Configure RTOS tick under 1ms versus portTICK_PERIOD_MS

simointe wrote on Monday, June 13, 2016:

(TMS570LC4, nested interrupt, C++, FreeRTOS V9.0.0rc2, compiler TI v5.2.7, rtos running ok).


#define portTICK_PERIOD_MS    ((TickType_t) 1000 / configTICK_RATE_HZ)

where tickType_t is unsigned long, it means that 1KHz is the maximum frequency I can setup the tick ?
portTICK_PERIOD_MS seems to be used in many places.

rtel wrote on Monday, June 13, 2016:

portTICK_PERIOD_MS is not used ANYWHERE in the FreeRTOS source code, it
is only provided as a convenience, and in fact, its use is not
recommended now as the pdTICKS_TO_MS() macro should be used in its place.

FreeRTOS V9.0.0 (not the release candidate) allows pdMS_TO_TICKS() to be
overridden, should the default implementation not give the accuracy
required (it considers speed more).

portTICK_PERIOD_MS and pdMS_TO_TICKS() is used in a lot of places in
example code and external components, but again for convenience, and
FreeRTOS has no dependency on it.

That all said - it is rarely a good idea to set the tick rate greater
than 1KHz - 100Hz being typical.