; CC5X Version 3.0E, Copyright (c) B. Knudsen Data
; C compiler for the PICmicro family
; ************ 19. Dec 1999 19:57 *************
processor 16F84
radix DEC
OPTION_REG EQU 0x81
PORTA EQU 0x05
TRISA EQU 0x85
PORTB EQU 0x06
TRISB EQU 0x86
PCLATH EQU 0x0A
INTCON EQU 0x0B
Carry EQU 0
Zero_ EQU 2
RP0 EQU 5
_TxOUT EQU 0
RxD_pin EQU 0
rxBuf EQU 0x0E
timeout EQU 0x0D
idx EQU 0x0C
idx_2 EQU 0x7F
GOTO main
; FILE D:\WINDOWS\DESKTOP\IRV00\SERIAL9.C
;/*
; * 9 bit BitBang Serial routines
; * 19/Dec/1999 JLS
; * (c) 1999 Jose Luiz Pinto Souto
; * souto@cryogen.com
; * CC5x Compiler (http://www.bknd.com)
; * 10 MHz operation
; */
;
;#include <16f84.h>
;
;#pragma update_RP 0 /* OFF */
;
;#define DEF_TRISA 0x00
;#define DEF_TRISB 0x01
;
;bit _TxOUT @ PORTA.0;
;bit RxD_pin @ PORTB.0;
;
;
;unsigned char rxBuf[2];
;
;void Delay_uSeg (unsigned char timeout);
;void TxSerial (void);
;void RxSerial (void);
;
;/*--------------------------------------------------------------------------*/
;void Delay_uSeg (unsigned char timeout) {
Delay_uSeg
MOVWF timeout
;/*--------------------------------------------------------------------------*/
;
; // delay = (3*timeout + 7) * 0.4uS (including call and return)
;
; while (1) {
m001 DECFSZ timeout,1 ; timeout--;
GOTO m001 ; if (timeout==0) {
NOP ; nop();
NOP ; nop();
RETURN ; return;
; }
; }
;
;}// Delay_uSeg
;
;/*--------------------------------------------------------------------------*/
;void TxSerial (void) {
TxSerial
;/*--------------------------------------------------------------------------*/
;
;/*
; ;---------------------------------------------------------------------------*
; ; Transmit 1 start bit Lo, 9 data bits and 1 stop bit Hi at 9600 bps
; ; Byte time = 1.144 mS
; ; Bit time = 104 uS (0.16% error @ 10 MHz)
; ; Input : rxBuf[0] = 9th bit (bit 0)
; ; rxBuf[1] = byte to be transmitted
; ; Output: byte transmitted by serial pin
; ;---------------------------------------------------------------------------*
;*/
;
; char idx;
;
BSF rxBuf,1 ; rxBuf[0] = rxBuf[0] | 0x02; // stop bit added
BCF 0x03,Carry ; Carry = 0; // start bit in carry
;
MOVLW .11 ; for (idx=11; idx; idx--) { // 3*0.4us=1.2us
MOVWF idx
m002 MOVF idx,1
BTFSC 0x03,Zero_
GOTO m003
BTFSS 0x03,Carry ; _TxOUT = Carry; // 4*0.4us=1.6us
BCF 0x05,_TxOUT
BTFSC 0x03,Carry
BSF 0x05,_TxOUT
MOVLW .80 ; Delay_uSeg(80); // (80*3+7)*0.4us = 98.8 us
CALL Delay_uSeg
RRF rxBuf,1 ; rxBuf[0] = rr(rxBuf[0]); // 1*0.4us=0.4us
RRF rxBuf+1,1 ; rxBuf[1] = rr(rxBuf[1]); // 1*0.4us=0.4us
DECF idx,1 ; } // 3*0.4us=1.2us
GOTO m002
m003 RETURN ;}
;
;/*--------------------------------------------------------------------------*/
;void RxSerial (void) {
RxSerial
