Questions tagged [nes]

For questions about the different versions and products of the NES (Nintendo Entertainment System)

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85
votes
7answers
26k views

Why would a NES game use an undocumented 1-byte or 2-byte NOP in production?

Reading the NESdev wiki page on CPU unofficial opcodes, I see a few games use an undocumented 2-byte NOP instuction in production: Puzznic, F-117A Stealth Fighter, and Infiltrator use $89 #i. Beauty ...
76
votes
2answers
17k views

Why does the Minus World exist?

In Super Mario Bros. for the NES and Famicom there exists a secret world, accessible by clipping through a wall to the first warp zone and entering the left-most pipe. This pipe will take you to ...
49
votes
3answers
8k views

What was Nintendo's Software Development Environment for NES Games?

(This question was inspired by my previous question What kind of software was used to develop Nintendo 64 titles?) The NES used a modified 6502 processor and most games were written in Assembly. ...
41
votes
1answer
5k views

How did Super Mario Bros. 3 create this tunnel vision effect?

In a certain section of World 8's map, the screen is black except for a small circle surrounding Mario (as seen below during this speedrun). After doing a little research, I discovered that the game'...
38
votes
5answers
5k views

Is it possible to make a ROM converter?

Based on my understanding, an emulator is necessary because the machine with the emulator on it (say Windows), doesn't execute the same machine code as the target platform (6502, for example). So what ...
35
votes
3answers
9k views

Were the dungeons in Legend of Zelda designed to fit together?

As can be seen in the image below, the dungeons of Legend of Zelda fit quite well together. Were they designed to be, or is this just a coincidence? Does this make them easier to store, with the ...
33
votes
3answers
3k views

Reconditioning and cleaning old Nintendo (and other) game cartridges

I used to blow the dust out of the cartridges but I heard that can actually damage the cartridge or the system itself. I am looking for the proper way to clean old Nintendo game cartridges (such as ...
33
votes
3answers
5k views

Did the NES do anything special to support coprocessors?

Some of the later NES/Famicom games contained not just ROM, but coprocessors for better sound and graphics than the original console hardware could provide, such as the MMC5: https://wiki.nesdev.com/w/...
31
votes
2answers
5k views

How did Elite on the NES work?

Elite was one of the earliest 3D games, wireframe only of course but still a remarkable accomplishment on 8-bit computers. Originating on the BBC micro, it was ported to many home computers, as well ...
29
votes
3answers
5k views

386SX, NES and how much did data lines really cost anyway?

In 1988, Intel introduced the 80386SX, most often referred to as the 386SX, a cut-down version of the 80386 with a 16-bit data bus mainly intended for lower-cost PCs aimed at the home, educational, ...
28
votes
2answers
3k views

How does the NES Light Gun work?

Modern motion detection video game systems (Wii/Wii U, Xbox Kinect, PS Move, etc.) need sensors to read for motion and user input. However, when you play Duck Hunt (and some other games) on the NES, ...
28
votes
1answer
4k views

How can I create a split-scroll effect in an NES game?

Games like Super Mario Bros. and Super Mario Bros. 3 were able to scroll the playfield but not the status bar: The status bars are clearly too big to be sprites, yet they don't scroll with the ...
23
votes
2answers
5k views

What is a subpixel in Super Mario Bros, and how does it relate to wall clipping?

What are "subpixels" in Super Mario Bros on the NES? How does it relate to wall clipping? At 4:42 in the following video, the notion is mentioned in the context of how it relates to "wall clipping": ...
22
votes
1answer
854 views

How does the NES PlayChoice arcade's security EPROM work?

I've read that the PlayChoice 10's security system includes a 64-bit serial EPROM that gets compared against the first 64 bits of code, and that it's possible to swap the ROMs between compatible ...
19
votes
2answers
5k views

Why do NES sprites flicker when there are a lot of them?

Sometimes, NES sprites flicker when there are a lot of them, like at 1:19 in this video of Super Mario Bros. Why did they do this?
19
votes
2answers
1k views

Is it possible to procedurally determine the number of cycles a particular instruction takes on a 6502?

Most emulators store the number of cycles a particular instruction takes in an array, and then adds any conditional cycles if needed (when crossing page boundaries, for example). I'm wondering if ...
17
votes
2answers
2k views

Can I run a NES emulator off the original cartridges?

Every NES emulator I've found runs off ROM dumps. Would it be possible to run an emulator using the original cartridges directly? It's probably not the most practical way of doing things, but the "...
16
votes
6answers
4k views

Can removing a cartridge from an NES (or any other cartridge-based game system) damage the hardware or software?

On some cartridge-based video game systems (NES, Game Boy Color, etc.) it is possible to remove the cartridge while the game system is still powered on. What kind of damage can this behavior do to ...
16
votes
4answers
5k views

Are NES turbo buttons internal to the controller?

As you may know, the classic NES controller was not the only NES controller that Nintedo released with the NES. These included the NES advantage, the NES Max, and the Dogbone. All of these new ...
16
votes
4answers
988 views

Best way to locate data on ROM? (6502 Processor)

Lately I've been interested in how old machines work, in particular an NES. While there are quite a few resources on the basic operations and even some games that have been totally broken down byte by ...
16
votes
1answer
3k views

How Did the 10NES lockout chip work?

One of the differences between the Japanese Famicom and the NES released outside of Japan is that the NES shipped with a lockout chip which prevented bootleg and imported games from working on the ...
16
votes
1answer
571 views

Does anyone know the specific differences between the NES-001 (NTSC) motherboard revisions?

On each Motherboard of an NES-001 (NTSC) there is a code: NES-CPU-xx These range from 04 to 11 (I think) I would like to know if these are all of the revisions of the NES and what major differences ...
15
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2answers
11k views

What are the differences between the Japanese Famicom and American NES?

In Japan, Nintendo's first home console was sold as the Family Computer (Famicom), while in the US it was later sold as the Nintendo Entertainment System (NES). Other than the region lock out for ...
14
votes
2answers
4k views

Is it possible to play Famicom games on the NES and utilize the extra sound channels?

I've seen there are adapters to convert Japanese Famicom games to work on the NES. You may have to remove the lockout chip, I can't remember. Anyway, many Famicom games included extra sound hardware ...
13
votes
1answer
2k views

What is the relationship between the Ricoh 2A03 and the MOS 6502?

The Ricoh 2A03 (and the 2A07) is the CPU in the well-known Nintendo Entertainment System. Apparently, the die is very similar indeed, as the slides in this video suggest https://www.youtube.com/watch?...
13
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2answers
816 views

NES repair - blue screen

I have an NES that was giving me a blinking red light when powering up. I had chalked this up to the 72-pin connector and set about cleaning it. After cleaning the connector and all games, the problem ...
12
votes
1answer
1k views

Did all NES “Black Box” games come in carts with five screws?

When the NES was released, there were a list of original titles from Nintendo such as Duck Hunt, Super Mario Bros. and Metroid. These titles came in a distinctive box that was mostly black. Plus, the ...
11
votes
4answers
1k views

8-bit console horizontal resolution

Some early consoles like the NES and the Sega Master had a horizontal screen resolution of 256. That sounds good for an 8-bit machine, until you consider that a sprite sometimes needs a slightly ...
11
votes
3answers
512 views

Why are NES cartridges grey while Famicom are rather colourful?

I've parsed a lot of websites and can't find answer anywhere. But still wonder to know why famicom cartridges are so colorful and different, but American and European cartridges grey only?
10
votes
3answers
1k views

Why are the PPU registers on the NES mirrored?

The NES Picture Processing Unit has eight memory-mapped registers to the CPU in registers $2000 to $2007. The are incompletely decoded, so they are mirrored every 8 bytes from register $2008 to $...
10
votes
4answers
1k views

Trying to understand what an “address latch” is while emulating the NES PPU

I'm attempting to emulate the NES PPU and I'm implementing its registers. In particular, reading from the PPU status register has the following effects: Reading the status register will clear D7 ...
9
votes
4answers
2k views

PAL NES in USA, 50Hz vs 60Hz

I was wondering if there existed a way to fix the difference in the running speeds of a PAL NES to run on TV's in the United States? Be it some converter or messing with the NES itself.
9
votes
5answers
871 views

Self-modifying code in commercial games for the (S)NES, Gameboy, Genesis/MD, PC Engine, Atari, etc

I'm curious if there are any extant examples of commercial games for classic consoles (let's say, pre-32-bit era here) which make uses of self-modifying code. As far as I know, all the systems I've ...
9
votes
2answers
1k views

How do NES/famicon games produce additional sound channels?

