Retromaster’s Electronics Projects

…related to old computers and other assorted stuff…

New Cumulus PCBs Working

Posted by retromaster on January 5, 2011

I finally managed to assemble one of the new Cumulus boards, and I am glad to report that it works fine :). As a matter of fact, I received the bare boards a few days ago but I did not have the 32Mhz oscillators handy so the boards had to wait a bit until I got the part.

Aside from some changes in the CPLD and PIC pin assignments, no changes to the firmware were necessary. In my first tests there did not seem to be stability problems. The only (rather strange) problem I encountered is that the LCD fails to initialize at times (showing nothing), but the PIC definitely keeps on running, because even in this state the floppy emulation works fine. Hopefully, this issue should be fixable.

Here is what’s next (in no particular order):

1. Fix the remaining (firmware) issues and implement some of the missing basic functionality (e.g. writes, user interface).
2. Prepare the enclosure and fit the board in it.
3. Order some CumuluBus PCBs.
4. Prepare the web page for Cumulus and release the current sources, gerbers, etc. under GPL.


7 Responses to “New Cumulus PCBs Working”

  1. Jay said

    This is excellent news! I am ready to order a couple of these .. Do you have any idea what your plans will be for selling them, and for how much? And .. How soon until I can get one!?

  2. retromaster said

    Not too long now, do not worry 🙂

    Regarding cost, I had originally posted a cost analysis on the defence-force forum. This has to be increased a bit since the CumuluBus buffer board (which is now mandatory) was not included there. But, to be on the safe side, I should say that even with very low volumes, the final cost would be definitely less than $100 per Cumulus+CumuluBus.

    But I would like to point out something, which you probably already realize: I am not really considering Cumulus as a “commercial product”. There is truly very little money to be gained by selling some units (maybe a dozen?). So, I am mainly considering this as a service to the Oric community. Since I do this mainly as a hobby, I am not even attempting to recover any costs. This is impossible anyway since most of the cost actually lies in the development, not in the hardware itself.

    In fact, I would even prefer being “paid” with hard-to-get, rare retro-computing hardware instead of actual money. For example, I’d love to lay my hands on a Telestrat :). That way I could also verify that Cumulus works with it :). I think as a retro-computer enthusiast you can understand why I feel this way…

  3. Chema said

    Oh man! This looks impressive… I would definitely want one of this if I can get my Atmos work.

    It is quite important to me that a project such as this sees the light, as my three Oric productions so far need disk to run.

    BTW, a quite interesting test for cumulus would be trying to make pinforic run on it. (

    It is an infocom interpreter which boots sedoric and runs the interpreter from the main disk and expects a fresh FAT formatted disk with the game file as the only file. As it works with 512-byte sectors, and uses the routines in page 4 from the OS, it would be another nice test. I think image at least from Zork are included.

    Just an idea.

    Congratulations again for the excellent work!

  4. retromaster said

    Thanks, Chema 🙂 It’s nice to be able to support the Oric community with Cumulus 🙂

    If I am not mistaken, pinforic was on one of the very first disk images that I tried. Anyway, to make sure, I’ll try that image you’ve linked to at the first opportunity.


  5. Jay said

    Retro- I have a telestrat and I will verify it’s operation with your board almost immediately upon receiving the boards! I also was going to make hardware like this but you beat me to it .. But this sort of project was exactly what I got the telestrat for in the first place! If I had one of your boards right now I’d for sure be trying to help with the write feature, and so on .. So as soon as you are ready to add another set of eyes and fingers to the project let me know how to send you some cash and I’ll tell you my address!

    Btw, I have five atmos’s too .. And I really want to get them working with disc access. I’d be quite happy to trade off my telestrat to you, once things go into a usable state ..

  6. retromaster said

    Hmm, that sounds good 🙂 Anyway, I read later somewhere that the telestrat does contain a floppy controller, so if this information is true, it probably won’t work (or will not even need) the Cumulus. But I could use it with UFE or TFE, then, instead 🙂

    Anyway, you will definitely need a CumuluBus board to go with each Cumulus board. Those, I’ll need to order, too. So, hopefully, if all goes well, I think I may be able to send you one or two boards within a month.
    I’ll contact you by e-mail when the time comes…


  7. Great! I’m really ready to go .. can’t wait to finally experience Oric disc-based computing! 🙂

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