Search found 616 matches
- Thu Apr 18, 2024 3:48 am
- Forum: Demos
- Topic: Nightmare Fuel
- Replies: 4
- Views: 1262
Re: Nightmare Fuel
I was able to run it on my Model 2 via my MED v1, but it did crash eventually. Neat demo!
- Sun Feb 25, 2024 8:45 pm
- Forum: Pico
- Topic: Pico and Copera Info
- Replies: 0
- Views: 2814
Pico and Copera Info
I've been working on Sega Pico and Yamaha Copera (a Pico enhanced with some additional audio hardware) emulation recently. I figured it would be good to write up my findings. I'd like to start by thanking notaz for their existing Pico document, superctr for providing an archive of some Sega Pico sou...
- Fri Dec 15, 2023 6:51 pm
- Forum: Mega/SegaCD
- Topic: Replace the audio of one SGA file with another
- Replies: 1
- Views: 12104
Re: Replace the audio of one SGA file with another
There's some documentation of the format here. It sounds like the audio is uncompressed in the native PCM format of the Ricoh chip (sign-magnitude) so replacing it should be pretty straightforward. I don't think there are any off the shelf tools to do so though
- Fri Aug 04, 2023 10:55 pm
- Forum: Mega/SegaCD
- Topic: SEGA CD Mode 1
- Replies: 57
- Views: 352981
Re: SEGA CD Mode 1
FWIW, BlastEm nightly builds also have Mode 1 support these days and might run on a slightly less beefy machine. My CD compatibility is currently a fair bit worse at the moment, though I do much better on mcd-verficator. I think Genesis Plus GX also supports Mode 1 boot these days, but I've personal...
- Sun Feb 19, 2023 9:37 pm
- Forum: Video Display Processor
- Topic: Some DMA questions, Exodus emulator hangs
- Replies: 2
- Views: 6723
Re: Some DMA questions, Exodus emulator hangs
- Is the problem I see just something that is related to the Exodus emulator? I didn't encounter it yet on my Mega Drive model 2, or with other emulators. But maybe it does happen on other mega drive or genesis models and Exodus is just a better emulator than others? In general, if something doesn'...
- Tue Nov 08, 2022 5:38 am
- Forum: Megadrive/Genesis
- Topic: Enable / Disable vertical interrupts in Mode Register 2
- Replies: 3
- Views: 8708
Re: Enable / Disable vertical interrupts in Mode Register 2
I have already corrected the code (disabling VBL IRQ was unnecessary), but I wonder why it works on emulators (fusion, exodus, kgen) and not on the console. EDIT... Eh ... I already know what is wrong, instead of writing $ 8114 under mode set register #2 I wrote $ 8120 ... :( So you inadvertently s...
- Fri Nov 04, 2022 1:14 am
- Forum: Megadrive/Genesis
- Topic: Enable / Disable vertical interrupts in Mode Register 2
- Replies: 3
- Views: 8708
Re: Enable / Disable vertical interrupts in Mode Register 2
The only real restriction is that setting VDP registers also messes with the configured address/destination for writes/reads/DMA. The other thing to keep in mind is that disabling vertical interrupts this way is that it doesn't clear the interrupt pending state. So let's say you had vertical interru...
- Mon Aug 22, 2022 6:14 pm
- Forum: Demos
- Topic: [Sega MD] various test roms for emu's
- Replies: 3
- Views: 39728
Re: [Sega MD] various test roms for emu's
Yeah, TI_ has been posting results periodically in the BlastEm discord, but I've been slacking on fixing issues
- Fri Jul 29, 2022 11:39 pm
- Forum: Megadrive/Genesis
- Topic: Cart Design Questions
- Replies: 70
- Views: 156207
Re: Cart Design Questions
But before I hit the buy it now button on the 16 channel one, I just wanted to check, if this logic analyser can only sample at 16MHz for 16 channels at once, would that be fast enough for analysing the Mega Drive cartridge bus? In general, you need your sample rate to be at least twice as fast as ...
- Sat Jul 23, 2022 1:15 am
- Forum: Megadrive/Genesis
- Topic: Cart Design Questions
- Replies: 70
- Views: 156207
Re: Cart Design Questions
What is interesting is that if I involve the CE0 signal at all in my CPLD code, the retail reader fails to get any correct data off my cart. It only works if I only use CAS0. With CE0, the reader says it is an unknown cartridge with no name, 0MB of size and 0KB of SRAM size. I'm not sure why your c...
- Sat Jul 09, 2022 5:41 am
- Forum: Megadrive/Genesis
- Topic: Hunting down remaining emulator bugs
- Replies: 3
- Views: 8405
Re: Hunting down remaining emulator bugs
I guess MOVEM.W is just such a rare instruction that most games run fine even when its totally broken? So I think it's not so much that it's a super rare instruction, but that it's not very typical to do movem.w and then depend on the full longword value. There's that strange text crawl in Monster ...
- Tue Jun 07, 2022 7:34 am
- Forum: Megadrive/Genesis
- Topic: CRAM addresses?
- Replies: 3
- Views: 8031
Re: CRAM addresses?
I don't know how "c00000" addresses palette 0, color 0 So the VDP contains an internal address pointer and a separate register called CD which stores which type of RAM you want to access and whether you want to read or write it. The 32-bit command word you write to the control port sets both of the...
- Tue Apr 19, 2022 1:13 am
- Forum: Megadrive/Genesis
- Topic: 10 MB Flat cart using discrete logic
- Replies: 13
- Views: 36689
Re: 10 MB Flat cart using discrete logic
The Mega Everdrive supports 10MB flat carts so it's definitely been tried (and I can confirm DMA does not work in the >8MB region, though I suppose it's possible there's something specific to the MED implementation). Pretty sure this is the first discrete logic implementation though
- Sun Mar 20, 2022 4:19 pm
- Forum: SGDK
- Topic: Bank switching with SGDK
- Replies: 6
- Views: 16998
Re: Bank switching with SGDK
One little caveat here is that the way the Mega Everdrive handles SRAM with its extended "SSF2" mapper is not the same as the way the standard Sega mapper does. On the MED, one of the banks you can select is mapped to SRAM (except on the v1 which has no dedicated SRAM, though one of the banks is sav...
- Tue Feb 15, 2022 11:45 pm
- Forum: Megadrive/Genesis
- Topic: 10 MB Flat cart using discrete logic
- Replies: 13
- Views: 36689
Re: 10 MB Flat cart using discrete logic
I read about /DTACK (data transfer acknowledge), it needs to be assert for $80 0000 - $9F FFFF. I need to pull it low when accessing this area. I planned to assert it when /AS is low and the address lines match $80 0000 - $9F FFFF, meaning A23 high, A22 low and A21 low. Would using a 139 decoder wo...