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.
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.