; 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 (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