From: Alan Pearce <kiwiantipodean@googlemail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Mon, 5 Oct 2020 05:30:50 -0700
Subject: Re: [EE] Using a microcontroller as a peripheral?
Thread-Topic: [EE] Using a microcontroller as a peripheral?
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Just been looking into this myself. Check out the enhanced mode of the
parallel master port. That allows 4 addressable locations that make up
one 32 bit word inside the PIC32. it is described quite succinctly in
the FRM chapter.

On Mon, 5 Oct 2020 at 13:22, Neil Cherry <ncherry@linuxha.com> wrote:
>
> On 10/5/20 1:56 AM, madscientistatlarge wrote:
>
> > It depends on what you consider "a peripheral chip", i.e. embedded and =
controlled by an
> > external cpu, or do you mean using as a peripheral for some special fun=
ction (like the
> > soft power control on motherboards).  Do you include things like ethern=
et cards that
> > handle checksums/encryption to unload the main cpu?  And of course the =
PIC
> > microcontrollers were originally for I/O expansion of other micros or p=
ossibly larger
> > systems with a higher end cpu?  Burglar alarms with central monitoring =
would also
> > likely be included if they are not ancient (I.E. the burglar/fire alarm=
 has a micro,
> > and the Monitoring station uses desktops and/or servers for the monitor=
ing).
>
> My apologies, I did make that way too vague. Let me add specifics. I want=
 to use a PIC32
> as a peripheral chip like an 8255 and a 6850 and interfacing that to an e=
xisting
> microprocessor chip as a 6502, 6809 or Z180. I happen to have these board=
s, which is
> why I'm selecting these. This would be a parallel, 8 bit interface with a=
ddressing
> and control for accessing registers. I'm trying not to rewrite the firmwa=
re on
> these old boards.
>
> And yes I do see the irony of taking a chip infinitely more powerful than=
 the main
> CPU and turning it into a peripheral. But I want to start off with simple=
 (the
> 8255) and work to more complex (video chips) which really need to connect=
 to HDMI
> now.
>
> Oh, this is a side project. Not something for work.
>
> So far my Search-fu has me running running into the peripherals of the MC=
U not
> the MCU a peripheral of the CPU.
>
> --
> Linux Home Automation         Neil Cherry       ncherry@linuxha.com
> http://www.linuxha.com/                         Main site
> http://linuxha.blogspot.com/                    My HA Blog
> Author of:      Linux Smart Homes For Dummies
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
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