Using-SyncUpdateDC-to-Reduce-Screen-Flicker.md

@@ -3,6 +3,7 @@ _How to use MiniGUI's synchronous update mechanism to reduce screen flicker._
 Table of Contents
 
 - [Overview](#overview)
+- [Principle](#principle)
 - [Usage](#usage)
 - [Restrictions](#restrictions)
 
@@ -33,8 +34,11 @@ Generally, we can use one of the following ways to eliminate this flicker:
    same as the first method.
 1. Use the new synchronous update mechanism introduced in MiniGUI 3.2.x.
 
-This documents describes how to the synchronous update mechanism to
-reduce screen flicker.
+This documents describes how to use the synchronous update mechanism to
+reduce the screen flicker.
+
+## Principle
+
 
 ## Usage