From c6e045dd2266235e6ee742c05a632f1a6621debe Mon Sep 17 00:00:00 2001
From: freq-mod <32672779+freq-mod@users.noreply.github.com>
Date: Mon, 1 May 2023 21:26:06 +0200
Subject: [PATCH] add es5506 doc

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+# Ensoniq ES5506 (OTTO)
+
+Sample-based synthesis chip used in a bunch of Taito arcade machines and PC sound cards like Soundscape Elite. A variant of it was the heart of the well-known Gravis Ultrasound.
+
+it supports a whooping 32 channels of 16-bit PCM and:
+
+- Real time digital filters
+- Frequency interpolation
+- Loop start and stop positions for each voice (bidirectional and reverse looping)
+- Internal volume multiplication and stereo panning
+- Hardware support for envelopes
+
+# effects
+
+- `10xx`: set waveform.
+- `11xx`: set filter mode (0-3)
+- `120x`: set pause (bit 0). Pauses the sample until the bit is unset, where it will then resume where it left off.
+- `14xx`: set filter coefficient K1 low byte.
+- `15xx`: set filter coefficient K1 high byte.
+- `16xx`: set filter coefficient K2 low byte.
+- `17xx`: set filter coefficient K2 high byte.
+- `18xx`: set filter coefficient K1 slide up.
+- `19xx`: set filter coefficient K1 slide down.
+- `1Axx`: set filter coefficient K2 slide up.
+- `1Bxx`: set filter coefficient K2 slide down.
+- `20xx`: set envelope count.
+- `22xx`: set envelope left volume ramp.
+- `23xx`: set envelope right volume ramp.
+- `24xx`: set envelope filter coefficient K1 ramp.
+- `25xx`: set envelope filter coefficient K1 ramp (slower).
+- `26xx`: set envelope filter coefficient K2 ramp.
+- `27xx`: set envelope filter coefficient K2 ramp (slower).
+- `3xxx`: set coarse filter coefficient K1. 
+- `4xxx`: set coarse filter coefficient K2. 
+- `81xx`: set panning (left channel).
+- `82xx`: set panning (right channel).
+- `88xx`: set panning (rear channels).
+- `89xx`: set panning (rear left channel).
+- `8Axx`: set panning (rear right channel).
+- `9xxx`: set sample offset (x256).
+- `DFxx`: set sample playback direction.