// Non Blocking receive
// Return number of bytes read
uint32_t USBDeviceClass::recv(uint32_t ep, void *_data, uint32_t len)
{
	if (!_usbConfiguration)
		return -1;

	if (available(ep) < len)
		len = available(ep);

#ifdef PIN_LED_RXL
	digitalWrite(PIN_LED_RXL, LOW);
	rxLEDPulse = TX_RX_LED_PULSE_MS;
#endif

	armRecv(ep);

	usbd.epBank0DisableTransferComplete(ep);

	memcpy(_data, udd_ep_out_cache_buffer[ep], len);

	// release empty buffer
	if (len && !available(ep)) {
		// The RAM Buffer is empty: we can receive data
		usbd.epBank0ResetReady(ep);

		// Clear Transfer complete 0 flag
		usbd.epBank0AckTransferComplete(ep);
	}

	return len;
}

// Non Blocking receive
// Return number of bytes read
uint32_t USBDeviceClass::recv(uint32_t ep, void *_data, uint32_t len)
{
	if (!_usbConfiguration)
		return -1;

	if (available(ep) < len)
		len = available(ep);

	armRecv(ep);

	usbd.epBank0DisableTransferComplete(ep);

	memcpy(_data, udd_ep_out_cache_buffer[ep], len);

	// release empty buffer
	if (len && !available(ep)) {
		// The RAM Buffer is empty: we can receive data
		usbd.epBank0ResetReady(ep);

		// Clear Transfer complete 0 flag
		usbd.epBank0AckTransferComplete(ep);
	}

	return len;
}

void USBDeviceClass::handleEndpoint(uint8_t ep)
{
#if defined(CDC_ENABLED)
	if (ep == CDC_ENDPOINT_OUT)
	{
		// The RAM Buffer is empty: we can receive data
		//usbd.epBank0ResetReady(CDC_ENDPOINT_OUT);

		// Handle received bytes
		if (available(CDC_ENDPOINT_OUT))
			SerialUSB.accept();
	}
	if (ep == CDC_ENDPOINT_IN)
	{
		// NAK on endpoint IN, the bank is not yet filled in.
		usbd.epBank1ResetReady(CDC_ENDPOINT_IN);
		usbd.epBank1AckTransferComplete(CDC_ENDPOINT_IN);
	}
	if (ep == CDC_ENDPOINT_ACM)
	{
		// NAK on endpoint IN, the bank is not yet filled in.
		usbd.epBank1ResetReady(CDC_ENDPOINT_ACM);
		usbd.epBank1AckTransferComplete(CDC_ENDPOINT_ACM);
	}
#endif

#if defined(PLUGGABLE_USB_ENABLED)
	// Empty
#endif
}

uint8_t USBDeviceClass::armRecv(uint32_t ep)
{
	uint16_t count = usbd.epBank0ByteCount(ep);
	if (count >= 64) {
		usbd.epBank0SetByteCount(ep, count - 64);
	} else {
		usbd.epBank0SetByteCount(ep, 0);
	}
	return usbd.epBank0ByteCount(ep);
}

void USBDeviceClass::flush(uint32_t ep)
{
	if (available(ep)) {
		// RAM buffer is full, we can send data (IN)
		usbd.epBank1SetReady(ep);

	 	// Clear the transfer complete flag
		usbd.epBank1AckTransferComplete(ep);
	}
}

uint32_t USBDeviceClass::armSend(uint32_t ep, const void* data, uint32_t len)
{
	memcpy(&udd_ep_in_cache_buffer[ep], data, len);

	// Get endpoint configuration from setting register
	usbd.epBank1SetAddress(ep, &udd_ep_in_cache_buffer[ep]);
	usbd.epBank1SetMultiPacketSize(ep, 0);
	usbd.epBank1SetByteCount(ep, len);

	return len;
}

bool USBDeviceClass::attach()
{
	if (!initialized)
		return false;

	usbd.attach();
	usbd.enableEndOfResetInterrupt();
	usbd.enableStartOfFrameInterrupt();

	_usbConfiguration = 0;
	return true;
}

void USBDeviceClass::setAddress(uint32_t addr)
{
	usbd.epBank1SetByteCount(0, 0);
	usbd.epBank1AckTransferComplete(0);

	// RAM buffer is full, we can send data (IN)
	usbd.epBank1SetReady(0);

