 //Initial PCA control register //PCA timer stop running //Clear CF flag //Clear all module interrupt flag //Reset PCA base timer CL = 0; CH = 0; CMOD = 0x02; CCAP0H = CCAP0L = 0x80; CCAPM0 = 0x42; CCAP1H = CCAP1L = 0xff; PCAPWM1 = 0x03; CCAPM1 = 0x42; Tel:86-755-82948412 //Set PCA timer clock source as Fosc/2 //Disable PCA timer overflow interrupt //PWM0 port output 50% duty cycle square wave //PCA module-0 work in 8-bit PWM mode //and no PCA interrupt . d e mit Li //PWM1 port output 0% duty cycle square wave //PCA module-1 work in 8-bit PWM mode //and no PCA interrupt U C M //PCA timer start run website：www.STCMCU.com 247 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 2. Assembly code listing: *------------------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited --------------------------------------------*/ ;/* --- STC 1T Series MCU PCA module output PWM wave Demo -----------*/ ;/* --- Mobile: (86)13922809991 ----------------------------------------------------*/ ;/* --- Fax: 86-755-82905966 --------------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ---------------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ----------------------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------------------*/ . d e t i m ;/*Declare SFR associated with the PCA */ CCON EQU 0D8H CCF0 BIT CCON.0 CCF1 BIT CCON.1 CR BIT CCON.6 CF BIT CCON.7 CMOD EQU 0D9H CL EQU 0E9H CH EQU 0F9H CCAPM0 EQU 0DAH CCAP0L EQU 0EAH CCAP0H EQU 0FAH CCAPM1 EQU 0DBH CCAP1L EQU 0EBH CCAP1H EQU 0FBH CCAPM2 EQU 0DCH CCAP2L EQU 0ECH CCAP2H EQU 0FCH CCAPM3 EQU 0DDH CCAP3L EQU 0EDH CCAP3H EQU 0FDH ;PCA control register ;PCA module-0 interrupt flag ;PCA module-1 interrupt flag ;PCA timer run control bit ;PCA timer overflow flag ;PCA mode register ;PCA base timer LOW ;PCA base timer HIGH ;PCA module-0 mode register ;PCA module-0 capture register LOW ;PCA module-0 capture register HIGH ;PCA module-1 mode register ;PCA module-1 capture register LOW ;PCA module-1 capture register HIGH ;PCA module-2 mode register ;PCA module-2 capture register LOW ;PCA module-2 capture register HIGH ;PCA module-3 mode register ;PCA module-3 capture register LOW ;PCA module-3 capture register HIGH ;---------------------------------------- ORG 0000H LJMP MAIN ;---------------------------------------- ORG 0100H MAIN: MOV CCON, #0 ;Initial PCA control register ;PCA timer stop running ;Clear CF flag ;Clear all module interrupt flag C T S 248 STC MCU Limited. U C M Li website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 CLR MOV MOV MOV A ; CL, A ;Reset PCA base timer CH, A ; CMOD, #02H ;Set PCA timer clock source as Fosc/2 ;Disable PCA timer overflow interrupt ;------------------------------ MOV A, #080H ; MOV CCAP0H,A ;PWM0 port output 50% duty cycle square wave MOV CCAP0L,A ; MOV CCAPM0,#42H ;PCA module-0 work in 8-bit PWM mode and no PCA interrupt ;------------------------------ MOV A, #0C0H ; MOV CCAP1H,A ;PWM1 port output 25% duty cycle square wave MOV CCAP1L,A ; MOV CCAPM1,#42H ;PCA module-1 work in 8-bit PWM mode and no PCA interrupt ;------------------------------ SETB CR ;PCA timer start run SJMP $ ;---------------------------------------- END C T S STC MCU Limited. U C M . d e mit Li website：www.STCMCU.com 249 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.8 Demo Program for PCA clock base on Timer 1 overflow rate ;/*-------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited ----------------------------------*/ ;/* --- STC 1T Series achieve adjustable frequency PWM output-----*/ ;/* --- Mobile: (86)13922809991 ------------------------------------------*/ ;/* --- Fax: 86-755-82905966 ----------------------------------------------*/ ;/* --- Tel: 86-755-82948412 -----------------------------------------------*/ ;/* --- Web: www.STCMCU.com -----------------------------------------*/ ;/* If you want to use the program or the program referenced in the */ ;/* article, please specify in which data and procedures from STC */ ;/*------------------------------------------------------------------------------*/ . d e t i m ;/*Declare SFR associated with the ADC */ IPH EQU 0B7H ;Interrupt priority control register high byte CCON EQU 0D8H ;PCA control register CCF0 BIT CCON.0 ;PCA module-0 interrupt flag CCF1 BIT CCON.1 ;PCA module-1 interrupt flag CR BIT CCON.6 ;PCA timer run control bit CF BIT CCON.7 ;PCA timer overflow flag CMOD EQU 0D9H ;PCA mode register CL EQU 0E9H ;PCA base timer LOW CH EQU 0F9H ;PCA base timer HIGH CCAPM0 EQU 0DAH ;PCA module-0 mode register CCAP0L EQU 0EAH ;PCA module-0 capture register LOW CCAP0H EQU 0FAH ;PCA module-0 capture register HIGH CCAPM1 EQU 0DBH ;PCA module-1 mode register CCAP1L EQU 0EBH ;PCA module-1 capture register LOW CCAP1H EQU 0FBH ;PCA module-1 capture register HIGH U C M C T S Li ;/*Define working LED */ LED_MCU_START EQU P1.7 LED_5ms_Flashing EQU P1.6 LED_1S_Flashing EQU P1.5 Channel_5mS_H EQU 01H Channel_5mS_L EQU 00H ;PCA module-1 5ms counter high byte @ 18.432MHz ;PCA module-1 5ms counter low byte @ 18.432MHz Timer0_Reload_1 EQU 0F6H Timer0_Reload_2 EQU 0ECH ;Timer0 auto reload value (-10) ;Timer0 auto reload value (-20) PWM_WIDTH ;low duty EQU 0FFH Counter EQU 030H 250 ;counter value STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;---------------------------------------- ORG 0000H LJMP MAIN ORG 003BH LJMP PCA_interrupt ;---------------------------------------- MAIN: ORG 0050H CLR MOV MOV ACALL ACALL LED_MCU_START SP,#7FH Counter,#0 PAC_Initial Timer0_Initial ;Turn on MCU working LED ;initial Counter var ;initial PCA ;Initial Timer0 . d e mit Li MAIN_Loop: ;------------------------------ MOV TH0,#Timer0_Reload_1 ;Set Timer0 overload rate 1 MOV TL0,#Timer0_Reload_1 MOV A,#PWM_WIDTH ;setting duty MOV CCAP0H,A ACALL delay MOV TH0,#Timer0_Reload_2 ;Set Timer0 overload rate 2 MOV TL0,#Timer0_Reload_2 ACALL delay C T S U C M ;------------------------------ MOV TH0,#Timer0_Reload_1 MOV TL0,#Timer0_Reload_1 MOV A,#PWM_WIDTH ACALL RL_A ;change duty ACALL RL_A MOV CCAP0H,A ACALL delay MOV TH0,#Timer0_Reload_2 MOV TL0,#Timer0_Reload_2 ACALL delay ;------------------------------ MOV TH0,#Timer0_Reload_1 MOV TL0,#Timer0_Reload_1 MOV A,#PWM_WIDTH ACALL RL_A ;change duty STC MCU Limited. ;Set Timer0 overload rate 1 ;Set Timer0 overload rate 2 ;Set Timer0 overload rate 1 website：www.STCMCU.com 251 www.STCMCU.com ACALL ACALL ACALL MOV ACALL MOV MOV ACALL Mobile:(86)13922809991 RL_A RL_A RL_A CCAP0H,A delay TH0,#Timer0_Reload_2 TL0,#Timer0_Reload_2 delay Fax:86-755-82905966 ;Set Timer0 overload rate 2 ;------------------------------ SJMP MAIN_Loop ;----------------------------------------RL_A: CLR C RRC A RET U C M ;----------------------------------------Timer0_Initial: MOV TMOD,#02H ;8-bit auto-reload MOV TH0,#Timer0_Reload_1 MOV TL0,#Timer0_Reload_1 SETB TR0 ;strat run RET C T S Tel:086-755-82948412 . d e t i m Li ;----------------------------------------PCA_Initial: MOV CMOD,#10000100B ;PCA timer base on Timer0 MOV CCON,#00H ;PCA stop count MOV CL,#0 ;initial PCA counter MOV CH,#0 MOV CCAPM0,#42H ;PCA module-0 as 8-bit PWM MOV PCA_PWM0,#0 ;PWM mode 9th bit ; MOV PCA_PWM0,#03H ;PWM will keep low level 252 MOV MOV MOV SETB SETB RET CCAP1L,#Channel_5mS_L ;initial PCA module-1 CCAP1H,#Channel_5mS_H CCAPM1,#49H ;PCA module-1 as 16-bit timer EA CR ;PCA counter start running STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;----------------------------------------PCA_Interrupt: PUSH ACC PUSH PSW CPL LED_5mS_Flashing ;Flashing once per 5ms MOV A,#Channel_5mS_L ADD A,CCAP1L MOV CCAP1L,A MOV A,#Channel_5mS_H ADDC A,CCAP1H MOV CCAP1H,A CLR CCF1 ;Clear PCA module-1 flag INC Counter MOV A,Counter CLR C SUBB A,#100 ;Count 100 times JC PCA_Interrupt_Exit MOV Counter,#0 CPL LED_1S,Flash PCA_Interrupt_Exit: POP PSW POP ACC RETI ;----------------------------------------delay: CLR A MOV R1,A MOV R2,A MOV R3,#80H delay_loop: NOP NOP NOP DJNZ R1,delay_loop DJNZ R2,delay_loop DJNZ R3,delay_loop RET ;---------------------------------------- END C T S STC MCU Limited. U C M . d e mit Li website：www.STCMCU.com 253 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 10.9 Using PWM achieve D/A Conversion function reference circuit 1 32 VDD P2.3 2 31 P2.1 RST 3 30 P2.0 RxD/P3.0 4 29 P1.7/ADC7 TxD/P3.1 5 28 P1.6/ADC6 P0.0 6 27 P1.5/ADC5 XTAL2 7 26 P0.3 XTAL1 8 25 P1.4/ADC4 INT0/P3.2 9 24 P1.3/ADC3 SOP-32 P2.2 P0.1 10 23 P0.2 INT1/P3.3 11 22 P1.2/ADC2/LVD ECI/T0/P3.4 12 21 P1.1/ADC1/CLKOUT1 PWM1/T1/P3.5 13 20 P1.0/ADC0/CLKOUT0 P2.4 14 19 P3.7/PWM0 P2.5 15 18 P2.7 VSS 16 17 P2.6 C T S 254 STC MCU Limited. U C M . d e t i m 10K 10K Li 104 D/A 104 website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Chapter 11. Serial Peripheral Interface (SPI) STC12C2052AD provides another high-speed serial communication interface, the SPI interface. SPI is a full-duplex, high-speed, synchronous communication bus with two operation modes: Master mode and Slave mode. Up to 3Mbit/s can be supported in either Master or Slave mode under the SYSclk=12MHz. Two status flags are provided to signal the transfer completion and write-collision occurrence. 