
Verifying Software with Timers and Clocks - heidibrayer
https://insights.sei.cmu.edu/sei_blog/2016/12/verifying-software-with-timers-and-clocks-stacs.html
======
amckinlay
I've always wondered how to use formal verification to prove software on 8 bit
microcontrollers. There are so many peripherals like PWM/timers/counters, ADC,
UART, and complicated configurations like clock prescalers, self-programming,
and interrupts.

~~~
planteen
Not to mention what the clock source is. PLLs (internal or external) can
become unlocked. RC oscillators have a lot of temperature dependence.

~~~
hermitdev
My most amusing observation of how much this can matter is the obvious obvious
pitch/tone change in rail road alerts (at-grade rail crossing signals) on the
Metra rail lines around Chicago in the winter. There is a noticeable
difference even between 30F and 10F. IIRC correctly (it's been a year since
I've been riding the train in the winter), the "beat" of the signal rapidly
increases at lower temperatures and the pitch also seems to increase.

Edited for clarity.