	// Wait for transfer to complete
	while (!usbd.epBank1IsTransferComplete(0)) {}

	// Set USB address to addr
	USB->DEVICE.DADD.bit.DADD = addr; // Address
	USB->DEVICE.DADD.bit.ADDEN = 1; // Enable
}

bool USBDeviceClass::detach()
{
	if (!initialized)
		return false;
	usbd.detach();
	return true;
}

uint8_t USBDeviceClass::armRecvCtrlOUT(uint32_t ep)
{
	// Get endpoint configuration from setting register
	usbd.epBank0SetAddress(ep, &udd_ep_out_cache_buffer[ep]);
	usbd.epBank0SetMultiPacketSize(ep, 8);
	usbd.epBank0SetByteCount(ep, 0);

	usbd.epBank0ResetReady(ep);

	// Wait OUT
	while (!usbd.epBank0IsReady(ep)) {}
	while (!usbd.epBank0IsTransferComplete(ep)) {}
	return usbd.epBank0ByteCount(ep);
}

uint32_t USBDeviceClass::recvControl(void *_data, uint32_t len)
{
	uint8_t *data = reinterpret_cast<uint8_t *>(_data);

	// The RAM Buffer is empty: we can receive data
	usbd.epBank0ResetReady(0);

	//usbd.epBank0AckSetupReceived(0);
	uint32_t read = armRecvCtrlOUT(0);
	if (read > len)
		read = len;
	//while (!usbd.epBank0AckTransferComplete(0)) {}
	uint8_t *buffer = udd_ep_out_cache_buffer[0];
	for (uint32_t i=0; i<len; i++) {
		data[i] = buffer[i];
	}

	return read;
}

void USBDeviceClass::init()
{
#ifdef PIN_LED_TXL
	txLEDPulse = 0;
	pinMode(PIN_LED_TXL, OUTPUT);
	digitalWrite(PIN_LED_TXL, HIGH);
#endif

#ifdef PIN_LED_RXL
	rxLEDPulse = 0;
	pinMode(PIN_LED_RXL, OUTPUT);
	digitalWrite(PIN_LED_RXL, HIGH);
#endif

	// Enable USB clock
	PM->APBBMASK.reg |= PM_APBBMASK_USB;

	// Set up the USB DP/DN pins
	PORT->Group[0].PINCFG[PIN_PA24G_USB_DM].bit.PMUXEN = 1;
	PORT->Group[0].PMUX[PIN_PA24G_USB_DM/2].reg &= ~(0xF << (4 * (PIN_PA24G_USB_DM & 0x01u)));
	PORT->Group[0].PMUX[PIN_PA24G_USB_DM/2].reg |= MUX_PA24G_USB_DM << (4 * (PIN_PA24G_USB_DM & 0x01u));
	PORT->Group[0].PINCFG[PIN_PA25G_USB_DP].bit.PMUXEN = 1;
	PORT->Group[0].PMUX[PIN_PA25G_USB_DP/2].reg &= ~(0xF << (4 * (PIN_PA25G_USB_DP & 0x01u)));
	PORT->Group[0].PMUX[PIN_PA25G_USB_DP/2].reg |= MUX_PA25G_USB_DP << (4 * (PIN_PA25G_USB_DP & 0x01u));

	// Put Generic Clock Generator 0 as source for Generic Clock Multiplexer 6 (USB reference)
	GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(6)     | // Generic Clock Multiplexer 6
	                    GCLK_CLKCTRL_GEN_GCLK0 | // Generic Clock Generator 0 is source
	                    GCLK_CLKCTRL_CLKEN;
	while (GCLK->STATUS.bit.SYNCBUSY)
		;

	USB_SetHandler(&UDD_Handler);

	// Reset USB Device
	usbd.reset();

	usbd.calibrate();
	usbd.setUSBDeviceMode();
	usbd.runInStandby();
	usbd.setFullSpeed();

	// Configure interrupts
	NVIC_SetPriority((IRQn_Type) USB_IRQn, 0UL);
	NVIC_EnableIRQ((IRQn_Type) USB_IRQn);

	usbd.enable();

	initialized = true;
}

void USBDeviceClass::sendZlp(uint32_t ep)
{
	// Set the byte count as zero
	usbd.epBank1SetByteCount(ep, 0);
}

// Blocking Send of data to an endpoint
uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
{
	uint32_t length = 0;

	if (!_usbConfiguration)
		return -1;
	if (len > 16384)
		return -1;

#if 0
// This shortcut has some issues:
// - sometimes it fails when sending an odd number of bytes (may be
//   due to memory alignment?)
// - the data pointer should point to "stable" data (and this is not
//   guaranteed by caller, it may be some sort of temporary buffer)
// - the SRAM is not guaranteed to start at 0x20000000

// All the above problems must be properly fixed before reenabling
// this part

	if ((unsigned int)data > 0x20000000)
	{
		// Buffer in RAM
		usbd.epBank1SetAddress(ep, (void *)data);
		usbd.epBank1SetMultiPacketSize(ep, 0);

		usbd.epBank1SetByteCount(ep, len);

		// Clear the transfer complete flag
		usbd.epBank1AckTransferComplete(ep);

		// RAM buffer is full, we can send data (IN)
		usbd.epBank1SetReady(ep);

		// Wait for transfer to complete
		while (!usbd.epBank1IsTransferComplete(ep)) {
			;  // need fire exit.
		}
		return 0;
	}
#endif

	// Flash area
	while (len != 0)
	{
		if (len >= 64) {
			length = 64;
		} else {
			length = len;
		}

		/* memcopy could be safer in multi threaded environment */
		memcpy(&udd_ep_in_cache_buffer[ep], data, length);

		usbd.epBank1SetAddress(ep, &udd_ep_in_cache_buffer[ep]);
		usbd.epBank1SetByteCount(ep, length);

		// Clear the transfer complete flag
		usbd.epBank1AckTransferComplete(ep);

		// RAM buffer is full, we can send data (IN)
		usbd.epBank1SetReady(ep);

		// Wait for transfer to complete
		while (!usbd.epBank1IsTransferComplete(ep)) {
			;  // need fire exit.
		}
		len -= length;
		data += length;
	}
	return len;
}

void USBDeviceClass::initEP(uint32_t ep, uint32_t config)
{
	if (config == (USB_ENDPOINT_TYPE_INTERRUPT | USB_ENDPOINT_IN(0)))
	{
		usbd.epBank1SetSize(ep, 64);
		usbd.epBank1SetAddress(ep, &udd_ep_in_cache_buffer[ep]);
		usbd.epBank1SetType(ep, 4); // INTERRUPT IN
	}
	else if (config == (USB_ENDPOINT_TYPE_BULK | USB_ENDPOINT_OUT(0)))
	{
		usbd.epBank0SetSize(ep, 64);
		usbd.epBank0SetAddress(ep, &udd_ep_out_cache_buffer[ep]);
		usbd.epBank0SetType(ep, 3); // BULK OUT

		// Release OUT EP
		usbd.epBank0SetMultiPacketSize(ep, 64);
		usbd.epBank0SetByteCount(ep, 0);
	}
	else if (config == (USB_ENDPOINT_TYPE_BULK | USB_ENDPOINT_IN(0)))
	{
		usbd.epBank1SetSize(ep, 64);
		usbd.epBank1SetAddress(ep, &udd_ep_in_cache_buffer[ep]);

		// NAK on endpoint IN, the bank is not yet filled in.
		usbd.epBank1ResetReady(ep);

		usbd.epBank1SetType(ep, 3); // BULK IN
	}
	else if (config == USB_ENDPOINT_TYPE_CONTROL)
	{
		// XXX: Needed?
// 		usbd.epBank0DisableAutoZLP(ep);
// 		usbd.epBank1DisableAutoZLP(ep);

		// Setup Control OUT
		usbd.epBank0SetSize(ep, 64);
		usbd.epBank0SetAddress(ep, &udd_ep_out_cache_buffer[ep]);
		usbd.epBank0SetType(ep, 1); // CONTROL OUT / SETUP

		// Setup Control IN
		usbd.epBank1SetSize(ep, 64);
		usbd.epBank1SetAddress(ep, &udd_ep_in_cache_buffer[0]);
		usbd.epBank1SetType(ep, 1); // CONTROL IN

		// Release OUT EP
		usbd.epBank0SetMultiPacketSize(ep, 64);
		usbd.epBank0SetByteCount(ep, 0);

		// NAK on endpoint OUT, the bank is full.
		usbd.epBank0SetReady(ep);
	}
}

bool USBDeviceClass::handleStandardSetup(USBSetup &setup)
{
	switch (setup.bRequest) {
	case GET_STATUS:
		if (setup.bmRequestType == 0)  // device
		{
			// Send the device status
			// TODO: Check current configuration for power mode (if device is configured)
			// TODO: Check if remote wake-up is enabled
			uint8_t buff[] = { 0, 0 };
			armSend(0, buff, 2);
			return true;
		}
		// if( setup.bmRequestType == 2 ) // Endpoint:
		else
		{
			// Send the endpoint status
			// Check if the endpoint if currently halted
			uint8_t buff[] = { 0, 0 };
			if (isEndpointHalt == 1)
				buff[0] = 1;
			armSend(0, buff, 2);
			return true;
		}