11.1 Special Function Registers related with SPI SPI Management SFRs Mnemonic Description SPCTL SPI Control Register SPSTAT SPI Status Register SPDAT SPI Data Register Address 85H 84H 86H Bit address and Symbol B7 B6 B5 SPCTL 85H bit B7 name SSIG C T S B3 B2 B1 SSIG SPEN DORD MSTR CPOL CPHA SPR1 SPIF WCOL - U C M 1. SPI Control register: SPCTL (Non bit-addressable) SFR name Address . d e mit B4 B6 SPEN B5 B4 Li DORD MSTR B0 Reset Value SPR0 0000,0100 00xx,xxxx 0000,0000 B3 B2 B1 B0 CPOL CPHA SPR1 SPR0 SSIG : Control whether SS pin is ignored or not. If SSIG=1, MSTR(SPCTL.4) decides whether the device is a master or slave. If SSIG=0, the SS pin decides whether the device is a master or slave. SS pin can be used as I/O port. SPEN : SPI enable bit. If SPEN=0, the SPI interface is disabled and all SPI pins will be general-purpose I/O ports. If SPEN=1, the SPI is enabled. DORD : Set the transmitted or received SPI data order. If DORD=1, The LSB of the data word is transmitted first. If DORD=0, The MSB of the data word is transmitted first. MSTR : Master/Slave mode select bit. If MSTR=0, set the SPI to play as Slave part. If MSTR=1, set the SPI to play as Master part. CPOL : SPI clock polarity select bit. If CPOL=1, SPICLK is high level when in idle mode. The leading edge of SPICLK is the falling edge and the trailing edge is the rising edge. If CPOL=0, SPICLK is low when idle. The leading edge of SPICLK is the rising edge and the trailing edge is the falling edge. CPHA : SPI clock phase select bit. If CPHA=1, Data is driven on the leading edge of SPICLK, and is sampled on the trailing edge. If CPHA=0, Data is driven when SS pin is low (SSIG=0) and changes on the trailing edge of SPICLK. Data is sampled on the leading edge of SPICLK. (Note : If SSIG=1, CPHA must not be 0, otherwise the operation is undefined) STC MCU Limited. website：www.STCMCU.com 255 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 SPR1-SPR0 : SPI clock rate select bit (when in master mode) SPI clock frequency select bit SPR1 SPR0 SPI clock (SCLK ) 0 0 CPU_CLK/4 0 1 CPU_CLK/16 1 0 CPU_CLK/64 1 1 CPU_CLK/128 CPU_CLK is CPU clock. When CPHA equals 0, SSIG must be 0 and SS pin must be negated and reasserted between each successive serial byte transfer. If the SPDAT register is written while SS is active(0), a write collision error results and WCOL is set. . d e t i m When CPHA equals 1, SSIG may be 0 or 1. If SSIG=0, the SS pin may remain active low between successive transfers(can be tied low at any times). This format is sometimes preferred for use in systems having a signle fixed master and a single slave configuration. U C M 2. SPI State register: SPSTAT (Non bit-addressable) SFR name Address SPSTAT SPIF : CDH bit B7 name SPIF C T S B6 B5 B4 WCOL - - Li B3 B2 B1 B0 - - - - SPI transfer completion flag. When a serial transfer finishes, the SPIF bit is set and an interrupt is generated if all the EADC_SPI (IE.6) bit, ESPI bit (AUXR.3) and the EA (IE.7) bit are set. If SS is an input and is driven low when SPI is in master mode with SSIG = 0, SPIF will also be set to signal the “mode change”.The SPIF is cleared in software by “writing 1 to this bit”. WCOL: SPI write collision flag. The WCOL bit is set if the SPI data register, SPDAT, is written during a data transfer. The WCOL flag is cleared in software by “writing 1 to this bit”. 3. SPI Data register : SPDAT (Non bit-addressable) SFR name Address SPDAT CFH bit B7 B6 B5 B4 B3 B2 B1 B0 name The SFR SPDAT holds the data to be transmitted or the data received. 256 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 5. Registers related with SPI interrupt : IE, AUXR, IP and IPH IE: Interrupt Enable Rsgister (Bit-addressable) SFR name Address IE A8H bit B7 name EA B6 B5 EPCA_LVD EADC_SPI B4 B3 B2 B1 B0 ES ET1 EX1 ET0 EX0 EA : disables all interrupts. If EA = 0,no interrupt will be acknowledged. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. EADC_SPI : Interrupt controller of Serial Peripheral Interface (SPI) and A/D Converter (ADC). If EADC_SPI = 0, Disable the interrupt of Serial Peripheral Interface (SPI) and A/D Converter (ADC). If EADC_SPI = 1, Enable the interrupt of Serial Peripheral Interface (SPI) and A/D Converter (ADC). AUXR: Auxiliary register (Non bit-addressable) SFR name AUXR Address 8EH . d e mit bit B7 B6 B5 B4 name T0x12 T1x12 UART_M0x6 EADCI Li B3 ESPI B2 ELVDI B1 - B0 - ELVDI : Enable/Disable interrupt from low-voltage sensor 0 : (default)Inhibit the low-voltage sensor functional block to generate interrupt to the MCU 1 : Enable the low-voltage sensor functional block to generate interrupt to the MCU U C M ESPI : Enable/Disable interrupt from Serial Peripheral Interface (SPI) 0 : (default)Inhibit the SPI functional block to generate interrupt to the MCU 1 : Enable the SPI functional block to generate interrupt to the MCU C T S EADCI : Enable/Disable interrupt from A/D converter 0 : (default) Inhibit the ADC functional block to generate interrupt to the MCU 1 : Enable the ADC functional block to generate interrupt to the MCU IPH: Interrupt Priority High Register (Non bit-addressable) SFR name Address IPH B7H bit B7 name - B6 B5 PPCA_LVDH PADC_SPIH B4 B3 B2 B1 B0 PSH PT1H PX1H PT0H PX0H IP: Interrupt Priority Register (Bit-addressable) SFR name Address IP B8H bit B7 name - B6 B5 PPCA_LVD PADC_SPI B4 B3 B2 B1 B0 PS PT1 PX1 PT0 PX0 PADC_SPIH, PADC_SPI : Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt priority control bits. if PADC_SPIH=0 and PADC_SPI=0, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 0). if PADC_SPIH=0 and PADC_SPI=1, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 1). if PADC_SPIH=1 and PADC_SPI=0, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 2). if PADC_SPIH=1 and PADC_SPI=1, Serial Peripheral Interface (SPI) and A/D Converter (ADC) interrupt are assigned lowest priority(priority 3). STC MCU Limited. website：www.STCMCU.com 257 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.2 SPI Structure S M CPU clock M S 8-bit shift register read data buffer S M clock logic C T S SPI interrupt request SPR1 MSTR . d e t i m Li SPR0 CPHA CPOL MSTR SPEN U C M SSIG SPI state register: SPSTAT DORD MSTR SPEN WCOL SPI Control SPIF clock SPI clock(host) SPR0 SPR1 selection I/O control MOSI P1.5 SCLK P1.7 SS P1.4 SPEN Clock divider 4, 16, 64, 128 MISO P1.6 SPI Control Register: SPCTL internal data bus SPI block diagram The SPI interface has three pins implementing the SPI functionality: SCLK(P1.7), MISO(P1.6), MOSI(P1.5). An extra pin SS(P1.4) is designed to configure the SPI to run under Master or Slave mode. SCLK, MOSI and MISO are typically tied together between two or more SPI devices. Data flows from master to slave on MOSI(Master Out Slave In) pin and flows from slave to master on MISO(Master In Slave Out) pin. The SCLK signal is output in the master mode and is input in the slave mode. If the SPI system is disabled, i.e, SPEN(SPCTL.6)=0, these pins are configured as general-purposed I/O port(P1.4 ~ P1.7). SS is thel slave select pin. In a typical configuration, an SPI master asserts one of its port pins to select one SPI device as the current slave. An SPI slave device uses its SS pin to determine whether it is selected. But if SPEN=0 or SSIG(SPCTL.7) bit is 1, the SS pin is ignored. Note that even if the SPI is configured as a master(MSTR/ SPCTL.4=1), it can still be converted to a slave by driving the SS pin low. When the conversion happened, the SPIF bit(SPSTAT.7) will be set. Two devices with SPI interface communicate with each other via one synchronous clock signal, one input data signal, and one output data signal. There are two concerns the user should take care, one of them is latching data on the negative edge or positive edge of the clock signal which named polarity, the other is keeping the clock signal low or high while the device idle which named phase. Permuting those states from polarity and phase, there could be four modes formed, they are SPI-MODE-0, SPI-MODE-1, SPI-MODE-2, SPI-MODE-3. Many device declares that they meet SPI machanism, but few of them are adaptive to all four modes. The STC12C5A60S2 series are flexible to be configured to communicate to another device with MODE-0, MODE-1, MODE-2 or MODE-3 SPI, and play part of Master and Slave. 