Re: [avr-gcc-list] Timer0 problem on AVR butterfly

[Ned Konz]

On Feb 10, 2006, at 3:28 PM, Dave wrote:

> Hello All,
>
> I'm having trouble with timer0 on my AVR butterfly.
> I'm trying to start the timer right before a routine
> and read it once the routine is done. I'm hoping to
> print the counted ticks on the LCD, but haven't had
> luck at all. The following is my code:
>
> TCCR0A = 1; // system clock frequency will be used
> TCNT0 = 0; // initial value for timer
> myRoutine();
> t = TCNT0;
>
> LCD_putc(0, t); // write t on digit 0
>
> Is there something wrong with my code? Are there any
> examples you can direct me to? Thank you.

Well, what's t declared as? I assume that it's compatible with TCNT0  
(which is an 8-bit register).

In fact, it's hard to tell what exactly the problem is with just that  
snippet. Also you don't say how you've been unlucky. What happened?  
What did you observe? What steps did you take to test your ideas as  
to what might be wrong?

Of course, a LCD_putc() will just put a character whose code is the  
same as the reading of TCNT0 on the display. And that assumes that  
there is a character that corresponds to that code. If you want to  
see a number, you'll have to do some more work.

And remember that this will only measure time delays up to 255 * the  
clock period. I forget what the Butterfly clock is running at, but

You might want to use Timer1 (though the stock Butterfly code uses  
it), as it's 16-bits.

I assume you've googled for

"avr butterfly" gcc

to find resources.

One I've found helpful is http://www.siwawi.arubi.uni-kl.de/ 
avr_projects/#bf_app

--
Ned Konz
address@hidden