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View Full Version : DIGITUS of Sweden, have I found a KIM-1 clone from 1982?



ajcc
May 7th, 2016, 08:45 AM
Found this strange 6502 based contraption that someone have soldered together and built a beautiful case for. It's number 8 and the PCB have a sticker that says "DIGITUS of Sweden, AB", and then there's just a revision number on the back of the PCB: MOP11-11-81 (Hello MOP if you're reading this!) The thrift shop store workers said it had come in donated from a company, wasn't given an answer about there being more stuff or not.

Haven't plugged it in yet, want to be sure it won't blow up and release the magic smoke before I do.

31026

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Routed cut-out for the keypad.

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Linear Power supply. Top one has a large transistor mounted to a heat sink. Lower board is just a 7812.


31034
Overview of PCB.

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MOS MPS 6502
MOS MPS 6530-003 (same as in KIM-1?)
MOS MPS6530

Are the 6530's combined 1kB mask ROM and I/O?

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2x2114 4-bit SRAM, 1kB total.

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Analog section for the Tape Drive interface?


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Back of PCB.

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Seems to be nothing behind the DIGIUTS label.

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MOP11-11-81


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Inside of the wooden box, very neat! Notice the routed cut-outs for the two headers, with extra space under them.

And that's sadly all I know about it for the moment.

jac_goudsmit
May 7th, 2016, 10:17 AM
Interesting!

Judging from the fact that it has two 6530's made by MOS, this must be an authorized KIM-1 replica (like the one Rockwell sold). Looks like it's in great shape, and the quality of the build appears very good (perhaps even better than the original KIM-1, on which you always see oxidized solder tin). I see 1981 and 1982 date codes on the chips, so this was probably built in 1982.

In answer to your question: each 6530 has 1K of ROM, an I/O port, a timer and 64 bytes RAM. The 6530-003 and 6530-002 contain the ROM images for the KIM-1.

I wouldn't be surprised if it works 100% when you plug it in.

Nice find!

===Jac

ajcc
May 7th, 2016, 10:44 AM
Decided to unplug the big header-connector and measure the voltages, got 4.82V on the 5V line before a electrolytic capacitor started smelling and venting. I couldn't hear any hum at all from the transformer, so I'm feeling quite positive that the two PSUs are usable. The 5V one got a big regulator IC and two transistors, the 12V is just a common 7812.

31042
The top began to poke up while it started to vent at the button.

Oh well :)

ajcc
May 7th, 2016, 11:01 AM
Interesting!

Judging from the fact that it has two 6530's made by MOS, this must be an authorized KIM-1 replica (like the one Rockwell sold). Looks like it's in great shape, and the quality of the build appears very good (perhaps even better than the original KIM-1, on which you always see oxidized solder tin). I see 1981 and 1982 date codes on the chips, so this was probably built in 1982.

In answer to your question: each 6530 has 1K of ROM, an I/O port, a timer and 64 bytes RAM. The 6530-003 and 6530-002 contain the ROM images for the KIM-1.

I wouldn't be surprised if it works 100% when you plug it in.

Nice find!

===Jac

Thank you!

Did Rockwell continue to make KIM-1s long after MOS and later Commodore?
The slogan of the company that made this is/was "From CHIP to SYSTEM", which makes me wonder if one of the engineers built this one for work.

ajcc
May 7th, 2016, 02:30 PM
31045

I replaced the caps, and you were right, it actually just worked :)
As you can see, I have moved the content of 0010 to 0011.

