vTaskDelayUntil on 16bit Microchip dsPIC33EV128GM104 doesn't work with 16bit ticks

mmr42 wrote on Wednesday, June 15, 2016:

the code I use is based on the example code reduced to the minimum:
2 tasks that make 2 LEDs blink. The task using vTaskDelay(100) works as expected
but the task using vTaskDelayUntil( &xLastWakeTime, xDelayMyTaskms) shows
an unpredictable behaviour with 16bit ticks. With 32bit ticks also vTaskDelayUntil
works on my system.
The last time I used FreeRTOS on a similar uC before was with FreeRTOS7.x
and i believe that it worked that days. But FreeRTOS tasks.c changed a lot in between.
Did anyone else try the 16bit ticks with FreeRTOS9 on a 16bit uC?

Microchip dsPIC33EV128GM104

XC16 (v1.26) compiler
FreeRTOS 9.0


#define configUSE_16_BIT_TICKS            1

Bug description:
vTaskDelay(100); // works as expected
vTaskDelayUntil( &xLastWakeTime, xDelayMyTaskms); // unpredictable behaviour


#define configUSE_16_BIT_TICKS            0

-> Everything is ok.


static void ledTask( void *pvParameters )
    TickType_t xLastWakeTime;
    const TickType_t xDelayMyTaskms = pdMS_TO_TICKS(100);
    int ledStatus = 0;
    /* Remove compiler warnings. */
    ( void ) pvParameters;

    /* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
    works correctly. */
    xLastWakeTime = xTaskGetTickCount();
    for( ;; ) {
        vTaskDelayUntil( &xLastWakeTime, xDelayMyTaskms);
        //vTaskDelay(pdMS_TO_TICKS(500) );
        if (ledStatus) {
            LED1 = 0;
            ledStatus = 0;
        else {
            LED1 = 1;
            ledStatus = 1;


rtel wrote on Thursday, June 16, 2016:

For some reason my reply to your post created a new thread, rather than replying here. This was my reply:

Can you confirm that:

  1. Your configTICK_RATE_HZ value is valid for using with pdMS_TO_TICKS
    (it is 1000 or less).
  2. The calculation pdMS_TO_TICKS( 100 ) gives the expected value in both
    cases, and is not over/under flowing in one case.