BPI-R3 First Boot: Serial port troubleshooting

Banana Pi Router design BPI-R3/R3 Mini(MT7986)
1

How do I get to the the serial port to work on my BPI-R3?

Basically I want to do this.

  • I have my serial port hooked up like this
  • I see /dev/ttyUSB0 populate in dmesg when I plug it in.
  • I’ve connected minicom to /dev/ttyUSB0 @ 115200 8N1 like it says here.
  • I removed the brltty package, which disconnects /dev/ttyUSB0.
  • I’ve dd’d the latest OpenWRT snapshot to an sdcard and put that in the BPI.
  • I’ve tried Hangup and initialize Modem in minicom

No matter what I do minicom reports “Offline” and I see nothing on the screen. I feel like I’m missing something fundamental. I think it’s even booted, because if I plug a cable into the WAN port and listen with tcpdump on the other end I see DHCP requests with Hostname “OpenWRT”. But I want to get the serial boot working so I can copy the image to the eMMC.

2

I figured it out. On the USB to TTL, the TX goes to the RX on the board and visa versa. Not TX<->TX, RX<->RX.

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