[sdiy] MIDI too fast?

Magnus Danielson magnus at rubidium.dyndns.org
Wed Jun 16 00:14:43 CEST 2010


On 06/15/2010 09:22 PM, Ingo Debus wrote:
>
> Am 15.06.2010 um 20:49 schrieb ASSI:
>
>> Well, each time a MIDI byte arrives the Poly gets an interrupt. The
>> hardware interrupt causes the CPU to save its 8 registers on the
>> stack.
>>
>> Thus, the stack grows and grows and grows until it reaches right down
>> into the top of the patch storage.
>
> So an interrupt service routine can be interrupted by an interrupt from
> the same source and of the same priority? Strange.

Yes, unless you block it.

Nobody can play so fast that it gets back-to-back (ducks).

It's an easy enough mistake to do. Interrupts has a habbit to interrupt. 
If you want to protect your interrupt processing you have to protect 
yourself. Re-entrant interrupt-processing can work if you know you won't 
trash the cash and you protect the key things. It may or may not do what 
you want thought.

Cheers,
Magnus



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