furnace/doc/7-systems/powernoise.md

# PowerNoise

a fantasy sound chip created by The Beesh-Spweesh! and jvsTSX for the Hexheld fantasy video game console.

its design employs linear-feedback shift registers (LFSR) for sound generation. this technology is used in many random number generators to produce noise, but it is also capable of producing other tones.

it has three noise channels and one "slope" channel capable of generating a variety of saw waves.

it outputs stereo sound with 4-bit volume control per channel and 2-bit master volume control.

refer to [its instrument type's documentation](../4-instrument/powernoise.md) for details on sound synthesis.

## effect commands

- `20xx`: **load LFSR value (low byte).**
  - on the slope channel, this sets its accumulator (from `00` to `7F`).
- `21xx`: **load LFSR value (high byte).**
- `22xx`: **write to I/O port A.**
- `23xx`: **write to I/O port B.**

## info

this chip uses the [PowerNoise](../4-instrument/powernoise.md) instrument editor.
PowerNoise: prepare to write some docs 2024-01-26 02:45:00 -05:00			`# PowerNoise`

name correction 2024-01-26 12:37:18 -05:00			`a fantasy sound chip created by The Beesh-Spweesh! and jvsTSX for the Hexheld fantasy video game console.`
PowerNoise: prepare to write some docs 2024-01-26 02:45:00 -05:00
			`its design employs linear-feedback shift registers (LFSR) for sound generation. this technology is used in many random number generators to produce noise, but it is also capable of producing other tones.`

			`it has three noise channels and one "slope" channel capable of generating a variety of saw waves.`

Tiny documentation updates. New info and chip options for Virtual Boy, slight update to PowerNoise. 2025-02-20 01:56:43 -05:00			`it outputs stereo sound with 4-bit volume control per channel and 2-bit master volume control.`
PowerNoise: prepare to write some docs 2024-01-26 02:45:00 -05:00
Tiny documentation updates. New info and chip options for Virtual Boy, slight update to PowerNoise. 2025-02-20 01:56:43 -05:00			`refer to [its instrument type's documentation](../4-instrument/powernoise.md) for details on sound synthesis.`
PowerNoise: prepare to write some docs 2024-01-26 02:45:00 -05:00
			`## effect commands`

			- `20xx`: load LFSR value (low byte).
			- on the slope channel, this sets its accumulator (from `00` to `7F`).
			- `21xx`: load LFSR value (high byte).
			- `22xx`: write to I/O port A.
			- `23xx`: write to I/O port B.

			`## info`

			`this chip uses the [PowerNoise](../4-instrument/powernoise.md) instrument editor.`