ttyTHS0 uart communication problem

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

hello，I set up the a system to collect MCU information through serial port, whitch’s name is “/dev/ttyTHS0”, but I can’t read any data. The system is connected directly to the MCU through a serial port.

The MCU serial port configuration is as follows.
MCU serial configuration

The “/dev/ttyTHS0” configuration is as follows.
stty -F /dev/ttyTHS0 -a
speed 115200 baud; rows 24; columns 80; line = 0;
intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = ; eol2 = ; swtch = ; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
-parenb -parodd -cmspar cs8 -hupcl -cstopb cread clocal crtscts
ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -iutf8
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop -echoprt -echoctl -echoke -flusho -extproc

2

Although ttyTHS0 could be set up as a serial console in Linux, I would be surprised if it works in prior boot stages since those stages only have the legacy driver (which would use ttyS0, but be the same physical UART). However, one glaring problem which shows up is that your windows terminal setup is showing “Baud rate: 460800”, and it should be 115200.

3

Sorry, I posted the wrong picture. In fact, the MCU serial port configuration is as follows. The baud rate is “115200”.
MCU serial configuration

4

If the port is correct, and if the UART is using 3.3V TTL logic level, then the above should work. You might try with XON/XOFF flow control (software only flow control), but I suspect if it were a software flow control problem, then you’d at least have seen some activity and it wouldn’t be completely blank.

If you happen to have an oscilloscope, then perhaps you could watch the RX and TX wires to see if it has a 3.3V square wave during times you expect data.