Re: MC68HC908GP32CP in-circuit

 To use the regular serial port, you will have to do your own EEROM
programming - the in-built code can only use its dedicated
bidirectional pin.
 See Motorola's AN2183 for the mechanics of programming the EEROM. The
main point is that you cannot execute the programming code from the
EEROM: you must copy it to RAM & execute from there. 
 It never hurts to include some means of recovering should your
programming fail part-way: you now have garbage code in the EEROM: so
how will you rescue your system? Typically, this means pulling /INT to
+9V, so forcing the hard-coded monitor to run. (Probably means a
jumper to isolate /INT from your other logic).
 I found it simpler to reserve the one pin for the Motorola code to
use, & build a separate dongle which plugs on my board when that
feature is needed. The dongle includes a +9V driver for /INT, and a
separate clock oscillator which can over-power the 32kHz crystal. The
other pins that Motorola's monitor needs at defined levels (not used
for data) are handled by assigning them as inputs in my design, &
providing pullup/down resistors as needed.

"spleen" <[EMAIL PROTECTED]> wrote:

:Hiya,
:
:Id like to implement in circuit program for the MC68HC908GP32CP. Ive looked
:into various solutions mostly provided by motorola using either there mon08
:cable or there spgrs cable (not sure if thats correct something like that)
:
:But ideally I would like to create or use a circuit where I could attach in
:my own cable that connects to the serial port, all the circuitry would be
:on-board.
:
:Cheers
:
:greg
:
:
:
: