In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Chong wrote:

With the flag checking, I have to put the flag check into each byte polling subloop. With flag checking at only one point in the main loop, the ATN interrupt or mode switch interrupt wouldn't be acted on until a byte polling subloop aborts the sequence check.

I guess I'm making a bit much ado about nothing. 5x oversample is not a bad margin of oversample with the flag checking in each subloop. As it stands, my data logger which tells me what sequences to look for is sampling at 5x oversample anyways. If I'm willing to accept that my measurement poll is oversampling at 5x, I should accept that 5x oversample is good enough for my device. I have speed paranoia because of inexperience. I got a bit of a shock when I first got a look at the GPIB signal with my crappy dusty steam powered 2MHz o'scope. It's been fun figuring out what tools I need to get into this area then figuring out how to use the things.

Thanks for the idea about checking for a single interrupt flag to catch the interrupt condition in the main subloops to save cycles. Checking the interrupt cause flag after exiting the subloop scan makes good timing sense. I'll set the ISR to set an "Interrupt Occured" flag and an "Interrupt Cause" flag so the subloops only look for the first flag then the second after exiting the scan routine then resetting them for subsequent use.

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