//----------------------------------------------------------------------------- // Jonathan Westhues, split Nov 2006 // piwi 2018 // // This code is licensed to you under the terms of the GNU GPL, version 2 or, // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- // Routines to support ISO 14443B. This includes both the reader software and // the `fake tag' modes. //----------------------------------------------------------------------------- #include "iso14443b.h" #include "proxmark3_arm.h" #include "common.h" // access to global variable: DBGLEVEL #include "util.h" #include "string.h" #include "crc16.h" #include "protocols.h" #include "appmain.h" #include "BigBuf.h" #include "cmd.h" #include "fpgaloader.h" #include "commonutil.h" #include "dbprint.h" #include "ticks.h" #ifndef RECEIVE_MASK # define RECEIVE_MASK (DMA_BUFFER_SIZE - 1) #endif #define RECEIVE_SAMPLES_TIMEOUT 64 // Guard Time (per 14443-2) #ifndef TR0 # define TR0 64 // TR0 max is 256/fs = 256/(848kHz) = 302us or 64 samples from FPGA #endif // Synchronization time (per 14443-2) #ifndef TR1 # define TR1 0 #endif // Frame Delay Time PICC to PCD (per 14443-3 Amendment 1) #ifndef TR2 # define TR2 0 #endif // 4sample #define SEND4STUFFBIT(x) tosend_stuffbit(x);tosend_stuffbit(x);tosend_stuffbit(x);tosend_stuffbit(x); static void iso14b_set_timeout(uint32_t timeout); static void iso14b_set_maxframesize(uint16_t size); // the block number for the ISO14443-4 PCB (used with APDUs) static uint8_t pcb_blocknum = 0; static uint32_t iso14b_timeout = TR0; /* ISO 14443 B * * Reader to card | ASK - Amplitude Shift Keying Modulation (PCD to PICC for Type B) (NRZ-L encodig) * Card to reader | BPSK - Binary Phase Shift Keying Modulation, (PICC to PCD for Type B) * * fc - carrier frequency 13.56 MHz * TR0 - Guard Time per 14443-2 * TR1 - Synchronization Time per 14443-2 * TR2 - PICC to PCD Frame Delay Time (per 14443-3 Amendment 1) * * Elementary Time Unit (ETU) is * - 128 Carrier Cycles (9.4395 µS) = 8 Subcarrier Units * - 1 ETU = 1 bit * - 10 ETU = 1 startbit, 8 databits, 1 stopbit (10bits length) * - startbit is a 0 * - stopbit is a 1 * * Start of frame (SOF) is * - [10-11] ETU of ZEROS, unmodulated time * - [2-3] ETU of ONES, * * End of frame (EOF) is * - [10-11] ETU of ZEROS, unmodulated time * * -TO VERIFY THIS BELOW- * The mode FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK which we use to simulate tag * works like this: * - A 1-bit input to the FPGA becomes 8 pulses at 847.5kHz (1.18µS / pulse) == 9.44us * - A 0-bit input to the FPGA becomes an unmodulated time of 1.18µS or does it become 8 nonpulses for 9.44us * * FPGA doesn't seem to work with ETU. It seems to work with pulse / duration instead. * * Card sends data ub 847.e kHz subcarrier * subcar |duration| FC division * -------+--------+------------ * 106kHz | 9.44µS | FC/128 * 212kHz | 4.72µS | FC/64 * 424kHz | 2.36µS | FC/32 * 848kHz | 1.18µS | FC/16 * -------+--------+------------ * * Reader data transmission: * - no modulation ONES * - SOF * - Command, data and CRC_B * - EOF * - no modulation ONES * * Card data transmission * - TR1 * - SOF * - data (each bytes is: 1startbit, 8bits, 1stopbit) * - CRC_B * - EOF * * FPGA implementation : * At this point only Type A is implemented. This means that we are using a * bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make * things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s) * */ //============================================================================= // An ISO 14443 Type B tag. We listen for commands from the reader, using // a UART kind of thing that's implemented in software. When we get a // frame (i.e., a group of bytes between SOF and EOF), we check the CRC. // If it's good, then we can do something appropriate with it, and send // a response. //============================================================================= //----------------------------------------------------------------------------- // Code up a string of octets at layer 2 (including CRC, we don't generate // that here) so that they can be transmitted to the reader. Doesn't transmit // them yet, just leaves them ready to send in ToSend[]. //----------------------------------------------------------------------------- static void CodeIso14443bAsTag(const uint8_t *cmd, int len) { int i; tosend_reset(); // Transmit a burst of ones, as the initial thing that lets the // reader get phase sync. // This loop is TR1, per specification // TR1 minimum must be > 80/fs // TR1 maximum 200/fs // 80/fs < TR1 < 200/fs // 10 ETU < TR1 < 24 ETU // Send TR1. // 10-11 ETU * 4times samples ONES for (i = 0; i < 20; i++) { SEND4STUFFBIT(1); } // Send SOF. // 10-11 ETU * 4times samples ZEROS for (i = 0; i < 10; i++) { SEND4STUFFBIT(0); } // 2-3 ETU * 4times samples ONES for (i = 0; i < 2; i++) { SEND4STUFFBIT(1); } // data for (i = 0; i < len; i++) { // Start bit SEND4STUFFBIT(0); // Data bits uint8_t b = cmd[i]; for (int j = 0; j < 8; j++) { SEND4STUFFBIT(b & 1); b >>= 1; } // Stop bit SEND4STUFFBIT(1); // Extra