furnace/doc/7-systems/zxbeep.md

# ZX Spectrum beeper

rather than having a dedicated sound synthesizer, early ZX Spectrum models had one piezo beeper, controlled by Z80 CPU and ULA chip. its capabilities should be on par with an IBM PC speaker... right?

not really - very soon talented programmers found out ways to output much more than one square wave channel. a lot of ZX beeper routines do exist, but Furnace only supports two engines:

- a Follin/SFX-like engine with 6 channels of narrow pulse wave and click drums.
- QuadTone: PWM-driven engine with 4ch of pulse wave with freely variable duty cycles and 1-bit PCM drums.

## effects

- **`12xx`**: set pulse width.
- **`17xx`**: trigger overlay drum.
  - `xx` is the sample number.
  - overlay drums are 1-bit and always play at 55930Hz (NTSC) or 55420Hz (PAL).
  - the maximum length is 2048!

## info

this chip uses the [Beeper](../4-instrument/beeper.md) or [Pokémon Mini/QuadTone](../4-instrument/pokemini.md) instrument editor.
lots of doc updates 2022-10-16 05:53:05 +00:00			`# ZX Spectrum beeper`
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 14:49:39 +00:00
lots of doc updates 2022-10-16 05:53:05 +00:00			`rather than having a dedicated sound synthesizer, early ZX Spectrum models had one piezo beeper, controlled by Z80 CPU and ULA chip. its capabilities should be on par with an IBM PC speaker... right?`
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 14:49:39 +00:00
remove references to versions 2023-09-10 22:58:49 +00:00			`not really - very soon talented programmers found out ways to output much more than one square wave channel. a lot of ZX beeper routines do exist, but Furnace only supports two engines:`
Update zxbeep.md 2023-07-09 12:21:12 +00:00
			`- a Follin/SFX-like engine with 6 channels of narrow pulse wave and click drums.`
			`- QuadTone: PWM-driven engine with 4ch of pulse wave with freely variable duty cycles and 1-bit PCM drums.`
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 14:49:39 +00:00
only one header per doc file 2023-09-11 00:34:13 +00:00			`## effects`
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 14:49:39 +00:00
Fixing something I botched. Hey, all those files I thought I clobbered! 2023-06-24 01:13:37 +00:00			- `12xx`: set pulse width.
			- `17xx`: trigger overlay drum.
fix documentation regarding ZX beeper samples 2022-08-16 03:44:55 +00:00			- `xx` is the sample number.
			`- overlay drums are 1-bit and always play at 55930Hz (NTSC) or 55420Hz (PAL).`
lots of doc updates 2022-10-16 05:53:05 +00:00			`- the maximum length is 2048!`
Documentation stuff! New page for the effect list, updates to chanOsc, and links to instrument types from every "system" page. 2023-08-04 16:11:53 +00:00
only one header per doc file 2023-09-11 00:34:13 +00:00			`## info`
Documentation stuff! New page for the effect list, updates to chanOsc, and links to instrument types from every "system" page. 2023-08-04 16:11:53 +00:00
don't mention Generic Sample ins type on sample ch ips that have their own ins types 2023-09-11 04:57:46 +00:00			`this chip uses the [Beeper](../4-instrument/beeper.md) or [Pokémon Mini/QuadTone](../4-instrument/pokemini.md) instrument editor.`