isStale function to detect if data has already been read between triggers/syncSampling

[silicondosa]

An isStale(devNum, I/O type, pinNum) function in quickDAQ which returns 1 if values have already been read/write after a trigger call would help see if data is stale and requires resync.

These values need to reset to 0 after each trigger (syncSampling) call and set after read/write.

Will help close an iss #2 in myoSyn library.

[silicondosa]

While this is still a good function to have, it is better to use iss #15 to solve myosyn/iss #2.