Systick using non-standard timer

[doceme]

Would it be possible to implement a systick timer with a timer peripheral that is not 16 or 32 bits?

For example, on a chip that doesn't have a systick interrupt, if I wanted to use an RTC peripheral that has a counter resolution of 24 bits, could I still use it's periodic interrupt handler to call osalOsTimerHandlerI() and simply ignore the overflow that happens at 0xFFFFFF? As long as I continue to get periodic interrupts at the desired systick frequency, it seems like I could still define OSAL_ST_RESOLUTION as 32 and typedef systime_t to uint32_t. From what I can tell, the systick time is stored in a variable and incremented on the call to osalOsTimerHandlerI(), but the timer peripheral's counter register is never checked to get the systick time. Does that make sense or am I missing something?

[Giovanni]

Hi,

It is possible to use any kind of timer for systick regardless the system time width. The Cortex-M port uses the Systick timer which is 24 bits wide.

The timer width must match the system time width ONLY if you want to use the tickless mode.

Giovanni

[doceme]

Makes sense. Thanks!