How to calculate Tim3 value for 192 KHz and 84MHz clock

[Robmar]

Using Tim3 with 84MHz clock, and need an 192 KHz trigger, for 96 KHz the prescaler is 875-1, clearly half that is a fraction, the calculators mentioned on line no longer work, is there a solution?

[AScha.3]

84M / 874 = 96,11 so...

84M / 437 = 192,22 - 0,1% from 192 . nobody can hear this , so whats the problem?

[waclawek.jan]

Which STM32?

No perfect soution for these numbers. You can dither, but it depends on application if that is acceptable.

If this is auto application, you should've started with a different crystal.

JW

[LCE]

Which STM32 are you using? Maybe you can do something with the PLL?

Or - also depending on the STM32 - use another input for timer clock / the extra I2S clock input.

Otherwise I agree to the above, especially: choose another crystal.

[gbm]

Wrong question. The correct one should be: how to get 192 kHz on my microcontroller. The answer is simple - set the main clock to be a multiple of 192 kHz, like 72 MHz. (72000000 / 192000 = 375).

[Robmar]

Haha yes sure, if only life was so simple. ​Commercial applications use the lowest cost MCU because business is competitive, our application is real-time, so we can't afford to degrade performance that much, but thanks

[gbm]

20% is not much. It doesn't look like a good practice to rely on just 20% performance difference in an application.