Old EPROM questions again, EPROM Programmer

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Thu Jul 29 23:07:03 2004

> My "not available" story: I was at my parents home over a long weekend when I
> finally got my wirewrapped 8080 system to the point where it could use a keyboard
> - as they lived in the country, there was no chance of scrounging one (I couldn't
> afford to BUY anything back then), so I decided to build one...

Off-thread, but majorly on-topic for the list...

A could of years before I built the programmer (this would be 1986 IIRC),
I was designing my own computer (which I've still not finished, you know
how these projects go on :-)). Anyway, I needed a keyboard, and I saw an
advert for cheap encoded QWERTY keyboards in the back of a magazine.
Since it was nearby I decided to investigate...

I did buy a keyboard, I still have it. I also bought a Philips P850
minicomputer, my first TTL-built processor. That's the machine that got
me into computer collecting/repair...

Just think... Had I been able to buy a PC-clone keyboard for a few pounds
in just about any computer shop, I may well have never found this hobby...

> I selected the 6809 in the first place because I had recent experience with it
> and suitable tools available...

I used the 6809 becuase I could cross-develop code on my CoCo (running
OS-9) which was by far the best development environment I had access to
at the time...

>
>
> >Incidentally, I've built a couple of instruments with microprocessors (as
> >opossed to microcontrollers) controlling them (actually I normally used
> >the 6809 -- nice chip), and I included commands to read/write/execute
> >from any location in mmeory. Sure helped debugging !.
>
> Yup - 6809 was an incredible chip - easy to multitask (and most people don't
> know what DP is for!) - I always include low level debugging features/commands,

It was a wonderful device. A nice clean instruction set, good addressing
modes (why no other 8 bit machine included PCR mode I do not know...),
easy to program.

> can be absolutely essential at times.

> >This was long before the days of the Internet in the UK. It wasn't easy to
> >find places to ask about borrowing a programmer.
>
> Not familier with UK companies etc. - this would have been somewhere in the
> mid 80's, and I was reasonably well past being a student ... but these are

About the same time, then.

> the kinds of things I would have tried had I still been in school:
> - Local companies that were "friendly" ... might involve having a friend
> who's dad worked there.

May have worked, altough I can't think of anyone who would have been able
to get me access to a programmer (and then there was the issue of
actually getting the data onto their machine, not many people could read
OS-9 disks...)

> - Local shops, schools etc.

Would not have worked. UK schools at that time did not have EPROM
programmers (I doubt they do now). Never saw a shop with one either.
Maybe I could have found somebody who made pirate BBC micro ROMs (this
seemed to be the common use for EPROM programemrs among the general
public at that itme...) and asked them to burn me a chip, but...

It was easier just to make a programmer.

> but.. especially in todays world (as you point out), having to get the "first"
> ROM programmed should not be a show stopper. Even that is only an issue if the

These days it's a lot easier.... I am sure many people here have, or have
access to, an EPROM programmer, and would program the odd chip if sent an
image. And it's a lot easier to transfer said image now than it was 20
years ago...

-tony
Received on Thu Jul 29 2004 - 23:07:03 BST