printf support when you program PRUs in beagle board AI

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1

Hi

I am just trying to print some values to check if the condition meets the requirement in beagle bone AI board. But it is not happening when I program PRUs.

Do I have to configure UART in PRU to achieve this capability?

please help me crack this, help would be appreciated,

thank you’
sreekanth m.

2

Hi

I am just trying to print some values to check if the condition meets the
requirement in beagle bone AI board. But it is not happening when I program
PRUs.

  I'm actually surprised you don't get some link error if you are using
printf() in a (C/C++) PRU program. The PRUs are not using an OS, so there
wouldn't be anything like STDOUT for a program running in a PRU.

Do I have to configure UART in PRU to achieve this capability?

BB Black example at

appears to have the PRU write the data to shared RAM, and a program running
in Linux reading the values for output. (NOTE: reference to "chapter 13"
applies to the first edition of the book -- it is chapter 15 in the 2nd)
(NOTE: Examples also seem to be using PRUSS driver, and not the newer
RemoteProc

https://processors.wiki.ti.com/index.php/PRU_Debugging#Place_.22printf.22_statements
Note that this also does not use printf() IN the PRU code, but rather in
whatever program was used to load/start the PRU, and it interfaces, again,
by monitoring shared memory into which the PRU has written.

3

Hi Dennis,

Thanks for the reply. I forgot to mention that I get linker erros if i use printf() statements.

4

The PRU Cookbook[1] has an example of using the UART and printf on the PRU[2]. Maybe it will help.

–Mark

[1] https://github.com/MarkAYoder/PRUCookbook
[2] https://markayoder.github.io/PRUCookbook/04debug/debug.html#_uart