Documented important (useful) change in 1.64 regarding ch3 mode

1 files changed, 6 insertions, 0 deletions

diff --git a/doc/esf.txt b/doc/esf.txt
index ab74399..d35d173 100644
--- a/doc/esf.txt
+++ b/doc/esf.txt
@@ -388,6 +388,12 @@ $F9rrnn: Set FM register in bank 1
         * It's possible to touch the global registers ($22~$2B in bank 0).
           Do it at your own risk. You may mess up with Echo's functionality,
           so be careful about it and make sure you know what you're doing.
+    
+    Since version 1.64, writes to register $27 are handled specially: only
+    bits 7-6 are passed as-is while bits 5-0 are left to Echo. This is
+    because this register selects ch3 mode but also has the bits that trigger
+    the timers. This way, streams can change ch3 mode without risking Echo
+    undoing the changes.
 
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