Add support for Pyramid tags (#1676)

* Add support for Pyramid tags
* Also add additional checks for AWID decoder to avoid missdetection

* lfrfid worker: reset GPIO_LOAD pin
* lfrfid: protocol viking, format
* lfrfid: protocol pyramid, format
* lfrfid: protocol paradox, format
* lfrfid: protocol jablotron, format
* lfrfid: protocol em4100, format
* lfrfid: increase reading time by 0.5s since protocol viking takes longer to read

Co-authored-by: SG <who.just.the.doctor@gmail.com>

lib/lfrfid/lfrfid_worker_modes.c

@@ -27,16 +27,16 @@
 
 #define LFRFID_WORKER_READ_DROP_TIME_MS 50
 #define LFRFID_WORKER_READ_STABILIZE_TIME_MS 450
-#define LFRFID_WORKER_READ_SWITCH_TIME_MS 1500
+#define LFRFID_WORKER_READ_SWITCH_TIME_MS 2000
 
-#define LFRFID_WORKER_WRITE_VERIFY_TIME_MS 1500
+#define LFRFID_WORKER_WRITE_VERIFY_TIME_MS 2000
 #define LFRFID_WORKER_WRITE_DROP_TIME_MS 50
 #define LFRFID_WORKER_WRITE_TOO_LONG_TIME_MS 10000
 
 #define LFRFID_WORKER_WRITE_MAX_UNSUCCESSFUL_READS 5
 
 #define LFRFID_WORKER_READ_BUFFER_SIZE 512
-#define LFRFID_WORKER_READ_BUFFER_COUNT 8
+#define LFRFID_WORKER_READ_BUFFER_COUNT 16
 
 #define LFRFID_WORKER_EMULATE_BUFFER_SIZE 1024
 
@@ -132,6 +132,8 @@ static LFRFIDWorkerReadState lfrfid_worker_read_internal(
 #ifdef LFRFID_WORKER_READ_DEBUG_GPIO
     furi_hal_gpio_init_simple(LFRFID_WORKER_READ_DEBUG_GPIO_VALUE, GpioModeOutputPushPull);
     furi_hal_gpio_init_simple(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, GpioModeOutputPushPull);
+    furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_VALUE, false);
+    furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, false);
 #endif
 
     LFRFIDWorkerReadContext ctx;
@@ -171,10 +173,16 @@ static LFRFIDWorkerReadState lfrfid_worker_read_internal(
         if(buffer_stream_get_overrun_count(ctx.stream) > 0) {
             FURI_LOG_E(TAG, "Read overrun, recovering");
             buffer_stream_reset(ctx.stream);
+#ifdef LFRFID_WORKER_READ_DEBUG_GPIO
+            furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, false);
+#endif
             continue;
         }
 
         if(buffer == NULL) {
+#ifdef LFRFID_WORKER_READ_DEBUG_GPIO
+            furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, false);
+#endif
             continue;
         }
 
@@ -261,24 +269,26 @@ static LFRFIDWorkerReadState lfrfid_worker_read_internal(
                         last_read_count = 0;
                     }
 
-                    string_t string_info;
+                    if(furi_log_get_level() >= FuriLogLevelDebug) {
-                    string_init(string_info);
+                        string_t string_info;
-                    for(uint8_t i = 0; i < protocol_data_size; i++) {
+                        string_init(string_info);
-                        if(i != 0) {
+                        for(uint8_t i = 0; i < protocol_data_size; i++) {
-                            string_cat_printf(string_info, " ");
+                            if(i != 0) {
+                                string_cat_printf(string_info, " ");
+                            }
+
+                            string_cat_printf(string_info, "%02X", protocol_data[i]);
                         }
 
-                        string_cat_printf(string_info, "%02X", protocol_data[i]);
+                        FURI_LOG_D(
+                            TAG,
+                            "%s, %d, [%s]",
+                            protocol_dict_get_name(worker->protocols, protocol),
+                            last_read_count,
+                            string_get_cstr(string_info));
+                        string_clear(string_info);
                     }
 
