In SX Microcontrollers, SX/B Compiler and SX-Key Tool, mumcs01 wrote:

So I'm trying to get a M41t82 Real-time clock to work. Its basically like a DS1307 except it supports I2C. I havent used the I2CRead/Write in SX/B yet. But here is my attempt. (Code Below). My problem is I can't seem to clear the Halt Bit (HT) or Oscillator fail bit. I want to verify my code is okay before I look at the hardware, Though I can't imagine my simple hardware setup is bad. Keep in mind, I'm clearing entire bytes in the code below, (Example. the halt bit is in $0C.6 , but I'm just writing zeros to all of register 0Ch, as I'm not using the other bits in the register for anything... I don't think this is a problem.  

[code]
' Blink1.sxb

DEVICE	SX28, OSCHS2,TURBO,STACKX,OPTIONX
FREQ	50_000_000

Led		Pin 	RA.0
RS485Out	Pin 	RA.1
Relay   	Pin	RA.3
RtcSda		Pin 	RC.6
RtcScl		Pin	RC.7
Program Setup_Time

' Constants
RtcId 		CON 	$D0 		
Ack 		CON 	0
Nak 		CON 	1

' Variables
temp		VAR	Byte

' Subroutines
Start		SUB
Read_Time	SUB


Setup_Time:
'Set and clear the Stop Bit	
	i2cstart RtcSda
	temp = RtcId
	temp.0 = 0
	i2csend rtcsda, temp
	i2csend rtcsda, $01
	i2csend rtcsda, %10000000
	i2cstop rtcsda
	pause 500

	i2cstart RtcSda
	temp = RtcId
	temp.0 = 0
	i2csend rtcsda, temp
	i2csend rtcsda, $01
	i2csend rtcsda, $00
	i2cstop rtcsda
	pause 500
	Start 

' Clear the byte with the halt bit
	i2cstart RtcSda
	temp = RtcId
	temp.0 = 0
	i2csend rtcsda, temp
	i2csend rtcsda, $0C
	i2csend rtcsda, 0
	i2cstop rtcsda
	pause 500

' Clear the Oscillator Fail Flag	
	i2cstart RtcSda
	temp = RtcId
	temp.0 = 0
	i2csend rtcsda, temp
	i2csend rtcsda, $0F
	i2csend rtcsda, 0
	i2cstop rtcsda
	pause 500
	return

Start:
	High Led
        Pause 500
	Low Led
	Read_Time
	Goto Start

' Get the second from 01h and display them
' Using RS485 to display output. 
Read_Time:
	i2cstart RtcSda
	temp = RtcId
	temp.0 = 0
	i2csend rtcsda, temp
	i2csend rtcsda, $01
	i2cstart RtcSda
	temp = RtcId
	temp.0 = 1
	i2csend rtcsda, temp
	i2cRecv rtcsda, temp, Nak
	i2cstop rtcsda
	Serout RS485Out, T9600, temp			
	return

[/code]

Any ideas.

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