Re: [avr-gcc-list] ATMega128 TWI problems

[Clemens Buchacher]

Hi,

On Sun, May 30, 2004 at 10:35:28AM -0700, Nick Brent wrote:
>  asm volatile ("cli"); //Turn off all interrupt sources

cli()/sei() are defined in <avr/interrupt.h>

> DDRD=0x00;   //set portD to all input
> PORTD=0x02;  //Turn on internal pullups on PORTD

No pull-up for SCL?

> /*------->START TWI Initialization<----------*/
> /* set the I2C bit rate generator to 100 kb/s (see pg. 202 & 206 in Mega128 
> datasheet)*/
> TWSR = TWSR & 0xFC; //TWPS = 0
> TWBR  = 18;   //TWBR = 18
> //SCL Frequency = (CPU Clock Frequency)/(16+2(TWBR)*4^TWPS)
> //CPU Clock Frequency = 16Mhz for MyRobot Brainboard

Set TWPS to 1 (or TWBR to 72) to generate a 100 kHz SCL clock frequency.


In addition, I agree to everything Rune mentioned.

Regards,
Clemens