static int
pn53x_usb_send(nfc_device *pnd, const uint8_t *pbtData, const size_t szData, const int timeout)
{
uint8_t abtFrame[PN53X_USB_BUFFER_LEN] = { 0x00, 0x00, 0xff }; // Every packet must start with "00 00 ff"
size_t szFrame = 0;
int res = 0;
if ((res = pn53x_build_frame(abtFrame, &szFrame, pbtData, szData)) < 0) {
pnd->last_error = res;
return pnd->last_error;
}
if ((res = pn53x_usb_bulk_write(DRIVER_DATA(pnd), abtFrame, szFrame, timeout)) < 0) {
pnd->last_error = res;
return pnd->last_error;
}
uint8_t abtRxBuf[PN53X_USB_BUFFER_LEN];
if ((res = pn53x_usb_bulk_read(DRIVER_DATA(pnd), abtRxBuf, sizeof(abtRxBuf), timeout)) < 0) {
// try to interrupt current device state
pn53x_usb_ack(pnd);
pnd->last_error = res;
return pnd->last_error;
}
if (pn53x_check_ack_frame(pnd, abtRxBuf, res) == 0) {
// The PN53x is running the sent command
} else {
// For some reasons (eg. send another command while a previous one is
// running), the PN533 sometimes directly replies the response packet
// instead of ACK frame, so we send a NACK frame to force PN533 to resend
// response packet. With this hack, the nextly executed function (ie.
// pn53x_usb_receive()) will be able to retreive the correct response
// packet.
// FIXME Sony reader is also affected by this bug but NACK is not supported
if ((res = pn53x_usb_bulk_write(DRIVER_DATA(pnd), (uint8_t *)pn53x_nack_frame, sizeof(pn53x_nack_frame), timeout)) < 0) {
pnd->last_error = res;
// try to interrupt current device state
pn53x_usb_ack(pnd);
return pnd->last_error;
}
}
return NFC_SUCCESS;
}
int
pn53x_usb_ack (nfc_device *pnd)
{
return pn53x_usb_bulk_write (DRIVER_DATA (pnd), (uint8_t *) pn53x_ack_frame, sizeof (pn53x_ack_frame), 0);
}