Search found 15 matches

by DarkMorford
Fri Jul 01, 2016 3:44 pm
Forum: Exodus
Topic: Mocking up a Sega CD
Replies: 5
Views: 3242

Re: Mocking up a Sega CD

I'm still interested in working on this for my own use and possibly contributing more formally to Exodus in the future to get Sega CD support working. I'm just not entirely sure where to start on it—do I start with the XML module file and then code the chips to fit that? Just start jumping in to the...
by DarkMorford
Thu Nov 26, 2015 1:09 am
Forum: Mega/SegaCD
Topic: Sega CD (US) BIOS Disassembly @ GitHub
Replies: 7
Views: 4043

Re: Sega CD (US) BIOS Disassembly @ GitHub

Ah, I stand corrected. Haven't gotten to the CD player portion of the BIOS code yet. :P
by DarkMorford
Wed Nov 25, 2015 6:35 pm
Forum: Mega/SegaCD
Topic: Sega CD (US) BIOS Disassembly @ GitHub
Replies: 7
Views: 4043

Re:

I'd like to approach this situation to ask for something I wanted to know since the start: How are the CDDA decibels read? I must have being missing something, but I really can't find anything about. I'm not entirely sure I understand your question, to be honest. Assuming you're talking about a gam...
by DarkMorford
Fri Nov 13, 2015 11:57 pm
Forum: Exodus
Topic: Mocking up a Sega CD
Replies: 5
Views: 3242

Re: Mocking up a Sega CD

Thanks, Nemesis, that makes a lot of sense. I do have schematics for the Sega CD floating around somewhere, I just need to find a place that'll print them full-size (A3 paper) so I have that for reference. As I mentioned in my original post, I'd like to make a "dumb" (i.e., not 100% accurate) 315-55...
by DarkMorford
Wed Jul 29, 2015 2:05 am
Forum: Exodus
Topic: Mocking up a Sega CD
Replies: 5
Views: 3242

Okay, so I've started adding a few more bits and pieces to my module configuration to be hooked in later; the full file is over on pastebin (to prevent a huge copy-paste in here). I can load this into Exodus, load the RAM image with the sub-CPU programs, and for the most part it's doing what I expec...
by DarkMorford
Tue Jul 28, 2015 2:04 am
Forum: Exodus
Topic: Mocking up a Sega CD
Replies: 5
Views: 3242

Mocking up a Sega CD

I'm trying to "wire up" a system in Exodus to help with disassembling/analyzing the Sega CD BIOS. For now I'm just wanting to mock up the main parts; I'll worry about accuracy later. Just to get started, I'm trying to hook up the 4 Mbit PRG-RAM, the two 1 Mbit Word RAM banks, and a fake set of Gate ...
by DarkMorford
Wed Jul 22, 2015 9:30 pm
Forum: Mega/SegaCD
Topic: CD Initial Program (IP) trying to write to ROM
Replies: 3
Views: 2422

I think the Z80's reset pin is active low, so writing a one is actually releasing reset not asserting it. Ah, that's right. I keep forgetting that the bus-request and reset lines are opposites, and I was thrown off because it didn't follow the "normal" sequence for talking to the Z80. I would guess...
by DarkMorford
Wed Jul 22, 2015 8:51 pm
Forum: Mega/SegaCD
Topic: CD Initial Program (IP) trying to write to ROM
Replies: 3
Views: 2422

CD Initial Program (IP) trying to write to ROM

In working on my BIOS disassembly, I've started taking a look at some commercial software to see how they interact with it. I came across this curious bit of code in the IP of "Penn and Teller's Smoke & Mirrors," and I'm not quite sure what to make of it. loc_FF0000: ; Disable all interrupts move #$...
by DarkMorford
Wed Jul 15, 2015 2:12 am
Forum: Mega/SegaCD
Topic: Sega CD (US) BIOS Disassembly @ GitHub
Replies: 7
Views: 4043

Those of you who are watching the GitHub repo have probably noticed by now that I've put up code for two out of the three sub-CPU program modules. (The third one is the CD player application, which I'm not too concerned about for now since I want to make my own software. I'll get to it eventually.) ...
by DarkMorford
Wed Jul 15, 2015 1:38 am
Forum: Megadrive/Genesis
Topic: Mapping Output Not Whats Expected
Replies: 7
Views: 1640

Hello and welcome, SegaDev! The problem seems to be a combination of my unfinished framework, some gaps in my teaching, and some confusion with the number of rows/columns in the map. I've expanded the rows/cols to 64x32 (you had 40x30 in there), and updated to the most recent version of my framewor...
by DarkMorford
Tue Jul 07, 2015 2:55 am
Forum: Mega/SegaCD
Topic: Sega CD (US) BIOS Disassembly @ GitHub
Replies: 7
Views: 4043

Sega CD (US) BIOS Disassembly @ GitHub

Hi, SpritesMinders! As I mentioned in another thread, I few weeks ago I started working on a disassembly of the Sega CD 2.00w (US) BIOS. I'm happy to say that I'm ready to open up at least part of it to the community! It's still very raw at the moment, and there are probably more subroutines I haven...
by DarkMorford
Thu Jul 02, 2015 3:36 pm
Forum: Mega/SegaCD
Topic: Is there a full/partial dissassembly of the Sega CD BIOS?
Replies: 4
Views: 2992

I started working on disassembling the US 2.00W BIOS a couple weeks ago. It's all still in an IDA Pro database file at the moment, but I'll see if I can't chop it up and put it on GitHub or something this weekend.
by DarkMorford
Thu Jul 02, 2015 5:27 am
Forum: Exodus
Topic: Exodus 2.0 + Open Source Release
Replies: 105
Views: 25520

Oh, wow. I just noticed that Exodus got a big update, and it looks great! Can't wait to start debugging with it! One thing I can't figure out though, just from playing with the interface, is how to get the different panels/dashboards to auto-hide. I can get them to dock to the main window, but they ...
by DarkMorford
Tue Apr 07, 2015 4:36 pm
Forum: Mega/SegaCD
Topic: SegaCD debugging emulator?
Replies: 12
Views: 5315

KanedaFr wrote:Did you notice GensKMod support Genny, SegaCD and 3X debug ? ;)
I did not notice that. Thanks!
by DarkMorford
Thu Mar 26, 2015 11:00 pm
Forum: Mega/SegaCD
Topic: SegaCD debugging emulator?
Replies: 12
Views: 5315

SegaCD debugging emulator?

I'm putting the finishing touches on the framework for my first Sega homebrew, and I'm thinking I'd like to move it over to the SegaCD platform because it'll be easier to test that on actual hardware compared to finding dev cartridges for a normal Genesis ROM. I've read through the Rex Sabio docs on...