The NES/famicon has always used the Ricoh 2A03, a modified MOS 6502 processor to generate the memorable music and sound effects of classic Nintendo games and continues to define the newer 8-bit / ...
8
votes
2answers
5k views

What was the point of the label on the bottom of the NES? [closed]

The original NES has a label printed onto it that the device would not "cause harmful interference". Why would they write that? Did people think the NES might be dangerous? Is this some kind of legal ...
8
votes
1answer
2k views

NES chips usage

I am curently studying NES architecture to create a NES emulator. While looking up the NES motherboard schematics (https://console5.com/wiki/Nintendo_NES-001), some of the chips usage are not clear to ...
8
votes
1answer
1k views

Can I use a UK power adapter in NTSC NES

I have an old US (NTSC) NES system which we found in the garage. Sadly the power supply is missing. As I now live in the UK, I was wondering if it is possible to use a UK NES power supply with it. ...
8
votes
1answer
645 views

Is there a database of the box contents for different versions of NES games?

I've recently become interested in collecting old NES games. I'm trying to find an original NES Legend of Zelda game CIB. However, I'm having trouble distinguishing different versions of the game. All ...
7
votes
2answers
409 views

NES/Famicom CPU address range allowable for cartridges

The postulated address range for CPU ROM (so-called "PRG-ROM") in cartridges is $8000..$FFFF, that is pre-decoded in NES/Famicom and the chipselect is fed to the cartridge. However, it is quite ...
7
votes
1answer
1k views

What is the Famicom “Pulse Line” of games? How many games are part of this line?

(This question was inspired by Did all NES "Black Box" games come in carts with five screws?) I've heard of the Famicom "Pulse Line" of games released in Japan shortly after the launch of ...
7
votes
2answers
367 views

NES only works when I press reset

My aunt gave me her old nes, it was really dirty. I opened it up, cleaned it really good, cleaned the games too. I had to get a new power pack and av cables for it. I plugged everything into my TV (...
5
votes
2answers
558 views

Why are the internals of NES Gamepaks so small compared to the case?

As you probably know, in the technology world, smaller is generally considered to be better. Companies compete to make the most portable phone, or the smallest laptop, but apparently Nintendo didn't ...
5
votes
2answers
799 views

Does the NES handle unlisted processor instructions differently from the Famicom?

As you may be aware, developers used unregistered machine codes in their games, as discussed in this thread. My question isn't why they would do this, but instead if these instructions yielded a ...
5
votes
2answers
377 views

Do TG16 games and software suffer from lag frame similar to NES Super Mario Bros?

As a speedrunning fan, I've watched hours of Super Mario Bros speedruns, and have heard the term "lag frame". I don't think it's similar to typical computer lag, but instead an extremely technical ...
5
votes
0answers
276 views

R.O.B can't move up or down

I got this R.O.B (Robotic Operating Buddy for the NES), first time I turned him on his arms wouldn't close, so I took him apart and cleaned him. I put the gears back into place. After turning him on ...
4
votes
2answers
549 views

Why does R.O.B. wear “glasses”?

So recently, I've been playing Gyromite (which sucks), with R.O.B. (which also sucks), and I noticed that he comes with sunglasses that he doesn't actually need to work properly. This was the case ...
4
votes
1answer
454 views

Is screen wrap on the NES a fault of the OAM?

On NES games such as The Legend of Zelda and Metroid, entities that get to close to the edge of the screen, whether that be the top, bottom, left, or right side wrap around to the other side of the ...
4
votes
1answer
618 views

SNES / old graphics: merging sprite's with background [closed]

I have one question about how old computers or consoles like Super NES merged background layer(s) and spirites. Or another way - how layers were merged to not overload a PPU / CPU? OR how about ...
4
votes
1answer
501 views

How did Konami games recognize the famous cheat code?

The famous Konami cheat code is the sequence up, up, down, down, left, right, left, right, B, A What original algorithm was used to detect that the code was entered? I can think of two possible ...
3
votes
1answer
281 views

Why didn't Famicom games use the Konami SCC for expansion audio?

There were a handful of Konami games on the Famicom that had additional sound chips (VRC6, VRC7, etc.) to enhance the audio of the games they were used in. Considering that the Famicom got many Konami ...