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Vybrid Silent U-Boot? U-Boot fiddling with devices behind the scenes?

Question asked by Jack Blather on Nov 18, 2014
Latest reply on Dec 1, 2014 by Jack Blather

I have a custom board that is based on the Vybrid Tower. Running U-Boot 2013.07 I have two issues:

 

1) I need U-boot to shut up. How does one do this?

2) U-boot seems to be fiddling with a device when it's just sitting at the command prompt.

 

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First issue: "1) I need U-boot to shut up. How does one do this?":::::

 

I tried:

 

- Changing CONFIG_SYS_UART_PORT in include/configs/vf610.h from "(1)" to another port (e.g. "(2)" ). No joy, Output still goes to UART1. This #define has no effect.

- Doing the suggestions in README.silent. No joy.

- Changing the "stdout" env var in U-Boot to a random string. I get an error when I do this.

- Setting the "silent" env var. No joy.

 

I may also need to prevent U-Boot from initializing the UART. How does one do this? Is there a 'hidden' #define that I need to know about?

 

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Second issue "2) U-boot seems to be fiddling with some devices when it's just sitting at the command prompt":::::

 

It looks like something is changing settings on the port PTA7 (on pin v15) after our MQX/M4 application has been launched and running. We have to set that port back to its correct value every once in a while.

 

I understand that U-boot does not use interrupts at all, is this true?

 

If U-boot does indeed have something that runs periodically via an IRQ), then that could be the culprit.

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