;/*--------------------------------------------------------------------------*/
;
;/*
; ;---------------------------------------------------------------------------*
; ; Receives 1 start bit Lo, 9 data bits and 1 stop bit Hi at 9600 bps
; ; Byte time = 1.144 mS
; ; Bit time = 104 uS (0.16% erro w/10 Mhz)
; ;
; ; False start bit check
; ;
; ; Start bit hunting timeout = 4*1.283ms
; ;
; ; Input : none
; ; Output : Carry = 1 => success
; ; rxBuf[0,1] = input byte +9th bit
; ; Carry = 0 => error (timeout or stop bit=0)
; ;---------------------------------------------------------------------------*
;*/
;
; char idx;
;
MOVLW .4 ; rxBuf[0] = 4; // 5.135 ms timeout
MOVWF rxBuf
CLRF idx_2 ; idx = 0;
;
; while (1)
; {
m004 BTFSS 0x06,RxD_pin ; while (RxD_pin) // input "high"
GOTO m005
; {
DECFSZ idx_2,1 ; if ((-- idx)==0)
GOTO m004
; {
DECFSZ rxBuf,1 ; rxBuf[0]--;
GOTO m004 ; if (rxBuf[0]==0)
; {
BCF 0x03,Carry ; Carry = 0;
RETURN ; return;
; }
; }
; }
;
m005 MOVLW .40 ; Delay_uSeg(40); // 1/2 bit delay (40*3+7)*0.4us=50.8us
CALL Delay_uSeg
BTFSC 0x06,RxD_pin ; if (RxD_pin)
GOTO m004 ; continue; // false start bit detection
;
MOVLW .1 ; rxBuf[0] = 0x01; // 9 bits counter and reception buffer
MOVWF rxBuf
CLRF rxBuf+1 ; rxBuf[1] = 0x00;
;
; do
; {
m006 MOVLW .81 ; Delay_uSeg(81); // (81*3+7)*0.4us=100us
CALL Delay_uSeg
NOP ; nop(); // 0.4us
NOP ; nop(); // 0.4us
BCF 0x03,Carry ; Carry = RxD_pin; // 1.2us bit read
BTFSC 0x06,RxD_pin
BSF 0x03,Carry
RRF rxBuf,1 ; rxBuf[0] = rr(rxBuf[0]); // 0.4us store and count
RRF rxBuf+1,1 ; rxBuf[1] = rr(rxBuf[1]); // 0.4us
; } // 1.2us
BTFSS 0x03,Carry ; while (Carry==0);
GOTO m006
MOVLW .81 ; Delay_uSeg(81); // (81*3+7)*0.4us=100us
CALL Delay_uSeg
NOP ; nop(); // 0.4us
BCF 0x03,Carry ; Carry = RxD_pin; // stop bit read
BTFSC 0x06,RxD_pin
BSF 0x03,Carry
RETURN ; return; // 100 us availiable
; }
;}
;
;
;/*--------------------------------------------------------------------------*/
;void main (void)
;/*--------------------------------------------------------------------------*/
;{
main
;
CLRF INTCON ; INTCON = 0; // no interrupts
CLRF PCLATH ; PCLATH = 0; // bank 0
MOVLW .1 ; PORTA = 1;
MOVWF PORTA
CLRF PORTB ; PORTB = 0;
BSF 0x03,RP0 ; RP0 = 1; // RAM bank 1
CLRF TRISA ; TRISA = DEF_TRISA;
MOVWF TRISB ; TRISB = DEF_TRISB;
MOVLW .195 ; OPTION = 0b11000011; // Prescaler Timer0 1:16
MOVWF OPTION_REG
BCF 0x03,RP0 ; RP0 = 0; // RAM bank 0
;
; while (1) {
;// RxSerial();
m007 MOVLW .1 ; rxBuf[0]=0x01; // 9th bit
MOVWF rxBuf
MOVLW .170 ; rxBuf[1]=0xAA; // test byte
MOVWF rxBuf+1
CALL TxSerial ; TxSerial();
GOTO m007 ; }
;
END
| file: /Techref/microchip/SERIAL9.ASM, 6KB, , updated: 1999/12/19 21:57, local time: 2025/1/12 16:54,
|
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