[En-Nut-Discussion] No voltage at ADC VCC

[Harald Kipp]

Daniel wrote:

> I'm using an Ehternut 1.3H.
> I cannot measure the voltage supply at the ADC Connector(Port F) between 
> VCC(Pin 1 or Pin 3) and GND(Pin 4). But I get my 5 volts if I measure 
> between the resistors R13(between VCC and Pin 1/3) and R15(between GND 
> and Pin 4).

Hi Daniel,

Please let me know where you got this info from. It's obviously wrong.

Please check the schematics. Pin 4 is unconnected. Ground is available
at 6, 8, 10...20.

Also note, that you either need to

1. apply a reference voltage at pin 2
2. or place a jumper to pin 1-2 to use the 5V supply as a reference
3. or enable the internal reference (see the ATmega128 datasheet)

For your software
http://www.ethernut.de/nutwiki/Analog_Input
may be helpful.

Harald