2022-02-02 22:59:28 +03:00
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#include "nfca.h"
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#include <string.h>
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#include <stdio.h>
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#define NFCA_CMD_RATS (0xE0U)
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2022-03-24 01:14:34 +03:00
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#define NFCA_CRC_INIT (0x6363)
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2022-02-02 22:59:28 +03:00
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typedef struct {
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uint8_t cmd;
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uint8_t param;
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} nfca_cmd_rats;
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static uint8_t nfca_default_ats[] = {0x05, 0x78, 0x80, 0x80, 0x00};
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static uint8_t nfca_sleep_req[] = {0x50, 0x00};
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2022-03-24 01:14:34 +03:00
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uint16_t nfca_get_crc16(uint8_t* buff, uint16_t len) {
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uint16_t crc = NFCA_CRC_INIT;
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uint8_t byte = 0;
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for(uint8_t i = 0; i < len; i++) {
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byte = buff[i];
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byte ^= (uint8_t)(crc & 0xff);
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byte ^= byte << 4;
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crc = (crc >> 8) ^ (((uint16_t)byte) << 8) ^ (((uint16_t)byte) << 3) ^
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(((uint16_t)byte) >> 4);
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}
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return crc;
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}
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void nfca_append_crc16(uint8_t* buff, uint16_t len) {
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uint16_t crc = nfca_get_crc16(buff, len);
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buff[len] = (uint8_t)crc;
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buff[len + 1] = (uint8_t)(crc >> 8);
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}
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2022-02-02 22:59:28 +03:00
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bool nfca_emulation_handler(
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uint8_t* buff_rx,
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uint16_t buff_rx_len,
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uint8_t* buff_tx,
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uint16_t* buff_tx_len) {
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bool sleep = false;
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uint8_t rx_bytes = buff_rx_len / 8;
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if(rx_bytes == sizeof(nfca_sleep_req) && !memcmp(buff_rx, nfca_sleep_req, rx_bytes)) {
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sleep = true;
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} else if(rx_bytes == sizeof(nfca_cmd_rats) && buff_rx[0] == NFCA_CMD_RATS) {
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memcpy(buff_tx, nfca_default_ats, sizeof(nfca_default_ats));
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*buff_tx_len = sizeof(nfca_default_ats) * 8;
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}
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return sleep;
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}
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