-                    FURI_LOG_D(
-                        TAG,
-                        "%s, %d, [%s]",
-                        protocol_dict_get_name(worker->protocols, protocol),
-                        last_read_count,
-                        string_get_cstr(string_info));
-                    string_clear(string_info);
-
                     protocol_dict_decoders_start(worker->protocols);
                 }
             }
@@ -321,6 +331,8 @@ static LFRFIDWorkerReadState lfrfid_worker_read_internal(
     free(last_data);
 
 #ifdef LFRFID_WORKER_READ_DEBUG_GPIO
+    furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_VALUE, false);
+    furi_hal_gpio_write(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, false);
     furi_hal_gpio_init_simple(LFRFID_WORKER_READ_DEBUG_GPIO_VALUE, GpioModeAnalog);
     furi_hal_gpio_init_simple(LFRFID_WORKER_READ_DEBUG_GPIO_LOAD, GpioModeAnalog);
 #endif

lib/lfrfid/protocols/lfrfid_protocols.c

@@ -8,6 +8,7 @@
 #include "protocol_fdx_b.h"
 #include "protocol_hid_generic.h"
 #include "protocol_hid_ex_generic.h"
+#include "protocol_pyramid.h"
 #include "protocol_viking.h"
 #include "protocol_jablotron.h"
 #include "protocol_paradox.h"
@@ -23,6 +24,7 @@ const ProtocolBase* lfrfid_protocols[] = {
     [LFRFIDProtocolFDXB] = &protocol_fdx_b,
     [LFRFIDProtocolHidGeneric] = &protocol_hid_generic,
     [LFRFIDProtocolHidExGeneric] = &protocol_hid_ex_generic,
+    [LFRFIDProtocolPyramid] = &protocol_pyramid,
     [LFRFIDProtocolViking] = &protocol_viking,
     [LFRFIDProtocolJablotron] = &protocol_jablotron,
     [LFRFIDProtocolParadox] = &protocol_paradox,

lib/lfrfid/protocols/lfrfid_protocols.h

@@ -17,6 +17,7 @@ typedef enum {
     LFRFIDProtocolFDXB,
     LFRFIDProtocolHidGeneric,
     LFRFIDProtocolHidExGeneric,
+    LFRFIDProtocolPyramid,
     LFRFIDProtocolViking,
     LFRFIDProtocolJablotron,
     LFRFIDProtocolParadox,

lib/lfrfid/protocols/protocol_awid.c

@@ -53,7 +53,7 @@ void protocol_awid_decoder_start(ProtocolAwid* protocol) {
     memset(protocol->encoded_data, 0, AWID_ENCODED_DATA_SIZE);
 };
 
-static bool protocol_awid_can_be_decoded(const uint8_t* data) {
+static bool protocol_awid_can_be_decoded(uint8_t* data) {
     bool result = false;
 
     // Index map
@@ -77,6 +77,12 @@ static bool protocol_awid_can_be_decoded(const uint8_t* data) {
         bool parity_error = bit_lib_test_parity(data, 8, 88, BitLibParityOdd, 4);
         if(parity_error) break;
 
+        bit_lib_remove_bit_every_nth(data, 8, 88, 4);
+
+        // Avoid detection for invalid formats
+        uint8_t len = bit_lib_get_bits(data, 8, 8);
+        if(len != 26 && len != 50 && len != 37 && len != 34) break;
+
         result = true;
     } while(false);
 
@@ -84,7 +90,6 @@ static bool protocol_awid_can_be_decoded(const uint8_t* data) {
 }
 
 static void protocol_awid_decode(uint8_t* encoded_data, uint8_t* decoded_data) {
-    bit_lib_remove_bit_every_nth(encoded_data, 8, 88, 4);
     bit_lib_copy_bits(decoded_data, 0, 66, encoded_data, 8);
 }
 

lib/lfrfid/protocols/protocol_em4100.c

@@ -264,7 +264,7 @@ bool protocol_em4100_write_data(ProtocolEM4100* protocol, void* data) {
 
