SpritesMind.Net

RE: Cartridge bigger than 32Mbits ?

Chilly Willy — Sun, 05 Feb 2012 21:19:57 +0100

Author: Chilly Willy
Posted: Sun Feb 05, 2012 8:19 pm (GMT 0)
Topic Replies: 20

ammianus wrote:

That is great info, thanks.

In your SH2 example, what is the type and value of "bank"? just an integer to represent an area?

Bank is an int between 0 and 9 (ten banks to make 5MB of rom).

Quote:

So there are banking "areas", is this right?

As mentioned earlier, the rom space of 4MB is split into 8 512KB sections. The first section cannot be changed, while all the rest can be set to any value from 0 to (# banks - 1). While the SEGA mapper allows up to 63 (32MB), flash carts currently only allow up to 9 since the biggest game ever made was 5 MB. At some point someone may make a cart that allows for the full range.

Quote:

Does each of the 0-8 areas have a fixed address? e.g. area 6 = 0x600000 ?

Regions
0 = 0x000000 - 0x07FFFF
1 = 0x080000 - 0x0FFFFF
2 = 0x100000 - 0x17FFFF
3 = 0x180000 - 0x1FFFFF
4 = 0x200000 - 0x27FFFF
5 = 0x280000 - 0x2FFFFF
6 = 0x300000 - 0x37FFFF
7 = 0x380000 - 0x3FFFFF

The SEGA mapper allows regions 1 to 7 to be changed. The NeoMyth only allows you to change regions 6 and 7. I don't know which regions the Everdrive allows, but to be compatible, it cannot change 0 and must also allow changes to 6 and 7.

Quote:

Also, reading through Devster's 32X guide, is this true?

Quote:

32X Cartridges...
When accessing the cartridge from the 68k and sh2, the sh2 gets to access it first. The
68k can only access cartridge rom from the bank areas. The 68k does not have full view
of the rom. The sh2 does not need any banking areas, and it has full view of the rom.

and he explained using the bankswitch as always switiching 1 MB to 0x900000 (or is that a typo):

Quote:

0x04.w Cartridge Bankswitching
-------------------------------
Write: Bits 0-1: Determines which 1 mb long cartridge ROM bank will appear at
0x900000-0x9FFFFF on the 68k. Each bank is one megabyte long.

Bankswitching Example Values (FOR THE 68k !!!)
0x0000: 0x900000-0x9FFFFF appears as 0x000000-0x0FFFFF ROM
0x0001: 0x900000-0x9FFFFF appears as 0x100000-0x1FFFFF ROM
0x0002: 0x900000-0x9FFFFF appears as 0x200000-0x2FFFFF ROM
0x0003: 0x900000-0x9FFFFF appears as 0x300000-0x3FFFFF ROM

Read: Reflects the bank that is set

Yes, that's all correct... unless you set the RV bit. While RV is set, the rom appears to the 68000 at the "normal" location. When RV is not set, the first 512KB of the rom space actually appears at 0x880000 to 0x8FFFFF. That is fixed and cannot be changed. If you run 68000 code from the rom in a 32X game, it should probably be in that space.

Also while RV is not set, the 68000 can reach the rest of the rom space by using a single bank at 0x900000 to 0x9FFFFF. That bank can be set to any 1MB offset inside the rom space as shown by the bankswitching table above. That is to reach the ROM SPACE - once you reach that rom space, the actual rom location is determined by the mapper as explained at the very top. So there are TWO bank switching mechanisms you need to deal with on the 32X - the bank for the 68000 while RV is not set, and the banks handled by the mapper in the cart itself.

RE: 32X strengths

ammianus — Sun, 05 Feb 2012 15:10:06 +0100

Author: ammianus
Posted: Sun Feb 05, 2012 2:10 pm (GMT 0)
Topic Replies: 41

What about using the CPU power and larger color palette for 2d games with a lot of animation through transforms (by software), or including 3d elements / effects?

I am thinking along the lines of Castlevania: Symphony of the Night, which had a lot of neat effects.
- The "3d" spinning coffin at save points
- A number of the enemies appeared to be collections of 2d polygons/sprites, so the movement was through transforms of those polygon "parts" instead of sprites of the whole character for each step of the animation. (maybe that's just an illusion). For example if memory serves this guy and his swords.http://faqsmedia.ign.com/faqs/image/article/762/762052/monster085.jpg, or http://faqsmedia.ign.com/faqs/image/article/762/762052/monster083.jpg
- Other effects like some of the spells, the fast moving clouds of some of the backgrounds, transparency of enemies, projectiles, fog.
- Obviously CD quality sound and the large size of that game are different animals due to storage size of a CD, but purely technically, some of the game elements that SotN did should be possible on 32X too?

