Off topic of the replica 1 but my next project

What have you built or do you want to design to go with your replica 1

Off topic of the replica 1 but my next project

Postby vbriel » May Thu 03, 2007 4:18 pm

The micro-KIM is a project I've been working on for a while and just now feel like this prototype is worth releasing as a production model. It is a clone of the KIM-1 reduced in size, a little more memory, RS232 interface and other features. It uses standard components and no custom microcontrollers! Software compatible with the original KIM-1 and yet improved in a few ways.

This is my priliminary page:

http://www.brielcomputers.com/micro-KIM.html

projected selling price is under $100 making this one of the most affordable 8-bit computer kits available today! Let me know what you guys think.

Don't worry, the replica 1 isn't going away, just adding to the lineup.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

good idea!

Postby scelbi8h » May Fri 04, 2007 7:51 am

it's a great idea, Vince. For me it comes on time, I was planning to build my own KIM-1 clone! :)

Since it uses no custom chips, could you sell only the main board? it's a good idea for those people like me who has thousands of little components at home :)

luis
scelbi8h
 
Posts: 21
Joined: May Sun 07, 2006 1:36 pm

Postby vbriel » May Fri 04, 2007 9:09 am

Yes, what I'm going to do is set up the site with option of board only, board with EPROM only, kit, assembled and the schematics will be available online.

If you have been thinking about this, then you have seen Ruud's site, maybe? It's a great site but there are errors where he writes about doing this. Decoding the memory properly was a trick that you'll see when I release my schematics.

I'll bet you can even wirewrap a micro-kim from the schematics with no problem.

I would expect boards to sell around $20-$25 depending on if the boardhouse is going to work with me or not. Of course I have just posted this notice here, I haven't told everybody. I'm not sure if there is a problem with the source code or not. If there is, I can't sell them with the code but there are ways around that.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

Postby fsafstrom » May Fri 04, 2007 10:20 am

How cool...

Don't know much about the KIM-1 so this would be a fun way of learning...

Will the expansion I/O port have the same pinout as the Replica 1 ?
Since I don't know the KIM-1, I have no idea if this is possible or not...
User avatar
fsafstrom
 
Posts: 154
Joined: Dec Tue 26, 2006 3:57 pm
Location: San Antonio, Texas

Postby vbriel » May Fri 04, 2007 10:42 am

LOL, I didn't know much about the KIM-1 either until I started this project. Actually, compared to the Apple 1 and replica 1 it is not as powerful but it still has cool features.

The expansion interface has a different pinout and does not have the 3 pre-decoded address lines $A000, $B000 and $C000 but most of the other signals are there.

The thing with the KIM-1 that I like is that it was one of the first single-board computers (if not the first) and it was the first computer made for the 6502, designed by Chuck Peddle as a development board for the 6502.

Believe it or not, the initial monitor program for the RS232 interface is very limited. You can only read/write one address at a time so dumping programs was an issue at first. Then I discovered the paper-tape function which dumps an address range of code in a block and reads it back in the same format! It actually works at 1200 baud faster than the replica 1 at 2400.

My next goal is to create a program and hardware to connect a Micro-KIM to a Replica 1 and share a bus or something in that format.

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

Postby cheese1113 » May Fri 04, 2007 4:42 pm

Sounds awesome Vince! I was actually looking into buying a KIM-1 but now I can save some money. :)
Max Wooden
cheese1113
 
Posts: 92
Joined: Nov Sun 13, 2005 2:49 am
Location: CA

Postby vbriel » May Fri 04, 2007 8:55 pm

Yeah, I have one but it is so bulky compared to the Micro-KIM and they have only 1K RAM. Plus to interface to RS232 you need to build an external circuit. Plus, having a single wall wart like one used in the replica 1 is cool and compact.

I'm going to see how long it last on a set of 4 D size batteries. Portable KIM-1 anybody?

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

some questions

Postby scelbi8h » May Sun 13, 2007 9:21 am

I've been reading manuals about KIM-1 and I have some questions:

why only 5 kb of memory? I know it's much more memory than the original, but if you could expand over 16 kb, it would be possible to load and run some BASIC interpreters (microsoft kb-9 was really nice, and available online). well I read it's not easy to expand over 8 kb... do you know why?