 void protocol_em4100_render_data(ProtocolEM4100* protocol, string_t result) {
     uint8_t* data = protocol->data;
-    string_printf(result, "ID: %03u,%05u", data[2], (uint16_t)((data[3] << 8) | (data[4])));
+    string_printf(result, "FC: %03u, Card: %05u", data[2], (uint16_t)((data[3] << 8) | (data[4])));
 };
 
 const ProtocolBase protocol_em4100 = {

lib/lfrfid/protocols/protocol_jablotron.c

@@ -162,12 +162,7 @@ LevelDuration protocol_jablotron_encoder_yield(ProtocolJablotron* protocol) {
 
 void protocol_jablotron_render_data(ProtocolJablotron* protocol, string_t result) {
     uint64_t id = protocol_jablotron_card_id(protocol->data);
-    string_printf(result, "ID: %llx\r\n", id);
+    string_printf(result, "ID: %llX\r\n", id);
-};
-
-void protocol_jablotron_render_brief_data(ProtocolJablotron* protocol, string_t result) {
-    uint64_t id = protocol_jablotron_card_id(protocol->data);
-    string_printf(result, "ID: %llx\r\n", id);
 };
 
 bool protocol_jablotron_write_data(ProtocolJablotron* protocol, void* data) {
@@ -207,6 +202,6 @@ const ProtocolBase protocol_jablotron = {
             .yield = (ProtocolEncoderYield)protocol_jablotron_encoder_yield,
         },
     .render_data = (ProtocolRenderData)protocol_jablotron_render_data,
-    .render_brief_data = (ProtocolRenderData)protocol_jablotron_render_brief_data,
+    .render_brief_data = (ProtocolRenderData)protocol_jablotron_render_data,
     .write_data = (ProtocolWriteData)protocol_jablotron_write_data,
 };

lib/lfrfid/protocols/protocol_paradox.c

@@ -155,7 +155,7 @@ void protocol_paradox_render_brief_data(ProtocolParadox* protocol, string_t resu
     uint8_t fc = bit_lib_get_bits(decoded_data, 10, 8);
     uint16_t card_id = bit_lib_get_bits_16(decoded_data, 18, 16);
 
-    string_cat_printf(result, "ID: %03u,%05u", fc, card_id);
+    string_cat_printf(result, "FC: %03u, Card: %05u", fc, card_id);
 };
 
