Jetson nano console have output but no input...

Autonomous Machines Jetson & Embedded Systems Jetson Nano
#1

Hi all,

I got my new jetson nano board, after i prepare a bootable sd card, and connect uart port, i can see boot log via console, but i can’t input anything, seems like RX pin is not working… does anyone noticed this problem?

best regards,
Flynn

#2

Just a guess…perhaps CTS/RTS flow control is enabled on one side, but not on the other. Check your serial console settings and make sure flow control is “off” or “software”.

#3

Just have RX/TX and GND cable connected between Jetson nano and my computer, so i am not using flow control, and it’s little weird to have flow control on uart console port.

Thanks your advice anyway…

#4

The point is that if the software is told to use flow control, but no CTS/RTS is connected, then what you described occurs. Can you check that CTS/RTS is not set in software somewhere?

#5

If CTS/RTS is the problem, then it must be settings on the Jetson nano side, because console can works with the same PC setting, same cable connection on another ARM board.

And i remember, when Jetson nano powered up, i can see c-boot log came out, then u-boot log, then, i should be able to stop auto booting by hitting the keyboard normally, but the thing is, i can’t. So, if CTS/RTS setting is not correct, the incorrect setting happens in c-boot or uboot phase.

#6

And it might be the Jetson side. I have not checked, but this would cause the issue if it is the case.

#7

HW handshaking only affects the transmitter not the receiver. Therefore, if HW handshaking is the issue that’s preventing your PC transmitting data to Jetson, it’s due to configuration of the transmitter (PC) not Jetson (receiver). Make sure HW handshaking is disabled in the terminal SW you’re running on your PC.

#8

Hi Stephen,

I think your explanation is correct, today i happen to find another different type of TTL to USB module, and i try to use that one, then, problem solved!!! the console’s input/output works great.

The module i used before using a CH340 chip, it doesn’t work. The other one is using FT232, and this works. Maybe like you said, CH340 does not configure the transmitter correctly, but i also tried to connect RX and TX pin of that CH340 board, i can see what i type on the screen, so i never doubt the problem is on CH340 chip…

Anyhow i can continue playing my nano board:)

This is CH340
https://detail.tmall.com/item.htm?spm=a230r.1.14.20.217f289aXFT4AA&id=41299186436&ns=1&abbucket=11
and this is FT232
https://detail.tmall.com/item.htm?spm=a230r.1.14.41.47cd289aJG7Wlv&id=43745465406&ns=1&abbucket=11

Thanks.

#9

Hi Stephen,

I think your explanation is correct, today i happen to find another different type of TTL to USB module, and i try to use that one, then, problem solved!!! the console’s input/output works great.

The module i used before using a CH340 chip, it doesn’t work. The other one is using FT232, and this works. Maybe like you said, CH340 does not configure the transmitter correctly, but i also tried to connect RX and TX pin of that CH340 board, i can see what i type on the screen, so i never doubt the problem is on CH340 chip…

Anyhow i can continue playing my nano board:)

This is CH340
https://detail.tmall.com/item.htm?spm=a230r.1.14.20.217f289aXFT4AA&id=41299186436&ns=1&abbucket=11
and this is FT232
https://detail.tmall.com/item.htm?spm=a230r.1.14.41.47cd289aJG7Wlv&id=43745465406&ns=1&abbucket=11

Thanks.

#10