Search found 152 matches

by LocalH
Sun Feb 14, 2010 4:35 am
Forum: Megadrive/Genesis
Topic: Z80 clocking
Replies: 7
Views: 5640

Waitstates will slightly corrupt DAC samples, as the DAC relies entirely on software timing for output of data. If you've ever played a PAL C64 SID tune on NTSC by only calling the music player 5 out of every 6 frames, you may have heard this type of error. I expect the audible error to be worse whe...
by LocalH
Sun Feb 14, 2010 3:53 am
Forum: Megadrive/Genesis
Topic: Benefits between SMD and BIN Format
Replies: 5
Views: 4943

Although you can find a lot of roms named *.smd, they are really in bin format renamed to *.smd extension. Not always. Sometimes such ROMs are actually SMD format (which can be confirmed by attempting to use them as BIN files, or by loading them in a hex editor). SMD should die as a distribution fo...
by LocalH
Sun Feb 14, 2010 3:39 am
Forum: Megadrive/Genesis
Topic: Help with Copier RAM Test
Replies: 16
Views: 13019

I'm not sure on the hardware differences between the SMD and the DPF, but Charles MacDonald's smdutil includes a facility to do a RAM test on the copier, which he does by uploading Z80 code and executing it. Perhaps this code could be modified to handle the full range of the DPF and any hardware dif...
by LocalH
Wed Jan 13, 2010 8:13 pm
Forum: Megadrive/Genesis
Topic: Regarding Flight
Replies: 4
Views: 3812

ROM is not reserved at all, you can use any ROM data to feed any I/O chip. VRAM is partially reserved - while tile data can go pretty much anywhere, you have to assign certain ranges of VRAM to the nametables, sprite tables, and horizontal scroll RAM. Those ranges are not hardcoded, however, and you...
by LocalH
Sun Dec 27, 2009 9:43 pm
Forum: Demos
Topic: MD xmas post card
Replies: 6
Views: 5372

I'm gonna try to make something for New Year's. I got a perfect image in mind too =P
by LocalH
Sun Dec 27, 2009 3:03 am
Forum: Demos
Topic: MD xmas post card
Replies: 6
Views: 5372

Nice demo, though. Thanks for the greet :)

Worked well on my Genesis. No bugs whatsoever (except for the charset being a little hard to read, and being unable to see your signature at the lower right corner because of RF =P)
by LocalH
Sat Dec 26, 2009 8:58 pm
Forum: Demos
Topic: MD xmas post card
Replies: 6
Views: 5372

You really love interlace mode 2, don't you =P
by LocalH
Tue Dec 22, 2009 5:18 am
Forum: Megadrive/Genesis
Topic: Super Magic Drive research thread
Replies: 133
Views: 268090

Ok, Charles got in touch with me and sent me his smdutil, and I dumped my unit's BIOS. Here's the binary . In the ROM is the following text: *** MAGIC DOS V4 *** PRODUCT MANAGER: LMM, DEBUG ENGINEER: JUS, BIOS PROGRAMMER: JSI, ALL RIGHTS RESERVED, COPYRIGHT 1992 BY JSI, CHINA COACH COMPANY LTD., FRO...
by LocalH
Mon Dec 21, 2009 2:31 am
Forum: Megadrive/Genesis
Topic: Stable interrupt discussion
Replies: 3
Views: 3287

One could get past that by using a 68k driver such as S1 SMPS and then simply don't use the Z80 at all, no DAC. =P

I seriously think this might be worth pursuing. Even still today people find new tricks on the C64 thanks to being able to abuse the system with such fine-grained control.
by LocalH
Fri Dec 18, 2009 8:24 am
Forum: Megadrive/Genesis
Topic: Super Magic Drive research thread
Replies: 133
Views: 268090

Hm, the more I look at this, the more I think this just loads the "upgrade" into RAM temporarily, rather than doing any sort of permanent upgrade. Here's the entirety of the code at $0200, before a shitton of FF bytes and the actual ROM: ROM:0000 ld hl, 0A000h ROM:0003 ld de, 0C000h ROM:0006 ld bc, ...
by LocalH
Fri Dec 18, 2009 6:53 am
Forum: Megadrive/Genesis
Topic: Super Magic Drive research thread
Replies: 133
Views: 268090

Super Magic Drive research thread

In a quest to get a working MS-DOS setup for my SMD800, I came across a few interesting things, and a need for a tool that I cannot find. First of all, does anyone have a copy of Charles MacDonald's SMDUTIL? The link on his website is 404, and I can not find it anywhere (have done about two solid ho...
by LocalH
Wed Dec 16, 2009 8:17 pm
Forum: Blabla
Topic: Fonzie!!
Replies: 37
Views: 26974

I'll undercut both of you and write the engine for the low, LOW sum of only $10,000. You can pay it half in advance and half after completion, or I'll give you a 25% discount if you can pay $7,500 in advance (in other words $7,500 in advance and nothing on completion).
by LocalH
Wed Dec 16, 2009 8:15 pm
Forum: Megadrive/Genesis
Topic: Sega Channel
Replies: 13
Views: 10022

King Of Chaos wrote:If I remember right, there was another Sega Channel beta cart on eBay not too long ago.
I think it was cart #6. I saw a scan of it, and it had the same date, thus I think it's the same build (Sega probably gang-wrote them for various demonstration and testing purposes).
by LocalH
Sat Dec 12, 2009 6:46 pm
Forum: Blabla
Topic: Fonzie!!
Replies: 37
Views: 26974

I don't think anyone's going to want to help you on this until you make an effort to try and learn the basics on your own. It's very rare that someone comes in, says "I have this idea", and people jump on board. Sometimes group projects do exist, but usually the ones who come up with such ideas alre...
by LocalH
Sat Dec 12, 2009 4:33 am
Forum: Megadrive/Genesis
Topic: Neo Myth Menu beta
Replies: 36
Views: 21173

INTs have to be disabled while the Neo Myth is doing its thing since often the exception table at 0 disappears depending on the mode the Neo Myth is in. However, I think setting a variable that's updated during the vertical blank int during those times the ints are on should be doable. I'll see if ...