Basically 'A' versions are just later revisions of the chip&sillicon. Usually they Add features such as comparators (aka 16F877A), BUT sometimes they cripple it (aka lowering maximum Timer1 oscilator frequncy from 200Khz to 32Khz for 16F628A, or change in Program memory writting with 16F877A). Generaly code written for nonA versions should run on A version WITH minor editing...
so if i want to get a PIC with as many pins as the 16f877 but with a comparator module, i have to get the 'A' version? i think the 16f628 (not the 16f628A) has a comparator module, right?
so if i want to get a PIC with as many pins as the 16f877 but with a comparator module, i have to get the 'A' version? i think the 16f628 (not the 16f628A) has a comparator module, right?
As Jay has suggested, ALL the 'A' means is that it's a later silicon revision, nothing else! - the later silicon 'may' include slightly different features, and even different technologies, but it doesn't mean anything else specifically.