There are some examples in the documentation that use a macro named portYIELD_FROM_ISR.  I can’t find this macro anywhere.  Can someone explain what I’m doing wrong? Regards, Dave

It depends on which port you are using.  Normally it is defined in portmacro.h.  Sometimes in portasm.s.  These files are in the FreeRTOSSourceportable\[compiler]\[processor] folder.

OK, so it’s not defined for the AVR (or most other ports).  Does that mean I can just use the taskYield macro from the ISR? Thanks, Dave

Your best bet is to look at the sample serial port driver that comes with a demo for the port you are using.  There is one for each port.  Copy what ever that does.