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Topic: Small Amount of Voltage Creeping from Pins - That Normal? (Read 410 times) previous topic - next topic

chaost

Hello :)

I have a Mega connected up to a circuit. Some things are not working as expected. I am in the process of troubleshooting but one thing i have noticed is that all of the digital and analogue pins are outputting a small voltage (even ground!). This includes the pins set to input.

Its only about 0.4 volts but i'm pretty sure that can't be right can it? I wouldn't expect the pins to let any voltage creep out unless set to output 5v.

If its not right, then it could be the Mega that has had it - we have been through a lot together including the odd 'mistake'  :smiley-red:

What do you guys reckon?

Many thanks.

Grumpy_Mike

Quote
This includes the pins set to input.

Pins set to inputs will be high impedance so a meter could measure anything from stray pickup. It doesn't men anything.

Pins set to outputs and set to low can have a voltage of 0.6V with 10mA flowing out of it.

chaost

Thanks Mike - Bit of a shame - was hoping the board had busted. Now i know its something to do with my dodgy wiring  :~

kf2qd

Do you have teh ground for your external circuit connected (tied) to the ground on your Mega board? that will cause all kinds of strange things to happen. Depending on what you are driving, you may want to put a resistor from that control point to ground. 1 KOhm is a good place to start. 220 Ohm would probably be minimum.

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