Home brew DRO

Sorry, Neil

... Of course Real Men don't need Breakout Boards !!

MichaelG.

Popping head over the parapet, as much of the above comes into the "What did Horace say, Winnie?" category, I posted a query some while back re. the item in the photo. It was purchased WITHOUT ANY instructions on the basis that it 'looked interesting'.

Can anyone advise me if the info available on the link kindly provided by Michael G is applicable/relevant to this bit of kit? Haven't done anything with it yet 'cos my electronics knowledge doesn't go much beyond recognising the + and - battery terminals!!

Rgds

Bill

Bill,

That looks lots of fun ... probably dates to the 1980s though.

We should all do some digging, and find the instructions for you.

Meanwhile; could you please give some of the numbers on the chips.

MichaelG.

Thank you for the fast reply, Michael. '80s? ... yes, wouldn't be at all surprised!

As best as I can read them, the 4 chips on the right hand board (as in the photo) are, from top left to bottom right as follows

Z8400APS, Z80A CPU

Z8420APS, Z80A PIO

8534, HM6116A3

8516ED, D8255 AC-5

ANY help much appreciated!!

Rgds

Bill

Z80 ?

I think you program them in Latin.

Bill,

Z80A confirms my assumption

So this Wikipedia page is a good place to start

Z80A is the CPU [Central Processing Unit], and is paired with PIO, which is a Programmable Input/Output device.

More to follow ...

MichaelG.

Ah - a Z80 board. Happy memories (at least I think they were) of soldering hundreds of connections on my Nascom II, a mere snip at about £195 (might have been £395 even?) as a kit of parts circa 1980. Anyway after a very long weekend of soldering (and re-soldering) all the joints, I finally managed to get the red LED to blink on and off once a second using Z80 machine code - hand coded!! (Yes, a bit like Latin John).

"Look at that!" I told my wife exultantly - "It's working!!"

"What's working Dear?"

"The computer's working - the lights going on and off"

"Yes I can see that - but what does the light going on and off mean?"

"It means the computers working"

"Well if I paid all that money for something I'd expect it to work too. The light on my washing machine comes on when its working but at least it's doing something useful. So what's this thing doing?"

"It's making the light go on and off"

"Ok, don't bother, I can see you have no intention of giving me a straight answer" (and she walked off in a Huff)

So you will understand why I don't show my wife any of my new 'chippery' these days - she never quite got over the first one!!

Regards, IanT

John - very much looking forward to your update!

Oh, sorry Jack - went off on a bit of a tangent there (not unusual these days)

I threw all my old 'Personal Computer Worlds' away some years ago but in the late 70's there were quite a few 8085, 6502 and Z80 SBC's around (Single Board Computers) mostly imported from the US. This looks to be one on them - possibly with an extension board. I can see a couple of eProms there I think and these would have held a simple boot system/monitor programme to drive the LED display and to probably to allow you to connect to some form of mass storage (most probably cassette-tape based).

It may even have an 8K Basic in firmware there for you to use. As Michael mentions, you probably have some of the Zilog peripheral chips there such as the PIO and maybe an SIO. The monitor programme will let you access them if you can find the port addresses. I don't recognise the "Plymouth" brand but that may well be simply the UK Importer. Have a look under the PCBs and see if there is another brand name there (in the etch somewhere). It looks kind of familiar but it was all a long time ago now.

If you can find the original manufacturer's name - I suspect you will also find that there is some info on the web about the firmware (monitor software) too.

Good Luck!

IanT

John, that would be much appreciated.

Apologies to the OP for the partial Hi-Jack.

Regards

Paul

I have nothing against breakout boards! In a sense my STK500 is one. The Arduino etc. are brialliant for anyone without the means to make their own PCBs. (the computer is the MK1 by the way, it's successor has hugely more RAM and is all SMT with very tiny pins

Bill's computer looks wonderful. I suggest you contact the Old Computer Museum, who may be able to tell you what it is, or who will be even more interested in it if they can't!

Neil

Bill

If you go well down the "wikki" page that Michael Gilligan linked you'll find a link to a device called a "Microprofessor 1" (link). This was made by Acer and looks pretty much exactly the same as your device. It was made as an educational unit to teach machine programming, which would fit in with whats apparent on the board along side the processor unit, as that looks like an in/out board to interface with the real world motors and sensors. I'd hazard a guess that the "Plymouth" reference is either Plymouth University or polytechnic of some sort - not sure what they had in the mid 80's - and the whole package was something used on one of their courses.

The above might all be a load of waffle but it also might help with identifying the beastie.

Keith

Microprofessor rang a faint bell.

Blimey! They still make them HERE you can even get a slightly modified version of the accessory board, down to the motor with the boat prop on it.

Shouldn't be hard to get a manual.

Neil

The board on the left will be run off the PIO which is a parallel port. You might be better off just running it off a PC parallel port, even an Arduino.

One thing I remember from the the late seventies when I was running Harrow Computer Group was how people kept saying " Computer at home? What use is that? No way I'm going to get one."

It's got 2K of Static RAM and they are still selling them

My reaction was pretty much the same as Neil's - Blimey!!

Looks like your problem is solved though Jack!

IanT

"
I'd hazard a guess that the "Plymouth" reference is either Plymouth University or polytechnic of some sort - not sure what they had in the mid 80's"

it was a Polytechnic at the time. The unit reminds me of ones that we were given during one of the courses, for writing in machine code and, huge leap forward, in assembler. I recall it being simpler without the motor or whatever it is on the board. I also recall that it was 6800 based rather than Z80, but my memory may be fading, perhaps this is a later example since I left in 1984. I don't think that the poly made their own units but there were a number of small businesses and offshoots based in the little industrial parks around Plymouth at the time so perhaps thats where it came from.

Simon

On another note, I have just received my free complimentary copy of Digital Machinist which has a long and interesting article on Arduinos causing me to order a board and some extras.

Something like that is the ideal way to realise what ghastly inefficient use is made of the resources in a modern PC!

Neil

.

Neil,

What an amazing find !

... The mind boggles

MichaelG.

.

and ... Bill,

It looks like you're onto a winner.

.

P.S. ... Before anyone tells me off; PIO is Peripheral Input/Output.

Edited By Michael Gilligan on 05/10/2013 22:16:10

Gordon Bennett!!! What a response - looks to have stirred up a whole host of nostalgia!

Many thanks to all. I'll get stuck into those links and see what the few undamaged brain cells can make of the information there. Given that this is unexplored 'jungle' territory for me, I may well be back for some guidance again.

Thanks again

Rgds

Bill

Please make it do something useful, Bill

It would be a joy to see this controlling a Dividing Head.

MichaelG.

.

Meanwhile; here is some bedtime reading for the "nostalgists"

Thanks to the wonders of t'internet ...

here is the User Manual for the MPF-IP

MichaelG.