6502 Front Panels

[CommodoreZ]

In the same vein as the Altair 8800 or Nova 1200 or other minis/micros have front panels, which historic (about 40 years or older) 6502-based machines contain front panels of that type? I'm not talking about the type of keypad designs seen on the KIM-1, or SYM-1, or the more advanced designs like the AIM-65, or anything that comes with video output by default. No TIM either by default either. I'm talking about data entry involving toggle switches, and LEDs, possibly 7-segment displays showing hexadecimal -- something in that same spirit of a machine with no ROMs, and the operator has to load in even the most fundamental programs.

As of right now, I'm aware of only 4 historical examples:

#1 Ohio Scientific OSI-300 (1975): a simple trainer, front panel, 6502, and 128 bytes of RAM. Doesn't need anything else, nice and cheap way to learn the processor, but you have to live in zero-page, and you have no expandability. No automatic address incrementing, and beyond loading data into RAM, all other status controls involve flipping multiple switches in sequence. I've seen a few examples over the years, and own one of the modern mini-OSI-300 replicas.

#2 Ohio Scientific OSI-400 (1976): an optional front panel directly based on the 300 was suggested in the manual for the 400. It's the same methodology extended out to a 16-bit address space. Who knows if anyone ever built one, however if you have built one for a 400, I'd love to hear about it. I already asked the folks on OSIweb long ago, and heard of no such examples.

#3 David Brader's Kompuutar (1977): a homebrew machine described in Byte Magazine from November of 1977. As far as I can tell, a one-off since no evidence indicates that anyone besides David built one to his instructions. If someone did, I would love to hear about it. The only other piece of information about it is an addendum in a later issue, but no other historical references to this machine appear to have been recorded within the scope of the modern internet. I contacted him last year, but he wasn't interested in talking about the project's history. Can't say I didn't try...
Byte Magazine Volume 02 Number 11

#4 CGRS Microtech System 6000 (1978): a multi-board 6502-based S-100 machine where it isn't a secondary processor. Multiple configurations exist with a variety of price points and features in mind, several of which include a DMA front panel with switches and 7-segment displays. Who knows if this one is software controlled or not, we don't have complete documentation as far as I know. I previously thought the board was intended for a SYM-1, but it's very much it's own thing. I've seen examples of both a CPU board and a front panel from this machine, but they were from different revisions and incompatible, I believe.
CGRS Brochure on deramp.com, photos and document scans on vintagecomputer.net

Why bother with all this? I think they're cool. I've been digging into it for a few years now, and figured I should reach out more in search for other vintage examples that I may have missed. Do you know of any more?

[L0uis.m]

What about the Ritro AMI-COS 6800, made in the Netherlands !

See also:https://www.transistorforum.nl/forum/in ... d&id=52221

Sad enough I own only a switch panel part of the front of which the wires are roughly cut off.

But it gave me the idea to use it for a 6502 single step/cycle monitor,
see: viewtopic.php?f=4&t=8388&p=112946#p112946

[CommodoreZ]

L0uis.m wrote:

What about the Ritro AMI-COS 6800, made in the Netherlands !

Cool machine. I don't speak Dutch, but I don't think there is any mention of this machine using a 6502 at any point within the thread you linked.

[plasmo]

Altair 8800 was my first experience with personal computer. I still have an Altair 680. I like their front panels very much and I’ve kicked around several design concepts to emulate the front panel functionality. If you look behind the Altair front panels you’ll find a large pc board with dozen or more IC’s plus lots resistors for switches and LEDs. Operationally it is very tedious and error prone to enter even a small program via the front panel.
Ultimately my prototyped front panel emulation was using a CPLD to replace 74xx IC that displayed address/data with 7-segment displays and received user inputs via a PS2 keyboard. I can enter 50-byte program pretty quickly and single step or run the program. I have a working version for Z80, but I didn’t pursue it further because I felt it was not as ‘cool’ as Altair’s rows of switches and LEDs. The Z80 prototype is here, maybe there are enough interests to do the 6502 version.
https://www.retrobrewcomputers.org/doku ... frontpanel
Bill

[Yuri]

The one I know of is called the PERSEUS-8, as seen here:
https://hackaday.io/project/179196-pers ... 2-computer

The guy later added a second module to it refereed to as the PERSEUS-9:
https://hackaday.com/2022/07/29/perseus ... have-been/

[CommodoreZ]

Yuri wrote:

The one I know of is called the PERSEUS-8, as seen here:
https://hackaday.io/project/179196-pers ... 2-computer

The guy later added a second module to it refereed to as the PERSEUS-9:
https://hackaday.com/2022/07/29/perseus ... have-been/

I'm familiar with his work, and I love it. He's very meticulous with all of his projects.

However, these do not fit the criteria of being historical examples, which is what I'm currently looking for.

[L0uis.m]

Hello CommodoreZ,

CommodoreZ wrote:

Cool machine. I don't speak Dutch, but I don't think there is any mention of this machine using a 6502 at any point within the thread you linked.

The 6502 was a successor of the 6800, it is essentially a simplified, less expensive and faster version of that design, sold for less than one-sixth the cost of a 6800.

The switchboard seemes compatible, that's what gave me the idea

[BigDumbDinosaur]

CommodoreZ wrote:

L0uis.m wrote:

What about the Ritro AMI-COS 6800, made in the Netherlands !

Cool machine.  I don't speak Dutch, but I don't think there is any mention of this machine using a 6502 at any point within the thread you linked.

That unit doesn’t have a 6502 in it and thus doesn’t belong in the category of historic (about 40 years or older) 6502-based machines with minicomputer-like front panels.  Yes, the 6800 is an ancestor of the 6502 (although not the only one), but the two MPUs are significantly different to the extent that calling the 6502 a “simplified, less expensive and faster version” of the 6800 is doing a gross disservice to the 6502 and the folks who designed it.

[L0uis.m]

Hi BDD,

BigDumbDinosaur wrote:

Yes, the 6800 is an ancestor of the 6502 (although not the only one), but the two MPUs are significantly different to the extent that calling the 6502 a “simplified, less expensive and faster version” of the 6800 is doing a gross disservice to the 6502 and the folks who designed it.

They were not my words, I just quoted Wikip.

[BigDumbDinosaur]

L0uis.m wrote:

They were not my words, I just quoted Wikip.

Ah, yes!  Wikipedia...the paragon of factual correctness and neutral exposition.  In reading their 6502 article, I got the impression that a Motorola fanboy had a hand in editing the history section. 

BTW, the other ancestor of the 6502 (and the 6800) is the DEC PDP series.  If you examine the latter’s instruction set, you’ll get a feeling of more than passing familiarity—many mnemonics are the same and do more-or-less the same things.  We normally think of the 6502 instruction set as being a copy of the 6800’s, minus some of the latter’s oddities (e.g., CLR and TST).  The reality is both derived much of their instruction sets—and some other programming concepts—from the PDP series.

[Martin_H]

BigDumbDinosaur wrote:

BTW, the other ancestor of the 6502 (and the 6800) is the DEC PDP series.  If you examine the latter’s instruction set, you’ll get a feeling of more than passing familiarity—many mnemonics are the same and do more-or-less the same things.  We normally think of the 6502 instruction set as being a copy of the 6800’s, minus some of the latter’s oddities (e.g., CLR and TST).  The reality is both derived much of their instruction sets—and some other programming concepts—from the PDP series.

Somewhere on this forum commodorejohn and I discussed how the 6502's zero-page addressing is vaguely similar to the PDP-8 and CDC-160. Basically, all three machines had the same problem of how to index RAM without having any registers as wide as the address bus. But I haven't been able to find it.