bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Discuss modifications you have done or plan to do to your Dreamcast or any other hardware, or discuss devices you want to build. If your console does not work or is acting up, ask about fixing it in here.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by BlueCrab »

There's no known way to boot the system off of anything but the GD-ROM drive without replacing the BIOS.

The IDE interface is simply a fun thing to play with after the system is booted. It could, of course, be paired with a BIOS replacement as Dan Potter was doing with his navi project.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Anthony817 »

What about putting an sdiso of the OS on a sd card and launching it via Dreamshell? It would be able to boot without the GDR drive and everybody is happy. :grin:

With the Dreamshell bios mod, you could have this fully working with no moving parts but the HDD. Anyway, while the SD adapters are no true GDR drive replacement, they could accentuate this IDE interface, by being the medium that the os is loaded from. Kinda like loading an OS from a solid state partition, and having a standard HDD for various programs and whatnot just like many pc's do.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Quzar »

Anthony817 wrote:What about putting an sdiso of the OS on a sd card and launching it via Dreamshell? It would be able to boot without the GDR drive and everybody is happy. :grin:

With the Dreamshell bios mod, you could have this fully working with no moving parts but the HDD. Anyway, while the SD adapters are no true GDR drive replacement, they could accentuate this IDE interface, by being the medium that the os is loaded from. Kinda like loading an OS from a solid state partition, and having a standard HDD for various programs and whatnot just like many pc's do.
Like he said: 'without replacing the BIOS'
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by spinksy »

Anymore progress ?
Dreamcast, it's still thinking.

Over-clocked : Dreamcast currently running at 240Mhz (switchable)

Internal VGA, extra cooling fans, disc activity LED, SD card reader done :-)

Dreamcast HD wanted
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Neoblast »

The thing that could work without changing the bios, is like the sd adapter for the gamecube, the one that replaces the lens...

Creating some sort of pcb which translates sega's SPI to IDE ( for hard drives ) or something like SD's or USB storage media...

So the dreamcast would still "think" there's a GD DRIVE there...

All the documentation required and the specifications to do it are out there, point is having the neccessary knowledge and time to do something like that.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Quzar »

Neoblast wrote:The thing that could work without changing the bios, is like the sd adapter for the gamecube, the one that replaces the lens...

Creating some sort of pcb which translates sega's SPI to IDE ( for hard drives ) or something like SD's or USB storage media...

So the dreamcast would still "think" there's a GD DRIVE there...

All the documentation required and the specifications to do it are out there, point is having the neccessary knowledge and time to do something like that.
deunan of makaron did that. It's MUCH more complex than simply changing the BIOS. http://dknute.livejournal.com/2008/12/16/
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Calavera »

Would it be possible to hook an IDE CD-ROM drive to this? I know it would only play backups due to CD-Drives being unable to read GDs but I wonder if it is possible. The reason I ask is because such a device has already been released for the 3DO, allowing to use any IDE CD drive if your factory drive has quit working, I've heard it also improves load times.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Neoblast »

It is more difficult to develop, but easier to use for the end user.
These gadgets could be mass produced, changing the bios is a mess anytime.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Ex-Cyber »

IIRC, the problem with mass-producing an easy GD-ROM replacement is that the connector isn't made anymore. Tooling for connectors is generally pretty damn expensive.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Neoblast »

Ex-Cyber wrote:IIRC, the problem with mass-producing an easy GD-ROM replacement is that the connector isn't made anymore. Tooling for connectors is generally pretty damn expensive.

Actually I think they are made, don't remember the product number but I know of someone who does, he was researching that very same thing. You can order connectors in bulk...
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Quzar »

Neoblast wrote:It is more difficult to develop, but easier to use for the end user.
These gadgets could be mass produced, changing the bios is a mess anytime.
Someone could easily develop a packaging for a replacement bios chip that simply piggybacks onto the current one. I believe only one leg need be cut from the original to make a new one work, all the rest of the legs just need contact with those already in place.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Ex-Cyber »

IIRC, it would more likely piggyback onto the Flash chip rather than the BIOS ROM, since you want a Flash pinout and not a mask ROM pinout (they're usually different because of /WE vs. an extra address pin).
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Quzar »

I'm not sure why you would think the flash chip would have anything to do with it. I'm basing my notion off Dan's work with NAVI where he did the same thing and left the ability to switch back to the 'stock' firmware:

Look at step 4.

http://cadcdev.sourceforge.net/hdwrprj/navi/

Replacing/piggybacking a chip onto the flash chip would do very little, as there's nothing interesting you can really put into there that you can't already do by simply editing it.
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Ex-Cyber »

I meant that you'd run the chip select from the BIOS, not put the piggybacked chip in the Flash address space. You'd just be using the flash to get at the address/data/OE/WE pins. Come to think of it, though, I'm not sure it would be the same footprint for a decently sized Flash chip. It's been a while since I've been inside my DC.

edit: actually, does the BIOS run directly from ROM, or does it copy itself to RAM first? If the latter, shouldn't it be possible to just commandeer the stock DC flash for a bootloader/patcher by wiring the Flash and ROM /CE signals to a switch that swaps them around?
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Quzar »

The only thing that gets written to memory are the syscalls IIRC. This is what allows them to be hooked into (I believe that's how dcload does it's iso emulation).
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by Sidewinder »

damn shame what they did to that dog.... I mean... sad that no one else seemed to finish this. I know that there's a harddrive mod that replaces the GDROM drive but I'd like to KEEP my gdrom. seeing as I've spent years taking care and repairing my 3 dreamcasts I rather like the disc based options on occasion. After checking the technical manuals the G2 bus has protocols and applications specifically in tagging that would identify the drive as PCI device and can use ATA standards in the asynchronous mode. Naturally booting straight from the drive without classifying it as a 'sega legit' device (Serial ID6 0x000c) or perhaps just a prototype. There are bits available for a simple IDE interface as well as simple ISA interface but seems that if you were to gain any specific usability out of them it would need information in the registers to make it usable.
I suppose if everyone else has given up on this task I'll take it one cause it would be nice to have a working GDROM drive but a usable (if perhaps slow) IDE drive for development purposes. I do, however, think there's a way to allow the system to think it's allowed to boot from the HDD as the Katana system has an option specifically for that (naturally it's a develoment kit) purpose. Seems we might just need a dump of a Katana's rom to check to see perhaps what's different
|darc|
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Re: bitmaster's IDE/G2 interface aka DREAMCAST HARD DRIVE>!!!

Post by |darc| »

Sidewinder wrote: Thu Mar 07, 2024 3:22 pmI know that there's a harddrive mod that replaces the GDROM drive but I'd like to KEEP my gdrom. seeing as I've spent years taking care and repairing my 3 dreamcasts I rather like the disc based options on occasion.
The G1 hard drive mod already can be configured with GD-ROM + HDD at the same time! This is how I have it set up on my development system. I have a dual BIOS system where BIOS bank A is the standard Sega BIOS (with region-free patch) to boot from a disc and BIOS bank B is a bootloader menu allowing to boot from the hard drive or SD card.
Sidewinder wrote: Thu Mar 07, 2024 3:22 pmI do, however, think there's a way to allow the system to think it's allowed to boot from the HDD as the Katana system has an option specifically for that (naturally it's a develoment kit) purpose. Seems we might just need a dump of a Katana's rom to check to see perhaps what's different
I'm pretty sure this is an emulation of the GD-ROM drive, so it wouldn't really apply
It's thinking...
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