;
	list p=16F84, f=inhx8m  ;Enter device name 
				;printed on the probe
				;connected to your pod.
	include <P16F84.INC>
	
	;RS232 transmit function
	; assume 10mHz clock
	; instruction cycle of .4uS

count    EQU     H'000C'
txreg    EQU     H'000D'
delay    EQU     H'000E'
MCount   EQU     H'000F'


clockrate EQU   10000000
baudrate  EQU   9600
fclk      EQU   clockrate/4
baudconst EQU   .85 ;((fclk/baudrate)- 2)/3
baudhalf  EQU   baudconst >> 2

#define _tx     PORTA, 0
#define _rx     PORTA, 1
	org     0               ;start address 0

	clrf    PORTA
	bsf     STATUS, RP0
	movlw   B'01010'
	movwf   TRISA
	bcf     STATUS, RP0
	bsf     _tx

	nop
	nop
	nop

loop2        
;        movlw   D'10'
;        movwf   MCount
;movlw    'U'
;call    Xmtr
;Loop
;        movf    MCount,w
;        call    Table
;        call    Xmtr
;        decfsz  MCount,f 
;        goto    Loop

call    Rcvr
addlw   1
call    Xmtr

goto loop2

Table
	addwf   PCL
	retlw   ' '
	retlw   't'
	retlw   'm'
	retlw   'X'
	retlw   ' '
	retlw   '2'
	retlw   '3'
	retlw   '2'
	retlw   'S'
	retlw   'R'
	retlw   '*'
	

Xmtr    
	movwf   txreg     
	movlw   8
	movwf   count
	bcf     _tx             ; Start bit
X_next  call    WaitOneBit      ; Wait one bit width
	rrf     txreg, F        ; Output the next data bit
	btfsc   STATUS, C
	 bsf     _tx
	btfss   STATUS, C
	 bcf     _tx
	decfsz  count, f
	 goto    X_next         ; Repeat
	call    WaitOneBit      ; Wait one bit width
	bsf     _tx             ; Stop bit
	call    WaitOneBit
	return

Rcvr
	btfsc   _rx             ; Wait for the start bit
	 goto   Rcvr
	call    WaitHalfBit    ; Wait through half of the first bit
	movlw   8
	movwf   count
	clrf    txreg
R_next  call    WaitOneBit     ; Wait through the previous bit
	bcf     STATUS, C
	btfsc   _rx
	 bsf    STATUS, C
	rrf     txreg, F
	decfsz  count, F
	 goto   R_next
	call    WaitOneBit      ; Wait through the stop bit
	movf    txreg, W     
	return

WaitOneBit
	movlw   baudconst      ; Wait one bit width
	movwf   delay
txbaudwait 
	decfsz  delay, f
	 goto    txbaudwait
	return

WaitHalfBit
	movlw   baudhalf
	movwf   delay
txbaudwaithalf
	decfsz  delay, f
	 goto    txbaudwaithalf
	return


	end