 bool protocol_paradox_write_data(ProtocolParadox* protocol, void* data) {

lib/lfrfid/protocols/protocol_pyramid.c

@@ -0,0 +1,277 @@
+#include <furi.h>
+#include <toolbox/protocols/protocol.h>
+#include <lfrfid/tools/fsk_demod.h>
+#include <lfrfid/tools/fsk_osc.h>
+#include "lfrfid_protocols.h"
+#include <lfrfid/tools/bit_lib.h>
+
+#define JITTER_TIME (20)
+#define MIN_TIME (64 - JITTER_TIME)
+#define MAX_TIME (80 + JITTER_TIME)
+
+#define PYRAMID_DATA_SIZE 13
+#define PYRAMID_PREAMBLE_SIZE 3
+
+#define PYRAMID_ENCODED_DATA_SIZE \
+    (PYRAMID_PREAMBLE_SIZE + PYRAMID_DATA_SIZE + PYRAMID_PREAMBLE_SIZE)
+#define PYRAMID_ENCODED_BIT_SIZE ((PYRAMID_PREAMBLE_SIZE + PYRAMID_DATA_SIZE) * 8)
+#define PYRAMID_DECODED_DATA_SIZE (4)
+#define PYRAMID_DECODED_BIT_SIZE ((PYRAMID_ENCODED_BIT_SIZE - PYRAMID_PREAMBLE_SIZE * 8) / 2)
+
+typedef struct {
+    FSKDemod* fsk_demod;
+} ProtocolPyramidDecoder;
+
+typedef struct {
+    FSKOsc* fsk_osc;
+    uint8_t encoded_index;
+    uint32_t pulse;
+} ProtocolPyramidEncoder;
+
+typedef struct {
+    ProtocolPyramidDecoder decoder;
+    ProtocolPyramidEncoder encoder;
+    uint8_t encoded_data[PYRAMID_ENCODED_DATA_SIZE];
+    uint8_t data[PYRAMID_DECODED_DATA_SIZE];
+} ProtocolPyramid;
+
+ProtocolPyramid* protocol_pyramid_alloc(void) {
+    ProtocolPyramid* protocol = malloc(sizeof(ProtocolPyramid));
+    protocol->decoder.fsk_demod = fsk_demod_alloc(MIN_TIME, 6, MAX_TIME, 5);
+    protocol->encoder.fsk_osc = fsk_osc_alloc(8, 10, 50);
+
+    return protocol;
+};
+
+void protocol_pyramid_free(ProtocolPyramid* protocol) {
+    fsk_demod_free(protocol->decoder.fsk_demod);
+    fsk_osc_free(protocol->encoder.fsk_osc);
+    free(protocol);
+};
+
+uint8_t* protocol_pyramid_get_data(ProtocolPyramid* protocol) {
+    return protocol->data;
+};
+
+void protocol_pyramid_decoder_start(ProtocolPyramid* protocol) {
+    memset(protocol->encoded_data, 0, PYRAMID_ENCODED_DATA_SIZE);
+};
+
+static bool protocol_pyramid_can_be_decoded(uint8_t* data) {
+    // check preamble
+    if(bit_lib_get_bits_16(data, 0, 16) != 0b0000000000000001 ||
+       bit_lib_get_bits(data, 16, 8) != 0b00000001) {
+        return false;
+    }
+
+    if(bit_lib_get_bits_16(data, 128, 16) != 0b0000000000000001 ||
+       bit_lib_get_bits(data, 136, 8) != 0b00000001) {
+        return false;
+    }
+
+    uint8_t checksum = bit_lib_get_bits(data, 120, 8);
+    uint8_t checksum_data[13] = {0x00};
+    for(uint8_t i = 0; i < 13; i++) {
+        checksum_data[i] = bit_lib_get_bits(data, 16 + (i * 8), 8);
+    }
+
+    uint8_t calc_checksum = bit_lib_crc8(checksum_data, 13, 0x31, 0x00, true, true, 0x00);
+    if(checksum != calc_checksum) return false;
+
+    // Remove parity
+    bit_lib_remove_bit_every_nth(data, 8, 15 * 8, 8);
+
+    // Determine Startbit and format
+    int j;
+    for(j = 0; j < 105; ++j) {
+        if(bit_lib_get_bit(data, j)) break;
+    }
+    uint8_t fmt_len = 105 - j;
+
+    // Only suppport 26bit format for now
+    if(fmt_len != 26) return false;
+
+    return true;
+}
+
+static void protocol_pyramid_decode(ProtocolPyramid* protocol) {
+    // Format
+    bit_lib_set_bits(protocol->data, 0, 26, 8);
