Questions tagged [nes]

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

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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 ...
JAL's user avatar
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83 votes
3 answers
22k 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 ...
wizzwizz4's user avatar
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77 votes
2 answers
16k views

Why does the infamous "ENGAGERIDLEYMOTHERFUCKER" Metroid password break NES emulators?

For those who are unfamiliar, the original NES Metroid was one of many NES games to use passwords as a means to save progress. Later, this password system was leveraged to create unusual effects in ...
Badasahog's user avatar
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51 votes
3 answers
15k 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. ...
JAL's user avatar
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43 votes
1 answer
6k 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'...
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39 votes
5 answers
7k 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 ...
Badasahog's user avatar
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38 votes
3 answers
13k 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 ...
SQB's user avatar
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36 votes
1 answer
12k views

Why did the NES not allow rotated sprites?

I'm taking a look at the chapter on sprites from a NES programming guide at famicom.party. There is a little table which describes what the different sprite attribute flags do: Bit # Purpose 7 Flips ...
Jojo's user avatar
  • 567
36 votes
3 answers
6k 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/...
rwallace's user avatar
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36 votes
1 answer
6k 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 ...
NobodyNada's user avatar
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33 votes
3 answers
5k 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 ...
Tim Penner's user avatar
33 votes
2 answers
7k 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 ...
rwallace's user avatar
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31 votes
2 answers
11k 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": ...
AlphaCentauri's user avatar
30 votes
5 answers
7k views

Were the classic game consoles *technically* able to play both NTSC and PAL games, if ignoring artificial region lock-in?

I'm not asking if they were region-free; I know they weren't generally. I'm asking if, given an NTSC-supporting PAL TV, an NTSC game cartridge, and a PAL NES/SNES/N64/whatever, and also given some ...
D. S.'s user avatar
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30 votes
3 answers
8k views

Why did Nintendo name its console the "Famicom"?

The NES was known as the "Famicom" in Japan, short for "Family Computer". But why was it given an English name in Japan, given (I assume) most people wouldn't know what the words &...
komodosp's user avatar
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30 votes
3 answers
7k 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, ...
rwallace's user avatar
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30 votes
2 answers
4k 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, ...
wcarhart's user avatar
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25 votes
1 answer
1k 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 ...
joeforker's user avatar
  • 353
24 votes
1 answer
5k views

What is the "NES version" of the NES?

This text is displayed on many NES cartridges: This Game Pak cannot be used with the Mattel or NES versions of the Nintendo Entertainment System What is "the NES version" of the NES? Is it ...
D. R.'s user avatar
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22 votes
2 answers
23k 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 ...
wcarhart's user avatar
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21 votes
2 answers
9k 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?
NobodyNada's user avatar
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21 votes
3 answers
4k views

Could a single NES ROM cartridge run on both PAL and NTSC systems?

Most ROMs are labeled with "(Europe)" or "(USA)", meaning PAL or NTSC. However, some are labeled "(World)". At first, I didn't think twice about this, just assuming that ...
Preston's user avatar
  • 221
19 votes
3 answers
5k views

What is the purpose of mirrored memory regions in NES's CPU memory map? [duplicate]

[Please see answers to this related question as well] I've started reading the "official" NES Documentation and in page ten, it says that "memory locations $0000-$07FF are mirrored ...
anmomu92's user avatar
  • 193
19 votes
6 answers
6k 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 ...
JAL's user avatar
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19 votes
2 answers
2k 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 ...
w.brian's user avatar
  • 393
19 votes
1 answer
5k 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 ...
JAL's user avatar
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18 votes
1 answer
2k 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 ...
Console Stackup's user avatar
17 votes
4 answers
8k 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 ...
Badasahog's user avatar
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17 votes
2 answers
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 "...
Mark's user avatar
  • 8,547
17 votes
4 answers
2k 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 ...
Aquova's user avatar
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14 votes
2 answers
5k 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 ...
cbmeeks's user avatar
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14 votes
1 answer
4k 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?...
Omar and Lorraine's user avatar
13 votes
1 answer
4k views

Is the only reason that my PAL NES is able to run NTSC/American games that it's doing it on an EverDrive?

