Micro UK101

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marcusjambler
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Micro UK101

Post by marcusjambler » Sat Nov 10, 2018 2:31 pm

Hi All

I picked up a PCB for the Micro UK101 designed by Grant Searle.
It took a couple of hours and works first time :D
IMG_5417a.jpg
IMG_5422a.jpg
IMG_5424a.jpg
IMG_5428a.jpg
IMG_5427a.jpg
Serial MS Basic fun... :D

Marcus

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jonb
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Re: Micro UK101

Post by jonb » Sun Nov 11, 2018 9:50 pm

Nice one!

Where did you get the board from?

I built it using tripad Veroboard and point to point prototyping wire. The 8k BASIC is really old and still has the garbage collection bug. It's very satisfying to build one of these - although mine had an odd problem with the clock that prevented it working. I overcame it in the end, but lost a fair bit of hair.

After that I built a Multicomp, also one of Grant's designs. I run CP/M on it.
Last edited by jonb on Sun Nov 11, 2018 9:51 pm, edited 1 time in total.

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marcusjambler
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Re: Micro UK101

Post by marcusjambler » Sun Nov 11, 2018 10:54 pm

Where did you get the board from?
I got it from Ebay

Seller : eight_bit_forever

https://www.ebay.co.uk/itm/The-Micro-UK ... 2749.l2649

Marcus

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jonb
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Re: Micro UK101

Post by jonb » Mon Nov 12, 2018 7:03 am

That's not bad..

Take a look at his other items. Those fully populated C64 boards look very good value for money.

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marcusjambler
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Re: Micro UK101

Post by marcusjambler » Mon Nov 12, 2018 9:50 am

I built it using tripad Veroboard and point to point prototyping wire.
=D> Not for the feint hearted even on a small board.
The 8k BASIC is really old and still has the garbage collection bug
Is there a more up to date version I could slot in?
Those fully populated C64 boards look very good value for money.
Yes they do... I've a C64 mega games cartridge to build at some point... Amongst all the rest :lol:

Marcus

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jonb
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Re: Micro UK101

Post by jonb » Tue Nov 13, 2018 8:40 am

Hi Marcus

Not for the faint-hearted? You can say that again. I was soldering it on Mother's Day 2011 and Mrs JonB wasn't impressed.
IMG_5020.jpg
Point to point madness
IMG_5021.jpg
Layout is a clone of Grant's original board. Couple of chips missing: 6502 (now replaced), 74LS00 (scavenged, new one on order).
Is there a more up to date version I could slot in?
When I originally built it, I started a thread on 6502.org here: http://forum.6502.org/viewtopic.php?f=4&t=1795. It's a long read, but by page 11 I'd got it running and found the garbage collection bug: http://forum.6502.org/viewtopic.php?p=14409#p14409. I attempted to patch in OSI basic (which supposedly had the bug squashed) but it, too, failed to run the program. There is discussion of running ehBasic and TinyBasic on it; I was interested in ehBasic but as it needed some changes to the memory map (or, "the glue logic wiring"), I didn't take it further. I couldn't face that prototyping wire again...

A quick search for images of my board turned up at least one other properly designed and laid-out PCB: http://www.6502.org/users/sjgray/projec ... index.html. I'm going to see if this guy would like to share the KiCad design files as I can get them manufactured very cheaply.

Cheers
JonB
Last edited by jonb on Tue Nov 13, 2018 9:31 am, edited 2 times in total.

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marcusjambler
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Re: Micro UK101

Post by marcusjambler » Tue Nov 13, 2018 10:09 am

properly designed and laid-out PCB
Looks good... I'm pretty sure thats the schematic that arrived with my board.
I'll check when I get home...

Would be interesting to re-instate VDU and keyboard at some point [-o<

Marcus

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jonb
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Re: Micro UK101

Post by jonb » Tue Nov 13, 2018 6:08 pm

Your board is different; you can tell because the ICs are oriented differently.

Steve sent me his design files, so I can see he has captured the schematics in KiCad himself. Maybe this eBay fellow copied it - I hope he got Grant's permission.

BTW, Steve told me he hadn't got the board fabricated so doesn't know if it actually works. I have discussed it with him and I think the clock circuit might not work properly as the parts are spread out a bit. Would be simple to reconfigure / reroute. Also, it needs an expansion connector and this requires a bit of thought as the 6502 I/O is all memory mapped, so you'd need to be able to prevent RAM selection on an I/O request, somehow.

Hmm, reinstating VDU & keyboard... sure you want the expense? You could ask Grant to do it.. ;) Sounds like what you really want is a new UK101 PCB, cloned from the original. Now we're talking expensive.. but at least you'd be able to play "Invaders" on it!
Last edited by jonb on Tue Nov 13, 2018 6:16 pm, edited 2 times in total.

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Re: Micro UK101

Post by marcusjambler » Tue Nov 13, 2018 7:15 pm

Maybe this eBay fellow copied it
Looking at this schematic its been redrawn and the content is subtly different :

The 470uF electrolytic and diode across the power in.
The Max232 caps are 1uF.
Some of the serial port support lines are hardwired to each other instead of floating.

I'll scan it in tomorrow and post it here.
Sounds like what you really want is a new UK101 PCB, cloned from the original
[-o< yes indeed :lol:


Marcus
Last edited by marcusjambler on Tue Nov 13, 2018 7:18 pm, edited 1 time in total.

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