gnupic: Re: PIC Emulator...
Subject:
Re: PIC Emulator...
From:
Matthew Bowles ####@####.####
Date:
2 Mar 2000 22:36:33 -0000
Message-Id: <38BEEB38.C87F36E@dsp.com.au>
####@####.#### wrote:
>
> Matt wrote:
>
> ...
> > I only realised last night, even if we could gain control of the
> > parallel ports pins, and force them bi-directional, we still 10-15 pins
> > short on the 40pin devices.
> >
>
> also nobody will be happy if the port of the expensive new PC is burned by
> shortcut in hardware your trying to emulate.
>
> Even we need some additional pins for interfacing to the PC.
>
> > ...... - there has to be something in the
> > middle..like the XC9532.
> > can we start with trying to get a, maybe an 18 pin 16c71 going.
>
> yes.
>
> > and a theory, and just a theory, on pins.
>
> see for instance PIC16F8X manual, page 21 ...23. If we want to emulate
> we should meet at least the raw specification.
>
Naturally..
> > Could we solve it with
> > something less H/W orientated by using a PIC16F84/C84 to read control
> > words from a gpsim module, that knows how to drive the emulating pins.
> > or we could use a 16c74, for the extra I/o and even contemplate driving
> > the A/D ports. perhaps i'm dreaming without thinking again..
> > As for the control words, we make them generic, like put pin 5 high,
> > regardless of what pin 5 is. this way we don't need to allow for
> > different processors, the decision on what pins should be available is
> > left to the gpemu module. This also removes the nesseccity for a
> > re-programmable emulator control device.
> >
>
> The instantiation of the hardware is another thing, your right we need
> an easy and fast control protocol.
>
> Cause we have to simulate outputs AND inputs (as well as the MCLR-Pin)
> we should reuse the PIC approach with the TRIS and PORT register.
Explain.. I'm a bit lost on that little bit..
> The control language should also implement the PIC instructions for
> writing/reading a whole port-register complete as well as setting/testing
> single pins.
>
> For this we should start with emulating one PORT using maybe a PIC as interface
> hardware.
That is a good idea...
I am all for modularity, reusability (other engineer by-words, blah
blah) so perhaps we could make something that is easily multiplied to do
the whole PIC, but in steps. Such as we get a port going, so make 3 or 5
ports. Get a pin to do A/D, make all channels available. get serial
going, maybe the PSP on some of the 40 pin chips.
>
> > This is my thoughts, pick them to pieces.
>
> ... Done
>
> Bye Axel
Good
