Search found 81 matches

by Graz
Sun Jul 19, 2009 11:37 pm
Forum: Super 32X
Topic: Shared Memory
Replies: 16
Views: 6284

Well that stuffs my plan. So, what is the best way to get data generated by the 68K into the SH2 RAM? I want to implement a ring buffer for passing messages, but if I do it with the frame buffer RAM I'll have to synchronize after every flip. Any suggestions?
by Graz
Sun Jul 19, 2009 9:31 pm
Forum: Super 32X
Topic: Shared Memory
Replies: 16
Views: 6284

Shared Memory

Sorry if this question has been asked and answered - it isn't clear in any of the docs I have. Aside from the frame buffers, is there any region of RAM that is accessible to both the 68K and the SH2s on 32X?
by Graz
Fri Jun 19, 2009 11:07 pm
Forum: Video Display Processor
Topic: DMA Fill
Replies: 7
Views: 2932

DMA Fill

Hi All, I'm trying to do a DMA fill on a non-contiguous chunk of VRAM by setting auto-increment to > 2. I have a rectangular set of tiles laid out top-to-bottom, left-to-right as a sprite would be. Within the rectangle, every 8 bytes is one row down. What I want to do is draw a vertical line through...
by Graz
Sun Jan 25, 2009 12:18 am
Forum: Demos
Topic: [Request] Real machine test
Replies: 47
Views: 12780

Jorge Nuno wrote:I'm not :wink: It's that I only do DMA copies in VBlank. And clearing register $81 should disable all kinds of DMA, unless there is some obscure bug.
I see. I saw
Jorge Nuno wrote: Well the code is started with a move #$2700 to sr, so that accidental dma is not started.
and was quite puzzled. :D
by Graz
Sat Jan 24, 2009 10:04 pm
Forum: Demos
Topic: [Request] Real machine test
Replies: 47
Views: 12780

Well I though you were referring to Vblank DMAs, before the code inits properly. That's why the move to sr is right at the start. But now I'm doing a "MOVE.w #$8100, VDPControlport" after deactivating HBL/VBL. This should end with the accidental DMAs... I think you may be confusing DMA and interrup...
by Graz
Sun Jan 04, 2009 7:48 pm
Forum: Megadrive/Genesis
Topic: Standart data formats in SMD games
Replies: 10
Views: 4128

This is the case of matched headers, not real JPEG for sure. They open just fine in Paintshop Pro. The image size is small, but the files are about 7megs(!). I have no idea what all the extra data is or where it came from (the ROMs are at most 4 megs), but they do appear to be valid JPEGs. I wonder...
by Graz
Sun Jan 04, 2009 1:57 pm
Forum: Megadrive/Genesis
Topic: Standart data formats in SMD games
Replies: 10
Views: 4128

I used the same program to extract a large set of ROMs - almost complete. The extractor did find a lot of data, but a good chunk of it (~30%) isn't meaningful - perhaps the headers just matched the binary data by coincidence. There are some interesting things to note: The 'data in IFF' stuff all has...
by Graz
Fri Dec 19, 2008 11:38 pm
Forum: Hardware
Topic: ROM Emulation
Replies: 86
Views: 29210

One thing I haven't seen on a cart that would be nice is regular RAM. FlashROMs are okay, but with regular RAM you could make conversions of games that need more RAM than is available in the Genesis (like Doom). I'd like to see a cart with 4M of flash and 4M RAM (switchable) so that you can do cart...
by Graz
Wed Dec 17, 2008 12:49 am
Forum: Hardware
Topic: ROM Emulation
Replies: 86
Views: 29210

That looks very nicely made. You made that yourself? If so, that's pretty impressive. Who manufactured the PCB for you? I see that the flash is on the back. What's the FRAM for? Also, I can see a USB-OTG connector on the top. Is this device programmed over USB, or do you have to plug it into a progr...
by Graz
Sat Dec 13, 2008 10:14 pm
Forum: Hardware
Topic: USB MegaDrive DevKit
Replies: 32
Views: 27287

One of the sites I read a lot when I was learning about FPGAs is fpga4fun.com . It's geared towards the beginner and hobbyist. I got one of their dragon boards. It's a bit expensive given the size of the FPGA, but it's got a PCI interface, which is nice for building register-driven designs that don'...
by Graz
Sat Dec 13, 2008 8:37 pm
Forum: Hardware
Topic: USB MegaDrive DevKit
Replies: 32
Views: 27287

Wow, that's excellent. I'm very interested in these kinds of projects. Unfortunately I don't have access to home-brew PCB making equipment right now and so can't attempt anything too ambitious. As for making peripherals accessible to the 68K, I would suggest using an FPGA to build a bridge between t...
by Graz
Sat Dec 13, 2008 8:22 pm
Forum: Hardware
Topic: ROM Emulation
Replies: 86
Views: 29210

Actually, it was a device to many tasks, emulation ROMs and dumping including. Sounds interesting. Here's a flash programmer/ROM dumper I made. http://img255.imageshack.us/img255/4659/pict0003ex0.th.jpg This uses USB. I'm not a fan of parallel port stuff because if you get something wrong, you can ...
by Graz
Fri Dec 12, 2008 1:38 pm
Forum: Hardware
Topic: Super Game Gear
Replies: 10
Views: 3261

As far as I know, the game gear was compatible with most SMS games (via Master Gear Converter), but not the other way around - game gear had some hardware that MS did not (deeper color palette, etc.). If the game was just the SMS code in a GG cart, then it might work, but if it was written specifica...
by Graz
Fri Dec 12, 2008 1:31 pm
Forum: Hardware
Topic: ROM Emulation
Replies: 86
Views: 29210

Using COM port based link is not clever. Even at 115k speed uploading 4MBytes is very long. Code is downloaded from the PC via parallel port... The device uses serial and parallel ports together, serial for control and parallel for data transfer. As I said, it seems to download at around 100K bytes...
by Graz
Fri Dec 12, 2008 1:30 am
Forum: Hardware
Topic: ROM Emulation
Replies: 86
Views: 29210

Nice. How much did it cost you? As I mentioned, I picked up the PromICE for about $80 Canadian a while back. That plus a few cables, connectors and several hours of work got the job done. The ROM emulator is about 10 years old and would have been extremely expensive (100's or 1000's) when new. The ...