Timer Prescaler Application Clarification

[STuser2]

I did not understand the significance of the number 65536 in the below code

pHandle->OvfFreq = (uint16_t)(pHandle->TIMClockFreq / 65536U);
/* Set fixed to 150 ms */
 pHandle->HallTimeout = 150U;
 /* Compute the prescaler to the closet value of the TimeOut (in mS )*/
 pHandle->HALLMaxRatio = (pHandle->HallTimeout * pHandle->OvfFreq) / 1000U ;

 /* Align MaxPeriod to a multiple of Overflow.*/
 pHandle->MaxPeriod = pHandle->HALLMaxRatio * 65536UL;

My main confusion is how the OvfFreq with division of 65536 help the code to reduce the calculations. According to my understanding if TIMClockFreq = 170MHz then the time is T = 1/170Mhz i get overflow after 65535, so if the number of overflows are OverflowCnt then the total time elapsed will be 65535*1/170MHz*OverflowCnt + Input capture timer registers.

 

[MOBEJ]

hello @STuser2  ,

please in each STM32G4 project where you encounter this code ?

 for a deeper explanation and detailed understanding of this value, I recommend referring to the STM32G4 Reference Manual.Specifically, you can check the section on Advanced-control timers in the following document:

STM32G4 Series Reference Manual (RM0440)

This section thoroughly explains the timer architecture, including the 16-bit timer counter size (65536 counts), overflow behavior, and related timing calculations.

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