Search found 1665 matches

by kyuusaku
Tue Aug 07, 2012 5:27 pm
Forum: NES Hardware and Flash Equipment
Topic: iNES 48 / J9100287A / TAITO-TC0190FMC+PAL16R4
Replies: 12
Views: 4243

Re: iNES 48 / J9100287A / TAITO-TC0190FMC+PAL16R4

I think Don Doko Don 1 does use line interrupts, but only on certain levels (like Bubble Bobble 2). As to which mapper is supposed to implement what, I don't know, I think each ASIC should have been given its own mapper since the registers are only partially decoded in hardware. The issue with DDD2 ...
by kyuusaku
Tue Aug 07, 2012 12:10 am
Forum: NES Hardware and Flash Equipment
Topic: iNES 48 / J9100287A / TAITO-TC0190FMC+PAL16R4
Replies: 12
Views: 4243

Re: iNES 48 / J9100287A / TAITO-TC0190FMC+PAL16R4

iNES 48 and 33 are functionally the same mapper, they're probably hybridized for both ASIC types since the mirroring types can be merged. I thought the reason for two mappers was so that one would specifically NOT implement the IRQ counter for non-IRQ games which would otherwise break. This is how I...
by kyuusaku
Sat Jul 14, 2012 9:54 am
Forum: Newbie Help Center
Topic: King Colossus on the Genesis (sram save issues)
Replies: 26
Views: 5758

I see. Well the donor does not have ROM switching but it appears Sega introduced the lock feature with this specific 1992 board. The second '00 implements the discrete latch.
by kyuusaku
Thu Jul 12, 2012 10:47 pm
Forum: Newbie Help Center
Topic: King Colossus on the Genesis (sram save issues)
Replies: 26
Views: 5758

Positive... It uses the standard decoding for <= 16M games. From the scan I see it uses /LDSW (odd addresses) which IIRC is the most typical configuration as well. Also as to be expected you can see the game has 8 KiB/64 kilobits of SRAM too. There is absolutely nothing special about this cart.
by kyuusaku
Thu Jul 12, 2012 6:32 pm
Forum: Newbie Help Center
Topic: King Colossus on the Genesis (sram save issues)
Replies: 26
Views: 5758

There shouldn't be any differences... It's a Sega licensed game right? All licensed games follow the same rules. The only obscure configuration could be that the game is on a 24/32M board which has logic to swap ROM and RAM (and lock the RAM), but that board wasn't developed yet when this game was r...
by kyuusaku
Fri Jul 06, 2012 10:49 am
Forum: Newbie Help Center
Topic: King Colossus on the Genesis (sram save issues)
Replies: 26
Views: 5758

I can't remember exactly how this works... When you use byte mode writes the 68K puts the byte on both D15..8 and D7..0 so to handle writes you'd would only need to swap the write strobes, but I don't *think* it'll work for reads. For it to work the 68K would need pullups on the data bus, it'd AND D...
by kyuusaku
Thu Jul 05, 2012 7:23 pm
Forum: Newbie Help Center
Topic: King Colossus on the Genesis (sram save issues)
Replies: 26
Views: 5758

You don't need any extra logic, Genesis SRAM decoding is so simple for <=16M games, basically the upper half of the 32M of game address space (all 16M of it) is decoded to the SRAM. Why do you think the game needs 128 kbit/16 KiB of RAM? They don't make chips that size... It's also very unlikely tha...
by kyuusaku
Tue Jul 03, 2012 6:09 pm
Forum: SNESdev
Topic: MAD-1 discrete logic replacement
Replies: 23
Views: 10335

"no guarantees", this was maybe 4 years ago. I have no reason to believe it isn't correct... I dumped the logic manually using a binary counter in maybe 15 minutes so you could always verify it with a similar technique. In this application there's absolutely no reason to implement the MAD-1 logic, j...
by kyuusaku
Mon Jul 02, 2012 12:17 pm
Forum: SNESdev
Topic: MAD-1 discrete logic replacement
Replies: 23
Views: 10335

This is what I came up with a long time ago (after analyzing the chip, not using documents), it looks accurate but no guarantees Inputs: Pin 9 is A Pin 10 is B Pin 11 is C Pin 12 is D Pin 13 is E Pin 14 is F Pin 15 is G Outputs (active-low logic): Pin 1 is G E C' A + E C' B A Pin 2 is G F E D' C B A...
by kyuusaku
Wed Jun 20, 2012 1:44 pm
Forum: NESdev
Topic: Various questions about the color palette and emulators
Replies: 30
Views: 31835

In general MAME drivers can be considered some of the least accurate emulators. Almost all video hardware is "high-level" emulated, and the titles with line interrupts instead of a foreground layer are emulated with pseudo-line accuracy at best. I understand that some drivers are receiving more mode...
by kyuusaku
Tue Jun 19, 2012 10:55 am
Forum: NESemdev
Topic: Pixel aspect ratio and ddraw
Replies: 40
Views: 15312

Don't give up! The pixel aspect ratio is determined by the shape of NES video being displayed on an analog TV. Analog TV doesn't have pixels so the length of each oblong NES pixel must be calculated according to NES and TV signal timing. Just ignore the signal stuff, the ratio has been determined to...
by kyuusaku
Tue Jun 19, 2012 1:02 am
Forum: NESemdev
Topic: Pixel aspect ratio and ddraw
Replies: 40
Views: 15312

You render to a normal 256x240 surface, then resize it to 29 3 x240 using the API. "Padding" doesn't need to be considered if your emulator runs in a window. Technically the video should not be centered in the padding because it's not centered on a NES, it's actually offset the width of over 3 pixel...
by kyuusaku
Sun Jun 17, 2012 11:16 pm
Forum: SNESdev
Topic: Adding RAM retention to Game Doctor
Replies: 1
Views: 1262

What??? You know that's what the AC adapter input is for? Insert it and the DRAM & SRAM is retained... That's actually the GD's most famous selling point! Or get a 9V battery pack if for some reason you require it to be battery backed. Get a big one because it must keep the oscillator, ASIC and DRAM...
by kyuusaku
Fri Jun 08, 2012 1:28 am
Forum: SNESdev
Topic: YPbPr ouput mod for SNES consoles
Replies: 187
Views: 100175

I've even managed to get an SNES controller working without the +5V line connected. Somehow it pulls the power from the other lines by some magic I don't understand. Most chips have clamp diodes to suppress (mis)termination over/undershoot, ESD and overvoltage. As long as the input voltage is >0.6 ...
by kyuusaku
Thu Jun 07, 2012 4:30 pm
Forum: SNESdev
Topic: YPbPr ouput mod for SNES consoles
Replies: 187
Views: 100175

Doing things the right way is rarely necessary in life. I know that video needs to be terminated correctly. I know that TVs have very forgiving AGC and most people will never know that they're doing it wrong. I know that when issues do arise people will apply fallacies and will blame everything but ...