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I know you are supposed to ground out unused picaxe pins but was wondering if they should be set up as input or output or just leave the unused pins unlabeled.

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This is from the picaxe site.

"On ANY PICAXE where you have pins that can be input or output it is recommended that any tieing-down is done using resistors.


If you accidentally set a pin to Output-mode / high and had it directly tied down to ground then that would be a short circuit.

Or Output-mode/Low and tieing high also gives a short circuit.

Resulting in smoke, tantrums, Mum's credit card and an early bath.


So, care is needed and using a resistor will limit the current and afford some protection. Until you reach Green Belt in PICAXE I would suggest you use a resistor as standard practice - or let it float and see if OK, theoretically it shouldn't make much difference in 99.9% of cases.

It's in your hands."


I think most use 10K to ground, Shouldn't need them on the 20X2 but I had to use them on the 08M. Got to have the Serial in resistor to ground.

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Update: the M2 series of picaxe chips has internal pullups that I used to pull up the unused pins. Edited by johnnydeerhunter

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