+
+    // Facility Code
+    bit_lib_copy_bits(protocol->data, 8, 8, protocol->encoded_data, 73 + 8);
+
+    // Card Number
+    bit_lib_copy_bits(protocol->data, 16, 16, protocol->encoded_data, 81 + 8);
+}
+
+bool protocol_pyramid_decoder_feed(ProtocolPyramid* protocol, bool level, uint32_t duration) {
+    bool value;
+    uint32_t count;
+    bool result = false;
+
+    fsk_demod_feed(protocol->decoder.fsk_demod, level, duration, &value, &count);
+    if(count > 0) {
+        for(size_t i = 0; i < count; i++) {
+            bit_lib_push_bit(protocol->encoded_data, PYRAMID_ENCODED_DATA_SIZE, value);
+            if(protocol_pyramid_can_be_decoded(protocol->encoded_data)) {
+                protocol_pyramid_decode(protocol);
+                result = true;
+            }
+        }
+    }
+
+    return result;
+};
+
+bool protocol_pyramid_get_parity(const uint8_t* bits, uint8_t type, int length) {
+    int x;
+    for(x = 0; length > 0; --length) x += bit_lib_get_bit(bits, length - 1);
+    x %= 2;
+    return x ^ type;
+}
+
+void protocol_pyramid_add_wiegand_parity(
+    uint8_t* target,
+    uint8_t target_position,
+    uint8_t* source,
+    uint8_t length) {
+    bit_lib_set_bit(
+        target, target_position, protocol_pyramid_get_parity(source, 0 /* even */, length / 2));
+    bit_lib_copy_bits(target, target_position + 1, length, source, 0);
+    bit_lib_set_bit(
+        target,
+        target_position + length + 1,
+        protocol_pyramid_get_parity(source + length / 2, 1 /* odd */, length / 2));
+}
+
+static void protocol_pyramid_encode(ProtocolPyramid* protocol) {
+    memset(protocol->encoded_data, 0, sizeof(protocol->encoded_data));
+
+    uint8_t pre[16];
+    memset(pre, 0, sizeof(pre));
+
+    // Format start bit
+    bit_lib_set_bit(pre, 79, 1);
+
+    uint8_t wiegand[3];
+    memset(wiegand, 0, sizeof(wiegand));
+
+    // FC
+    bit_lib_copy_bits(wiegand, 0, 8, protocol->data, 8);
+
+    // CardNum
+    bit_lib_copy_bits(wiegand, 8, 16, protocol->data, 16);
+
+    // Wiegand parity
+    protocol_pyramid_add_wiegand_parity(pre, 80, wiegand, 24);
+
+    bit_lib_add_parity(pre, 8, protocol->encoded_data, 8, 102, 8, 1);
+
+    // Add checksum
+    uint8_t checksum_buffer[13];
+    for(uint8_t i = 0; i < 13; i++)
+        checksum_buffer[i] = bit_lib_get_bits(protocol->encoded_data, 16 + (i * 8), 8);
+
+    uint8_t crc = bit_lib_crc8(checksum_buffer, 13, 0x31, 0x00, true, true, 0x00);
+    bit_lib_set_bits(protocol->encoded_data, 120, crc, 8);
+}
+
+bool protocol_pyramid_encoder_start(ProtocolPyramid* protocol) {
+    protocol->encoder.encoded_index = 0;
+    protocol->encoder.pulse = 0;
+    protocol_pyramid_encode(protocol);
+
+    return true;
+};
+
+LevelDuration protocol_pyramid_encoder_yield(ProtocolPyramid* protocol) {
+    bool level = 0;
+    uint32_t duration = 0;
+
+    // if pulse is zero, we need to output high, otherwise we need to output low
+    if(protocol->encoder.pulse == 0) {
+        // get bit
+        uint8_t bit = bit_lib_get_bit(protocol->encoded_data, protocol->encoder.encoded_index);
+
+        // get pulse from oscillator