258 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 11.3 SPI Data Communication 11.3.1 SPI Configuration When SPI data communication, SPEN, SSIG, SS(P1.4) and MSTR jointly control the selection of master and slave. Table: SPI master and slave selection SPEN SSIG SS MSTR (P1.4) 0 X P1.4 X 1 0 0 0 1 0 1 0 1 0 0 1->0 Mode MISO (P1.6) MOSI (P1.5) SPI disable GPI/O P1.6 GPI/O P1.5 GPI/O P1.7 SPI is disabled. P1.4/P1.5/P1.6/ P1.7 as GPIO. Selected salve output input input Selected as slave input input Not selected. input input Convert from Master to Slave Unselected slave Hi-Z slave 0 1 1 C T S . d e mit Li MOSI and SCLK are in highimpedance state in order to avoid bus clash when master is highhighidle. Whether is SCLK pulled impedance impedance up or pulled down depends on input CPOL/SPCTL.3. But it do not be allowed that SCLK is suspended. U C M Master (idle) 1 output SPICLK Remark (P1.7) Master (active) output output MOSI and SCLK is strong pushpull output. 1 1 P1.4 0 slave output input input Slave 1 1 P1.4 1 Master input output output Master STC MCU Limited. website：www.STCMCU.com 259 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.3.2 SPI Data Communication Modes There are 3 SPI data communication modes: single master — single slave, dual devices configuration (both can be a master or slave) and single master — multiple slaves. Master Slave 8-bit shift register SPI clock generator MISO MISO MOSI MOSI SPICLK 8-bit shift register SPICLK Port /SS . d e t i m SPI single master — single slave configuration Li Master/Slave MISO 8-bit shift register SPI clock generator C T S CU MOSI M SPICLK /SS MISO MOSI Master/Slave 8-bit shift register SPICLK SPI clock generator /SS SPI dual device configuration, both can be a master or slave Master Slave #1 MISO MISO 8-bit shift register 8-bit shift register MOSI SPI clock generator SPICLK Port MOSI SPICLK /SS Slave #1 MISO 8-bit shift register MOSI SPICLK Port /SS SPI single master multiple slaves configuration 260 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 In SPI, transfers are always initiated by the master. If the SPI is enabled(SPEN=1) and selected as master, any instruction that use SPI data register SPDAT as the destination will starts the SPI clock generator and a data transfer. The data will start to appear on MOSI about one half SPI bit-time to one SPI bit-time after it. Before starting the transfer, the master may select a slave by driving the SS pin of the corresponding device low. Data written to the SPDAT register of the master shifted out of MOSI pin of the master to the MOSI pin of the slave. And at the same time the data in SPDAT register of the selected slave is shifted out of MISO pin to the MISO pin of the master. During one byte transfer, data in the master and in the slave is interchanged. After shifting one byte, the transfer completion flag(SPIF) is set and an interrupt will be created if the SPI interrupt is enabled. If SPEN=1, SSIG=0, SS pin=1 and MSTR=1, the SPI is enabled in master mode. Before the instruction that use SPDAT as the destination register, the master is in idle state and can be selected as slave device by any other master drives the idle master SS pin low. Once this happened, MSTR bit of the idle master is cleared by hardware and changes its state a selected slave. User software should always check the MSTR bit. If this bit is cleared by the mode change of SS pin and the user wants to continue to use the SPI as a master later, the user must set the MSTR bit again, otherwise it will always stay in slave mode. . d e mit Li The SPI is single buffered in transmit direction and double buffered in receive direction. New data for transmission can not be written to the shift register until the previous transaction is complete. The WCOL bit is set to signal data collision when the data register is written during transaction. In this case, the data currently being transmitted will continue to be transmitted, but the new data which causing the collision will be lost. For receiving data, received data is transferred into a internal parallel read data buffer so that the shift register is free to accept a second byte. However, the received byte must be read from the data register(SPDAT) before the next byte has been completely transferred. Otherwise the previous byte is lost. WCOL can be cleared in software by “writing 1 to the bit”. C T S STC MCU Limited. U C M website：www.STCMCU.com 261 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.3.3 SPI Data Modes CPHA/SPCTL.2 is SPI clock phase select bit which is used to setting the clock edge of Data sample and change. CPOL/SPCTL.3 is used to select SPI clock polarity. The following are some typical timing diagrams which depend on the value of CPHA/SPCTL.2 Clock Cycle 1 2 3 4 5 6 7 8 SCLK(CPOL=0) SCLK(CPOL=1) MOSI(input) DORD=0 DORD=1 MISO(output) DORD=0 MSB LSB MSB LSB DORD=1 6 1 5 2 4 3 3 4 6 1 5 2 4 3 3 4 Li SS pin(if SSIG bit=0) U C M . d e t i m 2 5 2 5 1 6 LSB MSB 1 6 LSB MSB undefined SPI slave transfer format with CPHA=0 C T S Clock Cycle 1 2 3 4 5 6 7 8 SCLK(CPOL=0) SCLK(CPOL=1) MOSI(input) MISO(output) SS pin(if SSIG bit=0) DORD=0 DORD=1 DORD=0 DORD=1 1) MSB LSB 6 1 5 2 4 3 3 4 2 5 1 6 LSB MSB MSB LSB 6 1 5 2 4 3 3 4 2 5 1 6 LSB MSB 1)undefined SPI slave transfer format with CPHA=1 262 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 1 Clock Cycle 2 3 Tel:86-755-82948412 4 5 6 7 Fax:86-755-82905966 8 SCLK(CPOL=0) SCLK(CPOL=1) MOSI(input) DORD=0 DORD=1 MSB LSB MISO(output) DORD=0 DORD=1 MSB LSB 6 1 5 2 4 3 3 4 2 5 1 6 6 1 5 2 4 3 3 4 2 5 1 6 SS pin(if SSIG bit=0) 1 SCLK(CPOL=0) SCLK(CPOL=1) C T S DORD=0 MOSI(input) DORD=1 MISO(output) DORD=0 DORD=1 U C M 2 MSB LSB MSB LSB 3 4 5 6 1 5 2 4 3 6 1 5 2 4 3 Li 6 LSB MSB . d e mit SPI master transfer format with CPHA=0 Clock Cycle LSB MSB 7 8 3 4 2 5 1 6 3 4 2 5 1 6 LSB MSB LSB MSB SS pin(if SSIG bit=0) SPI master transfer format with CPHA=1 *When P4SPI bit in AUXR1 register is set, the function of SPI is redirected from P3[7:4] to P4[7:4] pin by pin. STC MCU Limited. website：www.STCMCU.com 263 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.4 SPI Function Demo Programs (Single Master — Single Slave) 11.4.1 SPI Function Demo Programs using Interrupts (C and ASM) The following program,written in C language and assembly language, tests SPI function and applys to SPI single master single slave configuration. 1. C code listing: ;/*----------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -------------------------------------*/ ;/* --- STC 1T Series MCU SPI Demo (1 master and 1 slave) -----------*/ ;/* --- Mobile: (86)13922809991 ---------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 --------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ---------------------------------------------*/ ;/* If you want to use the program or the program referenced in the ----*/ ;/* article, please specify in which data and procedures from STC ----*/ ;/*-----------------------------------------------------------------------------------*/ #include "reg51.h" U C M #define MASTER #define FOSC 18432000L #define BAUD (256 - FOSC / 32 / 115200) C T S typedef unsigned char typedef unsigned int typedef unsigned long BYTE; WORD; DWORD; sfr AUXR = 0x8e; sfr #define #define sfr #define #define #define #define #define #define #define #define #define #define sfr sbit SPSTAT = 0x84; SPIF 0x80 WCOL 0x40 SPCTL = 0x85; SSIG 0x80 SPEN 0x40 DORD 0x20 MSTR 0x10 CPOL 0x08 CPHA 0x04 SPDHH 0x00 SPDH 0x01 SPDL 0x02 SPDLL 0x03 SPDAT = 0x86; SPISS = P1^3; sbit EADC_SPI = IE^5; #define ESPI 0x08; 264 STC MCU Limited. . d e t i m Li //define:master undefine:slave //Auxiliary register //SPI status register //SPSTAT.7 //SPSTAT.6 //SPI control register //SPCTL.7 //SPCTL.6 //SPCTL.5 //SPCTL.4 //SPCTL.3 //SPCTL.2 //CPU_CLK/4 //CPU_CLK/16 //CPU_CLK/64 //CPU_CLK/128 //SPI data register //SPI slave select, connect to slave' SS(P1.4) pin //AUXR.3 website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 void InitUart(); void InitSPI(); void SendUart(BYTE dat); BYTE RecvUart(); Tel:86-755-82948412 Fax:86-755-82905966 //send data to PC //receive data from PC /////////////////////////////////////////////////////////// void