Nownuri wrote: ↑
Wed Jun 27, 2018 9:34 am
I have two questions about the UART pins on RPi Zero W.
1. Are the pins protected against ESD? What would be the rating of the ESD protection, for instance, 15kV?
2. Do you always need to pull-up/down the TX pin? I observed that the RPi does not send data properly when the TX pin is not pulled up or down. I tested this using minicom.
No pull down is needed.
The voltage level of the other device must be 3V3 not 5V. If not 3V3 then a level shift circuit must be used on the RX pin.
There must be a ground wire connected between RPi and device.
Unless specified otherwise my response is based on the latest and fully updated Raspbian Buster w/ Desktop OS.