NES uses the 6502 CPU. This is the same chip used in Atari 2600 and Apple II machines.

Reference for 6502 Assembly

• Assembler CC65
• NES Programming reference
• NESDev.org
• NES Starter Kit - Example game code

On mac, install cc65 with brew install cc65. The ca65 is the assembly compiler.

.segment "HEADER"
    .byte "NES", $1A          ; Magic + iNES version
    .byte 1                   ; 1x 16KB PRG ROM bank (minimal)
    .byte 0                   ; 0x 8KB CHR ROM (or 1 if you add tiles)
    .byte %00000000           ; Mapper 0 (NROM), vertical mirroring, etc.
    .byte %00000000
    ; rest of header zeros

.segment "STARTUP"            ; Your code goes here
reset:
    sei                       ; Disable interrupts
    cld                       ; Clear decimal mode
    ldx #$FF
    txs                       ; Set stack pointer
    ; (Optional: basic PPU/APU init to avoid garbage)
forever:
    jmp forever               ; Infinite loop (does nothing)

.segment "VECTORS"            ; CPU vectors (required)
    .word 0                   ; NMI
    .word reset               ; Reset
    .word 0                   ; IRQ/BRK

.segment "CHARS"              ; Empty CHR if no graphics yet

Then compile and link with the following:

ca65 hello.s -o hello.o
ld65 -C nes.cfg -o hello.nes hello.o

Now there is a ROM named hello.nes.

• 2 pulse wave channels
• 1 triangle wave channel
• 1 noise channel
• 1 8-bit PCM channel

You can use FamiTracker or FamiStudio to generate .nsf files that you can use in games. FamiStudio also has the ability to generate a .nes ROM file directly that you can play in an emulator or put on a cartridge.

You can get software emulators for most platforms like:

• PC
• Browser
• Raspberry Pi
• Android Phone/Tablet

Aside from the original NES console, there are some modern tools out there

• Consoles
  • Hyperkin RetroN HD 1 - Plays NES cartridges and can use NES controllers
  • Old Skool CLASSIQ N HD - Another modern console that is compatible with original cartridges and controllers.
• Cartridges
  • EverDrive N8 PRO - This is an NES cartridge with a slot of a micro SD card so you can put your ROM on the SD card and play it on a console.
  • https://www.etsy.com/shop/MouseBiteLabs & https://github.com/MouseBiteLabs/- PCBs
• Controllers
  • You can get NES-style USB controllers at places like Walmart for about $12 USD.
  • You can also get NES-style controllers with the original connector to fit on an original NES or the Hyperkin RetroN 1 HD. A 2-pack of those controllers runs about $10 USD.
  • There are also wireless models available like 8Bitdo N30 2.4G Wireless Gamepad for Original NES which runs around $30 USD.
  • Hyperkin offers controllers like the Hyperkin “Cadet” Premium Controller for NES with 10 ft. Cable (Gray) for abot $12 USD.
  • Hyperkin also has wireless controller models like Hyperkin “Cadet” Premium BT Controller for NES/ PC/ Mac/ Android running around $32 USD. that has an NES connector or can be used via Bluetooth to other devices like your computer or a Raspberry Pi.