Search found 354 matches

by dvdmth
Sat Nov 28, 2009 3:14 pm
Forum: NES Hardware and Flash Equipment
Topic: ROM: Nestopia OK, PowerPak not OK?
Replies: 26
Views: 6237

In the Super NES world, ROM sizes other than powers of 2 are commonplace, and there is a proper way to handle it (which SNES emulators do). The proper method is to duplicate the last bank(s) of the ROM so that you end up with a power of 2 overall. For example, if you have 5 banks of data, the last b...
by dvdmth
Tue Mar 17, 2009 8:54 pm
Forum: NES Hardware and Flash Equipment
Topic: Getting the Game Genie graphics to work with MMC5 & 4-Sc
Replies: 9
Views: 4130

Does the Game Genie pass through the CIRAM /CE line, or does it always set CIRAM /CE to CHR /A13? If the CIRAM /CE line isn't passed through, then any game that maps any kind of memory to PPU $2000-2FFF will fail to work as expected. MMC5 games may or may not work, depending on how they use EXRAM. G...
by dvdmth
Mon Feb 09, 2009 2:44 pm
Forum: NES Hardware and Flash Equipment
Topic: CIC chips
Replies: 26
Views: 14168

Ah yes, the good ol' days of CIC RE... I so miss those days of disassembly and cracking the international seeds. I would LOVE to see the original implementation (not to mention see the SNES CIC figured out). I don't know if I will be able to help as I did before (how long ago was that...?), but if I...
by dvdmth
Sat Jan 03, 2009 11:10 am
Forum: NES Hardware and Flash Equipment
Topic: PowerPak + Tetramino = sprite flicker
Replies: 80
Views: 33942

I was hoping to get answers to my questions, but oh well. Here's my idea of what's happening. My theory is that the corruption is being caused by the fact that there are two different sections of OAM. The primary OAM, which is 256 bytes, contains all 64 sprites and is ultimately what is written to d...
by dvdmth
Thu Dec 25, 2008 1:37 pm
Forum: NES Hardware and Flash Equipment
Topic: PowerPak + Tetramino = sprite flicker
Replies: 80
Views: 33942

Some clarification: 1. If sprite 0 is the only sprite in range, then OAM $20-27 is corrupted. Suppose sprite 1 is the only one in range. Which sprite pair is corrupted? If I'm reading right, you're saying that the same pair is corrupted (OAM $20-27). Or, are you saying sprite 1 causes the same pair ...
by dvdmth
Wed Dec 24, 2008 1:00 pm
Forum: NES Hardware and Flash Equipment
Topic: PowerPak + Tetramino = sprite flicker
Replies: 80
Views: 33942

I seem to recall that if $2003 is non-zero it causes sprites 0 and 1 to change to whatever sprite pair $2003 is pointint to. For instance, if $2003 was $7D (part of sprite 31), then sprites 30 and 31 would replace sprites 0 and 1. I might not be remembering right though (it was quite a while ago whe...
by dvdmth
Tue Oct 07, 2008 8:16 am
Forum: NES Hardware and Flash Equipment
Topic: final fantasy I+II rom problem
Replies: 12
Views: 5174

coinheaven wrote:i have a repro, but have the same problem. also if it doesnt work on the power pak, then it wont work in real hardware
Unless something changed, the PowerPak doesn't have proper SXROM support.
by dvdmth
Wed Sep 03, 2008 1:06 pm
Forum: NESdev
Topic: Joystick read without using temp RAM intermediate.
Replies: 31
Views: 11000

On the Famicom, bit 2 of $4016 has the status of controller #2's microphone, which can change in the middle of reading. Also, anything plugged into the expansion port can screw things up. On the NES, however, this technique should work just fine. I would suggest getting the status of the upper bits ...
by dvdmth
Tue Aug 26, 2008 8:39 am
Forum: NESdev
Topic: MMC3's scanline counter
Replies: 23
Views: 7898

Also, during your V-Blank code, be sure to perform all VRAM updates BEFORE writing to the IRQ registers (especially $C001). Otherwise an IRQ may occur sooner than you expect. Similarly, if you turn off the PPU mid-frame, be advised that the IRQ counter will be adversely affected, so do not reconfigu...
by dvdmth
Sun Aug 17, 2008 4:33 pm
Forum: NESdev
Topic: Does changing loopy_v during 'hblank time' affect MMC3 irqs?
Replies: 10
Views: 4267

Changes to the VRAM address/scroll regs during rendering will not affect the MMC3. The CHR A12 line is what controls IRQ timing, and when rendering is active that line functions completely independently of the scroll regs. Accrssing $2007, however, will cause bus conflicts on the CHR lines, which ma...
by dvdmth
Fri Aug 15, 2008 2:17 pm
Forum: Reproduction
Topic: Are Mapper Revisions tied to certain games?
Replies: 3
Views: 2342

From Nestopia changelog, version 1.30:

Code: Select all

  - Mapper 4. Now defaulting to MMC3B IRQ hardware. Fixes "Star Trek - 25th Anniversary".
So it appears at lease one MMC3 game requires revision B.
by dvdmth
Fri Aug 08, 2008 7:52 am
Forum: NES Hardware and Flash Equipment
Topic: Mega man 5 and 6 for the NES
Replies: 12
Views: 5018

I'm not sure if there is a PAL version of Mega Man 6 (the game was released at the end of the NES's life span). There is a European version of Mega Man 5, but it's not legal to post where to get it on this forum (hint: Look for "(E)" or "(Europe)" in the file name).
by dvdmth
Mon Aug 04, 2008 11:18 am
Forum: NESemdev
Topic: game genie
Replies: 8
Views: 4757

For 8-letter codes, the compare value is tested every time the CPU reads from the address. It doesn't matter the reason the CPU is reading from there - only that the read happens. It can be part of an opcode (an "infinite lives" code typically works by changing a DEC instruction into a BIT or LDA), ...
by dvdmth
Wed Jul 30, 2008 10:04 am
Forum: NESemdev
Topic: Value of unimplemented bits on 2001 and 4017?
Replies: 7
Views: 3842

This is my understanding of register behavior on the Famicom/NES: For the Famicom, reading $4016 returns controller #1 serial data on bit 0, expansion port data (such as controller #3) on bit 1, and microphone data (from controller #2) on bit 2. Bits 3-7 are all open bus and remain unchanged from ea...
by dvdmth
Wed Jul 23, 2008 9:40 am
Forum: NES Hardware and Flash Equipment
Topic: Nintendo MMC-5. EXRAM - Can the CPU execute from it?
Replies: 25
Views: 16129

There's no reason I can think of why EXRAM cannot be used for code execution. The fact that Nestopia fails is likely due to optimizations designed at fetching instructions as quickly as possible. Those optimizations may not account for the possibility of special memory such as EXRAM. Nintendulator m...