+#define EM_PREAMBLE_LEN 6
+// download samples from device
+// and copy them to Graphbuffer
+bool downloadSamplesEM(){
+
+ // 8 bit preamble + 32 bit word response (max clock (128) * 40bits = 5120 samples)
+ uint8_t got[6000];
+ GetFromBigBuf(got, sizeof(got), 0);
+ if ( !WaitForResponseTimeout(CMD_ACK, NULL, 2500) ) {
+ PrintAndLog("command execution time out");
+ return FALSE;
+ }
+ setGraphBuf(got, sizeof(got));
+ return TRUE;
+}
+//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex
+bool doPreambleSearch(size_t *startIdx){
+
+ // sanity check
+ if ( DemodBufferLen < EM_PREAMBLE_LEN) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 demodbuffer too small");
+ return FALSE;
+ }
+
+ // skip first two 0 bits as they might have been missed in the demod
+ uint8_t preamble[EM_PREAMBLE_LEN] = {0,0,1,0,1,0};
+
+ // set size to 15 to only test first 4 positions for the preamble
+ size_t size = (15 > DemodBufferLen) ? DemodBufferLen : 15;
+ *startIdx = 0;
+ uint8_t found = 0;
+
+ // em only sends preamble once, so look for it once in the first x bits
+ for (int idx = 0; idx < size - EM_PREAMBLE_LEN; idx++){
+ if (memcmp(DemodBuffer+idx, preamble, EM_PREAMBLE_LEN) == 0){
+ //first index found
+ *startIdx = idx;
+ found = 1;
+ break;
+ }
+ }
+
+ if ( !found) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305 preamble not found :: %d", *startIdx);
+ return FALSE;
+ }
+ return TRUE;
+}
+
+bool detectFSK(){
+ // detect fsk clock
+ if (!GetFskClock("", FALSE, FALSE)) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: FSK clock failed");
+ return FALSE;
+ }
+ // demod
+ int ans = FSKrawDemod("0 0", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: FSK Demod failed");
+ return FALSE;
+ }
+ return TRUE;
+}
+// PSK clocks should be easy to detect ( but difficult to demod a non-repeating pattern... )
+bool detectPSK(){
+ int ans = GetPskClock("", FALSE, FALSE);
+ if (ans <= 0) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: PSK clock failed");
+ return FALSE;
+ }
+ //demod
+ //try psk1 -- 0 0 6 (six errors?!?)
+ ans = PSKDemod("0 0 6", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: PSK1 Demod failed");
+
+ //try psk1 inverted
+ ans = PSKDemod("0 1 6", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: PSK1 inverted Demod failed");
+ return FALSE;
+ }
+ }
+ // either PSK1 or PSK1 inverted is ok from here.
+ // lets check PSK2 later.
+ return TRUE;
+}
+// try manchester - NOTE: ST only applies to T55x7 tags.
+bool detectASK_MAN(){
+ bool stcheck = FALSE;
+ int ans = ASKDemod_ext("0 0 0", FALSE, FALSE, 1, &stcheck);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: ASK/Manchester Demod failed");
+ return FALSE;
+ }
+ return TRUE;
+}
+bool detectASK_BI(){
+ int ans = ASKbiphaseDemod("0 0 1", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: ASK/biphase normal demod failed");
+
+ ans = ASKbiphaseDemod("0 1 1", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM: ASK/biphase inverted demod failed");
+ return FALSE;
+ }
+ }
+ return TRUE;
+}
+
+// param: idx - start index in demoded data.
+bool setDemodBufferEM(uint32_t *word, size_t idx){
+
+ //test for even parity bits.
+ uint8_t parity[45] = {0};
+ memcpy( parity, DemodBuffer, 45);
+ if (!EMwordparitytest(parity) ){
+ PrintAndLog("DEBUG: Error - EM Parity tests failed");
+ return FALSE;
+ }
+
+ size_t size = removeParity(DemodBuffer, idx + EM_PREAMBLE_LEN, 9, 0, 44);
+ if (!size) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM Parity not detected");
+ return FALSE;
+ }
+ // set & copy to output
+ setDemodBuf(DemodBuffer, 40, 0);
+ *word = bytebits_to_byteLSBF(DemodBuffer, 32);
+ return TRUE;
+}
+
+// FSK, PSK, ASK/MANCHESTER, ASK/BIPHASE, ASK/DIPHASE
+// should cover 90% of known used configs
+// the rest will need to be manually demoded for now...
+bool demodEM4x05resp(uint32_t *word) {
+ size_t idx = 0;
+
+ if (detectASK_MAN() && doPreambleSearch( &idx ))
+ return setDemodBufferEM(word, idx);
+
+ if (detectASK_BI() && doPreambleSearch( &idx ))
+ return setDemodBufferEM(word, idx);
+
+ if (detectFSK() && doPreambleSearch( &idx ))
+ return setDemodBufferEM(word, idx);
+
+ if (detectPSK()) {
+ if (doPreambleSearch( &idx ))
+ return setDemodBufferEM(word, idx);
+
+ psk1TOpsk2(DemodBuffer, DemodBufferLen);
+ if (doPreambleSearch( &idx ))
+ return setDemodBufferEM(word, idx);
+ }
+ return FALSE;
+}
+
+//////////////// 4205 / 4305 commands
+int usage_lf_em4x05_dump(void) {
+ PrintAndLog("Dump EM4x05/EM4x69. Tag must be on antenna. ");