aychip

Emulator for the AY-3-8912 sound chip

Installation

npm install aychip

Usage

This package exports a class AYChip that is capable of generating audio waveforms in response to register writes. The constructor accepts an options object with the following properties:

• frequency (required) - The clock speed of the chip, in Hz.
• sampleRate (required) - The sample rate of the generated audio, in Hz.
• volume (optional) - The volume of the generated audio, as a number between 0 and 1. Defaults to 1.
• stereoMode (optional) - one of 'ABC', 'ACB', 'BAC', 'BCA', 'CAB', 'CBA' (case insensitive) indicating the positions to which each of the three AY channels should be panned. For example, 'ACB' means that channel A will be panned 50% left, channel C to the centre, and channel B 50% right. Any other value will be treated as all channels centred.
• panning (optional, takes precedence over stereoMode) - a list of three values from 0 to 1 indicating how far left or right each AY channel should be panned, with 0 being 100% left, 0.5 being centred, and 1 being 100% right. If neither stereoMode nor panning is specified, all channels will be centred.

The AYChip object provides the following methods:

• setRegister(reg, val) - Set the value of a register. reg is a number from 0 to 13, and val is a number from 0 to 255.
• reset() - Reset all registers to 0.
• generate(outputBuffer, offset, count) - Generate count samples of audio, writing them into outputBuffer - a two-element array of Float32Arrays for the left and right channels, of sufficient length to hold the requested number of samples. Samples will be written starting at offset.
• setPanning(panning) - Set the panning for all channels. panning is a list of three values from 0 to 1 indicating how far left or right each AY channel should be panned, with 0 being 100% left, 0.5 being centred, and 1 being 100% right.