Have several boards with problems keeping time accurately. We calibrate each board in factory test, but some boards have very large errors in the 1 Hz calibration signal and very jittery frequency readings. To make it more interesting, when there i...

Update: Using a USB analyzer shows that we get a one bit shift in the data when we have problems writing to a USB flash drive. It can be the CRC that is bit shifted, and other times it can be the data values that are bit shifted. This sounds like an ...