I am able to switch it off by adding the DigitalWrite(13, LOW) in the example sketch.
@Nick - putting Code: [Select]digitalWrite(13, LOW) in the loop without Code: [Select]pinMode(13, OUTPUT) in the setup does not change anything - the LED stays lit.
Hello everybody,I just received my UNO yesterday. I tried the blink example and it works without any problems. I then tried the fade example - the LED on pin 9 fades as it should, but the on-board LED (pin 13) is always on. It is the same with other examples as well (AnalogReadSerial, even BareMinimum).Fade uses a analogWrite() statement that requires it to be used onlywith a digital pins that have PWM output capabilities, pin 13 does not have PWM capabilities. A UNO has PWM only on pins 3, 5, 6, 9, 10, and 11. Is this normal behavior? Shouldn't the on-board LED be turned off?I am able to switch it off by adding the DigitalWrite(13, LOW) in the example sketch.Due to the changes made on Rev3 Uno and mega boards the on board pin13 LED is not longer directly driven by the AVR output pin but rather 'buffered' via a spare op-amp stage. This results in a floating input pin condition for the op-amp which can result in the led being on when it shouldn't be, but it's a rather random thing as the offset input value of the op-amp plays a role. The only way to be absolutly sure that the pin 13 led remains off is to do both a pinMode(13,OUTPUT) and a digitalWrite(13,LOW), best placed in your setup function.Lefty
Do you know what would cause that? I generally only use pin13 as the clk line on my SD card. Hope I didn't short something out. Does this mean that the op-amp is compromised and is the clock going to be out of sync when I do SPI?
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