Guard bit // For PICC it ranges 0-18us (1etu = 9us) //SEND4STUFFBIT(1); } // Send EOF. // 10-11 ETU * 4 sample rate = ZEROS for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); } // why this? for(i = 0; i < 2; i++) { SEND4STUFFBIT(1); } tosend_t *ts = get_tosend(); // Convert from last byte pos to length ts->max++; } //----------------------------------------------------------------------------- // The software UART that receives commands from the reader, and its state // variables. //----------------------------------------------------------------------------- static struct { enum { STATE_14B_UNSYNCD, STATE_14B_GOT_FALLING_EDGE_OF_SOF, STATE_14B_AWAITING_START_BIT, STATE_14B_RECEIVING_DATA } state; uint16_t shiftReg; int bitCnt; int byteCnt; int byteCntMax; int posCnt; uint8_t *output; } Uart; static void Uart14bReset(void) { Uart.state = STATE_14B_UNSYNCD; Uart.shiftReg = 0; Uart.bitCnt = 0; Uart.byteCnt = 0; Uart.byteCntMax = MAX_FRAME_SIZE; Uart.posCnt = 0; } static void Uart14bInit(uint8_t *data) { Uart.output = data; Uart14bReset(); } //----------------------------------------------------------------------------- // The software Demod that receives commands from the tag, and its state variables. //----------------------------------------------------------------------------- static struct { enum { DEMOD_UNSYNCD, DEMOD_PHASE_REF_TRAINING, DEMOD_AWAITING_FALLING_EDGE_OF_SOF, DEMOD_GOT_FALLING_EDGE_OF_SOF, DEMOD_AWAITING_START_BIT, DEMOD_RECEIVING_DATA } state; uint16_t bitCount; int posCount; int thisBit; uint16_t shiftReg; uint8_t *output; uint16_t len; int sumI; int sumQ; uint32_t startTime, endTime; } Demod; // Clear out the state of the "UART" that receives from the tag. static void Demod14bReset(void) { Demod.state = DEMOD_UNSYNCD; Demod.bitCount = 0; Demod.posCount = 0; Demod.thisBit = 0; Demod.shiftReg = 0; Demod.len = 0; Demod.sumI = 0; Demod.sumQ = 0; Demod.startTime = 0; Demod.endTime = 0; } static void Demod14bInit(uint8_t *data) { Demod.output = data; Demod14bReset(); } /* * 9.4395 us = 1 ETU and clock is about 1.5 us * 13560000Hz * 1000ms/s * timeout in ETUs (time to transfer 1 bit, 9.4395 us) * * Formula to calculate FWT (in ETUs) by timeout (in ms): * fwt = 13560000 * 1000 / (8*16) * timeout; * Sample: 3sec == 3000ms * 13560000 * 1000 / (8*16) * 3000 == * 13560000000 / 384000 = 35312 FWT * @param timeout is in frame wait time, fwt, measured in ETUs */ static void iso14b_set_timeout(uint32_t timeout) { #define MAX_TIMEOUT 40542464 // 13560000Hz * 1000ms / (2^32-1) * (8*16) if (timeout > MAX_TIMEOUT) timeout = MAX_TIMEOUT; iso14b_timeout = timeout; if (DBGLEVEL >= 3) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout); } static void iso14b_set_maxframesize(uint16_t size) { if (size > 256) size = MAX_FRAME_SIZE; Uart.byteCntMax = size; if (DBGLEVEL >= 3) Dbprintf("ISO14443B Max frame size set to %d bytes", Uart.byteCntMax); } /* Receive & handle a bit coming from the reader. * * 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 A -> ON once we have received the SOF and are expecting the rest. * LED A -> 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 */ static RAMFUNC int Handle14443bReaderUartBit(uint8_t bit) { switch (Uart.state) { case STATE_14B_UNSYNCD: if (!bit) { // we went low, so this could be the beginning of an SOF Uart.state = STATE_14B_GOT_FALLING_EDGE_OF_SOF; Uart.posCnt = 0; Uart.bitCnt = 0; } break; case STATE_14B_GOT_FALLING_EDGE_OF_SOF: Uart.posCnt++; if (Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit if (bit) { if (Uart.bitCnt > 9) { // we've seen enough consecutive // zeros that it's a valid SOF Uart.posCnt = 0; Uart.byteCnt = 0; Uart.state = STATE_14B_AWAITING_START_BIT; LED_A_ON(); // Indicate we got a valid SOF } else { // didn't stay down long enough before going high, error Uart.state = STATE_14B_UNSYNCD; } } else { // do nothing, keep waiting } Uart.bitCnt++; } if (Uart.posCnt >= 4) Uart.posCnt = 0; if (Uart.bitCnt > 12) { // Give up if we see too many zeros without a one, too. LED_A_OFF(); Uart.state = STATE_14B_UNSYNCD; } break; case STATE_14B_AWAITING_START_BIT: Uart.posCnt++; if (bit) { if (Uart.posCnt > 50 / 2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs // stayed high for too long between characters, error Uart.state = STATE_14B_UNSYNCD; } } else { // falling edge, this starts the data byte Uart.posCnt = 0; Uart.bitCnt = 0; Uart.shiftReg = 0; Uart.state = STATE_14B_RECEIVING_DATA; } break; case STATE_14B_RECEIVING_DATA: Uart.posCnt++; if (Uart.posCnt == 2) { // time to sample a bit Uart.shiftReg >>= 1; if (bit) { Uart.shiftReg |= 0x200; } Uart.bitCnt++; } if (Uart.posCnt >= 4) { Uart.posCnt = 0; } if (Uart.bitCnt == 10) { if ((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001)) { // this is a data byte, with correct // start and stop bits Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff; Uart.byteCnt++; if (Uart.byteCnt >= Uart.byteCntMax) { // Buffer overflowed, give up LED_A_OFF(); Uart.state = STATE_14B_UNSYNCD; } else { // so get the