Synth-DIY Yahoo! Groups Archives

Can you have split ADC usage

2013-05-14 by Dave McLaughlin

Hi all,

 

I have a small board from another project that only has PA0 to PA5 of an
ATMega324P brought out and I need to do the following:

 

1 pulse input (PA0/INT0)

2 ADC input (PA1 and PA2)

1 digital output (PA3)

I2C bus (PA4 and PA5)

 

Is it possible to use the ADC on PortA on only 2 channels, ie mixed digital
and analog like this?

 

I have tried but the 2 ADC channels (1 and 2) are always returning a 1023
bit reading. 

 

I have disabled the digital on those 2 channels.

 

 

Is this at all possible or am I going to have to build a small external ADC
board to do this over I2C?

 

 

Dave.

---

Very funny Scotty, now beam down my clothes.

---

 



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Re: [AVR-Chat] Can you have split ADC usage

2013-05-14 by John Samperi

At 12:23 PM 14/05/2013, you wrote:
>Is it possible to use the ADC on PortA on only 2 channels, ie mixed digital
>and analog like this?

Yes, do it all the time.

>I have tried but the 2 ADC channels (1 and 2) are always returning a 1023
>bit reading.
>I have disabled the digital on those 2 channels.

Have you also disabled the pull up resistors?

Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495
Website  http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************

RE: [AVR-Chat] Can you have split ADC usage

2013-05-14 by Dave McLaughlin

Yes, pull ups disabled

 

Even if I pull the input to GND it still reads 1023

 

I'll be back on it tonight so will try a few other ideas.

 

Dave.

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From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of John Samperi
Sent: 14 May 2013 09:57
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Can you have split ADC usage

 

  

At 12:23 PM 14/05/2013, you wrote:
>Is it possible to use the ADC on PortA on only 2 channels, ie mixed digital
>and analog like this?

Yes, do it all the time.

>I have tried but the 2 ADC channels (1 and 2) are always returning a 1023
>bit reading.
>I have disabled the digital on those 2 channels.

Have you also disabled the pull up resistors?

Regards

John Samperi

********************************************************
Ampertronics Pty. Ltd.
11 Brokenwood Place Baulkham Hills, NSW 2153 AUSTRALIA
Tel. (02) 9674-6495
Website http://www.ampertronics.com.au
*Electronic Design * Custom Products * Contract Assembly
********************************************************




 
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