CHG: minor correction to the em410xsim help text.

[proxmark3-svn] / armsrc / iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 9cd0cfdc9ceb8158a1cd5e5fe7238db5c58b3096..b9fb9baea308d476a961a3c9d1c77c85ce392768 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -15,7 +15,6 @@
 #include "util.h"
 #include "string.h"
 #include "cmd.h"
-
 #include "iso14443crc.h"
 #include "iso14443a.h"
 #include "crapto1.h"
@@ -260,6 +259,10 @@ void UartReset()
        Uart.parityBits = 0;                            // holds 8 parity bits
        Uart.startTime = 0;
        Uart.endTime = 0;
+       
+       Uart.byteCntMax = 0;
+       Uart.posCnt = 0;
+       Uart.syncBit = 9999;
 }
 
 void UartInit(uint8_t *data, uint8_t *parity)
@@ -279,12 +282,19 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
        if (Uart.state == STATE_UNSYNCD) {                                                                                      // not yet synced
        
                Uart.syncBit = 9999;                                                                                                    // not set
+               
+               // 00x11111 2|3 ticks pause followed by 6|5 ticks unmodulated           Sequence Z (a "0" or "start of communication")
+               // 11111111 8 ticks unmodulation                                                                        Sequence Y (a "0" or "end of communication" or "no information")
+               // 111100x1 4 ticks unmodulated followed by 2|3 ticks pause                     Sequence X (a "1")
+
                // The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from
-               // Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111)
-               // we therefore look for a ...xx11111111111100x11111xxxxxx... pattern 
+               // Sequence X followed by Sequence Y followed by Sequence Z     (111100x1 11111111 00x11111)
+               // we therefore look for a ...xx1111 11111111 00x11111xxxxxx... pattern 
                // (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
-#define ISO14443A_STARTBIT_MASK                0x07FFEF80                                                                      // mask is    00000111 11111111 11101111 10000000
-#define ISO14443A_STARTBIT_PATTERN     0x07FF8F80                                                                      // pattern is 00000111 11111111 10001111 10000000
+               //
+#define ISO14443A_STARTBIT_MASK                0x07FFEF80              // mask is    00001111 11111111 1110 1111 10000000
+#define ISO14443A_STARTBIT_PATTERN     0x07FF8F80              // pattern is 00001111 11111111 1000 1111 10000000
+
                if              ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
                else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
                else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
@@ -434,6 +444,11 @@ void DemodReset()
        Demod.highCnt = 0;
        Demod.startTime = 0;
        Demod.endTime = 0;
+       
+       //
+       Demod.bitCount = 0;
+       Demod.syncBit = 0xFFFF;
+       Demod.samples = 0;
 }
 
 void DemodInit(uint8_t *data, uint8_t *parity)
@@ -532,9 +547,7 @@ static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non
                                }
                        }
                }
-                       
        } 
-
     return FALSE;      // not finished yet, need more data
 }
 
@@ -1608,7 +1621,7 @@ bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_Start
 //-----------------------------------------------------------------------------
 static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receivedResponsePar, uint16_t offset)
 {
-       uint32_t c;
+       uint32_t c = 0x00;
        
        // Set FPGA mode to "reader listen mode", no modulation (listen
        // only, since we are receiving, not transmitting).
@@ -1622,7 +1635,6 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receive
        // clear RXRDY:
     uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 
-       c = 0;
        for(;;) {
                WDT_HIT();
 
@@ -1867,7 +1879,7 @@ void iso14443a_setup(uint8_t fpga_minor_mode) {
        DemodReset();
        UartReset();
        NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
-       iso14a_set_timeout(50*106); // 10ms default
+       iso14a_set_timeout(10*106); // 10ms default
 }
 
 int iso14_apdu(uint8_t *cmd, uint16_t cmd_len, void *data) {
@@ -2863,6 +2875,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
 
                                        // And ready to receive another response.
                                        DemodReset();
+
                                        // And reset the Miller decoder including its (now outdated) input buffer
                                        UartInit(receivedCmd, receivedCmdPar);
                                }