main() { InitUart(); InitSPI(); AUXR |= ESPI; EADC_SPI = 1; EA = 1; while (1) { #ifdef MASTER ACC = RecvUart(); SPISS = 0; SPDAT = ACC; #endif } } C T S //initial UART //initial SPI U C M . d e mit Li //for master (receive UART data from PC and send it to slave, //in the meantime receive SPI data from slave and send it to PC) //pull low slave SS //trigger SPI send /////////////////////////////////////////////////////////// void spi_isr() interrupt 5 using 1 { SPSTAT = SPIF | WCOL; #ifdef MASTER SPISS = 1; SendUart(SPDAT); #else SPDAT = SPDAT; #endif } //SPI interrupt routine 5 (002BH) //clear SPI status //push high slave SS //return received SPI data //for salve (receive SPI data from master and // send previous SPI data to master) /////////////////////////////////////////////////////////// STC MCU Limited. website：www.STCMCU.com 265 www.STCMCU.com Mobile:(86)13922809991 void InitUart() { SCON = 0x5a; TMOD = 0x20; AUXR = 0x40; TH1 = TL1 = BAUD; TR1 = 1; } Tel:086-755-82948412 Fax:86-755-82905966 //set UART mode as 8-bit variable baudrate //timer1 as 8-bit auto reload mode //timer1 work at 1T mode //115200 bps /////////////////////////////////////////////////////////// void InitSPI() { SPDAT = 0; SPSTAT = SPIF | WCOL; #ifdef MASTER SPCTL = SPEN | MSTR; #else SPCTL = SPEN; #endif } C T S /////////////////////////////////////////////////////////// void SendUart(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } //initial SPI data //clear SPI status //master mode U C M //slave mode . d e t i m Li //wait pre-data sent //clear TI flag //send current data /////////////////////////////////////////////////////////// BYTE RecvUart() { while (!RI); RI = 0; return SBUF; } 266 STC MCU Limited. //wait receive complete //clear RI flag //return receive data website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assemly code listing: ;/*----------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -------------------------------------*/ ;/* --- STC 1T Series MCU SPI Demo (1 master and 1 slave) -----------*/ ;/* --- Mobile: (86)13922809991 ---------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 --------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ---------------------------------------------*/ ;/* If you want to use the program or the program referenced in the ----*/ ;/* article, please specify in which data and procedures from STC ----*/ ;/*-----------------------------------------------------------------------------------*/ //#define MASTER AUXR DATA SPSTAT DATA SPIF EQU WCOL EQU SPCTL DATA SSIG EQU SPEN EQU DORD EQU MSTR EQU CPOL EQU CPHA EQU SPDHH EQU SPDH EQU SPDL EQU SPDLL EQU SPDAT DATA SPISS BIT 08EH 084H 080H 040H 085H 080H 040H 020H 010H 008H 004H 000H 001H 002H 003H 086H P1.3 C T S EADC_SPI ESPI //define:master undefine:slave . d e mit ;Auxiliary register ;SPI status register ;SPSTAT.7 ;SPSTAT.6 ;SPI control register ;SPCTL.7 ;SPCTL.6 ;SPCTL.5 ;SPCTL.4 ;SPCTL.3 ;SPCTL.2 ;CPU_CLK/4 ;CPU_CLK/16 ;CPU_CLK/64 ;CPU_CLK/128 ;SPI data register ;SPI slave select, connect to slave' SS(P1.4) pin Li U C M BIT IE.5 EQU 08H ;AUXR.3 ;////////////////////////////////////////////////////////// ORG 0000H LJMP RESET ORG 002BH SPI_ISR: PUSH ACC PUSH PSW MOV SPSTAT, #SPIF | WCOL STC MCU Limited. ;SPI interrupt routine 5(2BH) ;clear SPI status website：www.STCMCU.com 267 www.STCMCU.com Mobile:(86)13922809991 #ifdef MASTER SETB SPISS MOV A, SPDAT LCALL SEND_UART #else MOV SPDAT, SPDAT #endif POP PSW POP ACC RETI Tel:086-755-82948412 Fax:86-755-82905966 ;push high slave SS ;return received SPI data //for salve (receive SPI data from master and ; send previous SPI data to master) ;////////////////////////////////////////////////////////// . d e t i m ORG 0100H RESET: LCALL INIT_UART ;initial UART LCALL INIT_SPI ;initial SPI ORL AUXR, #ESPI ;enable SPI interrupt SETB EADC_SPI SETB EA MAIN: #ifdef MASTER //for master (receive UART data from PC and send it to slave, LCALL RECV_UART ; in the meantimereceive SPI data from slave and send it to PC) CLR SPISS ;pull low slave SS MOV SPDAT, A ;trigger SPI send #endif SJMP MAIN C T S U C M Li ;////////////////////////////////////////////////////////// INIT_UART: MOV MOV MOV MOV MOV SETB RET SCON, TMOD, AUXR, TL1, TH1, TR1 #5AH #20H #40H #0FBH #0FBH ;set UART mode as 8-bit variable baudrate ;timer1 as 8-bit auto reload mode ;timer1 work at 1T mode ;115200 bps(256 - 18432000 / 32 / 115200) ;////////////////////////////////////////////////////////// 268 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com INIT_SPI: MOV MOV #ifdef MASTER MOV #else MOV #endif RET Mobile:(86)13922809991 Tel:86-755-82948412 SPDAT, #0 SPSTAT, #SPIF | WCOL ;initial SPI data ;clear SPI status SPCTL, #SPEN | MSTR ;master mode SPCTL, #SPEN ;slave mode Fax:86-755-82905966 ;////////////////////////////////////////////////////////// SEND_UART: JNB TI, $ CLR TI MOV SBUF, A RET U C M ;////////////////////////////////////////////////////////// RECV_UART: JNB RI,$ CLR RI MOV A, SBUF RET RET C T S . d e mit ;wait pre-data sent ;clear TI flag ;send current data Li ;wait receive complete ;clear RI flag ;return receive data ;////////////////////////////////////////////////////////// END STC MCU Limited. website：www.STCMCU.com 269 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.4.2 SPI Function Demo Programs using Polling (C and ASM) 1. C code listing: ;/*-----------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited --------------------------------------*/ ;/* --- STC 1T Series MCU SPI Demo (1 master and 1 slave) ------------*/ ;/* --- Mobile: (86)13922809991 ----------------------------------------------*/ ;/* --- Fax: 86-755-82905966 --------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 ---------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ---------------------------------------------*/ ;/* If you want to use the program or the program referenced in the ----*/ ;/* article, please specify in which data and procedures from STC ----*/ ;/*----------------------------------------------------------------------------------*/ . d e t i m #include "reg51.h" Li //#define MASTER #define FOSC #define BAUD //define:master undefine:slave 18432000L (256 - FOSC / 32 / 115200) typedef unsigned char typedef unsigned int typedef unsigned long BYTE; WORD; DWORD; C T S U C M sfr AUXR = 0x8e; sfr #define #define sfr #define #define #define #define #define #define #define #define #define #define sfr sbit SPSTAT = 0x84; SPIF 0x80 WCOL 0x40 SPCTL = 0x85; SSIG 0x80 SPEN 0x40 DORD 0x20 MSTR 0x10 CPOL 0x08 CPHA 0x04 SPDHH 0x00 SPDH 0x01 SPDL 0x02 SPDLL 0x03 SPDAT = 0x86; SPISS = P1^3; void void void BYTE BYTE InitUart(); InitSPI(); SendUart(BYTE dat); RecvUart(); SPISwap(BYTE dat); 270 STC MCU Limited. //Auxiliary register //SPI status register //SPSTAT.7 //SPSTAT.6 //SPI control register //SPCTL.7 //SPCTL.6 //SPCTL.5 //SPCTL.4 //SPCTL.3 //SPCTL.2 //CPU_CLK/4 //CPU_CLK/16 //CPU_CLK/64 //CPU_CLK/128 //SPI data register //SPI slave select, connect to slave' SS(P1.4) pin //send data to PC //receive data from PC //swap SPI data between master and slave website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 /////////////////////////////////////////////////////////// void main() { InitUart(); InitSPI(); //initial UART //initial SPI while (1) { #ifdef MASTER //for master (receive UART data from PC and send it to slave, // in the meantime receive SPI data from slave and send it to PC) SendUart(SPISwap(RecvUart())); #else //for salve (receive SPI data from master and ACC = SPISwap(ACC); // send previous SPI data to master) #endif } } U C M /////////////////////////////////////////////////////////// void InitUart() { SCON = 0x5a; TMOD = 0x20; AUXR = 0x40; TH1 = TL1 = BAUD; TR1 = 1; } C T S . d e mit Li //set UART mode as 8-bit variable baudrate //timer1 as 8-bit auto reload mode //timer1 work at 1T mode //115200 bps /////////////////////////////////////////////////////////// void InitSPI() { SPDAT = 0; SPSTAT = SPIF | WCOL; #ifdef MASTER SPCTL = SPEN | MSTR; #else SPCTL = SPEN; #endif } STC MCU Limited. //initial SPI data //clear SPI status //master mode //slave mode website：www.STCMCU.com 271 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 /////////////////////////////////////////////////////////// void SendUart(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } //wait pre-data sent //clear TI flag //send current data /////////////////////////////////////////////////////////// BYTE RecvUart() { while (!RI); RI = 0; return SBUF; } /////////////////////////////////////////////////////////// C T S BYTE SPISwap(BYTE dat) { #ifdef MASTER SPISS = 0; #endif SPDAT = dat; while (!