Struggled with the subject. I'll try to explain.
I have three devices. I will refer to them as A,B, and C.
Device A will power device C. This will happen through a GPIO level trigger, through some relays etc.
Device B needs to communicate to/from Device C via TTL level UART comms. Minimally, that is 3 lines. TX,RX, GND.
However, device C GND will come through the power switching circuit through Device A.
Should I ultimately connect A and B GND together? B is not my device, and "untrusted".
Thanks for the input.
I have three devices. I will refer to them as A,B, and C.
Device A will power device C. This will happen through a GPIO level trigger, through some relays etc.
Device B needs to communicate to/from Device C via TTL level UART comms. Minimally, that is 3 lines. TX,RX, GND.
However, device C GND will come through the power switching circuit through Device A.
Should I ultimately connect A and B GND together? B is not my device, and "untrusted".
Thanks for the input.