From e40eec68d3b3754a100c703bdd890f2b66c7a8d8 Mon Sep 17 00:00:00 2001
From: nicco1690 <78063037+nicco1690@users.noreply.github.com>
Date: Sat, 11 Feb 2023 22:09:59 -0500
Subject: [PATCH] Refactoring + add DAC channel

---
 papers/doc/7-systems/sm8521.md | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/papers/doc/7-systems/sm8521.md b/papers/doc/7-systems/sm8521.md
index 85d5a9f97..693f435a2 100644
--- a/papers/doc/7-systems/sm8521.md
+++ b/papers/doc/7-systems/sm8521.md
@@ -6,7 +6,16 @@ Ultimately, most of the games for the Game.com ended up being failiures in the e
 
 However, for its time, it was a pretty competitively priced system. The Gameboy Color was to be released in a year for $79.95, while the Game.com was released for $69.99, and its later model, the Pocket Pro, was released in mid-1999 for $29.99 due to the Game.com's apparent significant decrease in value.
 
-The sound-related features and quirks of the SM8521 are as follows: 2 4-bit wavetable channels, a noise channel, 5-bit volume, and a low bit-depth output which means it distorts a lot. It also phase resets when you switch waves.
+In fact, most games never used the wavetable/noise mode of the chip. Sonic Jam, for example, uses a sine wave with a software-controlled volume envelope on the DAC channel (see below for more information on the DAC channel).
+
+The sound-related features and quirks of the SM8521 are as follows:
+- 2 4-bit wavetable channels
+- a noise channel (which can go up to a very high pitch, creating an almost periodic noise sound)
+- 5-bit volume
+- A low bit-depth output (which means it distorts a lot). 
+- It phase resets when you switch waves
+- 12-bit pitch with a wide frequency range
+- A software-controlled D/A register that (potentially) requires all other registers to be stopped to play. Due to this, it is currently, it is not implemented in Furnace as of version 0.6pre4.
 
 ## effect commands