diff --git a/doc/7-systems/c219.md b/doc/7-systems/c219.md
index 3c27f6f7e..89cffc7d6 100644
--- a/doc/7-systems/c219.md
+++ b/doc/7-systems/c219.md
@@ -11,7 +11,8 @@ this chip features:
 
 this chip is rather unique when it comes to sample memory. be sure to read this notice.
 
-the channels are PLEASE FINISH THIS LATER!
+the channels are in groups of four. a sample bank (128KB) may be selected for each group.
+if a sample that is on a different bank plays in a group, the group is switched to that bank, and other channels will be silenced.
 
 ## effects