Amstrad CPC

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Platform - CPC.png
Amstrad CPC
Amstrad CPC.jpg
Released: 1984-??-??
Discontinued: 199?-??-??
Developer: Amstrad
Type: Hardware

The Amstrad CPC (short for Colour Personal Computer) is an 8-bit home computer created and released by Amstrad. The built-in operating system mainly consists of a BASIC dialect which was developed specifically for the new platform by Locomotive Software.

The CPC has always been very popular in France. In German-speaking countries, it was distributed by Schneider and renamed to Schneider CPC. Magazines and users often call the platform just Amstrad or Schneider.

Games

Models

Amstrad themselves have always been inconsistent as to whether to spell models with a space.

CPC464

The original model has a built-in tape drive and 64 KB RAM.

CPC664

This short-lived model has a built-in 3-inch disk drive and 64 KB RAM.

CPC472

Spain temporarily put an import tax on computers with 64 KB or less RAM. To circumvent it, Amstrad socketed additional 8 KB RAM on the board, but did not actually connect it to anything and wrote a false explanation in the manual.

CPC6128

The most popular model has a built-in 3-inch disk drive and 128 KB RAM.

Music and Sound

The CPC has a General Instrument AY-3-8912 sound chip clocked at 1 Mhz, a Z80 CPU clocked at 4 Mhz, and a timer clocked at 300.481 Hz (six times the screen refresh).

This setup allows up to three square waves from 15–62500 Hz (almost thrice as high as a human can hear) and white noise from 2016–62500 Hz.

Just like the later Game Boy, the CPC has a built-in speaker which outputs all audio in mono, and a 3.5 mm jack to output in stereo. This is possible since the AY-3-891x chip family outputs each channel through its own pin. Similarly to the later Amiga, though, all panning is fixed: Channel A is always hard left, channel B in the middle, and channel C hard right.

Besides audio, the CPC keyboard and joysticks are connected through the AY-3-8912's single I/O port, so if the sound chip is removed, the whole computer will not respond.

Composition

Audio is often programmed in Z80 assembler and synchronized with the screen refresh, causing song tempos to be 94, 125, 150 or 188 BPM rather than anything between. Such soundtracks can be ripped as one AY file. Songs synchronized otherwise must be ripped as multiple YM files.

Links