So Many Replicas!

[sje]

I have a real Apple IIe I bought via a Usenet ad many years ago. Alas, it no longer boots and only displays gibberish on the screen. I never used it much, so it looks like I never get around to diagnosing and repairing it.

My own little project is breadboarding a W65C02S system with a fully functional front panel. Unlike Grant's projects, it isn't a replica of anything; rather, it's just plain retrocomputing. The W65C02S is a fixed up version of the original 6502; it's implemented in CMOS and can be run or stepped at any speed. Well, any speed below 14 MHz. My idea for the front panel is to have it be run by an Atmel AVR (only $14) and include full bus display and 6502 register access. But unlike any front panel machine I've ever seen, it will have a serial link (supplied by the AVR) that will provide a complete remote access facility. Each switch on the panel will be implemented with a momentary contact and so can be operated in "soft mode". The panel could even have an IR photodiode so I can use a handheld IR remote control.

A program load can originate with a typical computer connected to a USB/RS-232 converter that connects to the front panel AVR. At 19,200 bps the typical computer can tell the AVR to load 56 KB of RAM in about 30 seconds with a nice light show as a side benefit.

My idea is to use 64 KB of static RAM but map the upper 8 KB of the memory space to a boot PROM and various I/O chips. (The 6502 uses memory mapped I/O exclusively.) I'm also considering adding a second AVR accessible by the 6502 for I/O, timers, etc. This AVR could also be used to implement a TCP/IP stack and a physical Ethernet connection. Another idea is to have the second AVR run a compact flash card emulation of a disk subsystem.

What else? A non volatile real time clock and calendar chip. Maybe a speaker, and maybe several piezoelectric buzzers of different frequencies. Or an X10 control node. A cassette tape interface, maybe one that controls my little solid state voice recorder and its sixty hours of indexed audio storage. A modem with caller ID support so the machine can hang up on annoying solicitors. Possibly an MP3 player, although I think this would be a bit taxing of the 6502 capabilities. And then there's the obvious possibility of a retro video and keyboard interface. A D/A converter that runs an analog front panel meter that indicates processor utilization. A papertape reader, if only I could find an inexpensive papertape punch.

It may be that the initial breadboard realization won't run at a full 14 MHz, so I'm considering a wirewrap version the second time around. (The great mystery: why do wirewrap chip sockets cost more than some of the chips themselves?) I could eventually produce a two board design (panel on one PCB, 6502 system on the other) although I might need a little help on this. A case and power supply shouldn't cost too much if appropriate off the shelf products can be had cheaply.

[Aaron Teeling]

I originally posted this on the Vintage Computer Fourm while asking if anyone was constructing kits. I copy it here for those interested:

Everyone:

Andrew Lynch e-mailed me links to Grant Stockly site (again, outstanding work Grant): www.altairkit.com, Tod Fischer's IMSAI Series 2, www.IMSAI.net, and Mr. Roganti S-100 board reproductions at http://ragooman.home.comcast.net/rog_s-100.html. Thanks again Andrew.

It hasn't been a easy search for hardware and peripherals and hence why I ask. A google search hasn't been very fruitful and if it wasn't for an a thread in Applefritter two years ago, I wouldn't have know about Vince Briel's Replica 1 (which I enjoyed so much I sold it and built another one). Has anyone seen or heard of any European computer kits? BBC Micro or Apricot?

So... with the collective subject authority we have in this forum, please post what you know about available kits here.

COSMAC Elf Reproduction: www.sparetimegizmos.com

Apple-1 and KIM-1 Replicas: http://www.brielcomputers.com/

ZX-81 Kits from England: www.ZX81kit.com

ZX-81 Kits in New York: www.ZebraSystems.com

CF Drives for Apple-1 and Apple II: www.dreher.net

A-One, Apple-1 kit with accessories, Europe: www.achatz.nl

Semi-Virtual Disk (SVD) drive interface, various 80's computers: www.theSVD.com,
(appears as he has stopped shipping units but unclear if he is producing a newer version)

[sje]

I have one of Vince's Micro-KIM boards and it works as advertised. I'll probably get one of his 32 KB expansion boards to go with it.

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I'm continuing with my design for a 6502 (W65C02S specifically) system with a classical front panel. I'd probably not bother with this if there were some way of getting a new (kit or built) IMSAI 8080 or Altair 8800b. At the moment I'm waiting for parts. Eventually I'll make the schematic and BOM available.

[Geoff Harrison]

Originally Posted by sje

I'd probably not bother with this if there were some way of getting a new (kit or built) IMSAI 8080 or Altair 8800b.

David Griffith has a fairly nice IMSAI up on eBay right now. No disks, though.

Geoff.

[Grant Stockly]

Originally Posted by sje

I have one of Vince's Micro-KIM boards and it works as advertised. I'll probably get one of his 32 KB expansion boards to go with it.

----

I'm continuing with my design for a 6502 (W65C02S specifically) system with a classical front panel. I'd probably not bother with this if there were some way of getting a new (kit or built) IMSAI 8080 or Altair 8800b. At the moment I'm waiting for parts. Eventually I'll make the schematic and BOM available.

What about doing something with the 65C816? There is an affordable 512kbyte SRAM DIP too. You could use the $6 flash chips I used with the 680 to give it 512kbyte of eeprom style flash.

[sje]

Yes, the W65C816S was considered. And it still could be used in a modified design. But it just doesn't seem sufficiently retro!

[Grant Stockly]

I've been thinking about building an SBC out of all DIP parts that could run linux. Using a 64pin 68000, 32pin 512kb SRAM, etc. An inexpensive kit that has something in common with modern tools and software would be fun. A true "modern" computer kit. I wanted to limit it to DIP/PLCC/through hole parts since even coarse pitch SOIC parts are hard for some people.

I have had this idea since before the Altair kit ever came. Now I'm thinking it would be neat to have a 68000 and some memory on an S-100 card so that the Altair can run linux.

I know of at least one case where uCLinux has run on a 68000, but the FPGA company who built it for their core doesn't want to share the kernel patches.

I only suggest the 65816 because there are already a few 6502 kits out there.

I've been thinking about selling my Altair 8800 kit prototype. Its taking up space and I don't think I need to keep it for "memories". If you or anyone are interested, let me know.

One thing I would like to make in the future is a 6502 CPU board that is 100% compatible with the original Altair. This would allow a modified version of the Wozniak Apple 1 monitor to run on the Altair. If you prototyped your S-100 card in an Altair you would help accelerate me to that goal.

I would probably have a 6502 CPU chip, buffer chips, and a spot for a medium sized FLASH chip AND a 1702. The woz monitor would be
modified to use the 2SIO.

There IS a version of "CP/M" for the 6502. It would also be neat to run that!

Too many ideas and not enough time!

This is the prototype that I would be interested in getting rid of...

[sje]

It's Freescale that owns the 68000 IP, and they don't make DIPs of any kind. Old 68000 DIPs can be had, possibly salvaged from old Macs, Amigas, etc., for about US$20 each.

Anyway, a 68000 really needs a 68551 MMU to do Linux, and even that's a little clunky. I wouldn't try it with less than a 68030 as the base chip, and that was never made in DIP form.

[sje]

Originally Posted by Grant Stockly

I know of at least one case where uCLinux has run on a 68000, but the FPGA company who built it for their core doesn't want to share the kernel patches.

Failure to share in this case is very likely illegal due to GPL conditions.