Search found 594 matches

by Mask of Destiny
Wed Sep 02, 2020 2:30 am
Forum: Megadrive/Genesis
Topic: List of every detectable difference in Mega Drive revisions?
Replies: 17
Views: 1582

Re: List of every detectable difference in Mega Drive revisions?

That's something I didn't know, I mainly only commented among the actual consoles (except MD2 VA2, which I would like to get and a VA0 MD1). Discrete YM3438 has longer busy bit cycle from what I remember reading from nukeYKT core notes, compared to 2612 and ASIC which would be another way to detect...
by Mask of Destiny
Sat Aug 22, 2020 2:50 am
Forum: Megadrive/Genesis
Topic: List of every detectable difference in Mega Drive revisions?
Replies: 17
Views: 1582

Re: List of every detectable difference in Mega Drive revisions?

TmEE co.(TM) wrote:
Fri Aug 21, 2020 5:30 pm
YM3438 only appeared as a block integrated in the MD2 ASIC, which first appeared in MD1 VA7 (the awful sounding MD1s lol).
The Teradrive has a discrete YM3438 and in the other direction there are the MD2 VA2/VA2.3 which have a discrete YM2612.
by Mask of Destiny
Thu Aug 20, 2020 5:26 am
Forum: Megadrive/Genesis
Topic: List of every detectable difference in Mega Drive revisions?
Replies: 17
Views: 1582

Re: List of every detectable difference in Mega Drive revisions?

These are the detectable differences I am personally aware of * Open bus behavior of the Z80 bus (MD1 VA3 and later always return FF, earlier consoles will return last value read) * Discrete YM2612 vs Integrated YM3438 (the latter allows status to be properly read on all addresses) * Open bus behavi...
by Mask of Destiny
Fri May 31, 2019 8:14 pm
Forum: Mega/SegaCD
Topic: Bike shedding a new CD-ROM format
Replies: 20
Views: 8387

Re: Bike shedding a new CD-ROM format

I can't find good documentation on what CHD actually does with CDs. So in it's most basic form a CHD is a series of compressed "hunks" of data. Hunks are relatively small (512KB max supposedly) and are compressed individually to allow reasonably random access. For CDs, extra metadata is stored to h...
by Mask of Destiny
Thu May 30, 2019 9:32 pm
Forum: Mega/SegaCD
Topic: Bike shedding a new CD-ROM format
Replies: 20
Views: 8387

Re: Bike shedding a new CD-ROM format

For most "normal" CD-ROM imaging needs, I kind of feel like MAME's CHD format is probably the right way to go. The lack of proper documentation is a bummer, but it handles multi-track data well and can store raw F1 frames + subcode data. It also supports lossless compression of tracks including FLAC...
by Mask of Destiny
Sun Apr 28, 2019 4:06 pm
Forum: Megadrive/Genesis
Topic: Z80 bus + I/O mapping redux
Replies: 7
Views: 4680

Re: Z80 bus + I/O mapping redux

As promised, here's that test ROM and here's the source . * a00000-a0ffff => [8-bit bus] Z80 (A15 is ignored) So this is actually a funny one. On the 68K side, all 16 data lines are connected (via the IO chip because apparently they ran out of pins on the bus arbiter, lol), but the bus being connect...
by Mask of Destiny
Fri Apr 26, 2019 3:18 pm
Forum: Megadrive/Genesis
Topic: Z80 bus + I/O mapping redux
Replies: 7
Views: 4680

Re: Z80 bus + I/O mapping redux

bgvanbur states the Z80 can write to 68K main-CPU RAM (e00000-ffffff), but reads return 0xff. It's further comments that reads return different values on different systems. Stef finds that writes do not work. Steve Snake says they used to on the earliest models. For what it's worth, I have a test R...
by Mask of Destiny
Wed Apr 24, 2019 4:21 pm
Forum: Demos
Topic: MD-NICCC - a 3D Mega Drive experience by TiTAN
Replies: 56
Views: 21514

Re: MD-NICCC - a 3D Mega Drive experience by TiTAN

Stef wrote:
Wed Apr 24, 2019 2:40 pm
Are you speaking about Starfox on SNES or something else ?
Pretty sure Sik is talking about the SNES port of the ST-NICC demo which was also released at Revision this year.
by Mask of Destiny
Fri Apr 05, 2019 9:59 pm
Forum: Demos
Topic: Tänzer, a "ninja" game (Dev Diary thread)
Replies: 290
Views: 70956

Re: Tänzer, a "ninja" game (Dev Diary thread)

notaz, what revision is your MD1?
by Mask of Destiny
Wed Apr 03, 2019 6:44 pm
Forum: Cartridge
Topic: EEPROM mapping for homebrew
Replies: 9
Views: 4736

Re: EEPROM mapping for homebrew

My 2 cents: standardizing the mapping (i.e. which address and which I2C bits are connected where) is good, but I think allowing the size to be specified in the header is desirable. It might make sense to pick a single "mode" (i.e. how the address is sent), but from my perspective supporting any of t...
by Mask of Destiny
Thu Mar 28, 2019 5:21 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 8361

Re: BlastEm 0.6.0

Hello folks, I've released the next version in the 0.6.X series: BlastEm 0.6.2 . The most notable change for developers is that I have fixed a regression in GDB remote debugging support on Linux and other Unix-like systems (Windows was not affected AFAIK). There are also some small accuracy fixes an...
by Mask of Destiny
Mon Feb 11, 2019 6:48 pm
Forum: Blabla
Topic: 68000 Arcade systems programming
Replies: 14
Views: 6536

Re: 68000 Arcade systems programming

They're not on his site anymore, but Charles MacDonald actually wrote docs describing various Sega Arcade boards and they are archived at various places:
Pre-System 16
System 16B
System 18
System C2
X-Board
System 24
by Mask of Destiny
Sun Jan 27, 2019 3:45 am
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 8361

Re: BlastEm 0.6.0

Cool. Yeah, that definitely finds the rom.db. It's probably how I built the project, but it doesn't actually show anything when I run a rom. I get a blank screen and the following error: "Failed to open shader file default.v.glsl for reading" Shaders are expected to be in the "sharers" subdirectory...
by Mask of Destiny
Thu Jan 24, 2019 10:00 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 8361

Re: BlastEm 0.6.0

Sounds good, I'll give it a go later on. BTW, love the debugging modes on this. This should be very handy! Glad you like them. I have pushed some changes to allow for building a more standard filesystem hierarchy friendly binary. If you want to try it out, grab tip from the repo and build with the ...
by Mask of Destiny
Mon Jan 14, 2019 8:47 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 8361

Re: BlastEm 0.6.0

Installing in Linux is kind of awkward, since it is not looking in standard locations for config files. /etc/, ~ (according to README). The location of blastem.cfg is standard for a per-user config file. It is true that my tarball is a self-contained package rather than something that's designed to...