+ if (tracing && DecodeTag.len > 0) {
+ LogTrace(DecodeTag.output, DecodeTag.len, 0, 0, NULL, false);
+ }
+
+ return DecodeTag.len;
+}
+
+
+//=============================================================================
+// An ISO15693 decoder for reader commands.
+//
+// This function is called 4 times per bit (every 2 subcarrier cycles).
+// Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
+// LED handling:
+// LED B -> ON once we have received the SOF and are expecting the rest.
+// LED B -> OFF once we have received EOF or are in error state or unsynced
+//
+// Returns: true if we received a EOF
+// false if we are still waiting for some more
+//=============================================================================
+
+typedef struct DecodeReader {
+ enum {
+ STATE_READER_UNSYNCD,
+ STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF,
+ STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF,
+ STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF,
+ STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4,
+ STATE_READER_RECEIVE_DATA_1_OUT_OF_4,
+ STATE_READER_RECEIVE_DATA_1_OUT_OF_256
+ } state;
+ enum {
+ CODING_1_OUT_OF_4,
+ CODING_1_OUT_OF_256
+ } Coding;
+ uint8_t shiftReg;
+ uint8_t bitCount;
+ int byteCount;
+ int byteCountMax;
+ int posCount;
+ int sum1, sum2;
+ uint8_t *output;
+} DecodeReader_t;
+
+
+static int Handle15693SampleFromReader(uint8_t bit, DecodeReader_t* DecodeReader)
+{
+ switch(DecodeReader->state) {
+ case STATE_READER_UNSYNCD:
+ if(!bit) {
+ // we went low, so this could be the beginning of a SOF
+ DecodeReader->state = STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF;
+ DecodeReader->posCount = 1;
+ }
+ break;
+
+ case STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF:
+ DecodeReader->posCount++;
+ if(bit) { // detected rising edge
+ if(DecodeReader->posCount < 4) { // rising edge too early (nominally expected at 5)
+ DecodeReader->state = STATE_READER_UNSYNCD;
+ } else { // SOF
+ DecodeReader->state = STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF;
+ }
+ } else {
+ if(DecodeReader->posCount > 5) { // stayed low for too long
+ DecodeReader->state = STATE_READER_UNSYNCD;
+ } else {
+ // do nothing, keep waiting
+ }
+ }
+ break;
+
+ case STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF:
+ DecodeReader->posCount++;
+ if(!bit) { // detected a falling edge
+ if (DecodeReader->posCount < 20) { // falling edge too early (nominally expected at 21 earliest)
+ DecodeReader->state = STATE_READER_UNSYNCD;
+ } else if (DecodeReader->posCount < 23) { // SOF for 1 out of 4 coding
+ DecodeReader->Coding = CODING_1_OUT_OF_4;
+ DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+ } else if (DecodeReader->posCount < 28) { // falling edge too early (nominally expected at 29 latest)
+ DecodeReader->state = STATE_READER_UNSYNCD;
+ } else { // SOF for 1 out of 4 coding
+ DecodeReader->Coding = CODING_1_OUT_OF_256;
+ DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+ }
+ } else {
+ if(DecodeReader->posCount > 29) { // stayed high for too long
+ DecodeReader->state = STATE_READER_UNSYNCD;
+ } else {
+ // do nothing, keep waiting
+ }
projects / proxmark3-svn / blobdiff