LED problem
Apologies if this is something simple I'm overlooking, but I am working through the What's·a Microcontroller tutorial and I ran across a problem.· When building a LED circuit my LED isn't lighting up.· It did the very first time I tried it, then when I went to write a program that would make it blink once per second - nothing.· Now I can't even get the LED to light at all.· Ideas?
Comments
If you have a MultiMeter (everyone should), check and see if you are getting power during the pulse.
Also what is the program you wrote?
DO
DO
HIGH 14
PAUSE 500
LOW 14
PAUSE 500
LOOP
"It did the very first time I tried it, then when I went to write a program that would make it blink once per second - nothing."
A couple of questions:
Did you breakdown and rebuild your circuit from the first time?
The LED does have a polarity, in the event of rebuilding your circuit, did the LED get reversed?
Are you using a current limiting resistor in series with the LED? If not you could have burnt the LED out.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
If you were using the 470 Ohm resistor, it is highly unlikely that you burnt out the LED. I also noticed that your code uses pin 14.... The likely candidates would be that the
LED is reversed, or you are not connected to p14 (This is the Physical pin 19 on the 24-pin DIP BS2 package)
looking over the obvious... have you checked your battery?
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.