xavier uart1 on 40pin

Hi NV people

how to send data on uart1?
when i use command to send data, i can’t see any Signal

echo ‘test’ > /dev/ttyTHS0

That would work, but there is some setup which may be required. For example, if your port is set for CTS/RTS flow control, then no signal will appear until CTS is asserted. If two ports are involved, and not just a single port, then both ports would need to have the same settings. The best way to “cheat” for testing the UART is to loopback…connect that port’s TX to its own RX, and its CTS to its own RTS. Check again, and probably there will be some signal.

FYI, “/dev/ttyTHS0” is the same hardware as “/dev/ttyS0”, but using a different DMA-capable driver. This is the serial console, and I would expect putting it in loopback is a bad idea if it is actually a terminal (unless the Xavier changed something I missed, and this might be the case).

EDIT: I checked on the actual serial console. Turns out it is “/dev/ttyTCU0”. See:

grep tty /proc/cmdline