+int usage_lf_em_write(void) {
+ PrintAndLog("Write EM 4x05/4x50/4x69. Tag must be on antenna. ");
+ PrintAndLog("");
+ PrintAndLog("Usage: lf em writeword [h] <address> <data> <pwd>");
+ PrintAndLog("Options:");
+ PrintAndLog(" h - this help");
+ PrintAndLog(" address - memory address to write to. (0-15)");
+ PrintAndLog(" data - data to write (hex)");
+ PrintAndLog(" pwd - password (hex) (optional)");
+ PrintAndLog("samples:");
+ PrintAndLog(" lf em writeword 1");
+ PrintAndLog(" lf em writeword 1 deadc0de 11223344");
+ return 0;
+}
+
+#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 10 to only test first 4 positions for the preamble
+ size_t size = (10 > DemodBufferLen) ? DemodBufferLen : 10;
+ *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 - EM4305: FSK clock failed");
+ return FALSE;
+ }
+ // demod
+ int ans = FSKrawDemod("0 0", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: 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 - EM4305: PSK clock failed");
+ return FALSE;
+ }
+ PrintAndLog("PSK response possibly found, run `data rawd p1` to attempt to demod");
+ 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 - EM4305: 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 - EM4305: ASK/biphase normal demod failed");
+
+ ans = ASKbiphaseDemod("0 1 1", FALSE);
+ if (!ans) {
+ if (g_debugMode) PrintAndLog("DEBUG: Error - EM4305: ASK/biphase inverted demod failed");
+ return FALSE;
+ }
+ }
+ return TRUE;
+}
+
+// param: idx - start index in demoded data.
+int setDemodBufferEM(uint8_t bitsNeeded, size_t idx){
+ if ( bitsNeeded < DemodBufferLen) {
+ setDemodBuf(DemodBuffer + idx + EM_PREAMBLE_LEN, bitsNeeded, 0);
+ CmdPrintDemodBuff("x");
+ return 1;
+ }
+ return -1;
+}
+
+// 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...
+int demodEM4x05resp(uint8_t bitsNeeded) {
+
+ size_t startIdx = 0;
+
+ if (detectASK_MAN() && doPreambleSearch( &startIdx ))
+ return setDemodBufferEM(bitsNeeded, startIdx);
+
+ if (detectASK_BI() && doPreambleSearch( &startIdx ))
+ return setDemodBufferEM(bitsNeeded, startIdx);
+
+ if (detectFSK() && doPreambleSearch( &startIdx ))
+ return setDemodBufferEM(bitsNeeded, startIdx);
+
+ if (detectPSK() && doPreambleSearch( &startIdx ))
+ return setDemodBufferEM(bitsNeeded, startIdx);
+
+ return -1;
+}
+
+int CmdReadWord(const char *Cmd) {
+ int addr, pwd;
+ bool usePwd = false;
+ uint8_t ctmp = param_getchar(Cmd, 0);
+ if ( strlen(Cmd) == 0 || ctmp == 'H' || ctmp == 'h' ) return usage_lf_em_read();
+
+ addr = param_get8ex(Cmd, 0, -1, 10);
+ pwd = param_get32ex(Cmd, 1, -1, 16);
+
+ if ( (addr > 15) || (addr < 0 ) || ( addr == -1) ) {
+ PrintAndLog("Address must be between 0 and 15");
+ return 1;
+ }
+ if ( pwd == -1 )
+ PrintAndLog("Reading address %d", addr);
+ else {
+ usePwd = true;
+ PrintAndLog("Reading address %d | password %08X", addr, pwd);
+ }
+
+ UsbCommand c = {CMD_EM4X_READ_WORD, {addr, pwd, usePwd}};
+ clearCommandBuffer();
+ SendCommand(&c);
+ UsbCommand resp;
+ if (!WaitForResponseTimeout(CMD_ACK, &resp, 2500)){
+ PrintAndLog("Command timed out");
+ return -1;
+ }
+
+ if (!downloadSamplesEM())
+ return -1;
+
+ int testLen = (GraphTraceLen < 1000) ? GraphTraceLen : 1000;
+ if (graphJustNoise(GraphBuffer, testLen)) {
+ PrintAndLog("Tag not found");
+ return -1;
+ }
+
+ //attempt demod:
+ //need 32 bits from a read word
+ return demodEM4x05resp(44);
+}
+
+int CmdWriteWord(const char *Cmd) {
+ uint8_t ctmp = param_getchar(Cmd, 0);
+ if ( strlen(Cmd) == 0 || ctmp == 'H' || ctmp == 'h' ) return usage_lf_em_write();
+
+ bool usePwd = false;
+ int addr = 16; // default to invalid address
+ int data = 0xFFFFFFFF; // default to blank data
+ int pwd = 0xFFFFFFFF; // default to blank password
+
+ addr = param_get8ex(Cmd, 0, -1, 10);
+ data = param_get32ex(Cmd, 1, -1, 16);
+ pwd = param_get32ex(Cmd, 2, -1, 16);
+
+ if ( (addr > 15) || (addr < 0 ) || ( addr == -1) ) {
+ PrintAndLog("Address must be between 0 and 15");
+ return 1;
+ }
+ if ( pwd == -1 )
+ PrintAndLog("Writing address %d data %08X", addr, data);
+ else {
+ usePwd = true;
+ PrintAndLog("Writing address %d data %08X using password %08X", addr, data, pwd);
+ }
+
+ uint16_t flag = (addr << 8 ) | usePwd;
+
+ UsbCommand c = {CMD_EM4X_WRITE_WORD, {flag, data, pwd}};
+ clearCommandBuffer();
+ SendCommand(&c);
+ UsbCommand resp;
+ if (!WaitForResponseTimeout(CMD_ACK, &resp, 1000)){
+ PrintAndLog("Error occurred, device did not respond during write operation.");
+ return -1;
+ }
+
+ if (!downloadSamplesEM())
+ return -1;
+
+ //todo: check response for 00001010 then write data for write confirmation!
+
+ //attempt demod:
+ //need 0 bits demoded (after preamble) to verify write cmd
+ int result = demodEM4x05resp(0);
+ if (result == 1)
+ PrintAndLog("Write Verified");
+
+ return result;
+}
+
+static command_t CommandTable[] = {
+ {"help", CmdHelp, 1, "This help"},
+ {"em410xdemod", CmdEMdemodASK, 0, "[findone] -- Extract ID from EM410x tag (option 0 for continuous loop, 1 for only 1 tag)"},
+ {"em410xread", CmdEM410xRead, 1, "[clock rate] -- Extract ID from EM410x tag in GraphBuffer"},
+ {"em410xsim", CmdEM410xSim, 0, "<UID> -- Simulate EM410x tag"},
+ {"em410xwatch", CmdEM410xWatch, 0, "['h'] -- Watches for EM410x 125/134 kHz tags (option 'h' for 134)"},
+ {"em410xspoof", CmdEM410xWatchnSpoof, 0, "['h'] --- Watches for EM410x 125/134 kHz tags, and replays them. (option 'h' for 134)" },
+ {"em410xwrite", CmdEM410xWrite, 0, "<UID> <'0' T5555> <'1' T55x7> [clock rate] -- Write EM410x UID to T5555(Q5) or T55x7 tag, optionally setting clock rate"},
+ {"em4x50read", CmdEM4x50Read, 1, "demod data from EM4x50 tag from the graphbuffer"},
+ {"readword", CmdReadWord, 1, "read EM4x05/4x69 data"},
+ {"writeword", CmdWriteWord, 1, "write EM405/4x69 data"},
+ {NULL, NULL, 0, NULL}