(SPSTAT & SPIF)); SPSTAT = SPIF | WCOL; #ifdef MASTER SPISS = 1; #endif return SPDAT; } 272 STC MCU Limited. . d e t i m //wait receive complete //clear RI flag //return receive data U C M Li //pull low slave SS //trigger SPI send //wait send complete //clear SPI status //push high slave SS //return received SPI data website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assemly code listing: ;/*----------------------------------------------------------------------------------*/ ;/* --- STC MCU International Limited -------------------------------------*/ ;/* --- STC 1T Series MCU SPI Demo (1 master and 1 slave) -----------*/ ;/* --- Mobile: (86)13922809991 ---------------------------------------------*/ ;/* --- Fax: 86-755-82905966 -------------------------------------------------*/ ;/* --- Tel: 86-755-82948412 --------------------------------------------------*/ ;/* --- Web: www.STCMCU.com ---------------------------------------------*/ ;/* If you want to use the program or the program referenced in the ----*/ ;/* article, please specify in which data and procedures from STC ----*/ ;/*-----------------------------------------------------------------------------------*/ . d e mit //#define MASTER //define:master undefine:slave AUXR DATA SPSTAT DATA SPIF EQU WCOL EQU SPCTL DATA SSIG EQU SPEN EQU DORD EQU MSTR EQU CPOL EQU CPHA EQU SPDHH EQU SPDH EQU SPDL EQU SPDLL EQU SPDAT DATA SPISS BIT ;Auxiliary register ;SPI status register ;SPSTAT.7 ;SPSTAT.6 ;SPI control register ;SPCTL.7 ;SPCTL.6 ;SPCTL.5 ;SPCTL.4 ;SPCTL.3 ;SPCTL.2 ;CPU_CLK/4 ;CPU_CLK/16 ;CPU_CLK/64 ;CPU_CLK/128 ;SPI data register ;SPI slave select, connect to slave' SS(P1.4) pin 08EH 084H 080H 040H 085H 080H 040H 020H 010H 008H 004H 000H 001H 002H 003H 086H P1.3 C T S Li U C M ;////////////////////////////////////////////////////////// RESET: ORG 0000H LJMP RESET ORG 0100H LCALL INIT_UART LCALL INIT_SPI STC MCU Limited. ;initial UART ;initial SPI website：www.STCMCU.com 273 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 MAIN: #ifdef MASTE //for master (receive UART data from PC and send it to slave, in the meantime LCALL RECV_UART ; receive SPI data from slave and send it to PC) LCALL SPI_SWAP LCALL SEND_UART #else //for salve (receive SPI data from master and LCALL SPI_SWAP ; send previous SPI data to master) #endif SJMP MAIN ;////////////////////////////////////////////////////////// INIT_UART: MOV MOV MOV MOV MOV SETB RET SCON, TMOD, AUXR, TL1, TH1, TR1 #5AH #20H #40H #0FBH #0FBH ;////////////////////////////////////////////////////////// C T S U C M INIT_SPI: MOV SPDAT, #0 MOV SPSTAT, #SPIF | WCOL #ifdef MASTER MOV SPCTL, #SPEN | MSTR #else MOV SPCTL, #SPEN #endif RET . d e t i m ;set UART mode as 8-bit variable baudrate ;timer1 as 8-bit auto reload mode ;timer1 work at 1T mode ;115200 bps(256 - 18432000 / 32 / 115200) Li ;initial SPI data ;clear SPI status ;master mode ;slave mode ;////////////////////////////////////////////////////////// SEND_UART: JNB TI, $ CLR TI MOV SBUF, A RET ;wait pre-data sent ;clear TI flag ;send current data ;////////////////////////////////////////////////////////// 274 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 RECV_UART: JNB RI, $ CLR RI MOV A, SBUF RET RET Tel:86-755-82948412 Fax:86-755-82905966 ;wait receive complete ;clear RI flag ;return receive data ;////////////////////////////////////////////////////////// SPI_SWAP: #ifdef MASTER CLR #endif MOV WAIT: MOV JNB MOV #ifdef MASTER SETB #endif MOV RET . d e mit SPISS ;pull low slave SS SPDAT, A ;trigger SPI send Li A, SPSTAT ACC.7, WAIT SPSTAT, #SPIF | WCOL ;wait send complete ;clear SPI status SPISS ;push high slave SS A, ;return received SPI data C T S U C M SPDAT ;////////////////////////////////////////////////////////// END STC MCU Limited. website：www.STCMCU.com 275 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.5 SPI Function Demo Programs (Each other as the Master-Slave) 11.5.1 SPI Function Demo Programs using Interrupts (C and ASM) 1. C code listing: /*--------------------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------------------*/ /* --- STC12C5Axx Series MCU SPI Demo(Each other as the master-slave) --*/ /* --- Mobile: (86)13922809991 -------------------------------------------------------*/ /* --- Fax: 86-755-82905966 -----------------------------------------------------------*/ /* --- Tel: 86-755-82948412 ------------------------------------------------------------*/ /* --- Web: www.STCMCU.com -------------------------------------------------------*/ /* If you want to use the program or the program referenced in the --------------*/ /* article, please specify in which data and procedures from STC --------------*/ /*---------------------------------------------------------------------------------------------*/ . d e t i m #include "reg51.h" #define FOSC #define BAUD typedef unsigned char typedef unsigned int typedef unsigned long BYTE; WORD; DWORD; C T S sfr AUXR = 0x8e; sfr #define #define sfr #define #define #define #define #define #define #define #define #define #define sfr sbit SPSTAT = 0x84; SPIF 0x80 WCOL 0x40 SPCTL = 0x85; SSIG 0x80 SPEN 0x40 DORD 0x20 MSTR 0x10 CPOL 0x08 CPHA 0x04 SPDHH 0x00 SPDH 0x01 SPDL 0x02 SPDLL 0x03 SPDAT = SPISS = U C M //Auxiliary register //SPI status register //SPSTAT.7 //SPSTAT.6 //SPI control register //SPCTL.7 //SPCTL.6 //SPCTL.5 //SPCTL.4 //SPCTL.3 //SPCTL.2 //CPU_CLK/4 //CPU_CLK/16 //CPU_CLK/64 //CPU_CLK/128 0x86; //SPI data register P1^3; //SPI slave select, connect to other MCU's SS(P1.4) pin sbit EADC_SPI = IE^5; #define ESPI 0x08; 276 Li 18432000L (256 - FOSC / 32 / 115200) STC MCU Limited. //AUXR.3 website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 void InitUart(); void InitSPI(); void SendUart(BYTE dat); BYTE RecvUart(); //send data to PC //receive data from PC bit MSSEL; //1: master 0:slave Fax:86-755-82905966 /////////////////////////////////////////////////////////// void main() { InitUart(); InitSPI(); AUXR |= ESPI; EADC_SPI = 1; EA = 1; while (1) { if (RI) { } } } //initial UART //initial SPI M CU . d e mit SPCTL = SPEN | MSTR; MSSEL = 1; ACC = RecvUart(); SPISS = 0; SPDAT = ACC; C T S Li //set as master //pull low slave SS //trigger SPI send /////////////////////////////////////////////////////////// void spi_isr( ) interrupt 5 using 1 //SPI interrupt routine 5 (002BH) { SPSTAT = SPIF | WCOL; //clear SPI status if (MSSEL) { SPCTL = SPEN; //reset as slave MSSEL = 0; SPISS = 1; //push high slave SS SendUart(SPDAT); //return received SPI data } else { //for salve (receive SPI data from master and SPDAT = SPDAT; // send previous SPI data to master) } } /////////////////////////////////////////////////////////// STC MCU Limited. website：www.STCMCU.com 277 www.STCMCU.com Mobile:(86)13922809991 void InitUart() { SCON = 0x5a; TMOD = 0x20; AUXR = 0x40; TH1 = TL1 = BAUD; TR1 = 1; } Tel:086-755-82948412 Fax:86-755-82905966 //set UART mode as 8-bit variable baudrate //timer1 as 8-bit auto reload mode //timer1 work at 1T mode //115200 bps /////////////////////////////////////////////////////////// void InitSPI() { SPDAT = 0; SPSTAT = SPIF | WCOL; SPCTL = SPEN; } /////////////////////////////////////////////////////////// void SendUart(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } C T S //initial SPI data //clear SPI status //slave mode U C M . d e t i m Li //wait pre-data sent //clear TI flag //send current data /////////////////////////////////////////////////////////// BYTE RecvUart() { while (!RI); RI = 0; return SBUF; } 278 STC MCU Limited. //wait receive complete //clear RI flag //return receive data website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assembly code listing: /*--------------------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------------------*/ /* --- STC12C5Axx Series MCU SPI Demo(Each other as the master-slave) --*/ /* --- Mobile: (86)13922809991 -------------------------------------------------------*/ /* --- Fax: 86-755-82905966 -----------------------------------------------------------*/ /* --- Tel: 86-755-82948412 ------------------------------------------------------------*/ /* --- Web: www.STCMCU.com -------------------------------------------------------*/ /* If you want to use the program or the program referenced in the --------------*/ /* article, please specify in which data and procedures from STC --------------*/ /*---------------------------------------------------------------------------------------------*/ AUXR DATA SPSTAT DATA SPIF EQU WCOL EQU SPCTL DATA SSIG EQU SPEN EQU DORD EQU MSTR EQU CPOL EQU CPHA EQU SPDHH EQU SPDH EQU SPDL EQU SPDLL EQU SPDAT DATA SPISS BIT 08EH 084H 080H 040H 085H 080H 040H 020H 010H 008H 004H 000H 001H 002H 003H 086H P1.3 C T S EADC_SPI ESPI MSSEL BIT . d e mit Li U C M BIT IE.5 EQU 08H 20H.0 ;Auxiliary register ;SPI status register ;SPSTAT.7 ;SPSTAT.6 ;SPI control register ;SPCTL.7 ;SPCTL.6 ;SPCTL.5 ;SPCTL.4 ;SPCTL.3 ;SPCTL.2 ;CPU_CLK/4 ;CPU_CLK/16 ;CPU_CLK/64 ;CPU_CLK/128 ;SPI data register ;SPI slave select, connect to other MCU's SS(P1.4) pin ;AUXR.3 ;1: master 0:slave ;////////////////////////////////////////////////////////// ORG 0000H LJMP RESET ORG 002BH ;SPI interrupt routine SPI_ISR: PUSH ACC PUSH PSW MOV SPSTAT, #SPIF | WCOL ;clear SPI status JBC MSSEL, MASTER_SEND STC MCU Limited. website：www.STCMCU.com 279 www.STCMCU.com Mobile:(86)13922809991 SLAVE_RECV: MOV SPDAT, SPDAT JMP SPI_EXIT MASTER_SEND: SETB SPISS MOV SPCTL, #SPEN MOV A, SPDAT LCALL SEND_UART SPI_EXIT: POP PSW POP ACC RETI ;////////////////////////////////////////////////////////// RESET: MAIN: ORG 0100H U C M MOV SP,#3FH LCALL INIT_UART LCALL INIT_SPI ORL AUXR, #ESPI SETB EADC_SPI SETB EA C T S Tel:086-755-82948412 Fax:86-755-82905966 //for salve (receive SPI data from master and ; send previous SPI data to master) ;push high slave SS ; ;reset as slave ;return received SPI data . d e t i m Li ;initial UART ;initial SPI JNB RI, $ ;wait UART data MOV SPCTL, #SPEN | MSTR ; ;set as master SETB MSSEL LCALL RECV_UART ;receive UART data from PC CLR SPISS ;pull low slave SS MOV SPDAT, A ;trigger SPI send SJMP MAIN ;////////////////////////////////////////////////////////// INIT_UART: MOV MOV MOV MOV MOV SETB RET SCON, TMOD, AUXR TL1, TH1, TR1 280 STC MCU Limited. #5AH #20H ,#40H #0FBH #0FBH ;set UART mode as 8-bit variable baudrate ;timer1 as 8-bit auto reload mode ;timer1 work at 1T mode ;115200 bps(256 - 18432000 / 32 / 115200) website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;////////////////////////////////////////////////////////// INIT_SPI: MOV MOV MOV RET SPDAT, #0 SPSTAT, #SPIF | WCOL SPCTL, #SPEN ;initial SPI data ;clear SPI status ;slave mode ;////////////////////////////////////////////////////////// SEND_UART: JNB TI, $ CLR TI MOV SBUF, A RET ;////////////////////////////////////////////////////////// U C M RECV_UART: JNB RI, $ CLR RI MOV A, SBUF RET RET C T S ;wait pre-data sent ;clear TI flag ;send current data . d e mit Li ;wait receive complete ;clear RI flag ;return receive data ;////////////////////////////////////////////////////////// END STC MCU Limited. website：www.STCMCU.com 281 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 11.5.2 SPI Function Demo Programs using Polling 1. C code listing: /*--------------------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------------------*/ /* --- STC12C5Axx Series MCU SPI Demo(Each other as the master-slave) --*/ /* --- Mobile: (86)13922809991 -------------------------------------------------------*/ /* --- Fax: 86-755-82905966 -----------------------------------------------------------*/ /* --- Tel: 86-755-82948412 ------------------------------------------------------------*/ /* --- Web: www.STCMCU.com -------------------------------------------------------*/ /* If you want to use the program or the program referenced in the --------------*/ /* article, please specify in which data and procedures from STC --------------*/ /*---------------------------------------------------------------------------------------------*/ . d e t i m #include "reg51.h" #define FOSC #define BAUD 18432000L (256 - FOSC / 32 / 115200) typedef unsigned char typedef unsigned int typedef unsigned long BYTE; WORD; DWORD; C T S U C M Li sfr AUXR = 0x8e; sfr #define #define sfr #define #define #define #define #define #define #define #define #define #define sfr sbit SPSTAT = SPIF WCOL SPCTL = SSIG SPEN DORD MSTR CPOL CPHA SPDHH SPDH SPDL SPDLL SPDAT = SPISS = 0x84; 0x80 0x40 0x85; 0x80 0x40 0x20 0x10 0x08 0x04 0x00 0x01 0x02 0x03 0x86; P1^3; //SPI status register //SPSTAT.7 //SPSTAT.6 //SPI control register //SPCTL.7 //SPCTL.6 //SPCTL.5 //SPCTL.4 //SPCTL.3 //SPCTL.2 //CPU_CLK/4 //CPU_CLK/16 //CPU_CLK/64 //CPU_CLK/128 //SPI data register //SPI slave select, connect to slave' SS(P1.4) pin void void void BYTE BYTE InitUart(); InitSPI(); SendUart(BYTE dat); RecvUart(); SPISwap(BYTE dat); 282 STC MCU Limited. //Auxiliary register //send data to PC //receive data from PC //swap SPI data between master website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 /////////////////////////////////////////////////////////// void main() { InitUart(); InitSPI(); //initial UART //initial SPI while (1) { if (RI) { SPCTL = SPEN | MSTR; //set as master SendUart(SPISwap(RecvUart())); SPCTL = SPEN; //reset as slave } if (SPSTAT & SPIF) { SPSTAT = SPIF | WCOL; //clear SPI status SPDAT = SPDAT; //mov data from receive buffer to send buffer } } } C T S U C M . d e mit Li /////////////////////////////////////////////////////////// void InitUart() { SCON = 0x5a; TMOD = 0x20; AUXR = 0x40; TH1 = TL1 = BAUD; TR1 = 1; } //set UART mode as 8-bit variable baudrate //timer1 as 8-bit auto reload mode //timer1 work at 1T mode //115200 bps /////////////////////////////////////////////////////////// void InitSPI() { SPDAT = 0; SPSTAT = SPIF | WCOL; SPCTL = SPEN; } STC MCU Limited. //initial SPI data //clear SPI status //slave mode website：www.STCMCU.com 283 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 /////////////////////////////////////////////////////////// void SendUart(BYTE dat) { while (!TI); TI = 0; SBUF = dat; } //wait pre-data sent //clear TI flag //send current data /////////////////////////////////////////////////////////// BYTE RecvUart() { while (!RI); RI = 0; return SBUF; } /////////////////////////////////////////////////////////// BYTE SPISwap(BYTE dat) { SPISS = 0; SPDAT = dat; while (!(SPSTAT & SPIF)); SPSTAT = SPIF | WCOL; SPISS = 1; return SPDAT; } C T S 284 STC MCU Limited. . d e t i m //wait receive complete //clear RI flag //return receive data U C M Li //pull low slave SS //trigger SPI send //wait send complete //clear SPI status //push high slave SS //return received SPI data website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 2. Assemly code listing: /*--------------------------------------------------------------------------------------------*/ /* --- STC MCU International Limited -----------------------------------------------*/ /* --- STC12C5Axx Series MCU SPI Demo(Each other as the master-slave) --*/ /* --- Mobile: (86)13922809991 -------------------------------------------------------*/ /* --- Fax: 86-755-82905966 -----------------------------------------------------------*/ /* --- Tel: 86-755-82948412 ------------------------------------------------------------*/ /* --- Web: www.STCMCU.com -------------------------------------------------------*/ /* If you want to use the program or the program referenced in the --------------*/ /* article, please specify in which data and procedures from STC --------------*/ /*---------------------------------------------------------------------------------------------*/ AUXR DATA SPSTAT DATA SPIF EQU WCOL EQU SPCTL DATA SSIG EQU SPEN EQU DORD EQU MSTR EQU CPOL EQU CPHA EQU SPDHH EQU SPDH EQU SPDL EQU SPDLL EQU SPDAT DATA SPISS BIT 08EH 084H 080H 040H 085H 080H 040H 020H 010H 008H 004H 000H 001H 002H 003H 086H P1.3 C T S ;Auxiliary register ;SPI status register ;SPSTAT.7 ;SPSTAT.6 ;SPI control register ;SPCTL.7 ;SPCTL.6 ;SPCTL.5 ;SPCTL.4 ;SPCTL.3 ;SPCTL.2 ;CPU_CLK/4 ;CPU_CLK/16 ;CPU_CLK/64 ;CPU_CLK/128 ;SPI data register ;SPI slave select, connect to slave' SS(P1.4) pin . d e mit Li U C M ;////////////////////////////////////////////////////////// RESET: MAIN: ORG 0000H LJMP RESET ORG 0100H LCALL INIT_UART LCALL INIT_SPI JB STC MCU Limited. RI, ;initial UART ;initial SPI MASTER_MODE website：www.STCMCU.com 285 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 SLAVE_MODE: MOV A, SPSTAT JNB ACC.7, MAIN MOV SPSTAT, #SPIF | WCOL ;clear SPI status MOV SPDAT, SPDAT ;return received SPI data SJMP MAIN MASTER_MODE: MOV SPCTL, #SPEN | MSTR ;set as master LCALL RECV_UART ;receive UART data from PC LCALL SPI_SWAP ;send it to slave, in the meantime, receive SPI data from slave LCALL SEND_UART ;send SPI data to PC MOV SPCTL, #SPEN ; ;reset as slave SJMP MAIN ;////////////////////////////////////////////////////////// INIT_UART: MOV MOV MOV MOV MOV SETB RET SCON, TMOD, AUXR, TL1, TH1, TR1 