diff --git a/api/HardwareSerial.h b/api/HardwareSerial.h
index b687cdf1..2684629f 100644
--- a/api/HardwareSerial.h
+++ b/api/HardwareSerial.h
@@ -42,48 +42,59 @@ namespace arduino {
 #define SERIAL_DATA_6        (0x200ul)
 #define SERIAL_DATA_7        (0x300ul)
 #define SERIAL_DATA_8        (0x400ul)
+#define SERIAL_DATA_9        (0x500ul)
 #define SERIAL_DATA_MASK     (0xF00ul)
 
 #define SERIAL_5N1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_NONE  | SERIAL_DATA_5)
 #define SERIAL_6N1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_NONE  | SERIAL_DATA_6)
 #define SERIAL_7N1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_NONE  | SERIAL_DATA_7)
 #define SERIAL_8N1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_NONE  | SERIAL_DATA_8)
+#define SERIAL_9N1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_NONE  | SERIAL_DATA_9)
 #define SERIAL_5N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_5)
 #define SERIAL_6N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_6)
 #define SERIAL_7N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_7)
 #define SERIAL_8N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_8)
+#define SERIAL_9N2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_NONE  | SERIAL_DATA_9)
 #define SERIAL_5E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_5)
 #define SERIAL_6E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_6)
 #define SERIAL_7E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_7)
 #define SERIAL_8E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_8)
+#define SERIAL_9E1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_EVEN  | SERIAL_DATA_9)
 #define SERIAL_5E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_5)
 #define SERIAL_6E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_6)
 #define SERIAL_7E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_7)
 #define SERIAL_8E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_8)
+#define SERIAL_9E2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_EVEN  | SERIAL_DATA_9)
 #define SERIAL_5O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_5)
 #define SERIAL_6O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_6)
 #define SERIAL_7O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_7)
 #define SERIAL_8O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_8)
+#define SERIAL_9O1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_ODD   | SERIAL_DATA_9)
 #define SERIAL_5O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_5)
 #define SERIAL_6O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_6)
 #define SERIAL_7O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_7)
 #define SERIAL_8O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_8)
+#define SERIAL_9O2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_ODD   | SERIAL_DATA_9)
 #define SERIAL_5M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_5)
 #define SERIAL_6M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_6)
 #define SERIAL_7M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_7)
 #define SERIAL_8M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_8)
+#define SERIAL_9M1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_MARK  | SERIAL_DATA_9)
 #define SERIAL_5M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_5)
 #define SERIAL_6M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_6)
 #define SERIAL_7M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_7)
 #define SERIAL_8M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_8)
+#define SERIAL_9M2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_MARK  | SERIAL_DATA_9)
 #define SERIAL_5S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_5)
 #define SERIAL_6S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_6)
 #define SERIAL_7S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_7)
 #define SERIAL_8S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_8)
+#define SERIAL_9S1           (SERIAL_STOP_BIT_1 | SERIAL_PARITY_SPACE | SERIAL_DATA_9)
 #define SERIAL_5S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_5)
 #define SERIAL_6S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_6)
 #define SERIAL_7S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_7)
 #define SERIAL_8S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_8)
+#define SERIAL_9S2           (SERIAL_STOP_BIT_2 | SERIAL_PARITY_SPACE | SERIAL_DATA_9)
 
 class HardwareSerial : public Stream
 {
@@ -103,4 +114,4 @@ class HardwareSerial : public Stream
 // XXX: Are we keeping the serialEvent API?
 extern void serialEventRun(void) __attribute__((weak));
 
-}
\ No newline at end of file
+}