Expansion board with more slots leading up to new expansion

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Expansion board with more slots leading up to new expansion

Postby vbriel » Mar Sun 08, 2009 11:41 pm

Here's a pdf of the new design for adding 4 slots to the Micro-KIM. This design troubled me for a long time because I didn't know exactly how I wanted it. Now I have it. There will be one female connector facing the male expansion pin on the left edge of the card. This will put the card directly over the Micro-KIM. The design work so that the exansion card won't take up room over to the left. No cable to attach, it will directly plug in. You can reach the jumper to unplug. It doesn't get in the way of the keyboard or the display.

I like this design and I'm going with this layout. If you want to mod it so you have 5 headers and a cable, feel free to do so. Or, you can even put the female connector on the other edge so it sticks out away from the board.

Now, I've got a design ready that adds the 2nd 6532. I've held off on this because I fear the 6532's may become hard to get. At this time, they are still available so I'm going to do this board probably next month.

You guys have been patient about expansion and the cassette interface. The cassette interface is nearly complete on the Micro-KIM from the original KIM-1. It is only missing 1 or 2 chips and some other misc components, I'll have to look at it again. I never attempted to do this because to be fair, I never got the cassette interface working on the replica 1 and I didn't think that I should release the Micro-KIM cassette interface until I had one for the replica 1. Well, I may never get the replica 1 cassette working so I'm going to pick this project up this summer.

I just ordered the Expansion board tonight. So, I will have a 4 slot board ready in about 2 weeks for $20 kit and a 6532 expansion board ready shortly after that. My real question for finishing this one is, should I add breadboard area or not? I like making tiny boards for the Micro-KIM like the 32K RAM card.

Oh yeah, the pdf is here:

http://www.brielcomputers.com/wik/image ... pander.pdf

Ok, opinions?

Vince
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Re: Expansion board with more slots leading up to new expans

Postby hanso » Mar Mon 09, 2009 4:20 pm

Looks great, welcome addition!

Dont worry about the cassette interface, the KIM-1 design is a way more robust design. Your 6532 design will have the possibility of adding relays for control of two cassette recorders? See the Micro Ade manual for the defacto standard way for that.

I would love to see a 6551 (or any UART IC) and a 6522 as a board next to the 32K RAM and the cassette interface. Thats what makes my KIM-1 useful.
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Postby AndyC » Mar Tue 10, 2009 9:21 am

Personally I don't think the breadboard area is necessary. Would very much like to see cassette support though.

Andy.
http://www.rastervision.co.uk - UK based electronics design and manufacture
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Postby vbriel » Mar Sun 15, 2009 12:14 pm

Well, it's about a week until the expansion board arrives and I'm looking into the cassette interface next. This issue I'm having is the cassette interface requires 12V to run the LM311. Two ways to solve this. One is to use a 12V wall wart or something like that, yuk. The other solution is a charge pump to generate the 12V from the 5V TTL line voltage. This requires a chip. The best one I've seen is from ST the ST662A. I can't find it in PDIP through hole so it would have to be so-8 surface mount. This means .050" spacing compared to .100" spacing on through hole. A little harder to solder, plus surface mount is never easy.

I'm still searching for this in stock in pdip somewhere. This is the only real holdup on the cassette design right now.

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Postby hanso » Mar Sun 15, 2009 2:25 pm

Maxim sells the PDIP equivalent MAX662A online in their shop.

Better avoid SMD in the kits.
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Postby vbriel » Mar Sun 15, 2009 4:30 pm

Yeah, a little more expensive at 3.62 in small bulk but that does what I need. Since I"m only driving the comparitor 30mA is more than enough.

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Postby vbriel » Mar Fri 27, 2009 8:17 am

Good news, the boards are in, they work of course but I haven't had time to work on the cassette interface. I will try and get started this weekend. The 2nd 6532 board is finished, just need to make a prototype to test it.

Will update when I get started on the cassette.

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Re: Expansion board with more slots leading up to new expans

Postby hanso » Apr Tue 28, 2009 11:48 am

vbriel wrote:..
You guys have been patient about expansion
..
I just ordered the Expansion board tonight. So, I will have a 4 slot board ready in about 2 weeks for $20 kit and a 6532 expansion board ready shortly after that.
Vince


Hm, perhaps we should nag you more for this! I see you are working on the Altair, and started the Replica 1 LE. And not on the micro-KIM!
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Postby vbriel » Apr Tue 28, 2009 8:01 pm

Actually, the expansion boards are done, I'll see if I can take a snapshot of it soon.

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Postby hanso » Oct Mon 05, 2009 11:55 am

vbriel wrote:Actually, the expansion boards are done, I'll see if I can take a snapshot of it soon.

Vince

Any progress on expansion board and expansion with second 6532?
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Re: Expansion board with more slots leading up to new expans

Postby kerryp24 » Jul Fri 23, 2010 8:21 am

What is the status on these boards.
Looks like nothing has been done in over 4 years.
I'd really be interested in getting one of these expansion boards as I have some ideas for add ons to my uKim.

Thanks.
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Re: Expansion board with more slots leading up to new expans

Postby garryj » Aug Sun 29, 2010 12:26 pm

Are the Micro-KIM expander and memory expansion board schematics still available? The forum links to MK_Expander.pdf and MKRAM.pdf are currently broken. Thanks!
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Re: Expansion board with more slots leading up to new expans

Postby Norbert » May Fri 27, 2011 4:22 pm

Hello Vince,

I have the following idea when thinking about further expansions of the Micro-Kim:

how about designing one complete interface board of the same size of the Micro-KIM, 'sandwiched' as the elektuur people did with their Junior Computer?

You cold solder the 40 pin connector on the mainboard vice-versa to connect the interface board directly to it or connect it by a short 40 pin cable.

Cheers
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