I installed and was happily running OpenBSD on my RockPro64 v2.1 for many months. At some point I needed to wipe and reinstall everything. When I attached the serial console as usual, I realized that I was only ever able to get serial output FROM the board, but was no longer ever able to send any serial TO the board.
I have performed all of the expected troubleshooting steps many, many times to figure out what the heck I'm doing wrong:
At this point I'm starting to think that I must either have inadvertently shorted the UART RX pin to something bad and blown the OC/OV/ESD protection in the silicon, or maybe there is even a manufacturing defect.
As my next debugging step I was going to start writing firmware to manually read the RX pin and see if it picks up signal changes, but I wanted to check with folks here and see if anyone has encountered this and/or if someone can suggest an easier debugging strategy.
Thanks much!
I have performed all of the expected troubleshooting steps many, many times to figure out what the heck I'm doing wrong:
- rechecked TX, RX, and GND connections
- rechecked serial terminal baudrate and settings (correct because I'm getting good serial output)
- swapped out different FTDI USB-serial cables
- confirmed I was able to use the same FTDI cable to send and receive on a different SBC
- connected both TX and RX lines to an oscilloscope (with serial decoding) to monitor that I was, indeed, sending and receiving valid serial data to/from the board
At this point I'm starting to think that I must either have inadvertently shorted the UART RX pin to something bad and blown the OC/OV/ESD protection in the silicon, or maybe there is even a manufacturing defect.
As my next debugging step I was going to start writing firmware to manually read the RX pin and see if it picks up signal changes, but I wanted to check with folks here and see if anyone has encountered this and/or if someone can suggest an easier debugging strategy.
Thanks much!