Search found 591 matches

by Mask of Destiny
Tue Aug 22, 2017 6:07 pm
Forum: Megadrive/Genesis
Topic: Interlace mode (LSMx=3)
Replies: 20
Views: 3487

Re: Interlace mode (LSMx=3)

Did you verified this theory on real hardware? I'll run a proper test tonight, but it would be quite bizarre for them to include the hardware necessary to store and use an extra bit on the MSB side if they're just going to discard a bit on the LSB side. The difference in the behavior of the HV coun...
by Mask of Destiny
Tue Aug 22, 2017 6:46 am
Forum: Megadrive/Genesis
Topic: Interlace mode (LSMx=3)
Replies: 20
Views: 3487

Re: Interlace mode (LSMx=3)

Last question, though ... is this correct for counter read-out? Sonic 2 doesn't use it, and I don't know of any other interlace "mode 2" game. //counter case 0xc00008: case 0xc0000a: case 0xc0000c: case 0xc0000e: { uint16 vcounter = state.vcounter; if(io.interlaceMode == 3) vcounter.bit(0) = vcount...
by Mask of Destiny
Tue Aug 22, 2017 12:23 am
Forum: Megadrive/Genesis
Topic: Interlace mode (LSMx=3)
Replies: 20
Views: 3487

Re: Interlace mode (LSMx=3)

Nah, the halving trick worked out beautifully. It will work, but the resolution of sprite positioning will be half of what it should be. For instance, you won't be able to position a sprite's first line on a line that's in the bottom field (short of modifying the SAT between fields anyway). Since y...
by Mask of Destiny
Tue Aug 22, 2017 12:01 am
Forum: Megadrive/Genesis
Topic: Interlace mode (LSMx=3)
Replies: 20
Views: 3487

Re: Interlace mode (LSMx=3)

What I think you are missing, as far as I can tell: - for vscroll, value read from VSRAM must be shifted right by one (VSRAM width is 11-bit but bit0 is ignored in interlaced mode 2) before being added to vcounter value (9-bit) - for sprites, when preparing the sprites list (i.e looking which sprit...
by Mask of Destiny
Mon Jul 31, 2017 9:55 pm
Forum: Tools
Topic: Blastem 0.5.0 - Many accuracy improvements, basic SMS support, runs OD2
Replies: 33
Views: 6479

Re: Blastem 0.5.0 - Many accuracy improvements, basic SMS support, runs OD2

I got a new machine which does have OpenGL working and i tried the interlace mode stuff and it seems that it doesn't actually show any interlacing, only one of the fields is ever shown. Weird. I assume this is with a recent nightly and not the stable release (important distinction due to some shade...
by Mask of Destiny
Tue Jul 11, 2017 9:30 pm
Forum: Video Display Processor
Topic: Is DMA Fill buggy?
Replies: 11
Views: 2415

Re: Is DMA Fill buggy?

The DMA Fill works as expected but also does 1 (even addrss) o 2 (odd addrss) more byte writes to another location, with the same data you provided for the DMA Fill. It's not the fill that's doing the extra writes. The write that triggers the fill works as normal and then the fill continues afterwa...
by Mask of Destiny
Tue Jul 11, 2017 6:31 pm
Forum: Video Display Processor
Topic: Is DMA Fill buggy?
Replies: 11
Views: 2415

Re: Is DMA Fill buggy?

DMA fill has a really hacky implementation in the VDP. The word you write is written normally and then after that, the DMA engine fills with one byte of that word. If you write another word before the fill is complete, that write will take place as normal and then the fill will continue with a byte ...
by Mask of Destiny
Sat Jul 08, 2017 4:32 am
Forum: Tools
Topic: Blastem 0.5.0 - Many accuracy improvements, basic SMS support, runs OD2
Replies: 33
Views: 6479

Re: Blastem 0.5.0 - Many accuracy improvements, basic SMS support, runs OD2

...aaand here's one more. This ROM makes the emulator silently quit : http://www.tmeeco.eu/BitShit/PSMUSIC.BIN This ROM specifies that it has SRAM at the start of actual RAM. For silly reasons this caused a NULL pointer dereference. I've changed my RAM header parsing code to ignore anything that st...
by Mask of Destiny
Thu Jul 06, 2017 6:50 pm
Forum: Controls
Topic: controller auto reset
Replies: 18
Views: 3422

Re: controller auto reset

All six-button controllers will reset after a certain amount of time when read properly. There is no way to get a six-button controller back to the initial state without that reset.
by Mask of Destiny
Wed Jul 05, 2017 9:35 pm
Forum: Hardware
Topic: DIY controller not possible with AVR ?
Replies: 7
Views: 1846

Re: DIY controller not possible with AVR ?

If I were going for the full 6-button peripheral, I'd probably use a simple PAL/GAL. I'm actually fairly convinced that Sega used a 22V10 GAL. At the very least, the pin assignments on the chip they used are consistent with it being a 22V10. VCC and GND are in the right place. Buttons are connected...
by Mask of Destiny
Mon Jul 03, 2017 11:14 pm
Forum: Hardware
Topic: DIY controller not possible with AVR ?
Replies: 7
Views: 1846

Re: DIY controller not possible with AVR ?

oh...so trying to handle everything with the µC isn't always a good idea ;) But using a multiplexer, I don't see how you could force your own peripheral ID, like I asked on the another thread... Strictly speaking, using a mux doesn't preclude you having a non-standard peripheral ID. The peripheral ...
by Mask of Destiny
Thu Jun 29, 2017 6:08 pm
Forum: Collaboration
Topic: Griel's Quest: looking for translators
Replies: 11
Views: 5078

Re: Griel's Quest: looking for translators

Seems that while "pussy" and "chumino" means the same, the spanish word has a funny connotation, so I think I'll use your suggestion. Looking up the definition of chumino, pussy might be the right translation. Whether people will find it funny probably will depend on the audience. I only mentioned ...
by Mask of Destiny
Thu Jun 29, 2017 5:45 pm
Forum: Controls
Topic: controller auto reset
Replies: 18
Views: 3422

Re: controller auto reset

I'm not sure the exact reset value is known for the 6B controller. From looking at the PCB, it looks like it's probably using an RC-based timer which is probably going to vary in timing both from controller to controller and also with temperature. That said, the timing is such that if you have any k...
by Mask of Destiny
Wed Jun 28, 2017 7:40 am
Forum: Controls
Topic: ID ?
Replies: 3
Views: 1140

Re: ID ?

Mega Anser doesn't check for the Ten Key Pad (it just assumes it's always there) so I'm not sure if it actually has an ID. That's a good point. It's unclear whether it can produce a useful controller ID the way it's setup. The overall tl;dr is that Sega just relied on the particular behavior of eac...
by Mask of Destiny
Tue Jun 27, 2017 11:54 pm
Forum: Controls
Topic: ID ?
Replies: 3
Views: 1140

Re: ID ?

How the device implements it sort of depends on the device in question. For 3-button controllers it relies on both the fact that opposite directions can't physically be pressed at the same time combined with some of the inputs to the mux IC being tied to ground. So when TH is 1, D3-D0 represents the...