Software Timers

RTOS code often contains calls like:

vTaskDelay(1);
xQueueReceive(q, &msg, 10);
xTimerStart(timer, 0);

They all look like “wait for some time”. But RTOS time is usually not continuous, precise, and immediately executed. Many failures come from reading tick, delay, timeout, and software timers as precise real-time behavior.

A safer model is:

hardware clock generates tick
-> RTOS updates tick count
-> expired tasks or timers become ready/pending
-> scheduler decides when code actually runs
-> low power and interrupt masking change this path

So delay 10 ms is closer to “do not run until at least a tick boundary and then wait for scheduling” than “this code will run exactly 10 ms later”.