NES Technical Specifications

Dimensions

• Original Version: 10"w x 8"l x 2.5"h
• NES 2: 6"w x 7"l x 1.5"h
• Cartridge: 4.1"w x 5.5"l

CPU

Ricoh 8-bit processor based on MOS Technology 6502 core, custom sound hardware, and a restricted DMA controller on-die

• 1.79 MHz (NTSC), 1.66MHz (PAL)
• Main RAM: 16 KiB plus expanded RAM if present on the cartridge
• ROM: Up to 49128 bytes for ROM, expanded RAM, and cartridge I/O; bank switching can expand this by orders of magnitude

Audio

Five sound channels. 2 pulse-wave channels, variable duty cycle (25%, 50%, 75%, 87.5%), 16-level volume control, hardware pitch-bend support, supporting frequencies from 54 Hz to 28 kHz.

1 triangle-wave channel, fixed volume, supporting frequencies from 27 Hz to 56 kHz

1 white-noise channel, 16-level volume control, supporting two modes (by adjusting inputs on a linear feedback shift register) at 16 preprogrammed frequencies.

1 delta pulse-code modulation (DPCM) channel with 6 bits of range, using 1-bit delta encoding at 16 preprogrammed sample rates from 4.2 kHz to 33.5 kHz, also capable of playing standard PCM sound by writing individual 7-bit values at timed intervals.

Picture processing unit (PPU)

• Ricoh custom-made video processor
• 5.37MHz (NTSC), 5.32MHz (PAL)

Video output

RCA composite output and RF modulator output

PPU internal memory

2 Kbytes of on-die sprite position/attribute RAM ("OAM") : 28 bytes of on-die palette RAM (allowing for selection of background and sprite colors) on separate buses internal to the PPU

PPU external memory (Video RAM)

32 KBytes of RAM for tile maps and attributes on the NES board : 8 KBytes reserved for tile pattern ROM or RAM on the cartridge (with bankswitching, virtually any amount can be used within manufacture cost)

Colors and Display

Palette

48 colors and 5 grays in base palette; red, green, and blue can be individually darkened at specific screen regions.

Onscreen colors

25 colors on one scanline with a total of 50 diplayed colors on screen (background color + 4 sets of 3 tile colors + 4 sets of 3 sprite colors), not including color de-emphasis

Hardware-supported sprites

• Maximum onscreen sprites: 64 (without reloading sprites mid-screen)
• Sprite sizes: 8×8 or 8×16 pixels (selected globally for all sprites)
• Maximum number of sprites on one scanline: 8, using a flag to indicate when additional sprites are dropped (to allow the software to rotate sprite priorities, causing flicker)

Scrolling layers

1 layer, though horizontal scrolling can be changed on a per-scanline basis (as can vertical scrolling via more advanced programming methods)

Display Resolution

256×240 pixels, though NTSC games usually used only 256×224, as the top and bottom 8 scanlines are not visible on most television sets (see overscan); for additional video memory bandwidth, it was possible to turn off the screen before the raster reached the very bottom.

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