Two Years

It’s been 2 years since I’ve started making GDEMU – the project itself is much older but there were a lot of trials and errors before I got something small and cheap enough to consider making it available.

The plan was to finally show the PCE CD-ROM replacement prototype at this point but that got delayed, again. It took way more time to figure out the problem with Type-4 Saturns than I expected, and the reason why it didn’t work in the first place actually threw a huge wrench into PCE project. Plus, kinda by accident, I discovered that AVRs are pretty lousy at being SPI slaves and that pretty much killed my lastest idea. But I’m not giving up on that yet, looking for some workaround. I might actually order the PCB anyway just to test some other stuff. Next target is end of summer or so. Let’s see what happens to make me miss that one too🙂

Phoebe assembly and testing is going slower than Rhea, I started doing it in smaller batches that target specific Saturn type rather than configure and test each board last minute. That means I will be shipping them a bit out of order, plus there might be longer delay between your payment and the actual shipping taking place but no more than a few days. Hopefully I won’t mix up the orders. I expect to have 2/3 of the list done (though maybe not shipped) by the end of this week and the rest should be ready before April.

You might have noticed I’ve stopped responding to all the “when’s the next batch of …” questions. Frankly there’s no point, I answer one person and three other turn up and ask the very same qustion a day later. Plus if I actually had a specific date in mind I would’ve posted about it, so obviously I don’t know myself (yet). I’d say next Rhea/GDEMU runs will happen around April/May but possibly not at the same time and this is all guesswork at this point. So please be patient.

Lastly, a reminder that Phoebe flat cable connector is not ZIF (neither on the ODE nor on Saturn motherboard) and you should take extra care when installing the device. Actually the cable insertion is rather easy, removal can be a bitch though. Unless you really need to move the device between Saturns (not recommended in the long run) please install it once and leave it there. There haven’t been any accidents yet but I’ve managed to kill one connector already by not being careful enough during testing.

46 thoughts on “Two Years

  1. Thanks for the update! I’m sure you will solve any issue in the pce side!

    Happy “birthday” and thank you so much for let this happening!!!

  2. Happy Anniversary!

    Going an awesome job man!
    Quality of your products and support is A+
    Been enjoying my Dreamcast a lot more since I got a GDEMU installed and will await patiently for the next Phoebe batch🙂

    Keep up the good work!

  3. Congrats & Happy 2nd Birthday for the GDEMU Project!
    One Question: I tried to play “Super Street Fighter II X for Matching Service” with different cdi/gdi images but no luck to get this to work. Any hints?

    • The ReviveDC rips should work fine. I think that’s the one I’ve used in the past. The legit GDI works for me but, I only get the top left quarter of the screen with RGB. Same with Vampire Chronicle.

      • Not every game supports RGB cable, some pretend to do (flag not set) but will actually output it all wrong.

    • Use proper rips like trurip or tosec or RDC of that game since nothing is downsampled. Redump DC rips have known to cause some issues, due to the Track layout or something on certain games.

  4. PC Engine CD ODE would be amazing =]
    How are you planning on implementing it – via the ext bus or something else?

  5. I hope you will just emulate the laser pickup/motors instead of the complete cd-rom drive. this is the only way to keep 100% of compatibility + don’t bother with specfic connectors.

    • Yup, that’s the plan but emulating the whole analog part of the feedback loop is difficult and very demanding (CPU wise). Unless someone comes up with an ASIC dedicated to such emulation… Plus there are no no low-level dumps, in fact obtaining those would be tricky at best (and various groups already argue about secondary effects like “audio offset” – imagine the shitstorm when they hit the actual problem). Conversion from hi-level dumps to low-level is possible but would require even more CPU and does nothing to improve accuracy of the emulation.

      • Yeah I know it’s not an easy job, especially for first gen CD drives. Look at Sony Discman D50. PC-Engine CD-ROM hardware is based on this one.

  6. Thank You! I’ve followed you since you were back on the old blog, I remember you showing prototypes of what would become the GDEMU (might be fun to throw together a History Page with early prototype pictures). I love my GDEMU and my Dreamcast even more now that I’ve had it! You did an amazing job on it!

  7. “It took way more time to figure out the problem with Type-4 Saturns than I expected, and the reason why it didn’t work in the first place actually threw a huge wrench into PCE project.”

