1 files changed, 142 insertions, 0 deletions
diff --git a/lib/nfc/protocols/nfca.c b/lib/nfc/protocols/nfca.c
new file mode 100755
index 00000000..c401f8cc
--- /dev/null
+++ b/lib/nfc/protocols/nfca.c
@@ -0,0 +1,142 @@
+#include "nfca.h"
+#include <string.h>
+#include <stdio.h>
+#include <furi.h>
+
+#define NFCA_CMD_RATS (0xE0U)
+
+#define NFCA_CRC_INIT (0x6363)
+
+#define NFCA_F_SIG (13560000.0)
+#define T_SIG 7374 //73.746ns*100
+#define T_SIG_x8 58992 //T_SIG*8
+#define T_SIG_x8_x8 471936 //T_SIG*8*8
+#define T_SIG_x8_x9 530928 //T_SIG*8*9
+
+#define NFCA_SIGNAL_MAX_EDGES (1350)
+
+typedef struct {
+    uint8_t cmd;
+    uint8_t param;
+} nfca_cmd_rats;
+
+static uint8_t nfca_default_ats[] = {0x05, 0x78, 0x80, 0x80, 0x00};
+
+static uint8_t nfca_sleep_req[] = {0x50, 0x00};
+
+uint16_t nfca_get_crc16(uint8_t* buff, uint16_t len) {
+    uint16_t crc = NFCA_CRC_INIT;
+    uint8_t byte = 0;
+
+    for(uint8_t i = 0; i < len; i++) {
+        byte = buff[i];
+        byte ^= (uint8_t)(crc & 0xff);
+        byte ^= byte << 4;
+        crc = (crc >> 8) ^ (((uint16_t)byte) << 8) ^ (((uint16_t)byte) << 3) ^
+              (((uint16_t)byte) >> 4);
+    }
+
+    return crc;
+}
+
+void nfca_append_crc16(uint8_t* buff, uint16_t len) {
+    uint16_t crc = nfca_get_crc16(buff, len);
+    buff[len] = (uint8_t)crc;
+    buff[len + 1] = (uint8_t)(crc >> 8);
+}
+
+bool nfca_emulation_handler(
+    uint8_t* buff_rx,
+    uint16_t buff_rx_len,
+    uint8_t* buff_tx,
+    uint16_t* buff_tx_len) {
+    bool sleep = false;
+    uint8_t rx_bytes = buff_rx_len / 8;
+
+    if(rx_bytes == sizeof(nfca_sleep_req) && !memcmp(buff_rx, nfca_sleep_req, rx_bytes)) {
+        sleep = true;
+    } else if(rx_bytes == sizeof(nfca_cmd_rats) && buff_rx[0] == NFCA_CMD_RATS) {
+        memcpy(buff_tx, nfca_default_ats, sizeof(nfca_default_ats));
+        *buff_tx_len = sizeof(nfca_default_ats) * 8;
+    }
+
+    return sleep;
+}
+
+static void nfca_add_bit(DigitalSignal* signal, bool bit) {
+    if(bit) {
+        signal->start_level = true;
+        for(size_t i = 0; i < 7; i++) {
+            signal->edge_timings[i] = T_SIG_x8;
+        }
+        signal->edge_timings[7] = T_SIG_x8_x9;
+        signal->edge_cnt = 8;
+    } else {
+        signal->start_level = false;
+        signal->edge_timings[0] = T_SIG_x8_x8;
+        for(size_t i = 1; i < 9; i++) {
+            signal->edge_timings[i] = T_SIG_x8;
+        }
+        signal->edge_cnt = 9;
+    }
+}
+
+static void nfca_add_byte(NfcaSignal* nfca_signal, uint8_t byte, bool parity) {
+    for(uint8_t i = 0; i < 8; i++) {
+        if(byte & (1 << i)) {
+            digital_signal_append(nfca_signal->tx_signal, nfca_signal->one);
+        } else {
+            digital_signal_append(nfca_signal->tx_signal, nfca_signal->zero);
+        }
+    }
+    if(parity) {
+        digital_signal_append(nfca_signal->tx_signal, nfca_signal->one);
+    } else {
+        digital_signal_append(nfca_signal->tx_signal, nfca_signal->zero);
+    }
+}
+
+NfcaSignal* nfca_signal_alloc() {
+    NfcaSignal* nfca_signal = malloc(sizeof(NfcaSignal));
+    nfca_signal->one = digital_signal_alloc(10);
+    nfca_signal->zero = digital_signal_alloc(10);
+    nfca_add_bit(nfca_signal->one, true);
+    nfca_add_bit(nfca_signal->zero, false);
+    nfca_signal->tx_signal = digital_signal_alloc(NFCA_SIGNAL_MAX_EDGES);
+
+    return nfca_signal;
+}
+
+void nfca_signal_free(NfcaSignal* nfca_signal) {
+    furi_assert(nfca_signal);
+
+    digital_signal_free(nfca_signal->one);
+    digital_signal_free(nfca_signal->zero);
+    digital_signal_free(nfca_signal->tx_signal);
+    free(nfca_signal);
+}
+
+void nfca_signal_encode(NfcaSignal* nfca_signal, uint8_t* data, uint16_t bits, uint8_t* parity) {
+    furi_assert(nfca_signal);
+    furi_assert(data);
+    furi_assert(parity);
+
+    nfca_signal->tx_signal->edge_cnt = 0;
+    nfca_signal->tx_signal->start_level = true;
+    // Start of frame
+    digital_signal_append(nfca_signal->tx_signal, nfca_signal->one);
+
+    if(bits < 8) {
+        for(size_t i = 0; i < bits; i++) {
+            if(FURI_BIT(data[0], i)) {
+                digital_signal_append(nfca_signal->tx_signal, nfca_signal->one);
+            } else {
+                digital_signal_append(nfca_signal->tx_signal, nfca_signal->zero);
+            }
+        }
+    } else {
+        for(size_t i = 0; i < bits / 8; i++) {
+            nfca_add_byte(nfca_signal, data[i], parity[i / 8] & (1 << (7 - (i & 0x07))));
+        }
+    }
+}