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Re: [avr-gcc-list] measuring uC supply voltage
From: |
E. Weddington |
Subject: |
Re: [avr-gcc-list] measuring uC supply voltage |
Date: |
Sat, 23 Oct 2004 07:15:45 -0600 |
On 22 Oct 2004 at 19:03, JAMIE MORKEN wrote:
> Hi all,
>
> I am trying to figure out the best way to measure the 5V supply voltage for
> an atmega128. I am using the 5V supply as the ADC reference voltage. The
> problem I am seeing is when the 5V supply droops, the reference voltage will
> also droop. For other sensors I need to use the 5V reference voltage. Any
> ideas on how to solve this? Is it possible to switch to the internal 2.5V
> reference while the 5V external reference is still hooked up? Thanks,
>
I don't know about being able to switch over, but FYI, the internal reference
is not all that
accurate. I would suggest using an external voltage reference device, perhaps a
2.5V ref.
Unfortunately, I don't know a part number off hand (I'm more of a software
engineer, not a EE).
HTH
Eric