+// em4x05 & em4x69 chip configuration register definitions
+#define EM4x05_GET_BITRATE(x) (((x & 0x3F)*2)+2)
+#define EM4x05_SET_BITRATE(x) ((x-2)/2)
+#define EM4x05_MODULATION_NRZ 0x00000000
+#define EM4x05_MODULATION_MANCHESTER 0x00000040
+#define EM4x05_MODULATION_BIPHASE 0x00000080
+#define EM4x05_MODULATION_MILLER 0x000000C0 //not supported by all 4x05/4x69 chips
+#define EM4x05_MODULATION_PSK1 0x00000100 //not supported by all 4x05/4x69 chips
+#define EM4x05_MODULATION_PSK2 0x00000140 //not supported by all 4x05/4x69 chips
+#define EM4x05_MODULATION_PSK3 0x00000180 //not supported by all 4x05/4x69 chips
+#define EM4x05_MODULATION_FSK1 0x00000200 //not supported by all 4x05/4x69 chips
+#define EM4x05_MODULATION_FSK2 0x00000240 //not supported by all 4x05/4x69 chips
+#define EM4x05_PSK_RF_2 0
+#define EM4x05_PSK_RF_4 0x00000400
+#define EM4x05_PSK_RF_8 0x00000800
+#define EM4x05_MAXBLOCK_SHIFT 14
+#define EM4x05_FIRST_USER_BLOCK 5
+#define EM4x05_SET_NUM_BLOCKS(x) ((x+5-1)<<14) //# of blocks sent during default read mode
+#define EM4x05_GET_NUM_BLOCKS(x) (((x>>14) & 0xF)-5+1)
+#define EM4x05_READ_LOGIN_REQ 1<<18
+#define EM4x05_READ_HK_LOGIN_REQ 1<<19
+#define EM4x05_WRITE_LOGIN_REQ 1<<20
+#define EM4x05_WRITE_HK_LOGIN_REQ 1<<21
+#define EM4x05_READ_AFTER_WRITE 1<<22
+#define EM4x05_DISABLE_ALLOWED 1<<23
+#define EM4x05_READER_TALK_FIRST 1<<24
+