Pin Reset is slow?

ItsMeNick

Here is my simple code:

Main:
LOW led
IF PIN6 = 0 THEN Main
HIGH led
GOTO Main

When I put +5V to Pin6... the led lights as it should.
However, when i take the +5 away, it take about a second for the led to finally turn off.

What am I doing wrong?
Thanks,
-Nick

Jonathan

Nick,

Sounds like you need a 10k or so resistor tied to ground. This is ususally called a "pulldown" resistor. It will make the LED turn off correctly by making sure that the pin reads 0 as soon as yu remove Vdd.

Jonathan

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www.madlabs.info - Home of the Hydrogen Fuel Cell Robot

ItsMeNick

Thanks Jon... I'll get to radioshack and give it a try!

Jon Williams

Jonathan is right: you need a pull-up or pull-down on any input pin -- if you let it float then the results will be unpredictable. You might want to have a look at our "What's A Microcontroller?" text.

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Jon Williams
Applications Engineer, Parallax