diff --git a/libs/core/pins.cpp b/libs/core/pins.cpp
index 47f4c9d2..dbf49db3 100644
--- a/libs/core/pins.cpp
+++ b/libs/core/pins.cpp
@@ -19,7 +19,7 @@ enum class DigitalPin {
     C15 = CALLIOPE_ID_IO_P15, // LED matrix R3
     //P16 = MICROBIT_ID_IO_P16,
     C19 = MICROBIT_ID_IO_P19, // SCL
-    P20 = MICROBIT_ID_IO_P20, // SDA
+    C20 = MICROBIT_ID_IO_P20, // SDA
 };
 
 enum class AnalogPin {