I*m having trouble accessing the serial console for my APU2C4. I've tried 115200 8N1 as well as all speeds from 9600 to 230400, but I'm only receiving gibberish when I plug in the APU. I'm using a USB serial adapter with a CH341 chip. I've tried multiple adapters, cables, and APUs, but the result is always the same. When I plug two of the adapters in with the null modem cable, I do get proper transmission between two terminal windows; when I short pins 2 and 3 on the adapter, everything is echoed properly.
I've ordered an FTDI adapter just in case. Is there any other reason the console might not work properly?
Here's what I'm receiving in 115200 8N1:
$ sc -s 115200 /dev/cu.wchusbserial1420
Connected to /dev/cu.wchusbserial1420 at 115200 8N1, modem status ignored, no hardware handshake