Author Topic: Would it be possible to emulate the CD drive on an EverDrive?  (Read 7311 times)

0 Members and 1 Guest are viewing this topic.

Offline Great Hierophant

  • Sr. Member
  • ****
  • Posts: 263
  • Karma: +19/-0
    • View Profile
I believe it could be possible to emulate a CD drive with an EverDrive-like device in the Game Card/HuCart slot. 

The original CD-ROM connected to the console through the expansion bus connector.  Although the expansion bus has 69 pins to the card connector's 38, the CD attachment does not use most of those pins.  In fact, once you eliminate the video and audio inputs, the card connector is missing only one "necessary" pin, the CD detect.  (At least according to here : http://www.gamesx.com/misctech/pcebp.php)

The current EverDrive provides 4MB of RAM to store games, but presumably it can be used for other purposes.  Of course the EverDrive hardware may need the RAM for its functions. 

The CD Unit provides an extra 64KB of work RAM and 64KB of ADPCM sample RAM.  The System Card provides a 256KB ROM BIOS and the Super System Card provides a 256KB ROM BIOS and 192KB of work RAM.  The Arcade Card adds an additional 2MB.  In theory the current EverDrive has the RAM to support the drive functions.

The CD interface would only have to be emulated to the extent it transmits data to the RAM.  Perhaps the CD BIOS can be hacked to simplify the process.  The timings would need to be preserved. 

Audio is a bit tricky.  The card connector has a single audio input in, so if the EverDrive wanted to support stereo audio, it would have to add an audio mini-jack.  CD audio streams at 150KB/sec, which is well within the transfer specs of an SD card.  Turbo CDs are not copy protected, so a standard BIN/CUE file format should serve to keep the data and audio in sync.  ADPCM would need to be emulated, but if the current FPGA does not have sufficient logic cells, then perhaps a future EverDrive may have the capabilities.
« Last Edit: March 06, 2016, 09:15 PM by Great Hierophant »
Check Out My Vintage Video Game & Computing Blog : http://nerdlypleasures.blogspot.com/

Offline gojira54

  • Jr. Member
  • **
  • Posts: 88
  • Karma: +7/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #1 on: March 05, 2016, 09:24 PM »
This guy is already on it;
https://gdemu.wordpress.com/2016/01/05/frostbite/
Hopefully he or someone else can get an ODE completed for the PCE, I really really hate how unreliable the PCE CD systems are :/

Offline Great Hierophant

  • Sr. Member
  • ****
  • Posts: 263
  • Karma: +19/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #2 on: March 06, 2016, 04:28 AM »
With GDEMU, Rhea, PSIO, Optical Drive Emulators for the most popular disc-only consoles of the 1990s seem to be well in hand.  As for the Neo Geo, 3D0, Sega, PCE/Turbo Duo and Jaguar CDs, I do not know of any ODEs in development except as noted by the previous post. 

The Sega CD is actually much more complex than the PC Engine CD.  It has a 68000 coprocessor, more RAM, more PCM sound channels and additional graphical capabilities.  I wouldn't expect the Mega EverDrive to be able to emulate it. 
« Last Edit: March 06, 2016, 04:53 AM by Great Hierophant »
Check Out My Vintage Video Game & Computing Blog : http://nerdlypleasures.blogspot.com/

Offline Duo_r

  • Jr. Member
  • **
  • Posts: 55
  • Karma: +1/-0
    • View Profile
Would it be possible to emulate the CD drive on an EverDrive?
« Reply #3 on: April 09, 2016, 07:32 PM »
Any of those devices work ok? I read really bad reviews on the PSIO.


Sent from my iPhone using Tapatalk

Offline badsector

  • Jr. Member
  • **
  • Posts: 76
  • Karma: +7/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #4 on: April 10, 2016, 12:43 AM »
Where?
My EverDrives: EverDrive 64, EverDrive N8 (NES), Super EverDrive, EverDrive MD, EverDrive GB, Turbo EverDrive, Master EverDrive, EverDrive GG

Offline Greg2600

  • Sr. Member
  • ****
  • Posts: 287
  • Karma: +7/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #5 on: April 10, 2016, 01:33 AM »
softmod an original Xbox, the emulator runs all TurboCD or PCE CD games perfectly. 

Offline TDIRunner

  • Full Member
  • ***
  • Posts: 155
  • Karma: +9/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #6 on: April 10, 2016, 07:41 AM »
Any of those devices work ok? I read really bad reviews on the PSIO.


Sent from my iPhone using Tapatalk

GDEMU is fantastic.  I've been very happy with it.  Using the GDMenu solves the only major complaint I had, which was the lack of a menu. 
Maybe, just once, someone will call me "sir" without adding, "you're making a scene."

Turbo EverDrive    EverDrive N8    SD2SNES    EverDrive64 v3    EverDrive GB    EverDrive GBA    Master EverDrive    Mega EverDrive    EverDrive GG

Offline pckid

  • Full Member
  • ***
  • Posts: 114
  • Karma: +4/-1
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #7 on: April 10, 2016, 10:44 AM »
I believe it could be possible to emulate a CD drive with an EverDrive-like device in the Game Card/HuCart slot. 

