In SX Microcontrollers, SX/B Compiler and SX-Key Tool, user01 wrote:

My 68HC11 project is complete, but when show the temperature on the LCD it always show 28.5 oC, or in BCD - 00111001. I don't know why. I read the code couple of times to make sure that I didn't make something wrong. Can somebody help me.

This code I took from here: http://www.emicros.com/ds1620.htm and modify it little because it was showing 0 oC

This is fragments of the code:


RSTTEMP	equ	%00100000
I_O	equ	%00001000
SCLK	equ	%00010000




ReadTemperature:
	ldx	#REGBLK
	bset	DDRD,x %00111000
	bclr	PortD,x SCLK 
	bset	PortD,x RSTTEMP 
	ldaa	#$AA

	ldab	#8
ZS:
	bclr	PortD,x I_O	
	lsra
	bcc	NS
	bset	PortD,x I_O
NS:
	bset	PortD,x SCLK
	nop
	nop
	nop
	bclr	PortD,x SCLK
	decb
	bne	ZS

	clr	TempLSB
	clr	TempMSB
	bclr	DDRD,x I_O
	ldab	#8
JJ:
	nop
	nop
	nop
	bset	PortD,x SCLK 
	clc 
	brclr	PortD,x I_O HJ
   	sec
HJ:
	ror	TempLSB 
   	bclr	PortD,x SCLK
	decb	
	bne	JJ

	bset	PortD,x SCLK 
	brclr	PortD,x I_O AD
	ldaa	#1
	staa	TempMSB

AD:
	bclr	PortD,x SCLK
	bset	DDRD,x I_O	
	bclr	PortD,x RSTTEMP
	ldab	TempLSB
	rts




BCD2STR:
	psha
	anda	#$0F
	oraa	#$30
	staa	1,x
	pula
	asra
	asra
	asra
	asra
	anda	#$0F
	oraa	#$30
	staa	0,x
	rts




	ldaa	Str2+1
	cmpa	LastSecond
	beq	NoNewTemp
	staa	LastSecond
	jsr	ReadTemperature
	lsrb
	bcc	Set00
	ldaa	#'5'
	bra	Set05
Set00:
	ldaa	#'0'
Set05:
	staa	Str2+12

	clra
	tba
	ldx     #Str2+9
	jsr	BCD2STR
	clrb
	ldab    TempMSB
	cmpb    #$1
	bne     NoNewTemp
	ldaa    #'-'
	staa    Str2+8

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