toggle quoted messageShow quoted text
The serial data starts when the 1pps signal goes low. While the 1pps signal is active, there is no serial data. The important instant is the leading edge of the 1pps signal, which is clean.
73 Hans G0UPL
On Sat, Jan 9, 2021, 17:12 Bob M. <wa1mik@...> wrote:
Could that "grass" be when the actual NMEA data is being sent out of the QLG1? It seems to last about 0.5 to 0.6 seconds and might be present while the 1PPS signal is high, but we just can't see it. Could be cross-talk in the cable or on the board itself. Since the amplitude is so low I wouldn't expect it to be picked up by whatever is monitoring the 1PPS signal but anything's possible.