Momentum-Apps/lib/nfc_protocols/nfca.c

#include "nfca.h"
#include <string.h>
#include <stdio.h>

#define NFCA_CMD_RATS (0xE0U)

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};

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;
}