next byte now Uart.posCnt = 0; Uart.state = STATE_14B_AWAITING_START_BIT; } } else if (Uart.shiftReg == 0x000) { // this is an EOF byte LED_A_OFF(); // Finished receiving Uart.state = STATE_14B_UNSYNCD; if (Uart.byteCnt != 0) return true; } else { // this is an error LED_A_OFF(); Uart.state = STATE_14B_UNSYNCD; } } break; default: LED_A_OFF(); Uart.state = STATE_14B_UNSYNCD; break; } return false; } //----------------------------------------------------------------------------- // Receive a command (from the reader to us, where we are the simulated tag), // and store it in the given buffer, up to the given maximum length. Keeps // spinning, waiting for a well-framed command, until either we get one // (returns true) or someone presses the pushbutton on the board (false). // // Assume that we're called with the SSC (to the FPGA) and ADC path set // correctly. //----------------------------------------------------------------------------- static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) { // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen // only, since we are receiving, not transmitting). // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION); // Now run a `software UART' on the stream of incoming samples. Uart14bInit(received); while (BUTTON_PRESS() == false) { WDT_HIT(); if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR; for (uint8_t mask = 0x80; mask != 0x00; mask >>= 1) { if (Handle14443bReaderUartBit(b & mask)) { *len = Uart.byteCnt; return true; } } } } return false; } static void TransmitFor14443b_AsTag(uint8_t *response, uint16_t len) { // Signal field is off with the appropriate LED LED_D_OFF(); // Modulate BPSK FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK); AT91C_BASE_SSC->SSC_THR = 0xFF; FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR); // Transmit the response. for (uint16_t i = 0; i < len;) { // Put byte into tx holding register as soon as it is ready if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) { AT91C_BASE_SSC->SSC_THR = response[i++]; } } } //----------------------------------------------------------------------------- // Main loop of simulated tag: receive commands from reader, decide what // response to send, and send it. //----------------------------------------------------------------------------- void SimulateIso14443bTag(uint32_t pupi) { LED_A_ON(); // the only commands we understand is WUPB, AFI=0, Select All, N=1: // static const uint8_t cmdWUPB[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // WUPB // ... and REQB, AFI=0, Normal Request, N=1: // static const uint8_t cmdREQB[] = { ISO14443B_REQB, 0x00, 0x00, 0x71, 0xFF }; // REQB // ... and HLTB // static const uint8_t cmdHLTB[] = { 0x50, 0xff, 0xff, 0xff, 0xff }; // HLTB // ... and ATTRIB // static const uint8_t cmdATTRIB[] = { ISO14443B_ATTRIB, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; // ATTRIB // ... if not PUPI/UID is supplied we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922, // supports only 106kBit/s in both directions, max frame size = 32Bytes, // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported: uint8_t respATQB[] = { 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22, 0x00, 0x21, 0x85, 0x5e, 0xd7 }; // response to HLTB and ATTRIB static const uint8_t respOK[] = {0x00, 0x78, 0xF0}; // ...PUPI/UID supplied from user. Adjust ATQB response accordingly if (pupi > 0) { num_to_bytes(pupi, 4, respATQB + 1); AddCrc14B(respATQB, 12); } // setup device. FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Set up the synchronous serial port FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR); // allocate command receive buffer BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); uint16_t len, cmdsReceived = 0; int cardSTATE = SIM_NOFIELD; int vHf = 0; // in mV tosend_t *ts = get_tosend(); uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE); // prepare "ATQB" tag answer (encoded): CodeIso14443bAsTag(respATQB, sizeof(respATQB)); uint8_t *encodedATQB = BigBuf_malloc(ts->max); uint16_t encodedATQBLen = ts->max; memcpy(encodedATQB, ts->buf, ts->max); // prepare "OK" tag answer (encoded): CodeIso14443bAsTag(respOK, sizeof(respOK)); uint8_t *encodedOK = BigBuf_malloc(ts->max); uint16_t encodedOKLen = ts->max; memcpy(encodedOK, ts->buf, ts->max); // Simulation loop while (BUTTON_PRESS() == false) { WDT_HIT(); //iceman: limit with 2000 times.. if (data_available()) { break; } // find reader field if (cardSTATE == SIM_NOFIELD) { #if defined RDV4 vHf = (MAX_ADC_HF_VOLTAGE_RDV40 * SumAdc(ADC_CHAN_HF_RDV40, 32)) >> 15; #else vHf = (MAX_ADC_HF_VOLTAGE * SumAdc(ADC_CHAN_HF, 32)) >> 15; #endif if (vHf > MF_MINFIELDV) { cardSTATE = SIM_IDLE; LED_A_ON(); } } if (cardSTATE == SIM_NOFIELD) continue; // Get reader command if (!GetIso14443bCommandFromReader(receivedCmd, &len)) { Dbprintf("button pressed, received %d commands", cmdsReceived); break; } // ISO14443-B protocol states: // REQ or WUP request in ANY state // WUP in HALTED state if (len == 5) { if ((receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8) == 0x8 && cardSTATE == SIM_HALTED) || receivedCmd[0] == ISO14443B_REQB) { LogTrace(receivedCmd, len, 0, 0, NULL, true); cardSTATE = SIM_SELECTING; } } /* * How should this flow go? * REQB or WUPB * send response ( waiting for Attrib) * ATTRIB * send response ( waiting for commands 7816) * HALT send halt response ( waiting for wupb ) */ switch (cardSTATE) { //case SIM_NOFIELD: case SIM_HALTED: case SIM_IDLE: { LogTrace(receivedCmd, len, 0, 0, NULL, true); break; } case SIM_SELECTING: { TransmitFor14443b_AsTag(encodedATQB, encodedATQBLen); LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, false); cardSTATE = SIM_WORK; break; } case SIM_HALTING: { TransmitFor14443b_AsTag(encodedOK, encodedOKLen); LogTrace(respOK, sizeof(respOK), 0, 0, NULL, false); cardSTATE = SIM_HALTED; break; } case SIM_ACKNOWLEDGE: { TransmitFor14443b_AsTag(encodedOK, encodedOKLen); LogTrace(respOK, sizeof(respOK), 0, 0, NULL, false); cardSTATE = SIM_IDLE; break; } case SIM_WORK: { if (len == 7 && receivedCmd[0] == ISO14443B_HALT) { cardSTATE = SIM_HALTED; } else if (len == 11 && receivedCmd[0] == ISO14443B_ATTRIB) { cardSTATE = SIM_ACKNOWLEDGE; } else { // Todo: // - SLOT MARKER // - ISO7816 // - emulate with a memory dump if (DBGLEVEL >= DBG_DEBUG) Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsReceived); // CRC Check if (len >= 3) { // if crc exists if (!check_crc(CRC_14443_B, receivedCmd, len)) { if (DBGLEVEL >= DBG_DEBUG) { DbpString("CRC fail"); } } } else { if (DBGLEVEL >= DBG_DEBUG) { DbpString("CRC passed"); } } cardSTATE = SIM_IDLE; } break; } default: break; } ++cmdsReceived; } if (DBGLEVEL >= DBG_DEBUG) Dbprintf("Emulator stopped. Trace length: %d ", BigBuf_get_traceLen()); switch_off(); //simulate } //============================================================================= // An ISO 14443 Type B reader. We take layer two commands, code them // appropriately, and then send them to the tag. We then listen for the // tag's response, which we leave in the buffer to be demodulated on the // PC side. //============================================================================= /* * Handles reception of a bit from the tag * * This function is called 2 times per bit (every 4 subcarrier cycles). * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us * * LED handling: * LED C -> ON once we have received the SOF and are expecting the rest. * LED C -> OFF once we have received EOF or are unsynced * * Returns: true if we received a EOF * false if we are still waiting for some more * */ static RAMFUNC int Handle14443bTagSamplesDemod(uint16_t amplitude) { #define SUBCARRIER_DETECT_THRESHOLD 8 switch (Demod.state) { case DEMOD_UNSYNCD: if (amplitude > SUBCARRIER_DETECT_THRESHOLD) { Demod.state = DEMOD_PHASE_REF_TRAINING; Demod.sumI = amplitude; Demod.sumQ = amplitude; Demod.posCount = 1; } break; case DEMOD_PHASE_REF_TRAINING: if (Demod.posCount < 8) { if (amplitude > SUBCARRIER_DETECT_THRESHOLD) { // set the reference phase (will code a logic '1') by averaging over 32 1/fs. // note: synchronization time > 80 1/fs Demod.sumI += amplitude; Demod.sumQ += amplitude; Demod.posCount++; } else { // subcarrier lost Demod.state = DEMOD_UNSYNCD; } } else { Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF; } break; case DEMOD_AWAITING_FALLING_EDGE_OF_SOF: if (amplitude == 0) { // logic '0' detected Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF; Demod.posCount = 0; // start of SOF sequence } else { // maximum length of TR1 = 200 1/fs if (Demod.posCount > 200 / 4){ Demod.state = DEMOD_UNSYNCD; } } Demod.posCount++; break; case DEMOD_GOT_FALLING_EDGE_OF_SOF: Demod.posCount++; if (amplitude > 0) { // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges if (Demod.posCount < 9 * 2) { Demod.state = DEMOD_UNSYNCD; } else { LED_C_ON(); // Got SOF Demod.state = DEMOD_AWAITING_START_BIT; Demod.posCount = 0; Demod.bitCount = 0; Demod.len = 0; } } else { // low phase of SOF too long (> 12 etu) if (Demod.posCount > 14 * 2) { Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); } } break; case DEMOD_AWAITING_START_BIT: Demod.posCount++; if (amplitude > 0) { if (Demod.posCount > 6 * 2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs LED_C_OFF(); if (Demod.bitCount == 0 && Demod.len == 0) { // received SOF only, this is valid for iClass/Picopass return true; } else { Demod.state = DEMOD_UNSYNCD; } } } else { // start bit detected Demod.bitCount = 0; Demod.posCount = 1; // this was the first half Demod.thisBit = amplitude; Demod.shiftReg = 0; Demod.state = DEMOD_RECEIVING_DATA; } break; case DEMOD_RECEIVING_DATA: if (Demod.posCount == 0) { // first half of bit Demod.thisBit = amplitude; Demod.posCount = 1; } else { // second half of bit Demod.thisBit += amplitude; Demod.shiftReg >>= 1; // OR in a logic '1' if (Demod.thisBit > 0) Demod.shiftReg |= 0x200; Demod.bitCount++; // 1 start 8 data 1 stop = 10 if (Demod.bitCount == 10) { uint16_t s = Demod.shiftReg; // stop bit == '1', start bit == '0' if ((s & 0x200) && ((s & 0x001) == 0)) { // left shift to drop the startbit uint8_t b = (s >> 1); Demod.output[Demod.len] = b; Demod.len++; Demod.bitCount = 0; Demod.state = DEMOD_AWAITING_START_BIT; } else { // this one is a bit hard, either its a correc byte or its unsynced. Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); // This is EOF (start, stop and all data bits == '0' if (s == 0) return true; } } Demod.posCount = 0; } break; default: Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); break; } return false; } /* * Demodulate the samples we received from the tag, also log to tracebuffer */ static int GetTagSamplesFor14443bDemod(int timeout) { int samples = 0, ret = 0; BigBuf_free(); // Set up the demodulator for tag -> reader responses. Demod14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); // wait for last transfer to complete while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY)) // Setup and start DMA. FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER); // The DMA buffer, used to stream samples from the FPGA dmabuf16_t *dma = get_dma16(); if (FpgaSetupSscDma((uint8_t *) dma->buf, DMA_BUFFER_SIZE) == false) { if (DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); return -1; } // Signal field is ON with the appropriate LED: LED_D_ON(); // And put the FPGA in the appropriate mode FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER | FPGA_HF_READER_SUBCARRIER_848_KHZ | FPGA_HF_READER_MODE_RECEIVE_IQ); // uint32_t dma_start_time; uint16_t *upTo = dma->buf; for(;;) { uint16_t behindBy = ((uint16_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (DMA_BUFFER_SIZE - 1); if (behindBy == 0) continue; samples++; /* if (samples == 1) { // DMA has transferred the very first data dma_start_time = GetCountSspClk() & 0xfffffff0; } */ volatile uint16_t tagdata = *upTo++; if (upTo >= dma->buf + DMA_BUFFER_SIZE) { // we have read all of the DMA buffer content. upTo = dma->buf; // start reading the circular buffer from the beginning if (behindBy > (9 * DMA_BUFFER_SIZE / 10)) { Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy); ret = -1; break; } } if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) { // DMA Counter Register had reached 0, already rotated. AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dma->buf; // refresh the DMA Next Buffer and AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE; // DMA Next Counter registers } if (Handle14443bTagSamplesDemod(tagdata)) { ret = Demod.len; break; } if(samples > timeout && Demod.state < DEMOD_PHASE_REF_TRAINING) { ret = -1; LED_C_OFF(); break; } } FpgaDisableSscDma(); if (ret < 0) { return ret; } if (Demod.len > 0) { LogTrace(Demod.output, Demod.len, 0, 0, NULL, false); } return ret; } //----------------------------------------------------------------------------- // Transmit the command (to the tag) that was placed in ToSend[]. //----------------------------------------------------------------------------- static void TransmitFor14443b_AsReader(void) { FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER | FPGA_HF_READER_MODE_SEND_SHALLOW_MOD); LED_B_ON(); tosend_t *ts = get_tosend(); for (int c = 0; c < ts->max; c++) { uint8_t data = ts->buf[c]; for (int i = 0; i < 8; i++) { uint16_t send_word = (data & 0x80) ? 0x0000 : 0xffff; while (!(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))) ; AT91C_BASE_SSC->SSC_THR = send_word; while (!(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))) ; AT91C_BASE_SSC->SSC_THR = send_word; data <<= 1; } WDT_HIT(); } LED_B_OFF(); } //----------------------------------------------------------------------------- // Code a layer 2 command (string of octets, including CRC) into ToSend[], // so that it is ready to transmit to the tag using TransmitFor14443b(). //----------------------------------------------------------------------------- static void CodeIso14443bAsReader(const uint8_t *cmd, int len) { /* * Reader data transmission: * - no modulation ONES * - SOF * - Command, data and CRC_B * - EOF * - no modulation ONES * * 1 ETU == 1 BIT! * TR0 - 8 ETUS minimum. * * QUESTION: how long is a 1 or 0 in pulses in the xcorr_848 mode? * 1 "stuffbit" = 1ETU (9us) */ tosend_reset(); // Send SOF // 10-11 ETUs of ZERO for (int i = 0; i < 10; i++) tosend_stuffbit(0); // 2-3 ETUs of ONE tosend_stuffbit(1); tosend_stuffbit(1); // Sending cmd, LSB // from here we add BITS for (int i = 0; i < len; i++) { // Start bit tosend_stuffbit(0); // Data bits uint8_t b = cmd[i]; tosend_stuffbit(b & 1); tosend_stuffbit((b >> 1) & 1); tosend_stuffbit((b >> 2) & 1); tosend_stuffbit((b >> 3) & 1); tosend_stuffbit((b >> 4) & 1); tosend_stuffbit((b >> 5) & 1); tosend_stuffbit((b >> 6) & 1); tosend_stuffbit((b >> 7) & 1); // Stop bit tosend_stuffbit(1); // EGT extra guard time // For PCD it ranges 0-57us (1etu = 9us) // tosend_stuffbit(1); // tosend_stuffbit(1); // tosend_stuffbit(1); } // Send EOF // 10-11 ETUs of ZERO for (int i = 0; i < 10; i++) tosend_stuffbit(0); // Transition time. TR0 - guard time // 8ETUS