I'm using Arduino DUE to capture the TTL pulse and converted it into frequency/s. However, as soon as I connected the ground of the pulse generator to the ground of Arduino. The serial monitor just stop working, it doesn't update any readings anymore. I'm not sure why this happens. Does anyone come across this king of situation before?
It sounds like the supposed ground of the TTL logic is not really the ground potential. Could this be? Could you provide schematics or something?
Jonny_LI2410:
I'm using Arduino DUE to capture the TTL pulse and converted it into frequency/s. However, as soon as I connected the ground of the pulse generator to the ground of Arduino. The serial monitor just stop working, it doesn't update any readings anymore. I'm not sure why this happens. Does anyone come across this king of situation before?
I have noticed similar problems myself. Try doing this: before you connect the two grounds, connect each to a DVM and measure the AC and DC voltage between the two grounds before they are connected together. If I am right there is likely an easy fix but do the check first to see if it is the right track...
PE.