+ Dbprintf("Tag %s written with 0x%08x%08x\n",
+ card ? "T55x7":"T5555",
+ (uint32_t)(id >> 32),
+ (uint32_t)id);
+}
+
+//-----------------------------------
+// EM4469 / EM4305 routines
+//-----------------------------------
+// Below given command set.
+// Commands are including the even parity, binary mirrored
+#define FWD_CMD_LOGIN 0xC
+#define FWD_CMD_WRITE 0xA
+#define FWD_CMD_READ 0x9
+#define FWD_CMD_DISABLE 0x5
+
+uint8_t forwardLink_data[64]; //array of forwarded bits
+uint8_t * forward_ptr; //ptr for forward message preparation
+uint8_t fwd_bit_sz; //forwardlink bit counter
+uint8_t * fwd_write_ptr; //forwardlink bit pointer
+
+//====================================================================
+// prepares command bits
+// see EM4469 spec
+//====================================================================
+//--------------------------------------------------------------------
+// VALUES TAKEN FROM EM4x function: SendForward
+// START_GAP = 440; (55*8) cycles at 125Khz (8us = 1cycle)
+// WRITE_GAP = 128; (16*8)
+// WRITE_1 = 256 32*8; (32*8)
+
+// These timings work for 4469/4269/4305 (with the 55*8 above)
+// WRITE_0 = 23*8 , 9*8
+
+uint8_t Prepare_Cmd( uint8_t cmd ) {
+
+ *forward_ptr++ = 0; //start bit
+ *forward_ptr++ = 0; //second pause for 4050 code
+
+ *forward_ptr++ = cmd;
+ cmd >>= 1;
+ *forward_ptr++ = cmd;
+ cmd >>= 1;
+ *forward_ptr++ = cmd;
+ cmd >>= 1;
+ *forward_ptr++ = cmd;
+
+ return 6; //return number of emited bits
+}
+
+//====================================================================
+// prepares address bits
+// see EM4469 spec
+//====================================================================
+uint8_t Prepare_Addr( uint8_t addr ) {
+
+ register uint8_t line_parity;
+
+ uint8_t i;
+ line_parity = 0;
+ for( i=0; i<6; i++ ) {
+ *forward_ptr++ = addr;
+ line_parity ^= addr;
+ addr >>= 1;
+ }
+
+ *forward_ptr++ = (line_parity & 1);
+
+ return 7; //return number of emited bits
+}
+
+//====================================================================
+// prepares data bits intreleaved with parity bits
+// see EM4469 spec
+//====================================================================
+uint8_t Prepare_Data( uint16_t data_low, uint16_t data_hi) {
+
+ register uint8_t line_parity;
+ register uint8_t column_parity;
+ register uint8_t i, j;
+ register uint16_t data;
+
+ data = data_low;
+ column_parity = 0;
+
+ for(i=0; i<4; i++) {
+ line_parity = 0;
+ for(j=0; j<8; j++) {
+ line_parity ^= data;
+ column_parity ^= (data & 1) << j;
+ *forward_ptr++ = data;
+ data >>= 1;
+ }
+ *forward_ptr++ = line_parity;
+ if(i == 1)
+ data = data_hi;
+ }
+
+ for(j=0; j<8; j++) {
+ *forward_ptr++ = column_parity;
+ column_parity >>= 1;
+ }
+ *forward_ptr = 0;
+
+ return 45; //return number of emited bits
+}
+
+//====================================================================
+// Forward Link send function
+// Requires: forwarLink_data filled with valid bits (1 bit per byte)
+// fwd_bit_count set with number of bits to be sent
+//====================================================================
+void SendForward(uint8_t fwd_bit_count) {
+
+// iceman, 21.3us increments for the USclock verification.
+// 55FC * 8us == 440us / 21.3 === 20.65 steps. could be too short. Go for 56FC instead
+// 32FC * 8us == 256us / 21.3 == 12.018 steps. ok
+// 16FC * 8us == 128us / 21.3 == 6.009 steps. ok
+
+#ifndef EM_START_GAP
+#define EM_START_GAP 56*8
+#endif
+#ifndef EM_ONE_GAP
+#define EM_ONE_GAP 32*8
+#endif
+#ifndef EM_ZERO_GAP
+# define EM_ZERO_GAP 16*8
+#endif
+
+ fwd_write_ptr = forwardLink_data;
+ fwd_bit_sz = fwd_bit_count;
+
+ // Set up FPGA, 125kHz
+ LFSetupFPGAForADC(95, true);
+
+ // force 1st mod pulse (start gap must be longer for 4305)
+ fwd_bit_sz--; //prepare next bit modulation
+ fwd_write_ptr++;
+
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+ WaitUS(EM_START_GAP);
+
+ TurnReadLFOn(EM_ZERO_GAP);
+
+ // now start writting with bitbanging the antenna.
+ while(fwd_bit_sz-- > 0) { //prepare next bit modulation
+ if(((*fwd_write_ptr++) & 1) == 1)
+ WaitUS(EM_ONE_GAP);
+ else {
+ //These timings work for 4469/4269/4305
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+ WaitUS(EM_ZERO_GAP);
+ TurnReadLFOn(EM_ZERO_GAP);
+ }
+ }
+}
+
+void EM4xLogin(uint32_t pwd) {
+ uint8_t len;
+ forward_ptr = forwardLink_data;
+ len = Prepare_Cmd( FWD_CMD_LOGIN );
+ len += Prepare_Data( pwd & 0xFFFF, pwd >> 16 );
+ SendForward(len);
+ WaitMS(20);
+}
+
+void EM4xReadWord(uint8_t addr, uint32_t pwd, uint8_t usepwd) {
+
+ LED_A_ON();
+
+ uint8_t len;
+
+ //clear buffer now so it does not interfere with timing later
+ BigBuf_Clear_ext(false);
+
+ if (usepwd) EM4xLogin(pwd);
+
+ forward_ptr = forwardLink_data;
+ len = Prepare_Cmd( FWD_CMD_READ );
+ len += Prepare_Addr( addr );
+
+ SendForward(len);
+
+ DoAcquisition_config(TRUE);
+
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+ cmd_send(CMD_ACK,0,0,0,0,0);
+ LED_A_OFF();
+}
+
+void EM4xWriteWord(uint32_t flag, uint32_t data, uint32_t pwd) {
+
+ LED_A_ON();
+
+ bool usePwd = (flag & 0xF);
+ uint8_t addr = (flag >> 8) & 0xFF;
+ uint8_t len;
+
+ //clear buffer now so it does not interfere with timing later
+ BigBuf_Clear_ext(false);
+
+ if (usePwd) EM4xLogin(pwd);
+
+ forward_ptr = forwardLink_data;
+ len = Prepare_Cmd( FWD_CMD_WRITE );
+ len += Prepare_Addr( addr );
+ len += Prepare_Data( data & 0xFFFF, data >> 16 );
+
+ SendForward(len);
+
+ //Wait 20ms for write to complete
+ WaitMS(20);
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+ cmd_send(CMD_ACK,0,0,0,0,0);
+ LED_A_OFF();