I am not getting envolved in the discussion of what this PBK thing should
be.  I'm only responding about certain points of fact and misconceptions.

> > 4  -  The bootloader uses the hardware UART.  New firmware (except for
the
> > bootloader and the reset vector) can be uploaded into a 16F877 in about
37
> > seconds using 115.2Kbaud.
>
> That's one thing that cannot be done easily with a single processor
design.
> In fact I realize that's a deal killer because if the FT232 USB to serial
> design is used, that rate can be pumped all the way up to 2 Mbits/Sec.

This should not imply, however, that a 16F877 can then be programmed in 2
seconds.  The limiting factor is the time it takes the 877 to write to its
own program memory.  One time I worked out how long it would take to
transfer all the bytes at the full 115.2Kbaud rate, and I sorta remember the
answer was around 5 seconds.  In any case I remember the conclusion was that
the upload time was dominated by the flash memory write time.


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