+
+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;
+}
+
projects / proxmark3-svn / blobdiff