Tx pin problem due to current

Troubleshooting
1

Hi guys, I have accidentally plug the 5v of a circuit in the ground of a Photon and the ground of a circuit in the Tx pin of the Photon. I was wondering if this could have damaged the Photon. The Tx doesn’t seem to work now. This is not impossible that there is an other problem, but I want to know if this could be the problem.

Thanks !

2

This could definetly have damaged your device, but it does not necessarily mean that the whole thing got frazzled.

You might want to check other functionality tho’

You can even test the TX pin with a simple pinMode(TX, OUTPUT); and digitalWrite(TX, testLevel); to see if the GPIO pin is still alive.

1 Like
3

I think the tx pin is 5V tolerant: https://docs.particle.io/datasheets/photon-datasheet/#peripherals-and-gpio

4

Probably not reverse 5V (i.e. -5V) tolerant though.

EDIT: -0.3V https://docs.particle.io/datasheets/photon-datasheet/#i-o-characteristics

Most likely blew a protection diode or FET body diode, so the output will be stuck low.

5

Opps…

6

I have just confirm that the problem comes from the Photon. There isn’t any way to easily repair this I imagine… ?