U C M #5AH #20H #40H #0FBH #0FBH C T S . d e t i m Li ;set UART mode as 8-bit variable baudrate ;timer1 as 8-bit auto reload mode ;timer1 work at 1T mode ;115200 bps(256 - 18432000 / 32 / 115200) ;////////////////////////////////////////////////////////// INIT_SPI: MOV SPDAT, #0 MOV SPSTAT, #SPIF | WCOL MOV SPCTL, #SPEN RET ;initial SPI data ;clear SPI status ;slave mode ;////////////////////////////////////////////////////////// SEND_UART: JNB TI, $ CLR TI MOV SBUF, A RET 286 STC MCU Limited. ;wait pre-data sent ;clear TI flag ;send current data website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 ;////////////////////////////////////////////////////////// RECV_UART: JNB RI, $ CLR RI MOV A, SBUF RET RET ;wait receive complete ;clear RI flag ;return receive data ;////////////////////////////////////////////////////////// SPI_SWAP: CLR SPISS MOV SPDAT, A WAIT: MOV A, SPSTAT JNB ACC.7, WAIT MOV SPSTAT, #SPIF | WCOL SETB SPISS MOV A, SPDAT RET C T S U C M . d e mit ;pull low slave SS ;trigger SPI send Li ;wait send complete ;clear SPI status ;push high slave SS ;return received SPI data ;////////////////////////////////////////////////////////// END STC MCU Limited. website：www.STCMCU.com 287 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 Chapter 12. IAP / EEPROM The ISP in STC12C2052AD series makes it possible to update the user’s application program and non-volatile application data (in IAP-memory) without removing the MCU chip from the actual end product. This useful capability makes a wide range of field-update applications possible. (Note ISP needs the loader program preprogrammed in the ISP-memory.) In general, the user needn’t know how ISP operates because STC has provided the standard ISP tool and embedded ISP code in STC shipped samples.But, to develop a good program for ISP function, the user has to understand the architecture of the embedded flash. The embedded flash consists of 20 pages. Each page contains 512 bytes. Dealing with flash, the user must erase it in page unit before writing (programming) data into it.Erasing flash means setting the content of that flash as FFh. Two erase modes are available in this chip. One is mass mode and the other is page mode. The mass mode gets more performance, but it erases the entire flash. The page mode is something performance less, but it is flexible since it erases flash in page unit. Unlike RAM’s real-time operation, to erase flash or to write (program) flash often takes long time so to wait finish. . d e t i m Furthermore, it is a quite complex timing procedure to erase/program flash. Fortunately, the STC12C2052AD series carried with convenient mechanism to help the user read/change the flash content. Just filling the target address and data into several SFR, and triggering the built-in ISP automation, the user can easily erase, read, and program the embedded flash. U C M Li The In-Application Program feature is designed for user to Read/Write nonvolatile data flash. It may bring great help to store parameters those should be independent of power-up and power-done action. In other words, the user can store data in data flash memory, and after he shutting down the MCU and rebooting the MCU, he can get the original value, which he had stored in. C T S The user can program the data flash according to the same way as ISP program, so he should get deeper understanding related to SFR ISP_DATA, ISP_ADDRL, ISP_ADDRH, ISP_CMD, ISP_TRIG, and ISP_CONTR. 288 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 12.1 IAP / EEPROM Special Function Registers The following special function registers are related to the IAP/ISP/EEPROM operation. All these registers can be accessed by software in the user’s application program. Symbol ISP_DATA ISP_ADDRH ISP_ADDRL ISP_CMD ISP_TRIG ISP_CONTR Description ISP/IAP Flash Data Register ISP/IAP Flash Address High ISP/IAP Flash Address Low ISP/IAP Flash Command Register ISP/IAP Flash Command Trigger ISP/IAP Control Register C T S Address Value after Power-on or LSB Reset Bit Address and Symbol MSB E2H 1111 1111B E3H 0000 0000B . d e mit E4H E5H - - E6H U C M E7H - - Li - ISPEN SWBS SWRST CMD_FAIL - - MS1 WT2 WT1 0000 0000B MS0 xxxx x000B xxxx xxxxB WT0 0000 1000B 1. ISP/IAP Flash Data Register : ISP_DATA (Address: E2H, Non bit-addressable) ISP_DATA is the data port register for ISP/IAP operation. The data in ISP_DATA will be written into the desired address in operating ISP/IAP write and it is the data window of readout in operating ISP/ IAP read. 2. ISP/IAP Flash Address Registers : ISP_ADDRH and ISP_ADDRL ISP_ADDRH (address:E3H) is the high-byte address port for all ISP/IAP modes. ISP_ADDRH[7:5] must be cleared to 000, if one bit of ISP_ADDRH[7:5] is set, the IAP/ISP write function must fail. ISP_ADDRL (address:E4H) is the low port for all ISP/IAP modes. In page erase operation, it is ignored. STC MCU Limited. website：www.STCMCU.com 289 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 3. ISP/IAP Flash Command Register : ISP_CMD (Non bit -addressable) SFR name Address bit B7 B6 B5 B4 B3 B2 B1 B0 ISP_CMD E5H name - - - - - - MS1 MS0 B7~B2: Reserved. MS1, MS0 : ISP/IAP operating mode selection. IAP_CMD is used to select the flash mode for performing numerous ISP/IAP function or used to access protected SFRs. 0, 0 : Standby 0, 1 : Data Flash/EEPROM read. 1, 0 : Data Flash/EEPROM program. 1, 1 : Data Flash/EEPROM page erase. . d e t i m 4. ISP/IAP Flash Command Trigger Register : ISP_TRIG (Address: E6H, Non bit -addressable) ISP_TRIG is the command port for triggering ISP/IAP activity and protected SFRs access. If ISP_TRIG is filled with sequential 0x46h, 0xB9h and if ISPEN(ISP_CONTR.7) = 1, ISP/IAP activity or protected SFRs access will triggered. U C M Li 5. ISP/IAP Control Register : ISP_CONTR (Non bit-addressable) SFR name Address ISP_CONTR E7H bit C T S B7 B6 B5 B4 name ISPEN SWBS SWRST CMD_FAIL B3 B2 B1 B0 - WT2 WT2 WT0 ISPEN : ISP/IAP operation enable. 0 : Global disable all ISP/IAP program/erase/read function. 1 : Enable ISP/IAP program/erase/read function. SWBS: software boot selection control. 0 : Boot from main-memory after reset. 1 : Boot from ISP memory after reset. SWRST: software reset trigger control. 0 : No operation 1 : Generate software system reset. It will be cleared by hardware automatically. CMD_FAIL: Command Fail indication for ISP/IAP operation. 0 : The last ISP/IAP command has finished successfully. 1 : The last ISP/IAP command fails. It could be caused since the access of flash memory was inhibited. B3: Reserved. Software must write “0” on this bit when ISP_CONTR is written. 290 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 WT2~WT0 : Waiting time selection while flash is busy. Setting wait times CPU wait times Read WT2 WT1 WT0 (2 System clocks) 1 1 1 2 SYSclks 1 1 0 2 SYSclks 1 0 1 2 SYSclks 1 0 0 2 SYSclks 0 1 1 2 SYSclks 0 1 0 2 SYSclks 0 0 1 2 SYSclks 0 0 0 2 SYSclks Program (=55uS) Sector Erase (=21mS) Recommended System Clock Frequency (MHz) 55 SYSclks 110 SYSclks 165 SYSclks 330 SYSclks 660 SYSclks 1100 SYSclks 1320 SYSclks 1760 SYSclks 21012 SYSclks 42024 SYSclks 63036 SYSclks 126072 SYSclks 252144 SYSclks 420240 SYSclks 504288 SYSclks 672384 SYSclks ≤1MHz ≤ 2MHz ≤ 3MHz ≤ 6MHz ≤ 12MHz ≤ 20MHz ≤ 24MHz ≤ 30MHz . d e mit Note: Software reset actions could reset other SFR,but it never influences bits ISPEN and SWBS.The ISPEN and SWBS. The ISPEN and SWBS only will be reset by power-up action, while not software reset. CU Li 6. When the operation voltage is too low, EEPROM / IAP function should be disabled SFR name Address PCON 87H LVDF bit B7 M B6 B5 name SMOD SMOD0 LVDF C T S B4 B3 B2 B1 B0 POF GF1 GF0 PD IDL : Pin Low-Voltage Flag. Once low voltage condition is detected (VCC power is lower than LVD voltage), it is set by hardware (and should be cleared by software). STC MCU Limited. website：www.STCMCU.com 291 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 12.2 STC12C2052AD series Internal EEPROM Allocation Table STC12C2052AD series microcontroller's Data Flash (internal available EEPROM) address (and program space is separate) : if the application area of IAP write Data/erase sector of the action, the statements will be ignore and continue to the next one. Program in user application area (AP area), only operate IAP/ISP on Data Flash (EEPROM ) STC12C5052AD and STC12LE5052AD are excepted, this several types in the application area can modify the application STC12C2052AD series MCU internal EEPROM Selection Table STC12LE2052AD series