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Topic: Digital Write D0 & D1 LOW doesn't drive the pin low (Read 2 times) previous topic - next topic

retrolefty

What leds? wired to ground or +5vdc?
Led wired to output pins also require resistors, what value?

;)

So does rev 1 have some new behavior about pins 0 and 1 ? Or is it another opiboot feature?


Nick Gammon

Are these questions addressed at me?

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What leds?


Normal cheap ones. Forward voltage 1.92V.

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wired to ground


Yes.

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Led wired to output pins also require resistors, what value?


150 ohms.

I'm measuring 2.67 mA out of D0.

And 16.55 mA out of D1.

retrolefty


Are these questions addressed at me?

Quote
What leds?


Normal cheap ones. Forward voltage 1.92V.

Quote
wired to ground


Yes.

Quote
Led wired to output pins also require resistors, what value?


150 ohms.

I'm measuring 2.67 mA out of D0.

And 16.55 mA out of D1.


Just a tease, the real question is about the need for a serial.begin before pins 0 and 1 function as output pins? is that a new behaviour with rev1 or what?


Nick Gammon

Well I think that the Serial.begin takes over the pins. With it out you get to use them as you will.

Bear in mind the gentle pull-up of the USB chip. That is going to put some current on those pins. I think I commented on that before.

retrolefty


Well I think that the Serial.begin takes over the pins. With it out you get to use them as you will.

Bear in mind the gentle pull-up of the USB chip. That is going to put some current on those pins. I think I commented on that before.


Ok, I remember now the 1k series resistors to a signal output and signal input pins of the serial converter.

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