AVR-Chat

You wouldn't use PWM to do that, you'd simply use the timer to fire the 
ISR at the resolution you want.  For instance, if you want a 1KHz PWM 
and you want an 8 bit resolution then you'd need to set your timer to 
interrupt every (1ms/256).  Turn the LED on at the beginning of the 
cycle and off when you reach the count for the on-time you want.

DLC

Thomas Keller wrote:
>    OK, one guy wrote back and said it wasn't possible, but I don't think 
> that's
> correct, because the PWM can also trigger interrupts.  Again:
> 
>    I need to drive more than 20 mA to an LED being PWMed by an ATtiny25.
> I want to use the PWM module on timer/counter0 to drive an interrupt
> routine that sets and clears, as appropriate, a pair of GPIOs driving my 
> LED
> to ~~30-35 mA.  ( I really don't have the physical room in my 
> environment for
> one more transistor, very very tight environment)
> 
>    Problem is, the data sheet material on this particular issue has me 
> confused,
> not clear on what I should be doing.  Any help?
> 
> tom
> 
> 
> 
>  
> Yahoo! Groups Links
> 
> 
> 

-- 
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Dennis Clark          TTT Enterprises
www.techtoystoday.com
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