diff --git a/src/include/spd.h b/src/include/spd.h
index e8d35cf..2b07fb1 100644
--- a/src/include/spd.h
+++ b/src/include/spd.h
@@ -108,15 +108,20 @@
 
 
 /* SPD_MEMORY_TYPE values. */
-#define SPD_MEMORY_TYPE_FPM_DRAM         1
-#define SPD_MEMORY_TYPE_EDO              2
-#define SPD_MEMORY_TYPE_PIPELINED_NIBBLE 3
-#define SPD_MEMORY_TYPE_SDRAM            4
-#define SPD_MEMORY_TYPE_MULTIPLEXED_ROM  5
-#define SPD_MEMORY_TYPE_SGRAM_DDR        6
-#define SPD_MEMORY_TYPE_SDRAM_DDR        7
-#define SPD_MEMORY_TYPE_SDRAM_DDR2       8
-#define SPD_MEMORY_TYPE_SDRAM_DDR3       0xb
+enum spd_memory_type {
+	SPD_MEMORY_TYPE_UNDEFINED		= 0x00,
+	SPD_MEMORY_TYPE_FPM_DRAM		= 0x01,
+	SPD_MEMORY_TYPE_EDO			= 0x02,
+	SPD_MEMORY_TYPE_PIPELINED_NIBBLE	= 0x03,
+	SPD_MEMORY_TYPE_SDRAM			= 0x04,
+	SPD_MEMORY_TYPE_MULTIPLEXED_ROM		= 0x05,
+	SPD_MEMORY_TYPE_SGRAM_DDR		= 0x06,
+	SPD_MEMORY_TYPE_SDRAM_DDR		= 0x07,
+	SPD_MEMORY_TYPE_SDRAM_DDR2		= 0x08,
+	SPD_MEMORY_TYPE_FBDIMM_DDR2		= 0x09,
+	SPD_MEMORY_TYPE_FB_PROBE_DDR2		= 0x0a,
+	SPD_MEMORY_TYPE_SDRAM_DDR3		= 0x0b,
+};
 
 /* SPD_MODULE_VOLTAGE values. */
 #define SPD_VOLTAGE_TTL                  0 /* 5.0 Volt/TTL */