PIC Simple Question

The A (or B) versions that I have seen are just updates of the original chip. They usually involve a "shrink" to a newer manufacturing process and have fixes for errata found in the earlier chip. Other than attention to the errata, I am not aware of anything that the programmer needs to be concerned with. Sometimes the new version may have different errata which may be of more concern to a specific application than what was in the earlier version.

The 16F84A datasheet will tell you.

A small suggestion: don't multipost. I answered your message in another newsgroup sci.electronics.basics. But here it is again in comp.arch.embedded.

The question is appropriate to both groups. However by posting the same message individually in both groups you now split your answers, and readers such as myself now have to read it twice.

Just a friendly suggestion. When you get a chance take a read of my response in the ...basic newsgroup.

BAJ

the A version of any PIC chip is kind of like an update.

e.g. 16F628 and 16F628A

you always go for the A version... unless u are a complete wierdo.

As someone said earlier, the best way to tell is to look at the datasheets and compare. Some chips have added features as well. The only way to really tell what is different is to compare the datasheets.

The other difference you may want to look at is the prices. Later versions of chips are generally priced lower. This gives manufacturers an incentive to do the work necessary to update their design to accept the later chip, or the work to make sure that no changes are required. OTOH, unlike many other chip makers, Microchip will generally keep making the older chips so long as there is sufficient demand, so it might be cheaper to buy the more expensive chips than do the engineering work, in some cases.

Best regards, Spehro Pefhany

Or unless you read the data sheet. The 16F628A has different programming specs than the 16F628. A bitch when it is cheaper but can't be programmed by the older models of the PicStart +. Some of the A versions of the 16F87X series also have different programming specs.