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Re: [AVR-Chat] Prototypitis

2005-03-01 by Ivan Vernot


----- Original Message -----
From: "Dave VanHorn" <dvanhorn@dvanhorn.org>
To: <AVR-Chat@yahoogroups.com>; <AVR-Chat@yahoogroups.com>
Sent: Wednesday, March 02, 2005 10:22 AM
Subject: Re: [AVR-Chat] Prototypitis



>
> Got it, at least the first half.
> Genuine HomerCode(tm)
>

Doh!
Well at least you found the dumb mistake yourself rather than someone else
pointing out the 'obvious' ;-)

> The vector table needs to be JMPs, not Rjmps, as the JMPs are 4 bytes, and
> Rjmp is two.
> Which means that the int that's been driving me nuts is really T0OV.


_I_ would not trip over such a bug as _I_ let the C compiler worry about
this 'trivial minutae'


>
> That's good because I need T00V, but bad because T0 is running impossibly
fast.
> With the three bits set for prescale select, I've seen TCNT0 jump from A4
> to 7F in ONE instruction.
> Resetting the prescaler isn't helping, and it seems that any prescaler
> value results in the same thing, wether I do it in code, or clicking the
> bits in the ice.
> When this is happening, it's virtually guaranteed that the T0OV flag will
> be set when I exit the ISR.

Is this happeing _after_ you changed youre RJMP to JMPs?

I



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