AVR-Chat

Ciao
test the reference for stability. I use reference generator diodes, very stable and decoupling it from DC source.
 

Mauro Zanin
Logic Data

> To: AVR-Chat@yahoogroups.com
> From: wagnejam99@comcast.net
> Date: Fri, 26 Oct 2012 08:49:04 -0700
> Subject: Re: [AVR-Chat] Apparent non-linear output from ADC
> 
> How have you supplied AVcc? What are you using for reference? Does the reference have a bypass capacitor?
> 
> Jim Wagner
> Oregon Research Electronics
> On Oct 26, 2012, at 8:03 AM, Dave McLaughlin wrote:
> 
> > Hi all,
> > 
> > I have an ATMEGA32 and I am using the ADC to measure the power supply that
> > is connected to the device.
> > 
> > Having done a similar thing with other processors, I am stumped by what I am
> > seeing with the AVR device.
> > 
> > I have a potential divider on the input so that I can measure up to +32V
> > 
> > I have a 10K resistor to ground with a 56K resistor in series with the +
> > supply I want to monitor. The ADC in the datasheet suggest an input
> > resistance of 10K is the ideal load.
> > 
> > When I measure and do a calibration of the ADC at +24V I get a good reading.
> > I now set the supply to +12 and I get a reading of +1V above this.
> > 
> > I am busy taking readings to see if the readings are linear.
> > 
> > The ADC ref is a nice clean +5V from the supply (I am assuming ratiometric
> > on my design)
> > 
> > Has anyone any clues to why I am seeing this from the ADC?
> > 
> > Cheers
> > 
> > Dave.
> > 
> > ---
> > 
> > Very funny Scotty, now beam down my clothes.
> > 
> > ---
> > 
> > [Non-text portions of this message have been removed]
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
> 
> 
> 
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