minum? // Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF. // I'm guessing this is for the FPGA to be able to send all bits before we switch to listening mode // ensure that last byte is filled up for (int i = 0; i < 8 ; ++i) tosend_stuffbit(1); // TR1 - Synchronization time // Convert from last character reference to length tosend_t *ts = get_tosend(); ts->max++; } /* * Convenience function to encode, transmit and trace iso 14443b comms */ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len) { uint32_t time_start = GetCountSspClk(); CodeIso14443bAsReader(cmd, len); TransmitFor14443b_AsReader(); LogTrace(cmd, len, time_start, GetCountSspClk(), NULL, true); } /* Sends an APDU to the tag * TODO: check CRC and preamble */ uint8_t iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response) { LED_A_ON(); uint8_t message_frame[message_length + 4]; // PCB message_frame[0] = 0x0A | pcb_blocknum; pcb_blocknum ^= 1; // CID message_frame[1] = 0; // INF memcpy(message_frame + 2, message, message_length); // EDC (CRC) AddCrc14B(message_frame, message_length + 2); // send CodeAndTransmit14443bAsReader(message_frame, message_length + 4); // get response int ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); if (ret < 3) { LED_A_OFF(); return 0; } // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) { if (DBGLEVEL > 3) DbpString("CRC fail"); return 0; } // copy response contents if (response != NULL) memcpy(response, Demod.output, Demod.len); return Demod.len; LED_A_OFF(); } /** * SRx Initialise. */ static uint8_t iso14443b_select_srx_card(iso14b_card_select_t *card) { // INITIATE command: wake up the tag using the INITIATE static const uint8_t init_srx[] = { ISO14443B_INITIATE, 0x00, 0x97, 0x5b }; // SELECT command (with space for CRC) uint8_t select_srx[] = { ISO14443B_SELECT, 0x00, 0x00, 0x00}; CodeAndTransmit14443bAsReader(init_srx, sizeof(init_srx)); int ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); if (Demod.len == 0 || ret < 0) return 2; Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x [%02x %02x]", Demod.output[0], Demod.output[1], Demod.output[2]); // Randomly generated Chip ID if (card) card->chipid = Demod.output[0]; select_srx[1] = Demod.output[0]; AddCrc14B(select_srx, 2); CodeAndTransmit14443bAsReader(select_srx, sizeof(select_srx)); ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); if (Demod.len != 3 || ret < 0) return 2; // Check the CRC of the answer: if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) return 3; // Check response from the tag: should be the same UID as the command we just sent: if (select_srx[1] != Demod.output[0]) return 1; // First get the tag's UID: select_srx[0] = ISO14443B_GET_UID; AddCrc14B(select_srx, 1); CodeAndTransmit14443bAsReader(select_srx, 3); // Only first three bytes for this one ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); if (Demod.len != 10 || ret < 0) return 2; // The check the CRC of the answer if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) return 3; if (card) { card->uidlen = 8; memcpy(card->uid, Demod.output, 8); } return 0; } /* Perform the ISO 14443 B Card Selection procedure * Currently does NOT do any collision handling. * It expects 0-1 cards in the device's range. * TODO: Support multiple cards (perform anticollision) * TODO: Verify CRC checksums */ int iso14443b_select_card(iso14b_card_select_t *card) { // WUPB command (including CRC) // Note: WUPB wakes up all tags, REQB doesn't wake up tags in HALT state static const uint8_t wupb[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // ATTRIB command (with space for CRC) uint8_t attrib[] = { ISO14443B_ATTRIB, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00}; // first, wake up the tag CodeAndTransmit14443bAsReader(wupb, sizeof(wupb)); int ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); // ATQB too short? if (ret < 14) return -1; // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) return -2; if (card) { card->uidlen = 4; memcpy(card->uid, Demod.output + 1, 4); memcpy(card->atqb, Demod.output + 5, 7); } // copy the PUPI to ATTRIB ( PUPI == UID ) memcpy(attrib + 1, Demod.output + 1, 4); // copy the protocol info from ATQB (Protocol Info -> Protocol_Type) into ATTRIB (Param 3) attrib[7] = Demod.output[10] & 0x0F; AddCrc14B(attrib, 9); CodeAndTransmit14443bAsReader(attrib, sizeof(attrib)); ret = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); // Answer to ATTRIB too short? if (ret < 3) return -1; // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) return -2; if (card) { // CID card->cid = Demod.output[0]; // MAX FRAME uint16_t maxFrame = card->atqb[5] >> 4; if (maxFrame < 5) maxFrame = 8 * maxFrame + 16; else if (maxFrame == 5) maxFrame = 64; else if (maxFrame == 6) maxFrame = 96; else if (maxFrame == 7) maxFrame = 128; else if (maxFrame == 8) maxFrame = 256; else maxFrame = 257; iso14b_set_maxframesize(maxFrame); // FWT uint8_t fwt = card->atqb[6] >> 4; if (fwt < 16) { uint32_t fwt_time = (302 << fwt); iso14b_set_timeout(fwt_time); } } // reset PCB block number pcb_blocknum = 