diff --git a/papers/doc/7-systems/ay8930.md b/papers/doc/7-systems/ay8930.md
index 0c6323eb0..a562765e5 100644
--- a/papers/doc/7-systems/ay8930.md
+++ b/papers/doc/7-systems/ay8930.md
@@ -37,3 +37,5 @@ while emulation of this chip is mostly complete, the additional noise setup regi
 - `24xx`: set envelope period high byte.
 - `25xx`: slide envelope period up.
 - `26xx`: slide envelope period down.
+- `27xx`: set noise AND mask.
+- `28xx`: set noise OR mask.
\ No newline at end of file