https://github.com/lunar-rf/emu8910
Tiny General Instrument AY-3-8910 emulator core.
https://github.com/lunar-rf/emu8910
ay-3-8910 ay8910 chiptune emulator psg ym2149 zx-spectrum
Last synced: 28 days ago
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Tiny General Instrument AY-3-8910 emulator core.
- Host: GitHub
- URL: https://github.com/lunar-rf/emu8910
- Owner: lunar-rf
- Created: 2021-02-25T13:24:07.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2025-09-07T23:17:35.000Z (about 1 month ago)
- Last Synced: 2025-09-08T01:13:54.041Z (about 1 month ago)
- Topics: ay-3-8910, ay8910, chiptune, emulator, psg, ym2149, zx-spectrum
- Language: TypeScript
- Homepage: https://files.lunar.sh/apps/AYSir
- Size: 292 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
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README
# emu8910
```
______ _____ _____ ___ ______
/ __/ |/ / / / ( _ ) _ < / _ \
/ _// /|_/ / /_/ / _ \_, / / // /
/___/_/ /_/\____/\___/___/_/\___/
```
This repository contains a single file `Typescript` implementation of General Instrument's [`A-3-8910`](https://en.wikipedia.org/wiki/General_Instrument_AY-3-8910) `PSG` (programmable sound generator) in
less than `1K` lines and without any magic constants!
The emulator allows for fine tuning of the DAC look up table though modification of the following variables:
```
const DAC_DECAY = 1.3;
const DAC_SHIFT = 40;
```
It implements most of the `PSG's` original registers.
The offical datasheet for the `PSG` can be found [`here`](http://map.grauw.nl/resources/sound/generalinstrument_ay-3-8910.pdf).
> **Online Player/Emulator by DrSnuggles**
> [`player link`](https://files.lunar.sh/apps/AYSir/?engine=lunar) [[`source`](https://github.com/DrSnuggles/AYSir)]
Sound output is achieved in the browser through an `AudioContext()` hook.
This `emulator` also adds interrupt support (with variable frequency) for updating the `PSG's` registers.
> Note: `FIR` LPF data is generated procedurally.
Compile with `tsc emu8910.ts`.
To use simply create a `PSG49` object as follows:
```
var emu8910 = new PSG49(YM_CLOCK_ZX, 50);
```
Which sets the default clock speed (`1.75 MHz`) and interrupt frequency (`50 Hz`).
This exposes a `PSG` `register` file in the `emu8910.register` object:
```
emu8910.register.A_FINE
emu8910.register.A_COARSE
emu8910.register.B_FINE
emu8910.register.B_COARSE
emu8910.register.C_FINE
emu8910.register.C_COARSE
emu8910.register.NOISE_PERIOD
emu8910.register.MIXER
emu8910.register.A_VOL
emu8910.register.B_VOL
emu8910.register.C_VOL
emu8910.register.ENV_FINE
emu8910.register.ENV_COARSE
emu8910.register.ENV_SHAPE
```
The `register` file is then used to control the `PSG` or extract state information.
To play a `FYM` module:
```
song = new FYMReader();
emu8910.interrupt.routine =
emu8910.clock.frequency = song.getClockRate()
emu8910.interrupt.frequency = song.getFrameRate()
```
> Note: You can download modules from [https://ftp.modland.com/pub/modules/](https://ftp.modland.com/pub/modules/)
This sets the `ISR` (Interrupt Service Routine) function, `clock` and `interrupt` frequency for a specific module.
To stop playback:
```
emu8910.driver.device.suspend()
emu8910.interrupt.frequency = 0
```
To resume:
```
emu8910.driver.device.resume()
emu8910.interrupt.frequency = song.getFrameRate()
```
> Note: You can access the emulator's internal `register` file with `emu8910.register`.
These registers need to be updated at the frequency of the `ISR`.
Files:
* `src/emu8910.ts` - `core` emulator implementation.
* `fym.js` - `FYM` `(Fast YM)` format parser.
* `parser.js` - `PSG` register parser.
* `index.html` - `HTML` boilerplate.
To run demo start web server: `python -m http.server 8000` and navigate to `index.html`.
> Note: Click anywhere on the page to start audio output.
# Signature
```
+---------------------------------------+
| .-. .-. .-. |
| / \ / \ / \ + |
| \ / \ / \ / |
| "_" "_" "_" |
| |
| _ _ _ _ _ _ ___ ___ _ _ |
| | | | | | | \| | /_\ | _ \ / __| || | |
| | |_| |_| | .` |/ _ \| /_\__ \ __ | |
| |____\___/|_|\_/_/ \_\_|_(_)___/_||_| |
| |
| |
| Lunar RF Labs |
| https://lunar.sh |
| |
| Research Laboratories |
| Copyright (C) 2022-2024 |
| |
+---------------------------------------+
```