DPRG mailing list archives: [DPRG] Processor Communication via ADC

Fri Feb 15 12:37:02 CST 2008

Eric,

You could use a timer/counter in the microcontroller to generate a basic
voltage to frequency converter. Pass the output frequency through an
optocoupler to the next tier so that they remain isolated.

Use the counter in the receiver stage to measure the frequency and there
you have it. It's also something you could measure easily for
troubleshooting with a frequency counter.

Rick

-----Original Message-----
From: dprglist-bounces at dprg.org [mailto:dprglist-bounces at dprg.org] On
Behalf Of Eric Sumner
Sent: Thursday, February 14, 2008 1:31 PM
To: kip at kdream.com
Cc: dprglist
Subject: Re: [DPRG] Processor Communication via ADC

> Well you have to make sure the grounds stay the same.
>  And how accurate are you shooting for?  If you say 8 bits and use a
10
>  bit ADC and DAC then you have a chance.

Yes. 8/10 is exactly the situation that I'm looking at.

>  Why not use PWM?  A lot of processors have built in PWM generators,
and
>  Capture units. You can look at the timing ratio between high and low
or
>  between high and the total cycle. I think your accuracy would be
better.

PWM is certainly another option.  To offset the accuracy gain, there
are two relatively minor disadvantages for my application:
  * I don't need PWM or Input Capture for anything else in the
project, so it requires developing the code separately, instead of
simply integrating it with "existing" code.
  * For bench testing, it is easier to come by a DC voltage source
than a pulse generator.

  -- Eric
_______________________________________________
DPRGlist mailing list
DPRGlist at dprg.org
http://list.dprg.org/mailman/listinfo/dprglist