.nolist
    #include    "ti83plus.inc"
.list
.org    $9D93
.db    t2ByteTok, tAsmCmp

#define SEND_TIME	37

;*****PROGRAM EXECUTION STARTS HERE

start:
	call	turn_on			;serial line default state
	
	b_call(_RclAns)			;get data from ans variable
	b_call(_ConvOP1)		;get ans data into e
	
	ld		c, e			;send ans data
	call	send_byte
	
	ret						;exit
	
;**************************************************************
;* send_byte-sends a byte over serial
;* input byte is in register C
;* destroys a, b, c
;**************************************************************
send_byte:
	ld		a, c			;flip the byte's bits (because lows mean 1 on serial line)
	xor		255
	ld		c, a
	
	ld		b, 9			;counter
	scf						;start bit
send_byte0:
	jr		NC, send_byte1	;is it a one or a 0?
	nop						;waste time
	call	turn_off		;bring line low (send a 1)
	cp		0				;waste cycles
	cp		0
	cp		0
	jr		send_byte2		;skip the send 0 routine
send_byte1:
	call	turn_on			;bring line high (send a 0)
	nop						;waste time
	nop
	nop
	nop
	nop
	nop
	nop
	nop
send_byte2:
	ld		a, SEND_TIME	;delay time
send_byte3:		;(time-1)*14+5
	dec		a
	jr		NZ, send_byte3
	
	sra		c				;get the next bit into carry
	djnz	send_byte0		;we need to send all bits
	nop						;waste time
	nop
	nop
	nop
	
	call	turn_on			;bring line to default state (stop bit)
	
	ld		b, 255			;make sure we don't send new data too soon
	call	delay
	
	ret
	
;**************************************************************
;* delay-A short delay
;**************************************************************
delay:
	djnz	delay		;13 or 8
	ret					;10
	
;**************************************************************
;* turn_on-sets white wire high
;* destroys a
;**************************************************************
turn_on:
	ld		a, 0D0h		;ld set white wire high
    out		(0), a
	ret
	
;**************************************************************
;* turn_off-sets white wire low
;* destroys a
;**************************************************************
turn_off:
	ld		a, 0D2h		;set white wire low
    out		(0), a
	ret

.end
.end