majenko:
fungus:
majenko:
"Never assume anything as it makes an Ass out if U and Me"They're CMOS chips, so they use MOSFETs. It's rare for BJTs to be in logic / MCU chips these days.
OK...I retract everything I said so far.
You don't need to retract everything... It's still the case that you can't (or certainly shouldn't) use digital IO pins as ground. Sinks, yes, but not grounds.
that you can't (or certainly shouldn't) use digital IO pins as ground. Sinks, yes, but not grounds.
Well you make that sound like a physical law which should never be disobeyed. Using a digital output pin as a 'switchable ground' can be useful is several situations I have used in the past. Say for being able to dynamically turn power on and off to a low current sensor, or perhaps to control a low current 5vdc single coil latching relay. It's not standard practice of course, and if used needs to be analyzed carefully, but to imply that it is never to be considered as part of a designers tool kit of methods is somewhat simplistic in my opinion.
Lefty