Hi Jinx,

Thanks, I've been hoping it didn't sound like too unreasonable an idea.

While I dont have a huge amount of experience with PIC's, the few projects 
I've done have functioned well.

You are quite right with your comments about finding the original chip, and 
programming it ...  I had only provided the details because there were 
questions asked.

The only advantage may have been to find out the parameters for the reset 
and anything else that may have helped with understanding how it all worked.

The 'hardware questions' referred to the original post where I asked about 
the crystal eg.

I hadn't considered using the internal oscillator  ...  but after it was 
suggested I cant see why not  ... your thoughts? It's not like it needs to 
be super accurate  ...  we're just milking cows  :)

And also the supply. From the data sheets I see that 5.6 volts is too high.

I may just be showing my ignorance  ...  but if this other microcontroller 
has worked for 20 years with such a crude supply (5.6volt zener and a cap), 
is it possible that a 5 volt shunt regulator could be used  ..  (is there 
such a thing?) ... to keep it safe.

At present I only have two of these boards needing a new controller  ...  so 
naturally I am hoping for a heap more to make it really worthwhile.


Hi Thomas,

You suggested a PIC18F1320  ...  any particular reason?


Thanks again guys,

Regards,   Roger



----- Original Message ----- 
From: "Jinx" <joecolquitt@clear.net.nz>
To: "Microcontroller discussion list - Public." <piclist@mit.edu>
Sent: Thursday, 13 August, 2009 8:56 PM
Subject: Re: [PIC] Advise on replacing an obsolete micro with a PIC


>> Compared to some of the programs I have written this is
>> still a very simple ask
>
> It does look fairly straight-forward. I mentioned a while ago a
> friend who's industrial laminate cutter had packed a sad. Not
> very complicated, functionally, and it was around $2000+ to
> get a replacement PCB from the Italian manufacturer. Unknown
> to me someone had already quoted her $1700 to re-do it using
> a PLC, which disappointed me because it was well within the
> capability of a PIC. And particularly disappointed, for her, when
> the PLC man botched it and disappeared, leaving it unfinished,
> and it's working in a walking wounded fashion to this day
>
>>  ..  it's the hardware questions I want to get right first
>
> If you did find out what this micro is, what could you do about
> it, realistically ? If it's a 1991 device finding a replacement would
> be most unlikely, never mind getting it programmed
> 

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