Thomas Gaffney

A/D Design Question

Discussion created by Thomas Gaffney on Sep 27, 2006
Latest reply on Sep 27, 2006 by bigmac
Hello all,
I am using an A/D converter for the first time on the MC9S12XDP512.  The hw designer wants to perform more measurements than the 24 allotted inputs on this part (~30).  He plans on putting an external mux to select between 8 different inputs that go to one A/D input on the microcontroller.
My question is what is the best way to write software to handle this?  Should I use an interrupt or poll to see when a channel has been converted?  Should I do single-channel conversions and change the channel that is read is each ISR (not even sure if this can be done) or do a sequence and change the mux lines after each sequence is complete?  Finally, is there a better way to do this in hw than the above technique that makes the sw easier that I can tell the hw designer to implement (design is still in the early stages)?
Just looking for ideas because I don't want to reinvent the wheel so I appreciate any comments.