Channels and UART

[TSC]

I've set up a separate UART on my XMOS board, which is working fine.

I can print strings by calling

Code: Select all

my_printstr(txChan, "This is a string")

Because I have to pass an argument of a chanend, I can only use the my_printstr function in the one thread to which I have passed the chanend using the par statement. Also, I'm aware that memory sharing is not supported in XC.

Is there a way I can access my UART from any thread, like the regular printstr() function?

Thanks

[Bianco]

You can make your UART reading from multiple producer channels i.e.:

Code: Select all

int main() {
  chan c0, c1, c2;
  
  par {
    uart(c0, c1, c2);
    producer(c0);
    producer(c1);
    producer(c2);
  }
  
  return 0;
}

[TSC]

Thanks Bianco. I just wish I could use my own printstr from any thread with the ease of the built-in version.

I suppose I'll have to do something like you suggest, with select and case statements around the chanends in the UART.

[lilltroll]

There is a ptrintstr :> uart module to download at https://www.xmos.com/applications/utili ... og?ver=all
I have tested it in putty on the host. (If I understand the question)

DESCRIPTION:

This package contains a logging server that redirects print statements
over uart or over an XC channel.

[TSC]

EXACTLY what I wanted!

I just replaced my old UART code with the XLOG library, added a TX pin and updated the function names and everything works.

To think of all the time I spent getting the old UART working at all, and then thinking of ways to print without passing a chanend argument... when I could have just used XLOG.

It looks like XLOG does some very clever stuff grabbing and releasing channel ends as required. I had an idea something like that was needed, but didn't really know how to do it.

Huge thanks lilltroll, and good job whoever wrote the library.