Another UK101 user

Introduce yourself and reminisce
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IanB
Posts: 3
Joined: Sat Jan 11, 2020 4:52 pm

Another UK101 user

Post by IanB » Sat Jan 11, 2020 10:15 pm

I got my UK101 as a kit back in 1980 while I was still at school and used it for a couple of years before moving on to a BBC Micro in 1982.

Like others here, I made many mods to it and built several add-ons during that time and even came up with a mod myself that got published in the UK's PC world magazine.

Fortunately I kept it and it still works today, but only just, as the board often needs flexing or the chips need reseating to get it to boot after it's been left for a while. I think it needs a complete overhaul!

uk101-video.jpg
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uk101-top.jpg
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uk101-bottom.jpg
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The mod that was published in PC world eliminated the noise during screen access by synchronising the video circuitry to the CPU's phi1 clock so that there was never any conflict and thus no noise when the screen memory was written to and it didn't affect the speed of screen updates.

The same technique was used by other 6502 based systems like the Apple II and BBC micro and I'm surprised it wasn't designed like that to begin with as it didn't require any extra circuitry, just a slight re-arrangement of the signals although it may have made the timings on the screen memory a bit marginal.

PCWpage147.jpg
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I suppose a similar mod could be made to the Superboard.

Other mods I can remember were:
switchable 16 and 32 line display (Which also switched to 16 and 32 line versions of the 2K monitor ROM)
switchable WEMON monitor ROM
switchable BASIC ROMs
EXMON in EPROM
6821 PIA board (veroboard on the right) which I used to control a home made EPROM programmer and it also controlled a "VOXBOX" speech synthesizer
Creed 7B teleprinter interface (vertical veroboard on the left) with built in EPROM based driver so I could print listings

Unfortunately the teleprinter went to the scrapyard a long time ago :(

dave
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Joined: Tue Sep 09, 2008 5:24 am

Re: Another UK101 user

Post by dave » Sun Jan 12, 2020 3:34 am

Welcome Ian!

Nice machine, and interesting video mod.

Mark
Posts: 64
Joined: Tue Sep 16, 2008 6:04 am
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Re: Another UK101 user

Post by Mark » Mon Jan 13, 2020 10:23 pm

Welcome!
Nice UK101!
Was the black case common for UK101 users? Most of the older pictures I've seen had custom cases or bare boards.

I haven't seen that version of NEWMON (MONUK02), is it something you created? If you have time, It'd be great to get a dump of the ROM image. (It could be dumped via serial port if you're short on eprom readers - see below.)

This is the one I've seen...
newmon1.jpg
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newmon2.jpg
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And a bit of code to dump $F800-$FFFF to serial port. Capture audio or serial data & I can do the rest...

Code: Select all

 1 SAVE
 10 H$="0123456789ABCDEF"
 20 FOR I=63488 TO 65535
 30 C=PEEK(I)
 40 H = INT(C/16)+1 : L = C-( INT(C/16)*16)+1 
 50 A$ = MID$(H$,H,1) + MID$(H$,L,1) + " "
 70 PRINT A$; : NEXT
 100 POKE 517,0 : REM TURN OFF SAVE
 
Cheers,
-Mark

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IanB
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Joined: Sat Jan 11, 2020 4:52 pm

Re: Another UK101 user

Post by IanB » Tue Jan 14, 2020 2:52 am

Mark wrote:
Mon Jan 13, 2020 10:23 pm
Was the black case common for UK101 users? Most of the older pictures I've seen had custom cases or bare boards.
It was bought from the CompShop stand at the Breadboard'80 electronics exhibition at the same time as the kit so I guess it was their standard case option.
Mark wrote:
Mon Jan 13, 2020 10:23 pm
I haven't seen that version of NEWMON (MONUK02), is it something you created?
It was a custom patch of NEWMON by me. I reduced the startup message to free up some space and also indicate which version (16 or 32 line) was running as I made the 32 line mod switchable so needed a different monitor switched in at the same time. The extra "E" option jumped to an EPROM based version of EXMON, the extended monitor, originally supplied on tape and it also trapped CTRL-P to jump to some EPROM based driver code for the Creed 7B teleprinter. After CTRL-P everything printed to screen was also sent out of the 50 baud teleprinter interface. Using CTRL-P again toggled printing off.

Exmon manual here:
http://www.compukit.org/images/a/a7/Exmon.pdf
Mark wrote:
Mon Jan 13, 2020 10:23 pm
If you have time, It'd be great to get a dump of the ROM image.
It should be binary identical to NEWMON apart from my patches. I could do a copy if you still want it but it would probably crash without the extra support EPROMs.

Mark
Posts: 64
Joined: Tue Sep 16, 2008 6:04 am
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Re: Another UK101 user

Post by Mark » Tue Jan 14, 2020 6:33 am

Ah, makes sense. Thanks for the links and info.

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