[FAQ] TI-RTOS-PROC: How do I use custom output functions with SysMin?

The SysMin module allows users to add their own application specific output function. For example, this can be used to redirect the output to a UART or other peripheral. SysMin buffers data in a circular buffer. When you call System_flush() this data gets pushed to the output function. By default, this output function calls fwrite() (it is actually an internal function used by fwrite in the TI-compiler case) to output the characters to the CIO window in CCS.

Add this to your .cfg file:

SysMin = xdc.useModule('xdc.runtime.SysMin');
System.SupportProxy = SysMin;
SysMin.outputFxn = "&myOutputFunc";

And this output function to your .c file. You can replace the call to fwrite() below with a call to the IO operation of your choice.

#include <stdio.h> // for fwrite()

#include <xdc/std.h>
#include <xdc/runtime/System.h>
 
Void myOutputFunc(Char *buf, UInt size)
{
    fwrite(buf, sizeof(Char), size, stdout);
}

The circular buffer is output via the System_flush() API. You can call System_flush() after you call to System_printf() or you can call it in a background thread at lower priority. Note that your output function is called with interrupt disabled so you should be careful with the amount of time that your output function takes.