Bytronic 68000 MicroComputer Trainer Memory Map
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Author:  Lynton [ Thu Jul 16, 2015 5:53 pm ]
Post subject:  Bytronic 68000 MicroComputer Trainer Memory Map

Hi All,
I've been lucky enough to obtain a Bytronic 68000 Microcomputer Trainer but have no further information it.
I'm hoping to put this little system to use so I'm wondering if anyone knows if there is any documentation about this little board online anywhere?

The Bytronic website shows the board under "Micro-control" but has no further detailed information. I did ring them but they want £25 for a pdf of the user manual which to me seems absurd for something that's so old.

I suppose what I am after as a minimum would be the memory map of the system. I can work out the monitor commands and grab datasheets for the 68230, 68681, 68000 etc and piece together the complete picture I guess.

Don't get me wrong I don't mind parting with money for information but £25 seems a bit much to me??
I don't expect someone on here to "give" me a user manual but a pointer to at least a memory map of the system would be good. to get me started.

Many Thanks


England, UK

Author:  Lynton [ Sat Sep 10, 2016 10:08 am ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Hi all,
Have recently gone back to looking at this board but cannot get it working.
From the little information I have managed to find on the internet it seems it has a rather nice builtin monitor program so I'd expect to be able to get something out of it on a VT100 terminal but all I can get is junk characters from the board no matter what baud rate etc I select.
Not sure if it'll help in my quest to get it working but I have attached some pictures of the board in the hope some of you might recognize it.
If I change the positions of LK1,LK2,LK3 and LK4 (near EPROMs) the HALT light comes on when the board is powered up otherwise the HALT light is off.
I am assuming this light comes on because the 68000 has "lost its way" because it cannot now run the monitor in the EPROM's due to the addressing being incorrect with the altered link positions?
If that's the case then maybe, just maybe the board is actually running with the links in their original positions?

What can I do now do diagnose what's wrong (if anything) with this board?

Many Thanks


File comment: Bytronic 68000 Trainer Cover
68000_Trainer_Cover.jpg [ 191.95 KiB | Viewed 20592 times ]
File comment: Bytronic 68000 Trainer PCB View
68000_Trainer_Board.jpg [ 248.07 KiB | Viewed 20592 times ]

Author:  profkelly [ Sun Sep 11, 2016 6:41 pm ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Do you have any documentation? Source code? ROM dump?

Author:  Lynton [ Wed Sep 14, 2016 8:57 pm ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Hi Mr Kelly,
Unfortunately I have nothing. No documentation, ROM dumps or anything.
This is not looking too hopeful is it??!!!



Author:  profkelly [ Wed Sep 14, 2016 9:31 pm ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Just found this, not sure if it is an exact match.


Author:  Lynton [ Thu Sep 15, 2016 12:05 pm ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Hi Mr Kelly,
Yes that's the one. In fact I have gone ahead and bought it :-)
I have looked on EBay previously but didn't find anything!
In fact I am almost certain that seller is where I got the board from originally.

Thanks so much for that pointer, I really appreciate it.

Hopefully the manual will be of help and the board I have isn't broken.

Almost everything on the board is replaceable apart from the GAL's/PAL's and the Monitor ROM's so fingers crossed they are OK.

Kind Regards


Author:  Lynton [ Sat Sep 17, 2016 11:15 am ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Have just received the 68000 Trainer manual through the post.
I've had a read through paying particular attention to the serial connections and the diagnostics routines that run at start up and its looking like bad news.

On the board are 3 "Traffic Lights" that apparently should blink in unison for about 2 seconds at startup. This is the first diag test that is run (see attached picture).

When I power up my board the halt light flashes for a fraction of a second and the traffic lights all illuminate permanently with some garbage appearing on the serial port.

I've even tried a reset technique mentioned in the manual whereby the EEPROM that holds the baudrate settings can be cleared defaulting it back to 9600/8/N but that did no good.

Interestingly even though that test doesn't appear to run or at least run correctly the halt light doesn't come on.
As stated previously if I change the jumpers that select the RAM/ROM types used on the board the halt light does come on so it does seem to me that maybe the CPU is at least starting to execute some monitor code?

I have a spare 68681 DUART somewhere that I could swap in but I have this nasty feeling the monitor EPROMS have become corrupted due to age even though they have their quartz windows covered.

Oh well what a shame :-(


68K Diags 1.jpg
68K Diags 1.jpg [ 198.66 KiB | Viewed 20563 times ]

Author:  iansexton [ Sun Jan 08, 2017 5:51 pm ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Hi Lynton,
I stumbled on this post & wonder if you got this sorted?
I am one of the original designers of this board. It was actually designed at De Montfort University & supplied to Bytronics.
They don't look like original EPROMS in your board...
It's a long time since I used one of these! The board should have an on-board editor/assembler/debugger. I don't know how you are connecting but we used a straight 'ribbon cable' connector rather than a serial crossover.
The guy who wrote the firmware (Brian Bramer) has retired but I'm still in touch with him. If we can help in any way we'll certainly try!
Brian also wrote a book on 68000 assembler programming.

PM me if you need help - I'm not a regular here.


Author:  Lynton [ Sun May 28, 2017 8:56 am ]
Post subject:  Re: Bytronic 68000 MicroComputer Trainer Memory Map

Hi Ian,
Sorry for the long long delay in getting back to you.
I'm not a regular here either and have been really busy at work and haven't had time to do much 68000 stuff so your kind response went unnoticed, sorry.
Essentially I'd still love to get this board going somehow but for that I suppose I'd at least need to know what the memory map would have looked like and then maybe get another monitor up and running on the board.
I'm going to bet that either those EPROM's on the board are suffering "bit rot" after all these years or possibly if as you suggest they are not the originals then it may just be they are making the board do something that's not usual.

Any help you could offer would be really much appreciated and once again thanks so much for getting in touch.



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