Dwight Elvey
May 7th, 2016, 05:25 PM
Commodore made the first 6502 and built these boards
to show off the new uP.
The boards were really only intended as demonstration
boards but many engineers found it handy to use them as a basis
for their application.
Later Commodore had Rockwell and Synertek make both 6502s and
there family. These companies also made single board computers but
I was not aware that they made Kim-1 boards.
There are a lot of fun things to do with these.
There are several books written for these boards.
Dwight

jac_goudsmit
May 7th, 2016, 11:52 PM
I don't think Rockwell made many of them, but a little while ago, one showed up on eBay. We discussed it on this forum too. I didn't know until then that the KIM-1 design was also licensed to Rockwell. It looked exactly identical to all the KIM-1's I've ever seen, except the circuit board was green (like yours) instead of grey, and the capacitors were orange (like yours) instead of yellow.

Interesting by the way that the single-step switch is on the right; I think Commodore/MOS moved it to the top left corner in an early revision but I don't know exactly when (or why, for that matter).

===Jac

ajcc
May 7th, 2016, 11:56 PM
A friend recommended me The First Book of KIM, http://users.telenet.be/kim1-6502/6502/fbok.html. So I could punch in the first example and see if it was working. Have to do a lot more reading about the KIM-1 and the 6502, but it seems like it will be a fun time :)

Another showed me the Synertek SYM-1 which had EPROM sockets and was seemingly more of a generic controller than a plane demonstrator? Don't know if they made KIM-1 boards, only saw Rockwell KIM-1 boards while I was trying to ID my board.

Anyway, more as it happens!

Dwight Elvey
May 8th, 2016, 06:56 AM
To my knowledge, Synertek only made the SYM-1, SYM-2 and VIM-1
That were mostly Kim-1 compatible. My mention was about the 6502.
Synertek also made a keyboard that could be used as a terminate with
a video display, added ( KTM I recall ). It had 40 or 80 column.
Rockwell made the AIM-65 that included a thermal printer.
Dwight

ClassicHasClass
May 8th, 2016, 08:12 AM
Rather like the AIM-65, but the KIM was what really taught me 6502 assembly.

Zeela
October 4th, 2017, 07:32 AM
I'm digging up an old thread.

I've actually found another KIM-1 from Digitus of Sweden AB. And it has a lower serial number than ajcc's :)

So Ajcc, how did it go with your KIM-1? Did you do anything fun?

41079

Chuck(G)
October 4th, 2017, 08:22 AM
Commodore made the first 6502 and built these boards
to show off the new uP.

Woah, Dwight. The first 6502 (and the subsequent KIM-1) were manufactured by MOS Technology, starting in 1975, which was a spin-off from Allen-Bradley. Commodore didn't acquire MOS until late 1976. I think it's a little inaccurate to blame the 6502 on CBM. Tramiel wanted a reliable (read: captive) source of semiconductors for his venture--and he wanted Chuck Peddle.

To say that Commodore made the first 6502 is a bit disingenuous. One might as well say that Unisys made the first B5500.

Dwight Elvey
October 4th, 2017, 09:16 AM
Woah, Dwight. The first 6502 (and the subsequent KIM-1) were manufactured by MOS Technology, starting in 1975, which was a spin-off from Allen-Bradley. Commodore didn't acquire MOS until late 1976. I think it's a little inaccurate to blame the 6502 on CBM. Tramiel wanted a reliable (read: captive) source of semiconductors for his venture--and he wanted Chuck Peddle.

To say that Commodore made the first 6502 is a bit disingenuous. One might as well say that Unisys made the first B5500.

Yes, my error. I was just looking back on this and caught the error myself before reaching your post. I'm surprised no one else mentioned it.
I feel silly but I did know it was MOS and have no excuse for the miss-statement.
I was looking at the picture and noticed that the -002 chip didn't have a -002 on it. I could be wrong but I don't recall seeing
a MOS chip without the 002 on it.
One wonders if there was a difference in the code?
The chip is obviously operational as we saw the keyboard entry.
The -003 chip ran the cassette audio but I believe the -002 did all the serial,
display and keypad. ( I could be wrong about the serial ).
In any case, I'd be interested in a checksum of the ROM in the -002 position?
Since I've not seen that many MOS labeled chips, it could be more common than
I'd know.
Dwight