0; return 0; } // Set up ISO 14443 Type B communication (similar to iso14443a_setup) // field is setup for "Sending as Reader" void iso14443b_setup(void) { LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // Initialize Demod and Uart structs Demod14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); Uart14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Set up the synchronous serial port FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER); // Signal field is on with the appropriate LED FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER | FPGA_HF_READER_MODE_SEND_SHALLOW_MOD); SpinDelay(100); // Start the timer StartCountSspClk(); LED_D_ON(); } //----------------------------------------------------------------------------- // Read a SRI512 ISO 14443B tag. // // SRI512 tags are just simple memory tags, here we're looking at making a dump // of the contents of the memory. No anticollision algorithm is done, we assume // we have a single tag in the field. // // I tried to be systematic and check every answer of the tag, every CRC, etc... //----------------------------------------------------------------------------- static bool ReadSTBlock(uint8_t block) { uint8_t cmd[] = {ISO14443B_READ_BLK, block, 0x00, 0x00}; AddCrc14B(cmd, 2); CodeAndTransmit14443bAsReader(cmd, sizeof(cmd)); int res = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); FpgaDisableTracing(); // Check if we got an answer from the tag if (Demod.len != 6 || res < 0) { DbpString("[!] expected 6 bytes from tag, got less..."); return false; } // The check the CRC of the answer if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) { DbpString("CRC fail"); return false; } return true; } void ReadSTMemoryIso14443b(uint8_t numofblocks) { // Make sure that we start from off, since the tags are stateful; // confusing things will happen if we don't reset them between reads. //switch_off(); uint8_t i = 0x00; uint8_t *buf = BigBuf_malloc(sizeof(iso14b_card_select_t)); iso14443b_setup(); iso14b_card_select_t *card = (iso14b_card_select_t *)buf; uint8_t res = iso14443b_select_srx_card(card); // 0: OK 2: attrib fail, 3:crc fail, if (res > 0) goto out; Dbprintf("[+] Tag memory dump, block 0 to %d", numofblocks); ++numofblocks; for (;;) { if (i == numofblocks) { DbpString("System area block (0xFF):"); i = 0xff; } uint8_t retries = 3; do { res = ReadSTBlock(i); } while (!res && --retries); if (!res && !retries) { goto out; } // Now print out the memory location: Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i, (Demod.output[3] << 24) + (Demod.output[2] << 16) + (Demod.output[1] << 8) + Demod.output[0], (Demod.output[4] << 8) + Demod.output[5]); if (i == 0xff) break; ++i; } // Todo: iceman: send back read data to client. // reply_ng(..., ); out: switch_off(); // disconnect raw SpinDelay(20); } static void iso1444b_setup_sniff(void) { LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); // Initialize Demod and Uart structs Demod14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); Uart14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); if (DBGLEVEL > 1) { // Print debug information about the buffer sizes Dbprintf("[+] Sniff buffers initialized:"); Dbprintf("[+] trace: %i bytes", BigBuf_max_traceLen()); Dbprintf("[+] reader -> tag: %i bytes", MAX_FRAME_SIZE); Dbprintf("[+] tag -> reader: %i bytes", MAX_FRAME_SIZE); Dbprintf("[+] DMA: %i bytes", DMA_BUFFER_SIZE); } // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Setup for the DMA. FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER); // Set FPGA in the appropriate mode FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER | FPGA_HF_READER_SUBCARRIER_848_KHZ | FPGA_HF_READER_MODE_SNIFF_IQ); SpinDelay(20); // Start the SSP timer StartCountSspClk(); } //============================================================================= // Finally, the `sniffer' combines elements from both the reader and // simulated tag, to show both sides of the conversation. //============================================================================= //----------------------------------------------------------------------------- // Record the sequence of commands sent by the reader to the tag, with // triggering so that we start recording at the point that the tag is moved // near the reader. //----------------------------------------------------------------------------- /* * Memory usage for this function, (within BigBuf) * Last Received command (reader->tag) - MAX_FRAME_SIZE * Last Received command (tag->reader) - MAX_FRAME_SIZE * DMA Buffer - ISO14443B_DMA_BUFFER_SIZE * Demodulated samples received - all the rest */ void RAMFUNC SniffIso14443b(void) { uint32_t time_0 = 0, time_start = 0, time_stop; // We won't start recording the frames that we acquire until we trigger; // a good trigger condition to get started is probably when we see a // response from the tag. bool TagIsActive = false; bool ReaderIsActive = false; int lastRxCounter = DMA_BUFFER_SIZE; int8_t ci, cq; int maxBehindBy = 0; // Count of samples