diff --git a/df_datalink_sp/src/networking/phy_layer/phy_reg.h b/df_datalink_sp/src/networking/phy_layer/phy_reg.h
index b8e4de2..49b2361 100644
--- a/df_datalink_sp/src/networking/phy_layer/phy_reg.h
+++ b/df_datalink_sp/src/networking/phy_layer/phy_reg.h
@@ -33,7 +33,7 @@
 /**
  * Register: PHY_MAIN_CTRL
  */
-#define PHY_MAIN_CTRL 0X00000000U
+#define PHY_MAIN_CTRL 0x00000000U
 #define PHY_MAIN_CTRL_EN_SHIFT 0
 #define PHY_MAIN_CTRL_EN_WIDTH 1
 #define PHY_MAIN_CTRL_EN_MASK 0x00000001U