Objective Development Forums

Problems with ATMega88

2007-08-18T09:24:50+02:00

Fortunately our uni project doesn't require a large number of pins so we can avoid touching PB0-1 altogether. Being of electrical background myself I thought it easier to change the port rather then find out how to disable debugging from the hidkeys code (well assuming that is even what was causing the issues). At least we did get it working, thanks for the support.

Statistics: Posted by Guest — Sat Aug 18, 2007 9:24 am

Problems with ATMega88

2007-08-17T10:56:23+02:00

I've completely overlooked that... PD1 is not a good choice if you compile with debugging enabled or if you otherwise enable the UART transmitter.

If you can ensure that the UART transmitter is off, the driver should work with PD1.

Statistics: Posted by christian — Fri Aug 17, 2007 10:56 am

Problems with ATMega88

2007-08-17T09:25:51+02:00

uah I don't have an account so I can't edit, but that is supposed to say PD1 to PD5

Statistics: Posted by Guest — Fri Aug 17, 2007 9:25 am

Problems with ATMega88

2007-08-17T09:24:10+02:00

We have resolved the problem. I am not entirely sure why, an educated guess would be that the USART was interfering with the D- pin, but after moving D- from PB1 to PB5 and making changes to usbconfig.h accordingly it appears to be working.

Thanks for your help and patience.

Statistics: Posted by Guest — Fri Aug 17, 2007 9:24 am

Problems with ATMega88

2007-08-17T06:41:10+02:00

Hi Christian thanks for your help. I've taken over for the weekend from Stephan and I'll start by a complete rebuild of the original circuit. I will let you know how this progresses and if I can find the error.

Statistics: Posted by Guest — Fri Aug 17, 2007 6:41 am

Problems with ATMega88

2007-08-16T10:56:53+02:00

Sorry, but then I'm out of ideas...

Since the firmware has been tested very well, I would suspect that there is something wrong in the circuit...

Statistics: Posted by christian — Thu Aug 16, 2007 10:56 am

Problems with ATMega88

2007-08-15T23:21:44+02:00

Yes we changed the Makefile to compile for the Mega88 and we use PD1 and PD2 for USB and set DDRD to 0x00. All the code I used is in the original post. I can't provide a debug log.

Statistics: Posted by Stephan — Wed Aug 15, 2007 11:21 pm

Problems with ATMega88

2007-08-15T20:34:08+02:00

The test program does not use the timer: You never clear TOV0 in TIFR0 by writing 1 to it. The loop therefore runs at maximum speed. Otherwise it should output something like 22.888 Hz.

Having 12 MHz on CLKO should prove that the clock is correct, though.

Then we have the remaining questions: Have you initialized the USB pins as inputs? Have you changed the Makefile to compile for the Mega88 instead of Mega8 (the two are not binary compatible). And finally: Can you provide a debug log?

Statistics: Posted by christian — Wed Aug 15, 2007 8:34 pm

Problems with ATMega88

2007-08-15T15:52:37+02:00

I used this test program and measured a frequency of 666KHz.

#include
#include

static void initHardware(void)
{
DDRD |= (1 << DDD5);
PORTD &= ~(1 << PD5);

TCCR0B = 5; /* Set timer to scale at 1024 eg 12MHz/1024/ 256 for
overflow */
}

int main(void)
{
wdt_enable(WDTO_2S);
initHardware();
for(;;){ /* main event loop */
wdt_reset();
if(TIFR0 & (1 << TOV0)){ /* Check for overflow */
PORTD ^= (1 << PD5); /* Toggle pin */
}
}
return 0;
}

/* ------------------------------------------------------------------------- */

I also changed the lfuse to 0x9F to output the clock rate on PB0 and measured 12MHz.

Statistics: Posted by Stephan — Wed Aug 15, 2007 3:52 pm

Problems with ATMega88

2007-08-13T14:28:50+02:00

Can you make a simple test program which outputs a given frequency on a port pin and measure the frequency to make sure the clock rate is OK?

And are you sure you have initialized D+ and D- as input pins?

And, finally, if you enable debug level 2, can you capure the serial output?

Statistics: Posted by christian — Mon Aug 13, 2007 2:28 pm