What are good practices in I/O programming?

[windozeuser]

Hello board,

I am relatively new to embedded programming and design, and I just wanted to poke the more experienced programmers here for advice on good practices for safe and reliable I/O programming. By this I mean are there standard practices involved for example:

Waiting for a Port pin to go from high to low?

Changing a port from active high to active low?

These are architecture independent questions, for example if there's an igniter attached to a microcontroller that ignites propane gas, and a sensor goes from high to low, and you want to shut down the ignitier and make sure it's off by switching the PORT it's attached to, to low?

 

[arhi]

If you need to handle pin state changes the best way to do so is from interrupts. Different mcu's have different interrupt input pins (for e.g. on pic you can have trigger if any pin on B port change state). You can have a loop that check state of the pins and compare with previous state to detect change and direction of change (rising or dropping edge) but imho interrupt driven application is much better choice when you have to trigger some action by some change on the pin's