Search found 628 matches

by Mask of Destiny
Wed Dec 12, 2007 1:14 am
Forum: Demos
Topic: SEGA GENESIS VGM PLAYER
Replies: 48
Views: 66129

(the reason the full size of the cart can't be used is that the cart ram is at 2meg. I hav'nt written a rom builder yet that parses the vgm and at a convinient spot useing a free opcode to signal the player to jump over the ram. I'm so pressed for clocks that just adding the one extra range check ...
by Mask of Destiny
Wed Oct 17, 2007 8:20 pm
Forum: Sound
Topic: Official GEMS development kit + an unreleased game
Replies: 49
Views: 65227

Is that 16kbit/sec or 16kbyte/sec?

IIRC, with the old protocol I got somewhere in the neighborhood of 16 kilobytes/sec (128kbit/sec), maybe a little less. New protocol should be faster, but I don't think I've benchmarked it yet. I should be able to do a quick benchmark once I dig the code up again ...
by Mask of Destiny
Tue Oct 16, 2007 5:47 pm
Forum: Sound
Topic: Official GEMS development kit + an unreleased game
Replies: 49
Views: 65227

That will be fine if there is C source code for data transfer through that cable both for PC and SMD. Code must be 100% working because I don't have real hardware to test it by myself.
The source code I have is C on the PC side and 68K asm on the SMD side. If need be I could probably whip together ...
by Mask of Destiny
Thu Oct 11, 2007 9:01 pm
Forum: Sound
Topic: Official GEMS development kit + an unreleased game
Replies: 49
Views: 65227

Such a cable already exists:
http://www.retrodev.com/transfer.html

The protocol used is relatively simple. 4-bits data, 2-bits for handshaking. I can describe a working protocol in more detail if you like. I think the ISO file contains the source code for the Genesis side, though that's using my ...
by Mask of Destiny
Wed Oct 10, 2007 6:01 pm
Forum: Video Display Processor
Topic: TV safe area
Replies: 123
Views: 123928

I THINK the Sonic games use this for competition mode so that they don't have to do half-size patterns.
Only Sonic 2 uses this feature. Sonic 1 had no competition mode and Sonic 3/S&K use a separate tile and stick with the normal progressive mode. In fact, I'm pretty sure Sonic 2 is one of only a ...
by Mask of Destiny
Tue Oct 09, 2007 6:23 pm
Forum: Video Display Processor
Topic: SMS mode on MD/Genesis
Replies: 15
Views: 22081

It is my understanding that you can't use MD video mode (Mode 5) from the Z80 because it needs 16-bit writes.
Actually as it turns out both Mode 4 and Mode 5 require 16-bit writes in Genesis mode, but both work fine with 8-bit writes in SMS mode (though I have no idea whether or not Mode 5 DMA ...
by Mask of Destiny
Tue Sep 11, 2007 11:14 am
Forum: Blabla
Topic: More 315-5313 unknown stuff (speculation)
Replies: 52
Views: 57037


instead it uses 8 pins for pixel data (pin120-pin127(?) ), these ones get into a colourize chip (LOL) wasting the VDP crappy CRAM.
Are you sure its not 4bit (well, a tile is 4bit so far)? What are the other 4bits used for? Input data?!!
Well you need to know what pallete the current pixel uses ...
by Mask of Destiny
Tue Sep 11, 2007 2:21 am
Forum: Mega/SegaCD
Topic: Sega CD technical introduction
Replies: 15
Views: 28108

The core of the Sega CD architecture was a central 68000 processor that ran at 12Mhz and could operate in tandem with the 7.6Mhz Genesis' 68000 CPU. The Sega CD's CPU, however, is not considered to be significantly more capable than that of the Genesis CPU.
I could be mistaken, but I believe it's ...
by Mask of Destiny
Tue Sep 04, 2007 3:41 am
Forum: Blabla
Topic: Pentium 4's
Replies: 4
Views: 7399

Many P4s have a feature called hyperthreading. Basically, the processor has hardware to keep track of the execution state of 2 threads at once, but only has one set of execution hardware. It basically reduces the cost of a context switch between two threads if those threads are both running on the ...
by Mask of Destiny
Wed Aug 15, 2007 5:05 pm
Forum: Megadrive/Genesis
Topic: newbie creating genesis graphics
Replies: 68
Views: 68114

I don't think that document is entirely correct. I could have sworn that hilight white was brigther than regular white. Maybe I'm misremembering.
by Mask of Destiny
Wed Aug 15, 2007 2:24 am
Forum: Megadrive/Genesis
Topic: newbie creating genesis graphics
Replies: 68
Views: 68114

Hmm, doesn't look like it supports entering RGB values in hex. I guess we'll have to make due with decimal numbers. So when you're adding colors to your palette the values for red, green and blue should use one of the following values:
0, 32, 64, 96, 128, 160, 192, 224

Additionally, you shouldn't ...
by Mask of Destiny
Tue Aug 14, 2007 7:25 pm
Forum: Megadrive/Genesis
Topic: newbie creating genesis graphics
Replies: 68
Views: 68114

SMD palette is something like this:

http://shiru.untergrund.net/smdpal.png

Note that SMD able to display 1536 colors (but only 61 at once without any tricks), not 512, because it has special color mixing modes. But generally games displays only 61 colors from 512 from palette given above.
If ...
by Mask of Destiny
Tue Aug 14, 2007 1:32 am
Forum: Megadrive/Genesis
Topic: newbie creating genesis graphics
Replies: 68
Views: 68114

The Megadrive had four 15/16-color palettes (one color from each palette is used as transparent, but it can be used to color the backdrop) for a total of 61 colors onscreen. So basically each sprite can only use 15 colors and each background tile (8x8 pixel square on a particular background plane ...
by Mask of Destiny
Wed Aug 01, 2007 12:42 pm
Forum: Megadrive/Genesis
Topic: getting started
Replies: 21
Views: 20257

Any 68K assembler that can produce a raw binary output can be used.
by Mask of Destiny
Fri Jul 20, 2007 5:26 pm
Forum: Blabla
Topic: Do you like this my MD2 ?
Replies: 7
Views: 9830

Are you decoding or just conecting the segments to random lines?
I think it's just hardwired to display Sega (or as close as you can come on such a display anyway).

My Genesis has a minor modification which allows me to disconnect the /CART_IN signal (useful for dumping), but my wiring came ...