Search found 589 matches

by Mask of Destiny
Sun Apr 28, 2019 4:06 pm
Forum: Megadrive/Genesis
Topic: Z80 bus + I/O mapping redux
Replies: 7
Views: 374

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: 374

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: 49
Views: 1363

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: 31898

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: 617

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: 1732

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: 1411

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: 1732

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: 1732

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: 1732

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...
by Mask of Destiny
Mon Jan 07, 2019 6:30 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 1732

Re: BlastEm 0.6.0

There's only one little issue for me with it: checkboxes look like they mean the opposite they should, ie. a black checkbox means "enabled", which seems odd. Yeah, the default checkbox style is one of my biggest beefs with Nuklear. I'll have to see if there are any easy tweaks that can make it a bi...
by Mask of Destiny
Sat Jan 05, 2019 9:09 pm
Forum: Megadrive/Genesis
Topic: 68K inner workings
Replies: 3
Views: 669

Re: 68K inner workings

Have you had a look at the 68K patents? Looks like you've managed to figure out a lot from the schematic, but the US4325121 patent specifically has a lot of information about how the microcode/nanocode works and includes micro/nanocode listings for a pre-release version of the processor which might ...
by Mask of Destiny
Fri Jan 04, 2019 6:04 pm
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 1732

Re: BlastEm 0.6.0

v0.6.0 ended up being kind of buggy due to an abbreviated QA cycle. v0.6.1 fixes a number of issues and is now available here
by Mask of Destiny
Tue Jan 01, 2019 8:43 am
Forum: Tools
Topic: BlastEm 0.6.0
Replies: 15
Views: 1732

BlastEm 0.6.0

I've released a new version of my Gen/MD emulator. Big change this time is a new UI using the Nuklear toolkit. Unlike the old UI, you can actually change almost all config options through the UI rather than editing the config file. Of interest to developers are some improvements to the VDP debug vie...
by Mask of Destiny
Sat Dec 01, 2018 4:13 am
Forum: Exodus
Topic: Genesis 68K bus timing
Replies: 6
Views: 1192

Re: Genesis 68K bus timing

Here's a small collection of captures of various types of bus interactions. They are in Open Logic Sniffer Project format. Explanations below: direct_color_dma.olp - Capture of the start of 68K->VDP DMA from one of Chilly WIlly's Direct Color DMA samples (note that !CAS and !RAS here refer to VRAM !...