diff --git a/README.md b/README.md
index 41da05b..3e5dfbc 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,10 @@ Arduino based project running on my custom made board
 
 ## The software :
 
+### I2C Hardware addresses :
+* OLED screen : 0x3C
+* RTC DS3231 : 0x68
+
 ### External librairies used :
 * Adafruit_SSD1306 (not my work) [link](https://github.com/adafruit/Adafruit_SSD1306)
 * Adafruit-GFX (not my work) [link](https://github.com/adafruit/Adafruit-GFX-Library)