T

Hi there, I have moved your question to the Cortex-M forum. Many thanks.

Do it in software!

Dougster said:

How could such long period be implemented?

As 42Bastian Schick suggests - use software.

Have a timer configured to some suitable time interval - or "tick" - and then count the ticks to give the delay you require.

This is a general approach - not specific to Cortex-M; eg, it's how the Arduino millis() works ...

In fact, it's not even specific to microcontrollers - it's how mechanical clocks have worked for centuries!