flipperzero-firmware/applications/lf-rfid/helpers/encoder-emmarine.cpp
SG 46bc515c6a
Low frequency RFID app [Read stage] (#385)
* App Lfrfid: init
* HAL-resources: add external gpios
* HAL-pwm: fix frequency calculation
* App LFRFID: generic manchester decoder
* App LFRFID: em-marine decoder
* App iButton: fix dwt timing acquire
* App LFRFID: rfid reader
* App LFRFID: temporary read keys on read scene
* App LFRFID: remove atomic bool init.
* App LFRFID: add *.c to build
* App LFRFID: unstable HID decoder
* App LFRFID: HID-26 reading
* HAL OS: disable sleep
* App LFRFID: HID-26 reader: remove debug
* App LFRFID: static data decoder-analyzer
* App LFRFID: very raw Indala decoder
* App LFRFID: multiprotocol reader
* App LFRFID: more reliable HID decoder
* App LFRFID: syntax fix
* App LFRFID: simple read scene
* Gui: force redraw on screen stream connect
* HAL-OS: allow sleep
* App LFRFID: notify api, tune view, tune scene
* App LFRFID: simple rfid emulator
* App LFRFID: more scenes, more reliable EM decoder.
* App LFRFID: format fix
* App LFRFID: warning fix
* Api-hal-resources: add rfid pins, rename external pins
* App LFRFID: remove unused emulator
* App LFRFID: use new gpio hal api
* App accessor: use new ext gpio name
* App LFRFID: remove unused emulator
* App LFRFID: remove debug gpio
* Api-hal-resources: alternate functions init
* Api-hal-rfid: new api
* Api-hal-ibutton: new api
* Api-hal: new headers
* App LFRFID: use new api in reader subroutines
* App LFRFID: use new api in emulator subroutines
* App LFRFID: remove old app
* App LFRFID, App iButton: fix memleak
* Api-hal-rfid: comments
* App LFRFID: pulse joiner helper, it combines pulses of different polarity into one pulse suitable for a timer
* App LFRFID: pulse joiner, now can accept only ne pulse
* App LFRFID: pulse joiner, fixes
* App LFRFID: EM encoder and emulation
* App LFRFID: format fixes
* App LFRFID: emmarine encoder cleanup
* App LFRFID: HID Encoder blank
* App LFRFID: Indala Encoder blank
2021-05-04 16:21:16 +03:00

59 lines
1.4 KiB
C++

#include "encoder-emmarine.h"
#include <furi.h>
void EncoderEM::init(const uint8_t* data, const uint8_t data_size) {
furi_check(data_size == 5);
// header
card_data = 0b111111111;
// data
for(uint8_t i = 0; i < 5; i++) {
write_nibble(false, data[i]);
write_nibble(true, data[i]);
}
// column parity and stop bit
uint8_t parity_sum;
for(uint8_t c = 0; c < 4; c++) {
parity_sum = 0;
for(uint8_t i = 1; i <= 10; i++) {
uint8_t parity_bit = (card_data >> (i * 5 - 1)) & 1;
parity_sum += parity_bit;
}
card_data = (card_data << 1) | ((parity_sum % 2) & 1);
}
// stop bit
card_data = (card_data << 1) | 0;
card_data_index = 0;
}
void EncoderEM::write_nibble(bool low_nibble, uint8_t data) {
uint8_t parity_sum = 0;
uint8_t start = 0;
if(!low_nibble) start = 4;
for(int8_t i = (start + 3); i >= start; i--) {
parity_sum += (data >> i) & 1;
card_data = (card_data << 1) | ((data >> i) & 1);
}
card_data = (card_data << 1) | ((parity_sum % 2) & 1);
}
// data transmitted as manchester encoding
// 0 - high2low
// 1 - low2high
void EncoderEM::get_next(bool* polarity, uint16_t* period, uint16_t* pulse) {
*period = clocks_per_bit;
*pulse = clocks_per_bit / 2;
*polarity = (card_data >> (63 - card_data_index)) & 1;
card_data_index++;
if(card_data_index >= 64) {
card_data_index = 0;
}
}