FRESULT res1;
UINT cnt1;
uint8_t fsm_read_file(FIL * fil, uint16_t * buffer, uint16_t length) {
    res1 = f_read(fil, buffer, 16, &cnt1);
    for(uint16_t i = 0; i < length; i++) {
        buffer[i] = 0;
    }
    if(res1) {
        LOGE("Read sample file error", res1);
        return RET_ERROR;
    }
    if(cnt1 < 16) {
        return RET_FILE_FINISHED;
    }
    return RET_OK;
}