I have an original PAL NES console. To the best of my knowledge, it is entirely unmodified. I have an EverDrive N8 Pro inside on which I've put a bunch of European/PAL ROMs, but also a few NTSC/...
B. V.'s user avatar
  • 163
13 votes
3 answers
981 views

Why was "Flight Simulator II" never ported to the NES? Was it technically impossible?

In the magical mid-1990s, when we already had got our (second-hand) 486 PC and I had both a NES and SNES, I for some reason got my paws on an old Atari "XE Game System" (8-bit, 1987). It had ...
V. Colker's user avatar
  • 131
13 votes
2 answers
1k 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 ...
DanBig's user avatar
  • 231
12 votes
2 answers
5k views

What was the point of the label on the bottom of the NES?

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 ...
Badasahog's user avatar
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12 votes
3 answers
2k 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?
Lexx Tesla's user avatar
12 votes
1 answer
3k views

In Super Mario Bros., how can I start a simultaneous multiplayer game?

I happened to receive an old NES with Super Mario Bros. My kids pointed out that there's a two-player mode where both Mario and Luigi play at the same time. Does anybody know how to get it going? FWIW,...
AVIDeveloper's user avatar
12 votes
1 answer
2k views

How do retro supply stores prevent the controller rubber replacement parts from "expiring"?

My NES controller felt really awful. After ordering replacement rubber parts from a store, unscrewing my controller and replacing the original rubber parts with the new ones, it felt "like new&...
Gumesindo's user avatar
  • 121
12 votes
1 answer
2k 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 ...
cbmeeks's user avatar
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11 votes
3 answers
2k views

Why are the PPU registers on the NES mirrored?

[Please see answers to this related question as well] The NES Picture Processing Unit has eight memory-mapped registers to the CPU in registers $2000 to $2007. The are incompletely decoded, so they ...
JAL's user avatar
  • 9,512
11 votes
2 answers
2k views

What could SID do that APU could not?

Two of the more famous and highly regarded sound chips in the 8-bit era were the Commodore 64's SID and the Nintendo APU. Which of the two was overall better, seems to be a matter on which there is a ...
rwallace's user avatar
  • 60.3k
11 votes
2 answers
2k 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 ...
Badasahog's user avatar
  • 4,031
11 votes
4 answers
2k 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 ...
rwallace's user avatar
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11 votes
5 answers
3k views

Did the PAL version of Super Mario Bros. on the NES really have faster music, and if so, why?

I have a real PAL NES hooked up to a modern TV with an AV-to-HDMI adapter (yeah, I'm working on finding a CRT). I bought an EverDrive cartridge for it because I'm a poor person who cannot afford to ...
Lumen's user avatar
  • 111
11 votes
1 answer
476 views

On my NES, the color red displays as black. What could be the cause?

I have a NES, it is working normally, but one of the game colors appears as black. In the game Mario Bros 3, the name is in black, some blocks are black and the goombas too. What can it be?
Carlos Bueno's user avatar
11 votes
1 answer
751 views

Did the original Shadowgate for the Macintosh (1987) not have "take" or "leave" command?

I'm very familiar with what I consider to be the "real" version of Shadowgate -- the NES port. Today, I noticed this screenshot from the actual original: There is no "take" or &...
Loai Hopen's user avatar
10 votes
5 answers
2k 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 ...
junius's user avatar
  • 638
10 votes
4 answers
2k 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 ...
w.brian's user avatar
  • 393
10 votes
0 answers
373 views

What's so different about Super Mario Brothers World T-1 that it doesn't look like level data at all?

Youtube video here: https://youtu.be/E6qRbk5Cscw?t=1127 Most of the glitched worlds are clearly ROM fragments of world data being loaded, most of them out-of-alignment and being rather messed-up. This ...
Joshua's user avatar
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