In order to maximise the number of analogue inputs on the MSP430F5438A, would the following be possible/advisable:
1.) use P5.0 as Vref+ reference output for external circuitry (e.g. 2.5V), but also
2.) use P5.1 as an analogue input (A9) (in order to maximise the number of analogue inputs). i.e. NOT to have to use P5.1 as Vref- (lower reference) output, but to use AVSS instead, as the intention is to supply 2.5Vnom from the MSP as an external reference.
If possible, are there any disadvantages? It seems rather wasteful for P5.1 to HAVE to act as lower reference if this is just going to switch AVSS anyway. With careful (placement) layout, there should not have to be any performance penalties.