    -Any chance you could elaborate more on the actual cause? I’m just curious and enjoy reading about the technical challenges involved in fixing issues like this.

    • It’s pretty technical. Lets just say Atmel engineers dropped a ball on this one. Wouldn’t be the first time either😛

  8. I’m sure you’ll figure out the type-4 Saturns. Then you can turn your talents on another project.

  9. Are there reliable dumps of PCE games like with SS or DC? Last I heard, nor Trurip nor Redump had a method to properly dump these…

    • Yeah, due to mastering not being perfect back then many games have data tracks overlapping audio, or the other way around. This is actually normal for CDs, it’s why we have pre/post gaps. I’ll try to handle both corrected and not corrected rips, with only x1 speeds I have some CPU time to spare. So, as long as the dump is not really broken it should work fine.

  10. Regarding the Phoebe connectors – back in one of the testing cycles, the first board you sent me (the one still labelled Theia) got one of the pins dislodged on the ribbon connector, and it was impossible to pry it back in a working way. Luckily you included a replacement connector, so I could keep testing it once the type 4 issues had to be checked.

    So they DEFINITELY come loose if you reconnect them an extreme amount of times.

    But normal users should hopefully not experience this, unless they too start switching the thing between 4-5 Saturns a dozen times a day.

    • I think the new cables I got a tiny bit slimmer and less likely to cause this issue but I’d be careful anyway🙂

      • Sure, the connector is LIF (Low Insertion Force)

        I’m wondering if you are stil interested in FM-TOWNS CD-ROM emulation….

  11. I came late to the party, getting my Rhea early 2016 but it was worth the wait. Good luck with your future projects, I am always keeping an eye on your website for the latest news and updates. You are a true hero for many retro fans worldwide!

  12. Thank you for the update, and for starting these great projects in the first place🙂 I’m hoping to catch the next wave of Phoebe orders, so will keep an eye out.

  13. I got my Rhea a couple months ago, and it’s amazing, thanks.

    Regarding the PCE, your device will only work on the briefcase setup, is that correct? It won’t work on a Duo, for example, right?

  14. Hi there,
    I,ve been looking for an email for contact, but I didn’t find. Is there a way I can contact you? I have some questions regarding ordering and payment methods. Thank you. Love your job/hobby.

  15. It’s a dream of mine to get a GDEMU, hoping to catch the next batch. Love your work! =D

    • The overheating has nothing to do with the ODE itself. However, there are spikes on the 12v, since the ODE does not require 12v to run, only the original drives uses 12v. You can either remove the 12v or put a 300 ohm resistor on the 12v and Gnd.

      The heat issues occur because of no proper air flow, due to the removal of the GDROM. I personally used a cardboard air filter inside the case using a 300 ohm resistor on the PSU and there are no problems after 14 hours continous play. The heat problems people mention IMO are blown out of proportion and not as bad as it’s made out to be.

      • Any chance of a picture tutorial or an illustration of this mod somewhere so others can follow?
        I dont seem to have those issues but prevention is better than cure


      • Hi, can you tell me more about the cardboard air filter? Do you have pics?

  16. Happy Birthday for the GDEMU and Rhea/Phoebe Project.
    It’s been a whole year for receiving my first GDEmu and Rhea set.Thanks Deunan!And wish we will get to see the PCE suite in near future.


  17. As the date for the next batch isn’t known yet. What is the best way not to miss it? Is there a newsletter? Or do I have to check this blog again and again (which I’ll do if I have to.. ;-))? Any help appreciated, thanks!

  18. How did you actually start? I mean how did you start developing the tools and what did you use to communicate with the consoles (serial port)? Do you have the Dev Kits for them?

  19. Hoping more are available and an update comment will trigger an email, as well as daily checking for updates😉

  20. Was wondering if anyone has gotten “King of Fighters 95” to work with their RHEA? I’ve got the official KOF ’95 rom cart inserted firmly in the cartridge slot but always get a message on screen saying insert ROM cart and try again. My saturn console, game dumps, and rom cart are all Japanese region. I also tried different game dump types like .bin .cue, and .mdf. The cartridge slot is working properly when I use Action Replay.
    Any help would be appreciated! Thanks

    • Sorry, nevermind… just learned that the Saturn cartridge slot is getting finicky. Tried re-seating it a few times and now game loads fine🙂

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