ATMega48 - ADC0 (PC0) sinking 13mA current?

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Psychlow
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Posted by Psychlow: Sat. Oct 20, 2007 - 08:33 PM
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Any idea why ADC0 would sink 13mA current (verified on the STK500 LED port - LED0 lights up when the PORTC header is connected to the LED header) while the port should be configured for ADC usage with the digital input buffers disabled?

ADC1 is also set up as input and is running conversions, and it is sinking barely any current....

Thanks in advance!

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AVR Microcontrollers, megaAVR and tinyAVR
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Jepael
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Posted by Jepael: Sat. Oct 20, 2007 - 08:50 PM
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Well maybe it is an output? Show the code..

- Jani

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Psychlow
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Posted by Psychlow: Sat. Oct 20, 2007 - 08:59 PM
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Yeah, it's sinking current even when the device is erased.

Busted chip?

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Psychlow
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Posted by Psychlow: Sat. Oct 20, 2007 - 09:02 PM
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What's really odd is that it still does ADC just fine on that channel. It's just that it drops the voltage way down if there's resistance in serial with the voltage source.

Also, if I configure the pin as output, it behaves like a normal output. It will sink and source voltage normally depending on the PINC register.

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Psychlow
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Posted by Psychlow: Sat. Oct 20, 2007 - 09:22 PM
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Yeah, resistance between GND and PC0 pin is about 700 ohms. Resistance between GND and all the other input pins is approximately 4 megaohms (3.94, more precisely.)

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