Olin Lathrop wrote:

>I was surprised to see that you used either 18 pin or 40 pin, but not the 28
>pin.  I find the 28 pin the most useful general purpose package.
>
To tell you the truth, I hadn't really even considered the 28pin devices 
for proto work.  I have historically tried to keep the 28 pin version of 
the '877 around, but only for those cases where I've designed the 
circuit around a '877 and then figured out I only needed the number of 
I/O on the 28 pin for the "production" version.

The stuff I've done has generally fallen into two categories:

1) Really small stuff which you barely need a pic for (RS-232 to LCD 
conversion, etc.), and that the pin count is well defined.   Generally 
these will fit on the smaller 18 pin devices since all I typically would 
need is a TX, a RX, the ICD pins, and a couple of other pins.    There 
isn't enough difference between a 14, 16 or 18 pin PIC for me to even 
think about a smaller device, so I just grab the 'F88.   These are also 
generally things which are pretty well pre-designed before they get put 
into proto.

2) Larger projects for which the pin count is not well defined.  For 
instance, I recently did a project with a LCD, 3 inputs, one output, and 
dedicated ICD pins.  When  This would have probably fit on the 28 pin 
device, but I was considering a few other functions which may or may not 
have fit.   Generally these have been more of a "grab the biggest DIP 
part I have and stick it on the protoboard", then figure out how to 
drive X, Y, and Z with it type project, as opposed to a "I really know 
what I'm doing with devices X, Y, and Z"

The real advantage of the 40 pin parts for me is that I don't have to 
worry about whether or not I have the ports I need in the device I have 
on the board.   Generally the added with of the 40 pin device (although 
it *IS* a pain at times) isn't bad enough to justify the increased risk 
of having to rewire the entire board for the '877 when I figure out I 
need it later.

-forrest
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