Odd Retrocomputer Had A Graphics Coprocessor

[Noel’s Retro Lab] scored an unusual 1980s vintage computer sold in Japan and Spain. The Seconinsa FM-7 appears to be a popular Fujitsu Japanese computer altered to fit the Spanish market. They seem to be pretty rare, at least in our part of the world. The outside appearance was very nice for the time, with a large keyboard and plenty of expansion ports. But the board has an unusual feature considering the era — dual CPUs. One 6809 executed your program, and another 6809 handled graphics output. You can see the machine in the video below.

There are two 32K ROMs, but the machine specifications claim only 48K. After dumping the ROMs, it turns out one of the ROMs has two copies of the same data. You can imagine they might not want to decode the entire address space. It could be that they needed 16K of space for other devices.

It wasn’t just the ROMs. The video RAM is pretty strange, too, as [Noel] explains. There are even some static RAMs the computer doesn’t claim. It appears these act as communication pipes between the two CPUs. In fact, it turns out that even the keyboard has its own 4-bit CPU, so the machine actually has a total of 3 CPUs!

This was a heavy-duty design for the time it was built. [Noel] wanted to fire it up, but he had to figure out the cables since the computer didn’t have any with it. Some clever repurposing of stock cables provided monochrome video output. Color display was a bit more complicated, but not impossible.

[Noel] winds the video up with some history of the companies behind the machine. The Spanish government wanted to use the FM-7 in the classroom, but the program failed to materialize. Want to see what it was like to program the thing? Here’s the Basic reference manual (in Spanish). Most of the documentation for the machine is either in Spanish or Japanese.

While this certainly is a rare computer, at least there’s a record of its existence. If you want to see what a Japanese computer looked like a few decades earlier, check out the FACOM 128B.

16 thoughts on “Odd Retrocomputer Had A Graphics Coprocessor

  1. A lot of Arcade systems back in the day had multiple CPUs doing different things such as audio and video. The Sega System 16/18 boards used a 68000 for the CPU and video but also used a Z80 just for the audio.

      1. The Mega Drive was a cheaper version of the Sega System 16 arcade board. They did the same thing with the Dreamcast/Naomi, and the Saturn started as an attempt to make a home console version of 3D Model 1.

        Sega of Japan thought of themselves as an arcade company first, home console company second, and they suffered for it *hard* when it came to the Saturn, with a half-dozen CPUs intended to be programmed in hand-tuned assembly.

    1. I commented much the same under the actual video. Repeating bullshit claims does not better how I think about hackaday. I like noel channel. But saying the architecture with multiple CPU’s was at the time unique is straight up wrong. And even in homecomputer land you had things like the BBC master tube interface for a coprocessor.

  2. Many 80s computers featured two or more CPUs, and even some old floppy drives had multiple CPUs, often using Z80s. Some computers also had custom-made ICs like the VICII as a ‘GPU.’ But it’s always fascinating to see more exotic computer from the inside. 😁

    1. The IBM PGC graphics board, an ancestor of IBM VGA, had used an i8088 as a graphics processor.


      That being said, it’s understandable if someone of today is surprised by that.

      Because unlike now, CPUs were still general-purpose processors back in the day.
      An 8088/8086 or 80286 wasn’t a “PC processor”. It was just a processor.
      It could be used in all kinds of applications.

      As an processor on a single-board computer (SBC, also known as an “EMUF” in 80s W-Germany), as part of a telephone system which manages telephone calls in a city/town, or as a communications controller in a high-speed modem.

      This was before microcontrollers took over. While they did exist already (Intel 8051/8052), they lacked the RAM and processing power of larger SBCs. SBCs based on Z80, 6502, Motorola 68000 etc were like discreet versions of an microntroller.

      They compared like an Arduino Uno (uC) to an Raspberry Pi (SBC).
      The discreet versions also had more i/o ports, a real bus, serial/parallel ports and the ability to run complex programs (almost like OSes).

      1. Pleased you mentioned Single board computers. My 1st commercial job in I.T. was as a industrial and ministry of defence systems integration engineer, assembling and testing these types of systems. I’m an azure cloud engineer now, but miss tinkering with physical hardware.

  3. Lol, was going to say, multiple CPU was very common, and soon after that it became common to put math co-processors etc on die with CPU. And every peripheral might have another of the same or similar CPU: Printer, Floppy etc.

    1. Speaking of, I think the original HP Laserjet/Plus had an Motorola 68000.
      The same CPU as that Spanish girlfriend and the Sega Genesis.
      So it had blast processing, before the Genesis had! ;)

  4. MSX2 was awesome. πŸ‘ŒπŸ˜ƒ It had gems like “Snatcher”, “Metal Gear”, “Angelus”, “Aleste”, Prost.., err, “Princess Maker” and many more.
    Sharp X68K had many excellent arcade ports, too.
    And PC-98.. I think that one needs no further explanation. πŸ‘―β€β™‚οΈπŸ‘―β€β™€οΈ

  5. Everyone mentions pc’s with a z80 for audio or a dedicated graphics chip and claiming this is normal.
    What other pcs out there used a second identical cpu as the main cpu to do graphics?
    I know of none off hand.
    I think a couple of old arcade boards maybe had two of the same cpu’s but I can’t think of any pc’s that did this.

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