The original CD-ROM connected to the console through the expansion bus connector.  Although the expansion bus has 69 pins to the card connector's 38, the CD attachment does not use most of those pins.  In fact, once you eliminate the video and audio inputs, the card connector is missing only one "necessary" pin, the CD detect.  (At least according to here : http://www.gamesx.com/misctech/pcebp.php)

The current EverDrive provides 4MB of RAM to store games, but presumably it can be used for other purposes.  Of course the EverDrive hardware may need the RAM for its functions. 

The CD Unit provides an extra 64KB of work RAM and 64KB of ADPCM sample RAM.  The System Card provides a 256KB ROM BIOS and the Super System Card provides a 256KB ROM BIOS and 192KB of work RAM.  The Arcade Card adds an additional 2MB.  In theory the current EverDrive has the RAM to support the drive functions.

The CD interface would only have to be emulated to the extent it transmits data to the RAM.  Perhaps the CD BIOS can be hacked to simplify the process.  The timings would need to be preserved. 

Audio is a bit tricky.  The card connector has a single audio input in, so if the EverDrive wanted to support stereo audio, it would have to add an audio mini-jack.  CD audio streams at 150KB/sec, which is well within the transfer specs of an SD card.  Turbo CDs are not copy protected, so a standard BIN/CUE file format should serve to keep the data and audio in sync.  ADPCM would need to be emulated, but if the current FPGA does not have sufficient logic cells, then perhaps a future EverDrive may have the capabilities.

Hello

i think so it's possible, and it's not a problem in hardware for igor, but it's a probleme to code it in asm, for this card.

If an expert an asm, can help igor to modify this, it' ll be great Day : the "D" day, cause juste a pc engine to start all the game of the greatest library of the pc engine.

Same in the first time, we don't have adpcm emulator, just start an iso from hucard flash, it' ll be great.

So i wait this for a long time !

Offline Arnold101

  • Sr. Member
  • ****
  • Posts: 353
  • Karma: +4/-1
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #8 on: June 01, 2016, 02:13 AM »
softmod an original Xbox, the emulator runs all TurboCD or PCE CD games perfectly.
the genius. yes but not in 240p = useless

Offline RetroDanâ„¢

  • Newbie
  • *
  • Posts: 29
  • Karma: +2/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #9 on: July 14, 2016, 01:06 AM »
The Sega CD is actually much more complex than the PC Engine CD.  It has a 68000 coprocessor, more RAM, more PCM sound channels and additional graphical capabilities.  I wouldn't expect the Mega EverDrive to be able to emulate it.

But ultimately pointless to make an ODE for it, seeing as the Sega CD has ZERO copy protection.  "Oh, hello, Mister Burned Disc!  What's that, you say?  You'd like me to play you without any problems or hardware haggling at all?  Sounds lovely - I'll get right on that!"

Offline butfluffy

  • Hero Member
  • *****
  • Posts: 842
  • Karma: +46/-8
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #10 on: July 14, 2016, 04:28 AM »
the copy protection is not the reason why people want ODE solutions for some of these old systems. ok burning the backup and playing it just fine is a good thing but the issue with these old systems is just that they are old and the lasers wear out sooner or later.
 the best solution for any old cd based system is ODE devices, i would like to have ODE solutions for all old systems, i don't know if that will happen though.

Offline FeverDrive

  • Hero Member
  • *****
  • Posts: 1188
  • Karma: +52/-0
  • Blast Processing™ inside
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #11 on: July 14, 2016, 11:58 PM »
the best solution for any old cd based system is ODE devices, i would like to have ODE solutions for all old systems, i don't know if that will happen though.

There will be ODE devices for all the old systems, it's just a matter of time.

softmod an original Xbox, the emulator runs all TurboCD or PCE CD games perfectly. 

Shhhh, don't use that word around here, you could get in trouble.
And so I go fast.

Offline Missingno255

  • hi
  • Sr. Member
  • ****
  • Posts: 281
  • Karma: +12/-1
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #12 on: July 15, 2016, 09:32 AM »
the emulator

Quote
Shhhh, don't use that word around here, you could get in trouble.
EMULATOR

:D
Owned Everdrives: Everdrive MD, Mega Everdrive, Everdrive N8, Everdrive GB X5, Turbo Everdrive, Super Everdrive, Everdrive GBA

Misc Flashcarts: SD2SNES

Offline LDigital

  • Jr. Member
  • **
  • Posts: 86
  • Karma: +5/-0
    • View Profile
Re: Would it be possible to emulate the CD drive on an EverDrive?
« Reply #13 on: July 15, 2016, 06:27 PM »
despite its popularity and the demand for it, there will be no ODE for PCE for a long time, unless something comes out of left field from a different developer.

I have been following D's progress on it and am in contact with him from time to time and it seems as far away as ever at the moment due to time constraints.