Hello Jerry,
I can confirm the baud-rate setting in minicom is 115200/8n1.
I just did another experiment with an Arduino Uno flashed with GRBL on it.
When connected via USB to the Jetson Nano, it shows up on /dev/ttyACM0
and the serial communication (via minicom and the Arduino IDE serial monitor) works well.
Here is a sample of an incoming data stream from the Arduino (GRBL Settings):
Grbl 0.9j ['$' for help]
['$H'|'$X' to unlock]
$0=10 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=1 (dir port invert mask:00000001)
...
However when I connect the Arduino to the TX/RX pins of the Jetson Nano:
Pin 6 for ground and pins 8,10 for the UART the Arduino appears on port /dev/ttyTHS1 and the incoming data is corrupt:
Grbl 0.9⸮⸮⸮⸮⸮⸮K⸮⸮⸮⸮⸮u5)mH'|'$X' t⸮⸮]⸮⸮kk⸮դ⸮$0=10 (st⸮⸮⸮[⸮ ͕⸮⸮ (step i[X^KH[⸮֩H⸮I⸮B⸮ѕ⸮⸮⸮⸮⸮vert mask⸮⸮⸮JC!⸮S⸮B"⸮Ɂ⸮⸮⸮ѥ⸮⸮ert mask:LJC!S⸮B⸮ѕ⸮⸮⸮⸮⸮⸮⸮⸮nvert, bJC!RS⸮Bb⸮⸮⸮с⸮⸮⸮́⸮vert, bo⸮S⸮B⸮ɽ⸮⸮⸮⸮⸮⸮⸮⸮vert, boo⸮CS⸮B⸮х⸮⸮́ɕ⸮⸮⸮t mask:00⸮⸮⸮LLJCS⸮r⸮⸮⸮BRչ⸮ѥ⸮⸮⸮⸮⸮iation, mS⸮r⸮⸮⸮B
ɍ⸮ѽ⸮⸮Ʌ⸮⸮, mm)
$1⸮⸮⸮\Kс⸮⸮⸮⸮⸮ͱool)
$20⸮⸮⸮⸮ˋ⸮⸮⸮⸮⸮⸮ͱ⸮ol)
$21=⸮⸮⸮+⸮+ͱ⸮⸮⸮⸮⸮⸮22=1 (hom⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮
$23=0 (h⸮[+K⸮⸮⸮ٕ⸮с⸮⸮k:0000000⸮⸮CS⸮⸮⸮r⸮⸮⸮B⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮Y mm/min)
MOML⸮⸮BB⸮⸮⸮⸮⸮⸮͕⸮⸮Q mm/min)
⸮⸮ ⸮+⸮⸮⸮չ⸮⸮⸮͕⸮
...
The same setup on a Jetson Xavier NX results with a coherent serial data stream
Here is a photo of my wiring;
