RE: TED based motherboard

From: Bil Herd (
Date: 2007-04-05 14:42:55

I believe there were some limits to the lifetimes of the old EPROMS, the insulation on the cells that could be discharged by UV also leaked on their own (if memory serves) so I would not be surprised at anything they did 25 years later. 

The TED wakes up in PAL mode for timing reasons, coming up in PAL doesn't mean the processor set it.  I used to recognize things many years ago that did tell me the processor was running early like a jump to 40 column mode or horz offset jump or something like that.

II would be very suspicious of the hand-bonded sealed-with-scotch-tape processor.  One out of any TED should work as a replacement.

The main changes between old and new would be I/O.  There would be the banking that was later the software swapping for the Plus4 applications (and Magic Desk, etc) and also the latch for the keyboard.  There is literally only a couple of cycles difference between the read of data and the read of data from a latched IO location for the keyboard.  Other than that the design itself didn't go through many changed through the life in spite of it's many wrappings.


-----Original Message-----
From: [] On Behalf Of Grósz Attila
Sent: Thursday, April 05, 2007 5:59 AM
Subject: Re: TED based motherboard

MagerValp <> írta:

> I think it'd be fairly easy to adapt a basic 3.5 rom so
that it'll run
> on this motherboard. The kernal expects a coldstart vector
at $8001
> and a warmstart vector at $8003.

Yes, it is easy. I did so already in an emulator. It boots
to MONITOR but that's due to the fact that the keyboard
latch is not the same as in the final version (what Bil
mentioned about the 6529B) and it detects the RUN/STOP key
as pressed.

So, Anders, you could possible burn yourself a production
BASIC ROM and try to boot the thing up. It ought to work :-)


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