diff --git a/ports/arm/platforms/dm36x/dm36x-io.h b/ports/arm/platforms/dm36x/dm36x-io.h
index d420359..1df08cd 100644
--- a/ports/arm/platforms/dm36x/dm36x-io.h
+++ b/ports/arm/platforms/dm36x/dm36x-io.h
@@ -168,8 +168,9 @@
 #define DM36X_PSC_PTSTAT        0x128
 #define DM36X_PSC_PDSTAT        0x200
 #define DM36X_PSC_PDCTL1        0x304
-#define DM36X_PSC_MDSTAT_I2C    0x800 + (18 * 4)
-#define DM36X_PSC_MDCTL_I2C     0xA00 + (18 * 4)
+#define DM36X_PSC_MDSTAT_BASE   0x800
+#define DM36X_PSC_MDCTL_BASE    0xA00
+#define DM36X_PSC_MOD_I2C       18
 
 
 /** I2C registers */