I don't have Kolibri, but from youtube vidoes I am very impressed by the smoothness of the game and the nice detailed environment. Is that looking so well purely because of larger color palette?

What about a sort of car/bike racer like the Genesis Road Rash games, but again with more elements and better graphics? Or it always seemed to me that at high speeds or in 2-player mode, RR games became sort of jerky and the stuff would pop out at you from no where, perhaps the 32X could support a better framerate? I had Motocross 32X, and it kind of did some of these things with better graphics, although game play wasn't that great, more to do with game design than anything in the hardware I would think.

I am a big fan of classic 2d games/genres overall, would love to see some impressive stuff on 32x, expanding on what could be done on the MD, rather than more 3d FPS games (enough of them already!).

Edit: is sound capability of 32X the same as in the Genesis?

RE: Cartridge bigger than 32Mbits ?

ammianus — Sun, 05 Feb 2012 14:07:39 +0100

Author: ammianus
Posted: Sun Feb 05, 2012 1:07 pm (GMT 0)
Topic Replies: 20

Also, reading through Devster's 32X guide, is this true?

Quote:

and he explained using the bankswitch as always switiching 1 MB to 0x900000 (or is that a typo):

Quote:

RE: Cartridge bigger than 32Mbits ?

ammianus — Sun, 05 Feb 2012 13:57:46 +0100

Author: ammianus
Posted: Sun Feb 05, 2012 12:57 pm (GMT 0)
Topic Replies: 20

Chilly Willy wrote:

The 32X devkit docs and examples. The 32X can also use the standard SEGA mapper, but you have to remember a couple things:

Only the 68000 can access the mapper, so if the SH2 needs a map register updated, you have to communicate with the 68000 to do that.

Like when accessing the sram, disable ints on the 68000, set the RV bit, set the mapper register, clear the RV bit, then enable ints. Make sure the code doing this is in ram to avoid any issues with the rom changing. I made an example of using the mapper with the SH2, playing 5 MB worth of PCM audio.

The main parts are:

68000 code

Code:

set_cart_bank:
move.w #0x2700,sr /* disable ints */
andi.w #0x0007,d0 /* area */
add.w d0,d0
move.w 0xA15122,d1 /* COMM2 holds bank # */
andi.w #0x003F,d1
lea 0xA130F1,a0 /* bank control */
move.b #1,0xA15107 /* set RV */
move.b d1,0(a0,d0.w) /* set area to cart bank */
move.b #0,0xA15107 /* clear RV */
move.w #0,0xA15120 /* done */
move.w #0x2000,sr /* enable ints */
bra main_loop

SH2 code

Code:

MARS_SYS_COMM2 = bank;
MARS_SYS_COMM0 = 0x0606; // set area 6 to bank N
while (MARS_SYS_COMM0) ;
MARS_SYS_COMM2 = bank + 1;
MARS_SYS_COMM0 = 0x0607; // set area 7 to bank N+1
while (MARS_SYS_COMM0) ;

That shows the SH2 setting two different banks. As long as that code isn't in the bank area itself, you're okay. The first bank (512KB) can't be changed, so that shouldn't be a problem. You can only change banks 1 to 7, and the Neo Myth flash cart only supports changing banks 6 and 7, and only to a max of 10 banks (5MB). The Everdrive flash cart also only allows for 5MB, but I don't know which banks it allows you to change. The flash carts don't allow for the full range of what the SEGA mapper allows, only what is used by SSF2.

That is great info, thanks.

In your SH2 example, what is the type and value of "bank"? just an integer to represent an area?

So there are banking "areas", is this right?

0 - can't change
1 - 5 areas that could be changed, but not w/ neo myth cart?
6 - 7 areas can be changed w/ neo myth
8 - 9 other areas you can switch into 6 -7?
[10 - N] possible areas not supported by carts?

Does each of the 0-8 areas have a fixed address? e.g. area 6 = 0x600000 ?

Code:

int bank = 8; // want to switch to area 8
MARS_SYS_COMM2 = bank;
MARS_SYS_COMM0 = 0x0606; // set area 6 to bank 8
while (MARS_SYS_COMM0) ;
// read image , data or sounds from the address for area 6

RE: Cartridge bigger than 32Mbits ?

Chilly Willy — Sun, 05 Feb 2012 00:03:00 +0100

Author: Chilly Willy
Posted: Sat Feb 04, 2012 11:03 pm (GMT 0)
Topic Replies: 20

The 32X devkit docs and examples. The 32X can also use the standard SEGA mapper, but you have to remember a couple things:

Only the 68000 can access the mapper, so if the SH2 needs a map register updated, you have to communicate with the 68000 to do that.

Like when accessing the sram, disable ints on the 68000, set the RV bit, set the mapper register, clear the RV bit, then enable ints. Make sure the code doing this is in ram to avoid any issues with the rom changing. I made an example of using the mapper with the SH2, playing 5 MB worth of PCM audio.

