PlayStation System Overview

@PS_2

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Playstation

 · 2 months ago

CPU: Customized MIPS R3000A 32-bit RISC CPU (might be based on the LSI L64360 embedded CPU)

• Clocked at 33.8MHz.
• 32 32-bit general purpose registers (35 total if special hi, lo and pc registers are included, first register locked to zero).
• 4KB I-cache.
• 1KB D-cache repurposed as fast 'scratchpad' memory.
• Geometry Transformation Engine (GTE) for 3D vector calculations (accessed as cop2).
• No hardware floating point unit.

Graphics: Custom GPU

• Clocked at 33.8MHz (same as CPU, may need verification however).
• Supports display resolutions of 256x240 to 640x480 for NTSC and 256x256 to 640x512 for PAL (272 vertical lines is apparently possible for PAL as well).
• Supports displaying in 16-bit or 24-bit color depths (GPU only draws primitives in 16-bit).
• RGB555 pixel format (32K colors total) with mask bit for transparency/write protect masks.
• 1MB of VRAM (connected to GPU with 16-bit memory bus, not directly accessible by CPU).
• 2KB texture cache.
• Flat and shaded lines and polylines of up to virtually unlimited points.
• Fixed sized (1x1, 8x8, 16x16) and variable size flat and textured sprites.
• Flat and textured 3-point and 4-point polygons with optional shading (quads are drawn as two triangles).
• Supports 4-bit, 8-bit and 16-bit textures. 4-bit and 8-bit textures use color lookup tables or CLUTs as palettes.
• 4 semi-transparency blending modes.
• 24-bit color processing with final output converted to 16-bit with optional dithering (flawed on old 160pin GPUs resulting in banding on shaded textures).
• GPU draws entirely in 2D resulting to affine distortion and various depth clipping issues.
• VRAM addressed as a 1024x512 16bpp framebuffer divided into 32 64x256 pixel pages (when texture mapping). Used for display/draw buffers, textures and CLUTs.

Sound: Custom SPU

• 24 voices with ADSR, pitch and modulation parameters.
• Noise generator on any of the 24 voices.
• 512KB SPU RAM (not accessible by CPU).
• 44.1KHz mixing rate.
• Only supports ADPCM samples with loop start and loop end flags.
• Hardware reverb with programmable reverb registers.
• CD-ROM digital audio input and external digital audio input via expansion port.

CD-ROM: 2x speed CD-ROM drive

• Roughly 300KB/s maximum read speed.
• Wobble groove based disc authentication scheme (easily defeated by modchips).
• Supports CD-DA and CD-XA ADPCM audio playback.
• Hardware ADPCM decoder for CD-XA ADPCM audio tracks.
• CD-XA ADPCM sample rates of 18.9KHz or 37.8KHz in Mono or Stereo.
• Up to 32 ADPCM streams per CD-XA track (one channel at a time in playback, channel switching possible during playback).
• Supports simultaneous CD-XA playback and data streaming (commonly used in FMVs in conjunction with the MDEC).

Memory:

• 2MB DRAM (first 64KB of RAM used by system kernel).
• 1MB VRAM.
• 512KB SPU RAM.
• 512KB BIOS ROM.
• Expansion ROM via expansion port up to 512KB supported (in default mapping).

Storage: Memory Cards

• 128KB total capacity.
• 1 block is 8KB each.