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I'm trying to connect to a STN1110 chip via screen. Unfortunately I only get strange characters as response. enter image description here

My understanding is that this is due to the wrong baud rate. I tried several baud rates I could find for STN1100 (9600, 115200, 38400) but none of them work. Am I missing something? Thanks as always for your help.

Zuendi
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3 Answers3

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It seems like I found the solution. Screen was not the problem and the baud rate 9600 was the right one. After checking the wiring (thanks to a tipp from a budy of mine) we noticed that the ground of the ttl to usb adapter was not properly connected to the STN1110. After I fixed the ground everything worked fine.

Zuendi
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To use 921600 I did the following:

$ setserial /dev/ttyS0 port 0x3f8 uart 16550A baud_base 921600
$ stty -F /dev/ttyS0 921600

Then brought up "putty" and set the baud rate to 921600 connected to /dev/ttyS0.

Then executed an ST command: 

st sbr 921600

Seems to work.

jski
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  • Thanks for the answer. Unfortunately it did not work. Also I don't understand why I have to set the baud rate to 921600. In this tutorial (https://learn.sparkfun.com/tutorials/obd-ii-uart-hookup-guide#obd-commands) they say I have to use the following parameters: Configure the serial connection to 9600 bps, 8 data bits, 1 stop bit and no parity. Still I don't get anything other than question marks. – Zuendi Jan 29 '16 at 08:00
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connect via rs232 set br:9600 (default)

and to show all program protocol

atpps

if want to new br:38400 

atpp 0c sv 68

atpp 0c on

atz

the new connection are br:38400

Giulio Caccin
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Gap
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