AVR-Chat

Hi David,

> Then when the interrupt is serviced it is cleared by the CPU back to
> zero.  BTW, the docs do not say precisely WHEN during the interrupt
> service routine....  Anyway,  the docs say repeatedly that the flag
> can be cleared by the user BY WRITING A 1 TO THE FLAG REGISTER.  I
> have not tried this in real life, but I would have expected that the
> SW should write a zero to the register.  But apparently writing a 1
> to the register that already has a 1 will reset the 1.....

The reason that writing a 1 to it clears it is because if you write a
1 to some other bit in the same register, you're writing a zero to all
of the other bits.

-- 
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/