On Tue, 10 Oct 2000 14:41:43 -0400, you wrote: >Olin, > >Thanks for the great explanation on the way program memory reads occur = on >the 16F87X chips. > >Here is a question that doesn't seem to be answered by either the = datasheet >or your explanation: > >Given the 'canonical' way to read program memory: > > bsf eecon1,RD > nop > nop > > >what happens if an interrupt occurs during the 'nops' that are being >ignored? > >For writes the datasheet explicitly says they are 'queued' (ie: held off >until after the write completes), but for reads it isn't so clear. Might be safest to disable ints... >I'm guessing that they'll be held off, which has bad things to say about= my >attempt to have a zero jitter timer interrupt. Not necessarily a problem - you can synchronise the read - presumably you know when the timer int will happen, so for example you could wait for it to have finished before doing the read, if if this would take too long, look at the timer value and hold off the read til after the int only if it's close to the value that will cause the interrupt.=20 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.