diff --git a/components/epaper b/components/epaper
index b7c0868..7a9bee6 160000
--- a/components/epaper
+++ b/components/epaper
@@ -1 +1 @@
-Subproject commit b7c08684cb3fe5c1d26a27ab0010dcc91d68e1a1
+Subproject commit 7a9bee6f516b30027f157d050dc3434a072887bb
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 766c853..7847b98 100755
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -1,6 +1,6 @@
 idf_component_register(
     SRCS 
-        "app_main.c"
+        "app_main.cpp"
         "./src"
 
     INCLUDE_DIRS 
diff --git a/main/app_main.c b/main/app_main.cpp
similarity index 77%
rename from main/app_main.c
rename to main/app_main.cpp
index 39bf4e2..3bfb79e 100755
--- a/main/app_main.c
+++ b/main/app_main.cpp
@@ -3,9 +3,10 @@
  * @brief Main application source code
 */
 #include "app_main.h"
+#include "epd.h"
 
 /// @brief Main application entry point
-void app_main(void)
+extern "C" void app_main(void)
 {
     printf("Hello world!\n");
 }