[avr-gcc-list] AVR and external ADC

[john . johnson]

[Brandon Tolbert]
I have given up on the use of an external A/D converter in my project and I
was wondering if it would be possible to use the analog comparator found on
my AT90S2313? I am trying to measure voltage change in a remote temperature
sensor. Anyone have an opinion on the usefulness of the analog comparator?
I am new to AVR and microcontrollers in general but have been reading a
great deal lately. Any ideas will be much appreciated. Thanks B

[response]
We have used both. And both work well.
With one external ADCs we had to address it twice, once to start the
conversion, i.e. measurement, and once to read the measurement from the
device.  We have used external ADC devices driven by the AVR SPI port but
the byte wide (8 bit) way this uC peripheral works may give problems with
some devices. We have also implemented a bit-bashed SPI driver to get
around the 8 bit SPI peripheral and to add another SPI bus. Measuring a
voltage change in a "remote temperature sensor" may present problems if the
sensor is some distance from the uC and its internal ADC inputs.

John Johnson
Canada


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