diff --git a/HD44780.cpp b/HD44780.cpp
index 874e927..9c97ed3 100644
--- a/HD44780.cpp
+++ b/HD44780.cpp
@@ -24,6 +24,7 @@
 
 #include <cstdio>
 #include <cassert>
+#include <cstring>
 
 const char* LISTENING = "Listening                               ";