> On 16 Jun 2007 at 10:23, Peter P. wrote:
>
>> Even at 500kHz data must move 'into' the PIC every 2usec. This is
>> fairly fast esp. if it needs to be de-serialized (not necessarily 8
>> bits wide - I do not remember the width of sector marks and start
>> sequences on floppies) and then written into SRAM.

I didn't see Peter's original post for some reason, but as I said I did this
with two PICs.  The first was the smallest 14 bit core PIC available at the
time, which I think was the 16F627.  The operating loop for this PIC was
under 20 instructions long.  Today I could use a 12F629 (I think that's the
current smallest 14 bit core part) for the first PIC if keeping with the
same overall architecture.  The second PIC was a 16F877, and was the main
controller.

The bit rate is 500KHz, but there is only 1uS (5 instructions) between edges
often.  The 14 bit core (as apposed to the 12 bit core) was essential for
the first PIC.


********************************************************************
Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products
(978) 742-9014.  Gold level PIC consultants since 2000.
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist