Resistor value to keep input pin from floating

I have the output pin from one Picaxe 28X to the input pin of another 28X. I understand that the input pin must be connected to ground through a resistor in order to keep it from floating. What is the correct value for the resistor?
 

hippy

Technical Support
Staff member
You only need a pull-up or down to give a valid stable state when what normally drives that input is disconnected. This stops the program from seeing random input which may confuse it. When driving an input from another output you don't need a pull-up or pull-down.

You don't need pull-ups or pull-downs on floating pins which are not used, unless you are suffering interference problems or trying to achieve minimal current consumption.

Most pull-up or downs are usually 10K. Why ? No idea. There's probably some electrical explanaton somewhere, but it's a value which doesn't feel too low nor too high.
 
Top