>I am in the process of building an altimeter using a PIC and the
>MPX5100A sensor, which is very well suited due to the fact that it is
>fully temperature compensated. Is there any reason for using an
>external A/D converter instead of using something like the PIC16C71
>which has a four channel 8-bit A/D built in (besides the '84 EEPROM
>vs '71 EPROM)??

it depends on the accuracy you want,
8 bit A/D gives you 256 levels, assuming you want a range of (say) 0-25,000ft
this means the resolution is 100ft, and the accuracy is +- 1lsb = 200ft.
If this is good enough for your requirements then the internal A/D is fine
otherwise you have to do a bit better.

Chris Cain

>
>Cheers
>    Roland
>
>