12F629

test.asm

;gpasm -p P12f629 test.asm

#include <p12f629.inc>

	__CONFIG    _MCLRE_ON & _CP_OFF & _WDT_OFF & _INTRC_OSC_NOCLKOUT               ;Internal osc.

cblock 0x20
	CNT_A
;	CNT_B
	SAVE_W
	SAVE_STATUS
	txByte
	txBitsLeft
endc


	ORG 0x000
	goto init

	ORG 0x004
	goto isr

FtxByte
	MOVWF txByte
	MOVLW 8
	MOVWF txBitsLeft
	BSF STATUS, RP0 ;Bank 1
	CLRF CNT_A
txWaitBeforeStart
	BTFSS CNT_A, 0 ;Wait Till first (maybe unfinished Cycl) ends
	GOTO txWaitBeforeStart

	CLRF CNT_A
	BCF TRISIO, 0 ;Pull IO LOW
txWaitStartBit
	BTFSS CNT_A, 0
	GOTO txWaitStartBit

clkOutNextBit
	BTFSC txByte, 0 ;Skip if Bit 0 = 0
	BSF TRISIO, 0	;Let IO Float
	BTFSS txByte, 0	;Skip if Bit 0 = 1
	BCF TRISIO, 0	;Pull IO Low

	CLRF CNT_A
clkOutWaitNextBit
	BTFSS CNT_A, 0
	GOTO clkOutWaitNextBit

	RRF txByte, 1
	DECFSZ txBitsLeft, 1
	GOTO clkOutNextBit

	BSF TRISIO, 0   ;Let IO Float

	BCF STATUS, RP0 ;Bank 0
	CALL wait8
	RETURN
	
	
wait8
	BTFSS CNT_A, 4
	GOTO wait8
	RETURN


main
	nop
	SLEEP
	CLRWDT
	MOVLW 0xAA
	CALL FtxByte

	MOVLW 0x55
	CALL FtxByte

	MOVLW 0x00
	CALL FtxByte

	MOVLW 0xff
	CALL FtxByte
	GOTO main

init
	BSF STATUS, RP0	;Bank 1
	;BCF TRISIO, 0 ;GPIO= Output
	BSF TRISIO, 0 ;Just for emulator
	MOVLW b'00000001' ;Set TMR1IE = 1
	MOVWF PIE1
	BCF STATUS, RP0 ;Bank 0

	MOVLW b'11000000' ;Set GIE & PEIE = 1
	MOVWF INTCON

	MOVLW b'11111110'
	MOVWF TMR1H
	MOVLW b'01100101'
	MOVWF TMR1L

;	MOVLW b'00000101' ;Start Timer1
	MOVLW b'00000111' ;Start Timer1 Ext Clock
	MOVWF T1CON
	goto main

isr
	;SAVE VALUES
	MOVWF SAVE_W		;Save W to Memory
	SWAPF STATUS, 0		;Swap Status Nibbles and store in W
	MOVWF SAVE_STATUS	;Save Nibbleswappes Status in Memory
	
	BCF STATUS, RP0 ;Bank 0
	
	BCF PIR1, TMR1IF ;Clear Timer1 Interrupt
	
	BCF T1CON, 0
	MOVLW b'11111110'
	MOVWF TMR1H
	MOVLW b'01100101'
	MOVWF TMR1L
	BSF T1CON, 0

	INCF CNT_A, 1
;	BTFSC STATUS, Z
;	INCF CNT_B, 1
	
 ;	BSF STATUS, RP0 ;Bank 1
 ;	BTFSC CNT_A, 1 ;Goto tx_Float if CNT_A & 0x02
 ;	GOTO tx_Float
 ;	
 ;	BTFSC CNT_A, 2 ;Goto tx_Float if CNT_A & 0x04
 ;	GOTO tx_Float
 ;
 ;	BTFSC CNT_A, 3 ;Goto tx_Float if CNT_A & 0x08
 ;	GOTO tx_Float
 ;
 ;
 ;	BTFSC CNT_A, 0 ;Goto tx_Low if CNT_A & 0x01
 ;	GOTO tx_Low
 ;	
 ;	GOTO tx_Float
 ;tx_Low
 ;	BCF TRISIO, 0
 ;	GOTO end_txS
 ;tx_Float
 ;	BSF TRISIO, 0
;	GOTO end_txS
 ;end_txS
 ;	BCF STATUS, RP0 ;Bank 0
	
	;RESTORE VALUES
	SWAPF SAVE_STATUS, 0
	MOVWF STATUS
	SWAPF SAVE_W, 1		;SWAP REGISTER CONTENTS
	SWAPF SAVE_W, 0		;READ BACK AND SWAP

	RETFIE ;Return from interrupt


	end