KIM-1 has a cassete interface included in rom (although very slow, and it needs 12 V too). did you try this feature? does it works correctly? there is a program at net called KIMTAPE, ideal for making sound files to load into computer.

humm I had more questions but now I don't remember :P

Thanks again for a great project! Hope it will be available soon

Luis
scelbi8h
 
Posts: 21
Joined: May Sun 07, 2006 1:36 pm

Postby vbriel » May Sun 13, 2007 10:21 am

Well, I like the KIM-1 but it's decoding scheme for memory was horrible. It only decoded the first 8K of memory and so the 6502 just repeated what it saw. So $0001 is also $2001, really strange. To fix this problem, you have to disable the onboard memory only when the proper address range is not being selected yet $E000-FFFF must remained mirrored to function properly because this is where RESET and other features like NMI and IRQ get its addressing from.

If the project is successful in any way, I will produce an add-on board that uses more logic than I could fit on the Micro-KIM and I will add 32K RAM. I will also add the 2nd 6532 so you can do some of the small projects like the speaker and such that is in the original manual.

I just finished building the 2nd of 3 prototypes and I have to tell you that there is a lot of soldering compared to the replica 1. I can build a replica 1 in 45 minutes but the Micro-KIM took around 2 hours! This means that somebody who doesn't know where every part is will take 3-4 hours. Still, it worked right from the start and all tests are positive.

The 3rd prototype will probably be donated to the Vintage Computer Festival East 4.0 to help promote that show. I will build that one next week.

Chuck Peddle the creator of the 6502 will be there. More info here:

http://www.vintage.org/2007/east/

Also, just so you know, I have been running Tiny BASIC just fine. It is limited to no string variables but still is a great little basic.

I'll probably be dividing up the forum to add a section for the Micro-KIM soon so that there is no conflict with the replica 1.

Luis, have you emailed me to get on the list? If not, please do so because I'm using the list to determine if there is enough interest to go forward into production.

Cheers,

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

Postby fsafstrom » May Sun 13, 2007 11:41 pm

Vince,

I will be interested in the Micro-KIM.
However I would probably not buy one until X-mas since I'm still having fun with and expanding the Replica 1...
User avatar
fsafstrom
 
Posts: 154
Joined: Dec Tue 26, 2006 3:57 pm
Location: San Antonio, Texas

Don't worry about the time for construction...

Postby Aaron Teeling » May Mon 14, 2007 12:08 pm

... building the computers is a major part of the fun. 3-4 hours still sounds like a quick project.
Aaron Teeling
 
Posts: 84
Joined: Oct Mon 17, 2005 8:49 pm
Location: Virginia Beach, VA

Postby vbriel » May Mon 14, 2007 12:48 pm

fsafstrom wrote:Vince,

I will be interested in the Micro-KIM.
However I would probably not buy one until X-mas since I'm still having fun with and expanding the Replica 1...


Yeah, you guys are having more fun lately than me. Someday I'd like to actually build a robot (25 years I've talked about that one). Maybe one of my computers would make a good host controller, replilca 1 bot or kimbot!

Vince
User avatar
vbriel
Site Admin
 
Posts: 1184
Joined: Jul Tue 19, 2005 1:10 pm
Location: Ohio

Postby fsafstrom » May Tue 15, 2007 12:23 am

Robots are always fun... ;-)

Maybe I can write a servo controller through the 6522 on my expansion board...
That would be a good first step...

There are plenty of powerful motor controllers who accepts a servo signal.
Or maybe just a plain old H-bridge and use PWM...

To the drawing board... :P
User avatar
fsafstrom
 
Posts: 154
Joined: Dec Tue 26, 2006 3:57 pm
Location: San Antonio, Texas

I'm back :)

Postby scelbi8h » Apr Sun 06, 2008 6:46 am

Hello back! Because of some personal problems (now solved), I've been "disconnected" for almost a year. Now I'm looking again to this page, and I'm really surprised about microKIM-1. Last time I read it was only a project... and Vince was asking for interested people to help him decide if would be ok to sell this new computer.. :D (sorry Vince, I couldn't be into that list then!)

Well, I'll be around here again, hope I will have time to paint my replica case (abandoned since last May), and send any photo of it.

Kindest regards from Poland, and congratulations for your new microKim computer!

Luis
scelbi8h
 
Posts: 21
Joined: May Sun 07, 2006 1:36 pm


Return to Creation Room

Who is online

Users browsing this forum: No registered users and 3 guests

cron