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I wanted to test if my UART(ttyMT1) is working on my custom board (android project). I have 2 UARTs on my board- ttyMT0 & ttyMT1. UART ttymt0 is my debug port. I have microcom on my board as well.

Test1:

I connected Tx and Rx of ttyMT1 with a female to female jumper wire. Then, on my ADB, i opened microcom for ttyMT1 using the below command:

microcom -s 115200 /dev/ttyMT1

On my debug port (using minicom), ttyMT0, I transmitted to ttyMT1 using echo as shown :

echo -ne 'Hello' > /dev/ttyMT1

and i was able to get the transmitted data print (HELLO) on ttyMT1.

What i wanted to know was, is this enough to verify that my UART ttyMT1 is working fine or do i need to try something else?

Test2:

What i tried again was to connect ttyMT0 to my PC's usb port and ttyMT1 to another USB port of my PC using 2 separate USB to UART connectors. Then i opened 2 minicom, one for each and tried to transmit the same Hello from ttyMT0 to ttyMT1 (ttyMT0 shows as ttyUSB0 on my PC and ttyMT1 as ttyUSB1). But i didn't receive any print on ttyMT1. Why is that?.

p.s. I'm unable to type anything on ttyMT1. I probed ttyMT1 on Oscilloscope and i got the Tx signal but I didn't get anything on my scope when I probed on Rx.

Sourabrt
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1 Answers1

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I think you need to have SELinux permission to access serial port in android. However check this code here to read serial port : https://programmer.help/blogs/serial-port-operation-with-jni-method-under-android.html. It will require you JNI.

mzc
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