When would one would prefer to use an external pull-up resistor vs the internal:
pinMode(fanPin, INPUT_PULLUP);
Dredging through the forums and this site, the commonly recommended value for a pull-up resistor is seems to fall at 10K.
However, the ATmega32U4 datasheet's Table 29-1 says that RPU or "I/O Pin Pull-up Resistor" is between 20K and 50K ohms.
This question asks about internal vs external pull-ups for a simple button, but I'm asking in the general case.
What types of projects would fare better with internal pull-ups, and what type of projects would be better off with external pull-ups?
What are the considerations for preferring one over the other?
At the present, my project is hooking up an AM2302 / DHT22 temperature sensor.
OUTPUT_PULLUP
? Pulling an output high doesn't make a lot of sense. – tkausl Feb 12 '19 at 10:29OUTPUT_PULLUP
doesn't exist. Edited. – Tom Hale Feb 13 '19 at 2:28