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MartinKeppler

How to disable boot output to uart0?

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Hi guys,

 

I tried to disable console output on uart0 using this guide https://docs.armbian.com/User-Guide_Fine-Tuning/#how-to-toggle-boot-output

But I still get boot output on uart0.

 

Problem is, that I'm using uart0 for a java application. Java application crashes a few seconds after starting. I got the hint, that I should disable console output on this port, to make it working. See here: http://pi4j.com/example/serial.html

I think that's the problem, because if I unplug my serial device from uart0, java app doesn't crash.

 

I'm using Banana Pi.

Kernel is Verison 4.8.12.

Armbian is Jessie 5.24 with desktop.

 

How can I disable the output?

 

Yours,

Martin

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Armbian is a community driven open source project. Do you like to contribute your code?

I think it was discussed before.

UART0 output is used by:

  • u-boot and u-boot SPL (can be disabled only by recompiling u-boot)
  • kernel for the boot output (can be disabled via kernel command line)
  • login prompt (can be disabled with "systemctl disable serial-getty@ttyS0.service")

 

So an easier option may be to use any other UART port

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I think it was discussed before.

UART0 output is used by:

  • u-boot and u-boot SPL (can be disabled only by recompiling u-boot)
  • kernel for the boot output (can be disabled via kernel command line)
  • login prompt (can be disabled with "systemctl disable serial-getty@ttyS0.service")

 

So an easier option may be to use any other UART port

 

One of the most annoying is kernel because it continue to send occasionally message after boot. I use minicom on ttyS0 on a BPI to access console on other board, and those boards don't like at all the command "<0> usb0 no ipv6 router present"

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Thanks Guys.

 

Ok, sounds like it's really better to use uart3, for example.

I also been thinking that this topic was discussed early. I remember I read about, but couldn't find it anywhere.

 

Yours,

Martin

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Good morning,

 

I gave it a try and used uart3 on con3 with tx on pin8 and rx on pin10, but unfortunately there are also boot outputs. 

Next try is to use uart7 on J12 with rx on pin4 and tx on pin6.

 

I will report.

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My throws an excpetion with uart7:

 

java.io.IOException: Failed to SET terminal attribute for the serial port. (Error #5)

 

My is setting /dev/ttyS3 as uart7. Is this correct?

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