	case CLEAR_FEATURE:
		// Check which is the selected feature
		if (setup.wValueL == 1) // DEVICEREMOTEWAKEUP
		{
			// Enable remote wake-up and send a ZLP
			uint8_t buff[] = { 0, 0 };
			if (isRemoteWakeUpEnabled == 1)
				buff[0] = 1;
			armSend(0, buff, 2);
			return true;
		}
		else // if( setup.wValueL == 0) // ENDPOINTHALT
		{
			isEndpointHalt = 0;
			sendZlp(0);
			return true;
		}

	case SET_FEATURE:
		// Check which is the selected feature
		if (setup.wValueL == 1) // DEVICEREMOTEWAKEUP
		{
			// Enable remote wake-up and send a ZLP
			isRemoteWakeUpEnabled = 1;
			uint8_t buff[] = { 0 };
			armSend(0, buff, 1);
			return true;
		}
		if (setup.wValueL == 0) // ENDPOINTHALT
		{
			// Halt endpoint
			isEndpointHalt = 1;
			sendZlp(0);
			return true;
		}

	case SET_ADDRESS:
		setAddress(setup.wValueL);
		return true;

	case GET_DESCRIPTOR:
		return sendDescriptor(setup);

	case SET_DESCRIPTOR:
		return false;

	case GET_CONFIGURATION:
		armSend(0, (void*)&_usbConfiguration, 1);
		return true;

	case SET_CONFIGURATION:
		if (REQUEST_DEVICE == (setup.bmRequestType & REQUEST_RECIPIENT)) {

			initEndpoints();
			_usbConfiguration = setup.wValueL;

			#if defined(CDC_ENABLED)
			// Enable interrupt for CDC reception from host (OUT packet)
			usbd.epBank1EnableTransferComplete(CDC_ENDPOINT_ACM);
			usbd.epBank0EnableTransferComplete(CDC_ENDPOINT_OUT);
			#endif

			sendZlp(0);
			return true;
		} else {
			return false;
		}

	case GET_INTERFACE:
		armSend(0, (void*)&_usbSetInterface, 1);
		return true;

	case SET_INTERFACE:
		_usbSetInterface = setup.wValueL;
		sendZlp(0);
//.........这里部分代码省略.........

void USBDeviceClass::ISRHandler()
{

	if (_pack_message == true) {
		return;
	}
	// End-Of-Reset
	if (usbd.isEndOfResetInterrupt())
	{
		// Configure EP 0
		initEP(0, USB_ENDPOINT_TYPE_CONTROL);

		// Enable Setup-Received interrupt
		usbd.epBank0EnableSetupReceived(0);

		_usbConfiguration = 0;

		usbd.ackEndOfResetInterrupt();
	}

	// Start-Of-Frame
	if (usbd.isStartOfFrameInterrupt())
	{
		usbd.ackStartOfFrameInterrupt();
	}

	// Endpoint 0 Received Setup interrupt
	if (usbd.epBank0IsSetupReceived(0))
	{
		usbd.epBank0AckSetupReceived(0);

		USBSetup *setup = reinterpret_cast<USBSetup *>(udd_ep_out_cache_buffer[0]);

		/* Clear the Bank 0 ready flag on Control OUT */
		// The RAM Buffer is empty: we can receive data
		usbd.epBank0ResetReady(0);

		bool ok;
		if (REQUEST_STANDARD == (setup->bmRequestType & REQUEST_TYPE)) {
			// Standard Requests
			ok = handleStandardSetup(*setup);
		} else {
			// Class Interface Requests
			ok = handleClassInterfaceSetup(*setup);
		}

		if (ok) {
			usbd.epBank1SetReady(0);
		} else {
			stall(0);
		}

		if (usbd.epBank1IsStalled(0))
		{
			usbd.epBank1AckStalled(0);

			// Remove stall request
			usbd.epBank1DisableStalled(0);
		}

	} // end Received Setup handler

	uint8_t i=0;
	uint8_t ept_int = usbd.epInterruptSummary() & 0xFE; // Remove endpoint number 0 (setup)
	while (ept_int != 0)
	{
		// Check if endpoint has a pending interrupt
		if ((ept_int & (1 << i)) != 0)
		{
			// Endpoint Transfer Complete (0/1) Interrupt
			if (usbd.epBank0IsTransferComplete(i) ||
			    usbd.epBank1IsTransferComplete(i))
			{
				handleEndpoint(i);
			}
			ept_int &= ~(1 << i);
		}
		i++;
		if (i > USB_EPT_NUM)
			break;  // fire exit
	}
}

// Number of bytes, assumes a rx endpoint
uint32_t USBDeviceClass::available(uint32_t ep)
{
	return usbd.epBank0ByteCount(ep);
}