PIC RS232 routine

Sameer Sathe of sameerksathe shares this code:

This is the code to actually enter the code into mcu via USART , it will only accept the code unless & until u only press capital 'S'. Without using any Interrupt , its a poleing type code

;--------------------------------------------------------------------------------------		
USART_REC

		BANKSEL PIR1
		btfss	PIR1,RCIF				; Test for received data flag
		GOTO USART_REC_returns
		BTFSC RCSTA,OERR
		goto overerror                   ; check for over run error
		BTFSC RCSTA,FERR
		GOTO frameerror                  ; CHECK FOR FRAMING ERROR
		movf	RCREG,W					; Store data in W
		MOVWF	HAULT_KEY
	    goto HAULT_DECIDE
	

overerror
	bcf	rcsta,cren	;pulse cren off...
	movf	rcreg,w		;flush fifo
	movf	rcreg,w		; all three elements.
	movf	rcreg,w
	bsf	rcsta,cren	;turn cren back on.
					;this pulsing of cren
					;will clear the oerr flag.
					;enable interrupts.
	goto	USART_REC		;try again...	

frameerror
	movf	rcreg,w		;reading rcreg clears ferr flag.
	bsf	intcon,gie	;enable interrupts.
	goto	USART_REC		;try again...	
		
		
;--------------------------------------------------------------------------------------------
HAULT_DECIDE                        ; CHECK IF THE KEY PRESSED ID 'S' OR RESUME NORMAL SEND DATA FUNCTION
	MOVLW 0X53   ; capital S
	SUBWF HAULT_KEY
	BTFSS STATUS,C
	goto USART_REC_returns
	BTFSS STATUS,Z
	goto USART_REC_returns
	continue to key enter routine

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