Search found 155 matches

by org
Thu Sep 07, 2023 2:32 am
Forum: NESdev
Topic: Seeking Ricoh/Nintendo Japanese Famicom Documents
Replies: 3
Views: 1510

Re: Seeking Ricoh/Nintendo Japanese Famicom Documents

Also check this out, I restored some of the block diagrams: viewtopic.php?t=24367
by org
Thu Sep 07, 2023 2:26 am
Forum: NESemdev
Topic: CPU emulation method?
Replies: 16
Views: 3267

Re: CPU emulation method?

Dynamic recompilation as applied to the 6502 doesn't work very well because between instruction executions it usually requires precise synchronization with APU/PPU execution. And recompilation implies code optimization of some sort. Besides that, you need to make friends with the mappers somehow. An...
by org
Wed Jul 26, 2023 11:54 pm
Forum: Newbie Help Center
Topic: Understanding APU Emulation
Replies: 11
Views: 2486

Re: Understanding APU Emulation

Before you understand how to emulate APU, you first need to understand how APU itself works.

The first thing that comes to mind is nesdev wiki: https://www.nesdev.org/wiki/APU
by org
Sat Jun 24, 2023 11:36 pm
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Re: Sharp MMC1 Reverse Engineered

Fixed :beer:
by org
Tue Jun 13, 2023 2:55 am
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Re: Sharp MMC1A Reverse Engineered

Fixed a small inaccuracy: the dffre cell is actually dffrs (set used during MMC1 reset).

https://github.com/emu-russia/mappers/b ... s.md#dffrs

Updated waves for MMC1 reset.
by org
Sun Jun 11, 2023 3:02 am
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Re: Sharp MMC1A Reverse Engineered

Shift register is never reset. The divider that runs in parallel with the shift register and is responsible for turning on the register decoder is reset. The description on the nesdev wiki does not take this pecularity into account.
by org
Sat Jun 10, 2023 11:29 pm
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Re: Sharp MMC1A Reverse Engineered

Can we find out exactly how this works
I have added a test bench so that you can do your own experiments.

https://github.com/emu-russia/mappers/t ... MC1/icarus

As for the ignored-second-write, I am attaching the waves.
by org
Sat Jun 10, 2023 10:04 pm
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Re: Sharp MMC1A Reverse Engineered

Logisim adaptation made by andkorzh :beer:
by org
Thu Jun 08, 2023 7:53 am
Forum: NES Hardware and Flash Equipment
Topic: Sharp MMC1 Reverse Engineered
Replies: 9
Views: 1366

Sharp MMC1 Reverse Engineered

Hello.

MMC1 circuit reconstruction completed:

https://github.com/emu-russia/mappers/tree/main/MMC1

All the materials are there, including the topology and cell layout, as well as an automatically restored Verilog netlist.
by org
Mon Jun 05, 2023 11:58 am
Forum: NES Hardware and Flash Equipment
Topic: Famiclone Chips Museum
Replies: 9
Views: 2206

Re: Famiclone Chips Museum

by org
Sun May 21, 2023 12:26 pm
Forum: NESemdev
Topic: Proof of Concept - NES/Famicom emulator at the signal and logic circuit level
Replies: 1
Views: 1597

Re: Proof of Concept - NES/Famicom emulator at the signal and logic circuit level

2.0 released:

https://github.com/emu-russia/breaknes/ ... reaknes-20

In the settings, you can enable audio and video dump, I think this can be useful.
by org
Mon May 15, 2023 1:02 pm
Forum: NES Hardware and Flash Equipment
Topic: Famiclone Chips Museum
Replies: 9
Views: 2206

Re: Famiclone Chips Museum

Two NOACs are under the microscope today: the SUBOR SB-225 and the LIKO KL-235. In SUBOR, as it is stated on the motherboard, it turned out to be a banal 6561. But the LIKO has some kind of a weird thing: PA3088. We have never seen this before. SUBOR: https://drive.google.com/drive/u/0/folders/1-dU1...
by org
Mon May 15, 2023 10:21 am
Forum: NES Hardware and Flash Equipment
Topic: SUBOR/LIKO PCB Scans
Replies: 1
Views: 441

SUBOR/LIKO PCB Scans

Hi, I got a couple of popular famiclones in their time and photographed them with all the intimate details. SUBOR SB-225: https://drive.google.com/drive/u/0/folders/1-dU1ms39lwgdhIRu-1aOky4SJVKpEdXv LIKO KL-235: https://drive.google.com/drive/u/0/folders/1WOwd5iLHsX1CNpe-cHQfnRZPCYn2tplp According t...