How to precisely measure microseconds with STM32

Fri, 04 Sep 2015 09:41:12 +0000

I received this apparently simply question from a reader of this blog: how can I delay a fistful of microseconds in STM32? That is, how to measure microseconds precisely in STM32?

The answer is: there are several ways to do this, but some methods are more accurate and other ones are more versatile among different MCUs and clock configuration.

Let’s consider one member of the STM32F4 family: STM32F401RE, the MCU that equips the STM32Nucleo-F401RE board. This micro is able to run up to 84Mhz using internal RC clock. This means that ever 1µs, the clock cycles 84 times. So, we need a way to count 84 clock cycles to assert that 1µs is elapsed (I’m assuming that you can tolerate the internal RC clock 1% accuracy).

Microsecond on Carmine Noviello

How to precisely measure microseconds with STM32