6502.org

Hallo everybody.


Have somebody a Kim-1 for sale?

These, in good condition, go for a lot of money these days. I have seen them sell for over $3000.

I think most folks that have them hold on to them pretty tight.

Yep. Stupid me for not buying one when they went up to $150 and I said "stupid me for not buying one when they were $30."

Life is full of "shoulda-woulda-coulda."

One recently sold on ebay for around $230 or so but the seller didn't go into enough detail about tests and condition and he never responded to my question. My concern with the KIM-1 would be getting one with a bad 6532.

john

Briel Computers sells a Microkim which is a clone but you should have some handy soldering skills unless the preassembled and tested one is available.

They're not quit a KIM-1. They don't have the second 6530 equivalent.
They only have the one 6532.
One can run most code on them but I don't know if micro chess runs.
It might if he mapped the ram correctly.
If you had any application that needed the -003 I/O, it wouldn't work.
Dwight

If I remember the KIM schematic correctly, the second 6530's I/O was not connected to anything except the connector on the side of the board. Most code for the KIM-1 works fine but for some projects you have to change the code a little bit (for example, the clock that uses the 7-segment displays originally used the timer circuitry in the second 6530 so you have to change a couple of bytes to use the timer in the 6532).

Briel Computers also sold a board that added a second 6532 which should solve all those kinds of problems. That only leaves the missing cassette interface which is easy to work around (just use a terminal emulator on the serial port and record/replay the output). Unfortunately, Vince has been AWOL for a while now; people in the forums are asking what happened to their orders and are getting no reply. The last I heard of him was around April 2015 when I bought a Superboard III (OSI Challenger / UK101 replica) from him. Too bad, because I built several of his kits and it was a lot of fun.

Anyway, the MicroKim is based on Ruud Baltissen's "Make your own Kim-1" page, and the schematics for the MicroKim are still online. The 6532 may be somewhat hard to find (but easier than the 6530's), but you can always get two Atari VCS 2600 from eBay: each of them has one in there.

===Jac

PS: Oh, and for a Microchess version that runs on the MicroKim, check out this page. I didn't test it though.

The schematic has some select errors so if you intend to
build one, you'd need to fix those.
The RAM is not separated from the CS1 and CS2\ pins. In
the schematic, it shows the RS\ pin coming from a separate
pin of the decoder chip. That would not work. The 6530
treated the RAM enable as though it were another chip but for the
6532, the CS pins work for the entire device, including RAM.
The RS\ pin selects RAM or I/O.
Vince came across this but fixed it on his design.
Dwight

I believe the 6532 has been created with HDL but has anyone ever tried to recreate the 6530?

I don't know much about that chip...all references seem to point to the 6532. I wonder if a micro-controller could act as a drop-in replacement for the 6530?

It would be difficult to be a drop in. The problem is the clock would need to
not just be faster but also synchronous. With a 40MHz+ it might be able to
work. A 15MHz running synchronously could probably work fine. All assuming critical
instructions are 1 or 2 clock cycles.
Tinker Dwight

Yeah, it took me a while before I learned that lesson. Many people (including myself) believed that "Hey, my micro-controller runs at 16MHz and that old computer runs at 1MHz....so I can emulate the whole thing because I'm 16x faster!!!"

LOL....

So, yeah...I could see needing a mcu in the 40-100MHz range.

Such jobs are better suited for CPLD/FPGA.

The problem with a CPLD/FPGA method is it has to fit
the form factor of a 40 pin dip.
Most now days are physically too big for that job.
It could be done though.
One would most likely keep the ROM external. The RAM is
only 64 bytes might not be an issue.
Counters and I/O is trivial.
Dwight

There's a drop-in replacement for the TMS9918 which is a 40 PIN DIP. However, it's a small little board that is a little wide. But it physically fits in most replacement machines and consoles.

Something like the KIM-1 (which is an open board) could handle a small FPGA/CPLD daughtercard drop-in.

If one were inclined to build such a device.

The functionality of the 6532 and 6530 should be easy to emulate with a Propeller. There are just a few "minor" problems:

• The pinout of the 40-pin DIP Propeller doesn't match, but a multi-layer PCB with the SMD version of the Propeller might do the trick
• There are not enough I/O pins on the Propeller to emulate all the I/O one-to-one; it may be necessary to use e.g. one or two serializer/deserializer chips or a secondary propeller
• Officially the Propeller isn't 5V tolerant, though I never had a problem with that on my KimStar project

I'm planning on designing a KIM-1 / Elektor Junior expansion board for my L-Star project, where I will emulate the address bus/data bus parts of the 6530's in a Propeller but I'll probably implement the I/O ports as a high-speed serial connection to a secondary controller (Propeller or something else) that's connected to the keyboard and displays.

===Jac