MCU internal EEPROM Selection Table EEPROM Sector Begin_Sector End_Sector Type (Byte) Numbers Begin_Address End_Address . d e t i m STC12C1052AD/ STC12LE1052AD 10K 20 0000h 27FFh STC12C2052AD/ STC12LE2052AD 10K 20 0000h 27FFh STC12C3052AD/ STC12LE3052AD 10K 20 0000h 27FFh STC12C4052AD/ STC12LE4052AD 10K 20 0000h 27FFh C T S U C M Li The following series are special. User can modify the application the application area, all flash area can be modified as EEPROM STC12C5052AD/ STC12LE5052AD - 10 0000h 27FFh STC12C2052AD series MCU address reference table in detail (512 bytes per sector) STC12LE2052AD series MCU address reference table in detail (512 bytes per sector) Sector 1 Sector 2 Sector 3 Sector 4 Each sector 512 Start End Start End Start End Start End byte 0000H 01FFH 0200H 03FFH 0400H 05FFH 0600H 07FFH Sector 5 Sector 6 Sector7 Sector 8 Start End Start End Start End Start End Suggest the same 0800H 09FFH 0A00H 0BFFH 0C00H 0DFFH 0E00H 0FFFH times modified data Sector 9 Sector 10 Sector 11 Sector 12 Start End Start End Start End Start End in the same sector, 1000H 11FFH 1200H 13FFH 1400H 15FFH 1600H 17FFH each times modified Sector 13 Sector 14 Sector 15 Sector 16 data in different Start End Start End Start End Start End sectors, don't have 1800H 19FFH 1A00H 1BFFH 1C000H 1DFFH 1E00H 1FFFH to use full, of Sector 17 Sector 18 Sector 19 Sector 20 course, it was all to Start End Start End Start End Start End use 2000H 21FFH 2200H 23FFH 2400H 25FFH 2600H 27FFH 292 STC MCU Limited. website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 12.3 IAP/EEPROM Assembly Language Program Introduction ; /*It is decided by the assembler/compiler used by users that whether the SFRs addresses are declared by the DATA or the EQU directive*/ ISP_DATA DATA 0E2H or ISP_DATA EQU 0E2H ISP_ADDRH DATA 0E3H or ISP_ADDRH EQU 0E3H ISP_ADDRL DATA 0E4H or ISP_ADDRL EQU 0E4H ISP_CMD DATA 0E5H or ISP_CMD EQU 0E5H ISP_TRIG DATA 0E6H or ISP_TRIG EQU 0E6H ISP_CONTR DATA 0E7H or ISP_CONTR EQU 0E7H ;/*Define ISP/IAP/EEPROM command and wait time*/ ISP_IAP_BYTE_READ EQU ISP_IAP_BYTE_PROGRAM EQU ISP_IAP_SECTOR_ERASE EQU WAIT_TIME EQU 1 2 3 0 ;Byte-Read ;Byte-Program ;Sector-Erase ;Set wait time . d e mit Li ;/*Byte-Read*/ MOV ISP_ADDRH, #BYTE_ADDR_HIGH ;Set ISP/IAP/EEPROM address high MOV ISP_ADDRL, #BYTE_ADDR_LOW ;Set ISP/IAP/EEPROM address low MOV ISP_CONTR, #WAIT_TIME ;Set wait time ORL ISP_CONTR, #10000000B ;Open ISP/IAP function MOV ISP_CMD, #ISP_IAP_BYTE_READ ;Set ISP/IAP Byte-Read command MOV ISP_TRIG, #46H ;Send trigger command1 (0x46) MOV ISP_TRIG, #0B9H ;Send trigger command2 (0xB9) NOP ;CPU will hold here until ISP/IAP/EEPROM operation complete MOV A, ISP_DATA ;Read ISP/IAP/EEPROM data C T S U C M ;/*Disable ISP/IAP/EEPROM function, make MCU in a safe state*/ MOV ISP_CONTR, #00000000B MOV ISP_CMD, #00000000B ;MOV ISP_TRIG, #00000000B ;MOV ISP_ADDRH, #0FFH ;MOV ISP_ADDRL, #0FFH ;Close ISP/IAP/EEPROM function ;Clear ISP/IAP/EEPROM command ;Clear trigger register to prevent mistrigger ;Move 00 into address high-byte unit, ;Data ptr point to non-EEPROM area ;Move 00 into address low-byte unit, ;prevent misuse ;/*Byte-Program, if the byte is null(0FFH), it can be programmed; else, MCU must operate Sector-Erase firstly, and then can operate Byte-Program.*/ MOV ISP_DATA, #ONE_DATA ;Write ISP/IAP/EEPROM data MOV ISP_ADDRH, #BYTE_ADDR_HIGH ;Set ISP/IAP/EEPROM address high MOV ISP_ADDRL, #BYTE_ADDR_LOW ;Set ISP/IAP/EEPROM address low MOV ISP_CONTR, #WAIT_TIME ;Set wait time ORL ISP_CONTR, #10000000B ;Open ISP/IAP function MOV ISP_CMD, #ISP_IAP_BYTE_READ ;Set ISP/IAP Byte-Read command MOV ISP_TRIG, #46H ;Send trigger command1 (0x46) MOV ISP_TRIG, #0B9H ;Send trigger command2 (0xb9) NOP ;CPU will hold here until ISP/IAP/EEPROM operation complete STC MCU Limited. website：www.STCMCU.com 293 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 ;/*Disable ISP/IAP/EEPROM function, make MCU in a safe state*/ MOV ISP_CONTR, #00000000B MOV ISP_CMD, #00000000B ;MOV ISP_TRIG, #00000000B ;MOV ISP_ADDRH, #FFH ;MOV ISP_ADDRL, #0FFH Fax:86-755-82905966 ;Close ISP/IAP/EEPROM function ;Clear ISP/IAP/EEPROM command ;Clear trigger register to prevent mistrigger ;Move 00H into address high-byte unit, ;Data ptr point to non-EEPROM area ;Move 00H into address low-byte unit, ;prevent misuse ;/*Erase one sector area, there is only Sector-Erase instead of Byte-Erase, every sector area account for 512 bytes*/ MOV ISP_ADDRH, #SECTOT_FIRST_BYTE_ADDR_HIGH ;Set the sector area starting address high MOV ISP_ADDRL, #SECTOT_FIRST_BYTE_ADDR_LOW ;Set the sector area starting address low MOV ISP_CONTR, #WAIT_TIME ;Set wait time ORL ISP_CONTR, #10000000B ;Open ISP/IAP function MOV ISP_CMD, #ISP_IAP_SECTOR_ERASE ;Set Sectot-Erase command MOV ISP_TRIG, #46H ;Send trigger command1 (0x46) MOV ISP_TRIG, #0B9H ;Send trigger command2 (0xb9) NOP ;CPU will hold here until ISP/IAP/EEPROM operation complete U C M Li ;/*Disable ISP/IAP/EEPROM function, make MCU in a safe state*/ MOV ISP_CONTR, #00000000B MOV ISP_CMD, #00000000B ;MOV ISP_TRIG, #00000000B ;MOV ISP_ADDRH, #0FFH ;MOV ISP_ADDRL, #0FFH C T S 294 STC MCU Limited. . d e t i m ;Close ISP/IAP/EEPROM function ;Clear ISP/IAP/EEPROM command ;Clear trigger register to prevent mistrigger ;Move 00H into address high-byte unit, ; Data ptr point to non-EEPROM area ;Move 00H into address low-byte unit, ;prevent misuse website：www.STCMCU.com www.STCMCU.com Mobile:(86)13922809991 Tel:86-755-82948412 Fax:86-755-82905966 Little common sense: (STC MCU Data Flash use as EEPROM function) Three basic commands -- bytes read, byte programming, the sector erased Byte programming: "1" write "1" or "0", will "0" write "0".Just FFH can byte programming. If the byte not FFH, you must erase the sector , because only the "sectors erased" to put "0" into "1". Sector erased: only "sector erased" will also be a "0" erased for "1". Big proposal: 1. The same times modified data in the same sector, not the same times modified data in other sectors, won't have to read protection. . d e mit 2. If a sector with only one byte, that's real EEPROM, STC MCU Data Flash faster than external EEPROM, read a byte/many one byte programming is about 2 clock / 55uS. 3. If in a sector of storing a large amounts of data, a only need to modify one part of a byte, or when the other byte don't need to modify data must first read on STC MCU, then erased RAM the whole sector, again will need to keep data and need to amend data in bytes written back to this sector section literally only bytes written orders (without continuous bytes, write command). Then each sector use bytes are using the less the convenient (not need read a lot of maintained data). C T S Frequently asked questions: U C M Li 1. IAP instructions after finishing, address is automatically "add 1" or "minus 1"? Answer: not 2. Send 46 and B9 after IAP ordered the trigger whether to have sent 46 and B9 trigger? Answer: yes STC MCU Limited. website：www.STCMCU.com 295 www.STCMCU.com Mobile:(86)13922809991 Tel:086-755-82948412 Fax:86-755-82905966 12.4 EEPROM Demo Program (C and ASM) 1. C Code Listing /*-------------------------------------------------------------------------------*/ /* --- STC MCU International Limited ----------------------------------*/ /* --- STC 1T Series MCU ISP/IAP/EEPROM Demo ----------------*/ /* --- Mobile: (86)13922809991 -----------------------------------------*/ /* --- Fax: 86-755-82905966 ---------------------------------------------*/ /* --- Tel: 86-755-82948412 ----------------------------------------------*/ /* --- Web: www.STCMCU.com -----------------------------------------*/ /* If you want to use the program or the program referenced in the */ /* article, please specify in which data and procedures from STC */ /*-------------------------------------------------------------------------------*/ #include "reg51.h" #include "intrins.h" typedef unsigned char BYTE; typedef unsigned int WORD; U C M /*Declare SFR associated with the IAP */ sfr IAP_DATA = 0xE2; sfr IAP_ADDRH = 0xE3; sfr IAP_ADDRL = 0xE4; sfr IAP_CMD = 0xE5; sfr IAP_TRIG = 0xE6; sfr IAP_CONTR = 0xE7; C T S /*Define ISP/IAP/EEPROM command*/ #define CMD_IDLE 0 #define CMD_READ 1 #define CMD_PROGRAM 2 #define CMD_ERASE 3 . d e t i m Li //Flash data register //Flash address HIGH //Flash address LOW //Flash command register //Flash command trigger //Flash control register //Stand-By //Byte-Read //Byte-Program //Sector-Erase /*Define ISP/IAP/EEPROM operation const for IAP_CONTR*/ //#define ENABLE_IAP 0x80 //if SYSCLK