The main parts are:

68000 code

Code:

SH2 code

Code:

MARS_SYS_COMM2 = bank;
MARS_SYS_COMM0 = 0x0606; // set area 6 to bank N
while (MARS_SYS_COMM0) ;
MARS_SYS_COMM2 = bank + 1;
MARS_SYS_COMM0 = 0x0607; // set area 7 to bank N+1
while (MARS_SYS_COMM0) ;

Replace Road Rash II Music With Road Rash Music?

fshea31 — Sat, 04 Feb 2012 23:47:29 +0100

Author: fshea31
Posted: Sat Feb 04, 2012 10:47 pm (GMT 0) Subject: Replace Road Rash II Music With Road Rash Music?

Topic Replies: 0

Hello, I was on here a little over three years ago trying to get Road Rash working properly on my PS2 Genesis emulator. I couldn't figure it out, but I wanted to ask if my next idea was possible for a novice.

I was wondering if I could easily replace the music in Road Rash II with the music in the original Road Rash. The games are very similar, so I was hoping copying and replacing within a hex editor would be an option.

Thank you.

RE: Cartridge bigger than 32Mbits ?

ammianus — Sat, 04 Feb 2012 22:00:41 +0100

Author: ammianus
Posted: Sat Feb 04, 2012 9:00 pm (GMT 0)
Topic Replies: 20

Snake wrote:

Yup, this is official sega banking hardware. It annoys me slightly that this stuff has become known as "SF2 banking" or "PS4 banking" when its clearly documented (and well enough that it didn't need to be redocumented) in sega manuals as standard hardware.

This is probably a really noob question, but which document are you referring to exactly?

RE: Super Magic Drive research thread

KanedaFr — Sat, 04 Feb 2012 03:03:39 +0100

Author: KanedaFr
Posted: Sat Feb 04, 2012 2:03 am (GMT 0)
Topic Replies: 129

disassembly as soon as possible

RE: AbbayeMD

KanedaFr — Sat, 04 Feb 2012 03:01:29 +0100

Author: KanedaFr
Posted: Sat Feb 04, 2012 2:01 am (GMT 0)
Topic Replies: 7

Wow! you're working on an deluxe version of abbaye!

RE: Super Magic Drive research thread

greatfunky — Fri, 03 Feb 2012 13:27:09 +0100

Author: greatfunky
Posted: Fri Feb 03, 2012 12:27 pm (GMT 0)
Topic Replies: 129

Hi all !
I realized today that i have a smd with an undumped/unknown bios 3.3C .
So i have dumped it with my double pro fighter .

the difference between 3.3 & 3.3c : in the menu "load file , save file " is back again like in 3.1g version !
https://rapidshare.com/files/458231229/bios3.3c.rar

RE: Emulating Pioneer LaserActive (Mega-LD) games

Nemesis — Fri, 03 Feb 2012 09:36:28 +0100

Author: Nemesis
Posted: Fri Feb 03, 2012 8:36 am (GMT 0)
Topic Replies: 60

I've got this on the backburner for a few days while I work on other projects. I'll come back and have a fresh look at it again soon. The dumping program is very close to working now, so I don't think it'll take much longer.

RE: AbbayeMD

Moon-Watcher — Fri, 03 Feb 2012 01:43:26 +0100

Author: Moon-Watcher
Posted: Fri Feb 03, 2012 12:43 am (GMT 0)
Topic Replies: 7

Thanks guys for your advice and suggestions. AbbayeMD is still in development.

Recently I've been interviewed about AbbayeMD >> link (spanish)

RE: Emulating Pioneer LaserActive (Mega-LD) games

THE_MOOGLEKING — Thu, 02 Feb 2012 07:49:19 +0100

Author: THE_MOOGLEKING
Posted: Thu Feb 02, 2012 6:49 am (GMT 0)
Topic Replies: 60

How goes it? May be getting a copy of 3D Museum soon, so there's that on the table as well.

RE: 315-5339

Huge — Thu, 02 Feb 2012 02:32:14 +0100

Author: Huge
Posted: Thu Feb 02, 2012 1:32 am (GMT 0)
Topic Replies: 3

Excellent comparison pictures... I wonder how many Megadrive models there were total, and what the exact differences were between each model.

And one day, I'm surely going to start building a database on their parts numbers.

RE: Double-Screen?

Bitybity — Tue, 31 Jan 2012 00:38:57 +0100

Author: Bitybity
Posted: Mon Jan 30, 2012 11:38 pm (GMT 0)
Topic Replies: 8

Gigasoft wrote:

Then it should work correctly. How does the picture you get differ from what you intended?

The upper part of the screen with normal VScroll, and the other in vertical position $0000.