On Fri, Feb 3, 2017 at 2:00 PM, dwight <dkel...@hotmail.com> wrote: > I once worked with a device that came close to telling you > that U15 was failing. > > It was called a signature analyzer. > It was good as a first pass production tester. >
It required that the device under test be put in a state where the signals had predictable waveforms, since it basically was just computing a 16-bit hash of samples of the waveforms, referenced to clock and start signals. Typically the device under test would be put in a special signature test mode to do that. > It needed a pin bed to match the board under test. > For automated full-board testing, yes. But signature testing was also used with a probe on individual signals for field diagnostic purposes.
