diff --git a/c/src/lib/libchip/serial/mc68681.h b/c/src/lib/libchip/serial/mc68681.h
index 64b8d9800b..bb2b46187b 100644
--- a/c/src/lib/libchip/serial/mc68681.h
+++ b/c/src/lib/libchip/serial/mc68681.h
@@ -27,10 +27,21 @@ extern "C" {
 #define MC68681_STATUS          1
 #define MC68681_RX_BUFFER       2
 
+#define MC68681_MODE            0
 #define MC68681_CLOCK_SELECT    1
 #define MC68681_COMMAND         2
 #define MC68681_TX_BUFFER       3
 
+/*
+ *  Data Port bit map configuration
+ */
+
+#define MC68681_DATA_PORT_A               0
+#define MC68681_DATA_PORT_B               1
+  
+#define MC68681_DATA_BAUD_RATE_SET_1      0
+#define MC68681_DATA_BAUD_RATE_SET_2      2
+
 /*
  * Driver function table
  */
diff --git a/c/src/libchip/serial/mc68681.h b/c/src/libchip/serial/mc68681.h
index 64b8d9800b..bb2b46187b 100644
--- a/c/src/libchip/serial/mc68681.h
+++ b/c/src/libchip/serial/mc68681.h
@@ -27,10 +27,21 @@ extern "C" {
 #define MC68681_STATUS          1
 #define MC68681_RX_BUFFER       2
 
+#define MC68681_MODE            0
 #define MC68681_CLOCK_SELECT    1
 #define MC68681_COMMAND         2
 #define MC68681_TX_BUFFER       3
 
+/*
+ *  Data Port bit map configuration
+ */
+
+#define MC68681_DATA_PORT_A               0
+#define MC68681_DATA_PORT_B               1
+  
+#define MC68681_DATA_BAUD_RATE_SET_1      0
+#define MC68681_DATA_BAUD_RATE_SET_2      2
+
 /*
  * Driver function table
  */