+        bool advance = fsk_osc_next(protocol->encoder.fsk_osc, bit, &duration);
+
+        if(advance) {
+            bit_lib_increment_index(protocol->encoder.encoded_index, PYRAMID_ENCODED_BIT_SIZE);
+        }
+
+        // duration diveded by 2 because we need to output high and low
+        duration = duration / 2;
+        protocol->encoder.pulse = duration;
+        level = true;
+    } else {
+        // output low half and reset pulse
+        duration = protocol->encoder.pulse;
+        protocol->encoder.pulse = 0;
+        level = false;
+    }
+
+    return level_duration_make(level, duration);
+};
+
+bool protocol_pyramid_write_data(ProtocolPyramid* protocol, void* data) {
+    LFRFIDWriteRequest* request = (LFRFIDWriteRequest*)data;
+    bool result = false;
+
+    protocol_pyramid_encoder_start(protocol);
+
+    if(request->write_type == LFRFIDWriteTypeT5577) {
+        request->t5577.block[0] = LFRFID_T5577_MODULATION_FSK2a | LFRFID_T5577_BITRATE_RF_50 |
+                                  (4 << LFRFID_T5577_MAXBLOCK_SHIFT);
+        request->t5577.block[1] = bit_lib_get_bits_32(protocol->encoded_data, 0, 32);
+        request->t5577.block[2] = bit_lib_get_bits_32(protocol->encoded_data, 32, 32);
+        request->t5577.block[3] = bit_lib_get_bits_32(protocol->encoded_data, 64, 32);
+        request->t5577.block[4] = bit_lib_get_bits_32(protocol->encoded_data, 96, 32);
+        request->t5577.blocks_to_write = 5;
+        result = true;
+    }
+    return result;
+};
+
+void protocol_pyramid_render_data(ProtocolPyramid* protocol, string_t result) {
+    uint8_t* decoded_data = protocol->data;
+    uint8_t format_length = decoded_data[0];
+
+    string_cat_printf(result, "Format: 26\r\n", format_length);
+    if(format_length == 26) {
+        uint8_t facility;
+        bit_lib_copy_bits(&facility, 0, 8, decoded_data, 8);
+
+        uint16_t card_id;
+        bit_lib_copy_bits((uint8_t*)&card_id, 8, 8, decoded_data, 16);
+        bit_lib_copy_bits((uint8_t*)&card_id, 0, 8, decoded_data, 24);
+        string_cat_printf(result, "FC: %03u, Card: %05u", facility, card_id);
+    } else {
+        string_cat_printf(result, "Data: unknown");
+    }
+};
+
+const ProtocolBase protocol_pyramid = {
+    .name = "Pyramid",
+    .manufacturer = "Farpointe",
+    .data_size = PYRAMID_DECODED_DATA_SIZE,
+    .features = LFRFIDFeatureASK,
+    .validate_count = 3,
+    .alloc = (ProtocolAlloc)protocol_pyramid_alloc,
+    .free = (ProtocolFree)protocol_pyramid_free,
+    .get_data = (ProtocolGetData)protocol_pyramid_get_data,
+    .decoder =
+        {
+            .start = (ProtocolDecoderStart)protocol_pyramid_decoder_start,
+            .feed = (ProtocolDecoderFeed)protocol_pyramid_decoder_feed,
+        },
+    .encoder =
+        {
+            .start = (ProtocolEncoderStart)protocol_pyramid_encoder_start,
+            .yield = (ProtocolEncoderYield)protocol_pyramid_encoder_yield,
+        },
+    .render_data = (ProtocolRenderData)protocol_pyramid_render_data,
+    .render_brief_data = (ProtocolRenderData)protocol_pyramid_render_data,
+    .write_data = (ProtocolWriteData)protocol_pyramid_write_data,
+};

