diff --git a/Cart_Reader/README.md b/Cart_Reader/README.md
index 302c8ab..29fb9a7 100644
--- a/Cart_Reader/README.md
+++ b/Cart_Reader/README.md
@@ -63,3 +63,4 @@ GFX Lib: https://github.com/adafruit/Adafruit-GFX-Library
 BusIO: https://github.com/adafruit/Adafruit_BusIO    
 RGB Tools lib: https://github.com/joushx/Arduino-RGB-Tools  
 SI5351 lib: https://github.com/etherkit/Si5351Arduino  
+RTC lib: https://github.com/adafruit/RTClib (If you include an RTC)