Hi - My blinking light was running at half speed, and I assumed I'd set up the microprocessor clock wrong. After a couple hours checking all the clock configuration options, I found a small 2x error in the port.c timer setup... Here's the fix:

    // DRN: Timer clock input is system clock >>> DIVIDED BY 2 <<<
    // DRN: See DS39704A-page 14-6: bit 1 TCS:
    // DRN: Timerx Clock Source Select bit: 0 = Internal clock (FOSC/2)
    // DRN: line below fixed to reflect this...
    const unsigned long ulCompareMatch = ( ( (configCPU_CLOCK_HZ/2) / portTIMER_PRESCALE ) / configTICK_RATE_HZ ) - 1; // DRN
    // DRN: Was:    const unsigned long ulCompareMatch = ( ( configCPU_CLOCK_HZ / portTIMER_PRESCALE ) / configTICK_RATE_HZ ) - 1;

Note 1: the CPU clock on PIC24F is typically 32MHz, but the instruction clock is always 1/2 this value. The timer input takes the CPU clock/2.
Note 2: The CPU clock can be reduced in "Doze Mode" power-saving - this is not provided for in FreeRTOS.

Hope this is helpful !
Best Regards, Dave

That is curious - I'm sure I would have noticed that. Can you tell me which PIC part number you are using. Thanks.

Regards.

I'm using the PIC24FJ32GB004.
The documentation for the timer module for PIC24 family is here: http://ww1.microchip.com/downloads/en/DeviceDoc/39704a.pdf
See section 14.3 Register 14-1: TxCON: Type A Time Base Control bit 1
The clock definitions for these parts are a bit confusing:
CPU clock is 32MHz, also feeds peripherals (excepting USB).
Instruction clock is always half this at 16MHz (unless further divided in DOZE low-power mode).
Hope that helps,
Thanks,
Best Regards, Dave