Any measurement that needs resolution better than 255 counts.

Barometric pressure measurement for example is expected to be readable from
27.5 to 31.5 inHg with a resolution of 0.01inHg or 0.001inHg. At 8 bits you
only get ~0.016inHg resolution, 12 bits would give you 0.00098inHg
resolution.

Also, if both the A/D's have the +/-1LSB accuracy an 8 bit A/D will
contribute a lot more inaccuracy than the 12 bit A/D.

Paul

>
> This is in fact a class assignment, but it is for a senior-level design
> project in which the object is to design an educational development board
> for Cygnal Integrated Products' 'F020 MCU and provide laboratory
> modules to
> go with it.  Cygnal has expressed interest in a laboratory that would show
> the respective advantages of the 8- and 12-bit A/D (both on-chip).  So far
> our design team has been unable to think of a particular application where
> 8-bit resolution would produce detectably inaccurate results
> compared to the
> 12-bit converter.
>

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads