On Thu, 23 Jun 2005 20:54:48 -0400, you wrote:

>OK, maybe not necessarily limited to pics, but....
>
>So, I remember when I started reading about cpus/mcus a long time agon
>about why banking and paging came about.
>
>Being a beginer, I do find banking and paging to be a nusiance,
>nevermind making code a little more complex to deal with.
>
>But rather than trash the idea, what I wanted to know from the more
>experienced guys in the list is: are there any actual benefits to
>banking and paging?  Is there ever a situation where banking and paging
>actuall makes things easier/better?
>
>Thanks.
>
>
>-Mario

Most of the benefits are in instruction size, however there is an occasional side-benefit - A while
ago  did a keypad controller on a 16C57, which had to control 4 independent keypads, keeping lots of
status & mode info for each keypad. The RAM banking provided a very neat and elegant solution, using
one bank per keypad. Of course if it was 5 keypads it would have bene a different matter..!

RAM banking can occasionally be useful on the more recent parts, allowing a few tricks with
bit-set/clear instructions to do pointer wrapping.

However I think mostly it is a pain, but a necessary evil to get the parts cost sufficiently low. 

In this market, price, availability and peripheral mix are the only significant parameters-
architectural elegance or otherwise comes way down the list.   

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