On 22.07.21 13:31, Otto Moerbeek wrote: > On Thu, Jul 22, 2021 at 01:23:15PM +0200, Sven Seeberg wrote: >> [...] >> >> Has someone successfully used the serial device? Any hints? > > /dev/cuaU0 is for USB connected serial devices. From the demsg, you > should be able to figure out you are suppose to use a com(4) > interface. The device wil then be /dev/cua00 (or higher number).
Thanks. I thought I had tried this, but the different hardware revisions and all the different problems confused me. Here's the summary of my findings: 3B: UART works for setup and as tty in normal boot, Ethernet works as well, USB keyboards do not. After completing the network configuration, SSH can be used. HDMI monitors work after setting the tty to fb0 in the boot options. However, the serial device is not available even after freeing it in the boot options. All devices (cua00 to cua0b, cuaU0 to cuaU3) say they're not configured. I expect that a little trick could fix this, but I have now idea how to. 3B+: Serial device works, but USB/Ethernet does not. Therefore when taking away the tty via com0, there is no way of interacting with the OS. While using the tty, I get a "device busy" when trying "cu cua00". Definitely the least useful option. 4B: Serial device does not work. However, the network interface and USB work fine. I attached an USB UART adapter, which works. That allows interacting with the Pi with normal keyboard + HDMI monitor, SSH, and UART. Currently, I think this is the "best" setup. Cheers