lib/lfrfid/protocols/protocol_pyramid.h

@@ -0,0 +1,4 @@
+#pragma once
+#include <toolbox/protocols/protocol.h>
+
+extern const ProtocolBase protocol_pyramid;

lib/lfrfid/protocols/protocol_viking.c

@@ -173,7 +173,7 @@ bool protocol_viking_write_data(ProtocolViking* protocol, void* data) {
 
 void protocol_viking_render_data(ProtocolViking* protocol, string_t result) {
     uint32_t id = bit_lib_get_bits_32(protocol->data, 0, 32);
-    string_printf(result, "ID: %08lx\r\n", id);
+    string_printf(result, "ID: %08lX\r\n", id);
 };
 
 const ProtocolBase protocol_viking = {

lib/lfrfid/tools/bit_lib.c

@@ -129,6 +129,45 @@ bool bit_lib_test_parity(
     return result;
 }
 
+size_t bit_lib_add_parity(
+    const uint8_t* data,
+    size_t position,
+    uint8_t* dest,
+    size_t dest_position,
+    uint8_t source_length,
+    uint8_t parity_length,
+    BitLibParity parity) {
+    uint32_t parity_word = 0;
+    size_t j = 0, bit_count = 0;
+    for(int word = 0; word < source_length; word += parity_length - 1) {
+        for(int bit = 0; bit < parity_length - 1; bit++) {
+            parity_word = (parity_word << 1) | bit_lib_get_bit(data, position + word + bit);
+            bit_lib_set_bit(
+                dest, dest_position + j++, bit_lib_get_bit(data, position + word + bit));
+        }
+        // if parity fails then return 0
+        switch(parity) {
+        case BitLibParityAlways0:
+            bit_lib_set_bit(dest, dest_position + j++, 0);
+            break; // marker bit which should be a 0
+        case BitLibParityAlways1:
+            bit_lib_set_bit(dest, dest_position + j++, 1);
+            break; // marker bit which should be a 1
+        default:
+            bit_lib_set_bit(
+                dest,
+                dest_position + j++,
+                (bit_lib_test_parity_32(parity_word, BitLibParityOdd) ^ parity) ^ 1);
+            break;
+        }
+        bit_count += parity_length;
+        parity_word = 0;
+    }
+    // if we got here then all the parities passed
+    // return bit count
+    return bit_count;
+}
+
 size_t bit_lib_remove_bit_every_nth(uint8_t* data, size_t position, uint8_t length, uint8_t n) {
     size_t counter = 0;
     size_t result_counter = 0;
@@ -269,6 +308,36 @@ uint8_t bit_lib_reverse_8_fast(uint8_t byte) {
     return byte;
 }
 
+uint16_t bit_lib_crc8(
+    uint8_t const* data,
+    size_t data_size,
+    uint8_t polynom,
+    uint8_t init,
+    bool ref_in,
+    bool ref_out,
+    uint8_t xor_out) {
+    uint8_t crc = init;
+
+    for(size_t i = 0; i < data_size; ++i) {
+        uint8_t byte = data[i];
+        if(ref_in) bit_lib_reverse_bits(&byte, 0, 8);
+        crc ^= byte;
+
+        for(size_t j = 8; j > 0; --j) {
+            if(crc & TOPBIT(8)) {
+                crc = (crc << 1) ^ polynom;
+            } else {
+                crc = (crc << 1);
+            }
+        }
+    }
+
+    if(ref_out) bit_lib_reverse_bits(&crc, 0, 8);
+    crc ^= xor_out;
+
+    return crc;
+}
+
 uint16_t bit_lib_crc16(
     uint8_t const* data,
     size_t data_size,

lib/lfrfid/tools/bit_lib.h

@@ -7,6 +7,8 @@
 extern "C" {
 #endif
 
+#define TOPBIT(X) (1 << (X - 1))
+
 typedef enum {
     BitLibParityEven,
     BitLibParityOdd,
@@ -114,6 +116,27 @@ bool bit_lib_test_parity(
     BitLibParity parity,
     uint8_t parity_length);
 
+/**
+ * @brief Add parity to bit array
+ * 
+ * @param data Source bit array
+ * @param position Start position
+ * @param dest Destination bit array
+ * @param dest_position Destination position
+ * @param source_length Source bit count
+ * @param parity_length Parity block length
+ * @param parity Parity to test against
+ * @return size_t 
+ */
+size_t bit_lib_add_parity(
+    const uint8_t* data,
+    size_t position,
+    uint8_t* dest,
+    size_t dest_position,
+    uint8_t source_length,
+    uint8_t parity_length,
+    BitLibParity parity);
+
 /**
  * @brief Remove bit every n in array and shift array left. Useful to remove parity.
  * 
@@ -202,6 +225,27 @@ uint16_t bit_lib_reverse_16_fast(uint16_t data);
  */
 uint8_t bit_lib_reverse_8_fast(uint8_t byte);
 
+/**
+ * @brief Slow, but generic CRC8 implementation
+ * 
+ * @param data 
+ * @param data_size 
+ * @param polynom CRC polynom
+ * @param init init value
+ * @param ref_in true if the right bit is older
+ * @param ref_out true to reverse output
+ * @param xor_out xor output with this value
+ * @return uint8_t 
+ */
+uint16_t bit_lib_crc8(
+    uint8_t const* data,
+    size_t data_size,
+    uint8_t polynom,
+    uint8_t init,
+    bool ref_in,
+    bool ref_out,
+    uint8_t xor_out);
+
 /**
  * @brief Slow, but generic CRC16 implementation
  *