Serial port does not accept input; only outputs boot sequence and shows login prompt

Autonomous Machines Jetson & Embedded Systems Jetson Orin NX
1

I have connected a FTDI TTL-232R-3V3 USB to UART Cable with +3.3V TTL Level UART Signals cable to an Orin Nano, using only the TX and RX lines. Minicom and PuTTY (both with no flow control) running on Ubuntu 22.04LTS nicely show the entire boot sequence, ending with a login prompt - BUT I can’t login; typing has no effect using either appt. Is this the expected behavior?

Minicom configuration:

Welcome to minicom 2.8                                                                        
                                                                                              
OPTI+-----------------------------------------------------------------------+                 
Port| A -    Serial Device      : /dev/ttyUSB0                              |                 
    | B - Lockfile Location     : /var/lock                                 |                 
Pres| C -   Callin Program      :                                           |                 
    | D -  Callout Program      :                                           |                 
    | E -    Bps/Par/Bits       : 115200 8N1                                |                 
    | F - Hardware Flow Control : No                                        |                 
    | G - Software Flow Control : No                                        |                 
    | H -     RS485 Enable      : No                                        |                 
    | I -   RS485 Rts On Send   : No                                        |                 
    | J -  RS485 Rts After Send : No                                        |                 
    | K -  RS485 Rx During Tx   : No                                        |                 
    | L -  RS485 Terminate Bus  : No                                        |                 
    | M - RS485 Delay Rts Before: 0                                         |                 
    | N - RS485 Delay Rts After : 0                                         |                 
    |                                                                       |                 
    |    Change which setting?                                              |                 
    +-----------------------------------------------------------------------+
3

Hi robtow,

Are you using the devkit or custom board for Orin NX?
What’s your Jetpack version in use?

Do you mean that the RX works but TX not work?

Have you tried to connect TypeC port and using /dev/ttyACM* from your host to log-in?

4

Is your logic level 3.3V? I could see being able to receive signals of too high of a voltage, but failing TX if using a lower voltage, e.g., 1.8V.

5

Are you using the devkit or custom board for Orin NX?
What’s your Jetpack version in use?

Devkit. Jetpack 6, rev 2.

No, I don’t mean “[…] that the RX works but TX not work?”

That’s an inference, not an observable. The observable is that I see the entire boot sequence, but when I type nothing appears. That could be because TX is not working, because Minicom (and PuTTY) is not working, because the Orin’s software is not working, or a number of other reasons… including cabling.
I take it that it is not expected behavior for the debug serial port to be output only. :-)
So… can I force an output from the Orin side, by writing to a port in /dev?

Have you tried to connect TypeC port and using /dev/ttyACM* from your host to log-in?

rob@Coeus:~$ ls -l /dev/ttyACM*
crw-rw---- 1 root dialout 166, 0 Aug 13 14:56 /dev/ttyACM0

I tried that just now, using /dev/ttyACM0. It does not work; altho’ programming the Orin via the USBC port using the SDK manager did work - and the SDK manager currently does detect the Orin as connected. SSH and xtigervncviewer via WiFi work fine.

6

Is your logic level 3.3V? I could see being able to receive signals of too high of a voltage, but failing TX if using a lower voltage, e.g., 1.8V.

The FTDI TTL-232R-3V3 USB to UART Cable with +3.3V TTL Level UART Signals is spec’ed to 3.3V. I have not put a scope on the line, but I could.