received so far, so that we can include timing // information in the trace buffer. int samples = 0; iso1444b_setup_sniff(); // The DMA buffer, used to stream samples from the FPGA dmabuf16_t *dma = get_dma16(); uint16_t *upTo = dma->buf; // Setup and start DMA. if (!FpgaSetupSscDma((uint8_t *) dma->buf, DMA_BUFFER_SIZE)) { if (DBGLEVEL > 1) Dbprintf("[!] FpgaSetupSscDma failed. Exiting"); BigBuf_free(); return; } // time ZERO, the point from which it all is calculated. time_0 = GetCountSspClk(); // loop and listen for(;;) { int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (DMA_BUFFER_SIZE - 1); if (behindBy > maxBehindBy) { maxBehindBy = behindBy; } if (behindBy == 0) continue; ci = *upTo >> 8; cq = *upTo; uint16_t tagdata = *upTo; upTo++; lastRxCounter--; if (upTo >= dma->buf + DMA_BUFFER_SIZE) { // we have read all of the DMA buffer content. upTo = dma->buf; // start reading the circular buffer from the beginning again lastRxCounter += DMA_BUFFER_SIZE; if (behindBy > (9 * DMA_BUFFER_SIZE / 10)) { Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy); break; } } if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) { // DMA Counter Register had reached 0, already rotated. AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dma->buf; // refresh the DMA Next Buffer and AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE; // DMA Next Counter registers WDT_HIT(); if (BUTTON_PRESS()) { DbpString("Button pressed, cancelled"); break; } } samples++; // no need to try decoding reader data if the tag is sending if (TagIsActive == false) { LED_A_INV(); if (Handle14443bReaderUartBit(ci & 0x01)) { time_stop = GetCountSspClk() - time_0; LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, true); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } if (Handle14443bReaderUartBit(cq & 0x01)) { time_stop = GetCountSspClk() - time_0; LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, true); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } ReaderIsActive = (Uart.state > STATE_14B_GOT_FALLING_EDGE_OF_SOF); } // no need to try decoding tag data if the reader is sending - and we cannot afford the time if (!ReaderIsActive) { // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103 // LSB is a fpga signal bit. if (Handle14443bTagSamplesDemod(tagdata) >= 0) { time_stop = GetCountSspClk() - time_0; LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, false); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF); } } FpgaDisableSscDma(); if (DBGLEVEL >= 2) { DbpString("[+] Sniff statistics:"); Dbprintf("[+] uart State: %x ByteCount: %i ByteCountMax: %i", Uart.state, Uart.byteCnt, Uart.byteCntMax); Dbprintf("[+] trace length: %i", BigBuf_get_traceLen()); } switch_off(); } static void iso14b_set_trigger(bool enable) { g_trigger = enable; } /* * Send raw command to tag ISO14443B * @Input * param flags enum ISO14B_COMMAND. (mifare.h) * len len of buffer data * data buffer with bytes to send * * @Output * none * */ void SendRawCommand14443B_Ex(PacketCommandNG *c) { iso14b_command_t param = c->oldarg[0]; size_t len = c->oldarg[1] & 0xffff; uint32_t timeout = c->oldarg[2]; uint8_t *cmd = c->data.asBytes; int status; uint32_t sendlen = sizeof(iso14b_card_select_t); uint8_t buf[PM3_CMD_DATA_SIZE] = {0x00}; if (DBGLEVEL > 3) Dbprintf("14b raw: param, %04x", param); // turn on trigger (LED_A) if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER) iso14b_set_trigger(true); if ((param & ISO14B_CONNECT) == ISO14B_CONNECT) { iso14443b_setup(); clear_trace(); } if ((param & ISO14B_SET_TIMEOUT)) iso14b_set_timeout(timeout); set_tracing(true); if ((param & ISO14B_SELECT_STD) == ISO14B_SELECT_STD) { iso14b_card_select_t *card = (iso14b_card_select_t *)buf; status = iso14443b_select_card(card); reply_mix(CMD_HF_ISO14443B_COMMAND, status, sendlen, 0, buf, sendlen); // 0: OK -1: attrib fail, -2:crc fail, if (status != 0) goto out; } if ((param & ISO14B_SELECT_SR) == ISO14B_SELECT_SR) { iso14b_card_select_t *card = (iso14b_card_select_t *)buf; status = iso14443b_select_srx_card(card); reply_mix(CMD_HF_ISO14443B_COMMAND, status, sendlen, 0, buf, sendlen); // 0: OK 2: demod fail, 3:crc fail, if (status > 0) goto out; } if ((param & ISO14B_APDU) == ISO14B_APDU) { status = iso14443b_apdu(cmd, len, buf); reply_mix(CMD_HF_ISO14443B_COMMAND, status, status, 0, buf, status); } if ((param & ISO14B_RAW) == ISO14B_RAW) { if ((param & ISO14B_APPEND_CRC) == ISO14B_APPEND_CRC) { AddCrc14B(cmd, len); len += 2; } CodeAndTransmit14443bAsReader(cmd, len); // raw status = GetTagSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT); // raw FpgaDisableTracing(); sendlen = MIN(Demod.len, PM3_CMD_DATA_SIZE); reply_old(CMD_HF_ISO14443B_COMMAND, status, sendlen, 0, Demod.output, sendlen); } out: // turn off trigger (LED_A) if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER) iso14b_set_trigger(false); // turn off antenna et al // we don't send a HALT command. if ((param & ISO14B_DISCONNECT) == ISO14B_DISCONNECT) { switch_off(); // disconnect raw SpinDelay(20); } }