Internal Memory + VGA questions

[GhaleonX]

I've come across a couple things about using a SD card as a memory card for the DC, but can't seem to find a clear way to go about building one. I'm also still assuming that nobody's gotten a hdd to work at a decent speed and/or flash drives. Is it possible to load any games off the SD card, or is it working just like a VMU? I would like to build one of these as well.

I'm also thinking of wiring a VGA port; all the schematics I've found are confusing, however. Why can't I just wire it directly to the pins like on the xbox/360 (instead of adding capacitors, etc)?

[tom61]

I've never heard of using an SD card with a Dreamcast, are you sure you're not thinking of the Game Cube? You can forgo the caps, but your video will likely be dark.

[GhaleonX]

I've never heard of using an SD card with a Dreamcast, are you sure you're not thinking of the Game Cube?

http://www.emuforge.com/wiki/index.php? ... eamcast_SD" onclick="window.open(this.href);return false;

[tom61]

I've never heard of using an SD card with a Dreamcast, are you sure you're not thinking of the Game Cube?

http://www.emuforge.com/wiki/index.php? ... eamcast_SD" onclick="window.open(this.href);return false;

Rather interesting.

According to the Spanish page, right now it's only used to transfer save states to/from the VMU (via a program you have to load separately from a game), and for a handful of homebrew emulators. Not to say that it couldn't be made to load games, or hasn't been already.

As for making one, the Japanese page linked has a simple diagram: http://f17.aaa.livedoor.jp/~takotako/dc ... php#sdcard" onclick="window.open(this.href);return false;

[GhaleonX]

Thanx for the link and tidbit of info; what's more interesting, is from the "some english" that's on the page, it seems you can actually rip a GD-ROM to a SD card, which would've come in handy years ago (or still if you could get it to read the games from the SD card).

An idea just struck my brain to gut a CD changer that's collecting dust in my closet, and make it a Dreamcast with all my games.... shouldn't be too hard, I'd imagine, especially since it's much bigger than the DC (and probably has enough room to fit the mainboard in).... I'll check it out at least...

[tom61]

Thanx for the link and tidbit of info; what's more interesting, is from the "some english" that's on the page, it seems you can actually rip a GD-ROM to a SD card, which would've come in handy years ago (or still if you could get it to read the games from the SD card).

An idea just struck my brain to gut a CD changer that's collecting dust in my closet, and make it a Dreamcast with all my games.... shouldn't be too hard, I'd imagine, especially since it's much bigger than the DC (and probably has enough room to fit the mainboard in).... I'll check it out at least...

Woah... I don't think the page loaded fully last time I visited, that DCSDRip screenshot and mod to the front looks awesome. Time to run the page through Google Translate.

Edit: Google Translate didn't handle the page at all, Bablefish could do it though: http://babelfish.yahoo.com/translate_ur ... =Translate" onclick="window.open(this.href);return false;

Edit2: If you could find a way to integrate the loader program into the BIOS or a mod chip, you could potentially not need the Dreamcast's GD ROM at all for a portable.

[GhaleonX]

Well, that'd be quite nice. I'd definitely consider turning it into a portable if I could make it "drive-less". I'm re-considering using the CD changer, as when I opened it up, I wasn't entirely sure how I could wire it together
I'm sure I could figure it out without too much fuss, but since my workspace is quite limited at the time, I don't wanna take this project on until after I move.

In the meantime, I'd like to build my own adapter for PS2 controlers if I can. Does anybody have a schematic for one? I've even got some dead PS2's which I can use the control ports from (Though it'd be real nice if I could get a 360/PS3 controller to work).

[MegatronUK]

It's rather amazing what people are still managing to do with the Dreamcast after this length of time.

Solid-state storage and removal of optical drives is definitely the way to go.

[APE992]

Thanx for the link and tidbit of info; what's more interesting, is from the "some english" that's on the page, it seems you can actually rip a GD-ROM to a SD card, which would've come in handy years ago (or still if you could get it to read the games from the SD card).

An idea just struck my brain to gut a CD changer that's collecting dust in my closet, and make it a Dreamcast with all my games.... shouldn't be too hard, I'd imagine, especially since it's much bigger than the DC (and probably has enough room to fit the mainboard in).... I'll check it out at least...

Woah... I don't think the page loaded fully last time I visited, that DCSDRip screenshot and mod to the front looks awesome. Time to run the page through Google Translate.

Edit: Google Translate didn't handle the page at all, Bablefish could do it though: http://babelfish.yahoo.com/translate_ur ... =Translate" onclick="window.open(this.href);return false;

Edit2: If you could find a way to integrate the loader program into the BIOS or a mod chip, you could potentially not need the Dreamcast's GD ROM at all for a portable.

Erm sorry to bump a pseudo-old topic and burst your proverbial bubble, but that SD system uses bit banging which (based on my EXTREMELY rough understanding of the topic) is based a bit more around the MMC compatibility of the SD card rather than a full implementation of SD. The graphic down the page showing the LCD confirmed my suspicions when it said "bit banging"; I'm not a coder but I can tell you bit banging is nowhere near as fast as an actual gd-rom. Now why bitbanging and not a true implementation of the SD spec? You need to license the SD tech out and only so much of it is available for free. I'm guessing the full spec hasn't been reverse engineered or something otherwise you'd see the DC working with it on some level.

Or maybe its the fact the SD card is wired up through serial rather than a faster bus capable of more input and what not. Might be able to build an interface between the gd-rom hardware and an SD card though, need that electrical engineering degree first.

[tom61]

Erm sorry to bump a pseudo-old topic and burst your proverbial bubble, but that SD system uses bit banging which (based on my EXTREMELY rough understanding of the topic) is based a bit more around the MMC compatibility of the SD card rather than a full implementation of SD. The graphic down the page showing the LCD confirmed my suspicions when it said "bit banging"; I'm not a coder but I can tell you bit banging is nowhere near as fast as an actual gd-rom. Now why bitbanging and not a true implementation of the SD spec? You need to license the SD tech out and only so much of it is available for free. I'm guessing the full spec hasn't been reverse engineered or something otherwise you'd see the DC working with it on some level.

Or maybe its the fact the SD card is wired up through serial rather than a faster bus capable of more input and what not. Might be able to build an interface between the gd-rom hardware and an SD card though, need that electrical engineering degree first.

The speed of 'bit banging' is determined by the speed of the processor, interface and the efficiency of the program doing the driving. The SH-4 and the DC's serial port are both fairly capable. The serial port in it is much faster than the RS-232 serial you'd find on older PCs, and is capable of 1.5Mb/s in either direction.

Additionally, SD support up to and including SDHC is now supported with open drivers.

[marshallh]

the speed at which the DC software can bit-bang the serial port is not a problem, emulating the GD-ROM controller at a low enough level is the problem. You'd have to disassemble the BIOS, trap all the GD commands and add your own routines for SD.

[tom61]

the speed at which the DC software can bit-bang the serial port is not a problem, emulating the GD-ROM controller at a low enough level is the problem. You'd have to disassemble the BIOS, trap all the GD commands and add your own routines for SD.

Why is that an issue? I don't think most games access the GD-Rom hardware directly. Burns on a different media (CDROMs instead of GDROMs) work, streaming over serial works, and streaming over a network works as well. So even if they do need to be emulated, the code is out there already.