keyboard.c

LUFA (Lightweight USB Framework for AVRs) is my first foray into the world of USB. Originally based

				while (!(Endpoint_IsINReady()));
				Endpoint_ClearIN();
			}
			
			break;
		case REQ_SetIdle:
			if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
			{
				Endpoint_ClearSETUP();
				
				/* Get idle period in MSB */
				IdleCount = (USB_ControlRequest.wValue >> 8);
				
				/* Acknowledge status stage */
				while (!(Endpoint_IsINReady()));
				Endpoint_ClearIN();
			}
			
			break;
		case REQ_GetIdle:
			if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
			{		
				Endpoint_ClearSETUP();
				
				/* Write the current idle duration to the host */
				Endpoint_Write_Byte(IdleCount);
				
				/* Send the flag to the host */
				Endpoint_ClearIN();

				/* Acknowledge status stage */
				while (!(Endpoint_IsOUTReceived()));
				Endpoint_ClearOUT();
			}

			break;
	}
}

/** ISR for the timer 0 compare vector. This ISR fires once each millisecond, and increments the
 *  scheduler elapsed idle period counter when the host has set an idle period.
 */
ISR(TIMER0_COMPA_vect, ISR_BLOCK)
{
	/* One millisecond has elapsed, decrement the idle time remaining counter if it has not already elapsed */
	if (IdleMSRemaining)
	  IdleMSRemaining--;
}

/** Fills the given HID report data structure with the next HID report to send to the host.
 *
 *  \param ReportData  Pointer to a HID report data structure to be filled
 */
void CreateKeyboardReport(USB_KeyboardReport_Data_t* ReportData)
{
	uint8_t JoyStatus_LCL = Joystick_GetStatus();

	/* Clear the report contents */
	memset(ReportData, 0, sizeof(USB_KeyboardReport_Data_t));

	if (JoyStatus_LCL & JOY_UP)
	  ReportData->KeyCode[0] = 0x04; // A
	else if (JoyStatus_LCL & JOY_DOWN)
	  ReportData->KeyCode[0] = 0x05; // B

	if (JoyStatus_LCL & JOY_LEFT)
	  ReportData->KeyCode[0] = 0x06; // C
	else if (JoyStatus_LCL & JOY_RIGHT)
	  ReportData->KeyCode[0] = 0x07; // D

	if (JoyStatus_LCL & JOY_PRESS)
	  ReportData->KeyCode[0] = 0x08; // E
}

/** Processes a received LED report, and updates the board LEDs states to match.
 *
 *  \param LEDReport  LED status report from the host
 */
void ProcessLEDReport(uint8_t LEDReport)
{
	uint8_t LEDMask = LEDS_LED2;
	
	if (LEDReport & 0x01) // NUM Lock
	  LEDMask |= LEDS_LED1;
	
	if (LEDReport & 0x02) // CAPS Lock
	  LEDMask |= LEDS_LED3;

	if (LEDReport & 0x04) // SCROLL Lock
	  LEDMask |= LEDS_LED4;

	/* Set the status LEDs to the current Keyboard LED status */
	LEDs_SetAllLEDs(LEDMask);
}

/** Sends the next HID report to the host, via the keyboard data endpoint. */
static inline void SendNextReport(void)
{
	static USB_KeyboardReport_Data_t PrevKeyboardReportData;
	USB_KeyboardReport_Data_t        KeyboardReportData;
	bool                             SendReport = true;
	
	/* Create the next keyboard report for transmission to the host */
	CreateKeyboardReport(&KeyboardReportData);
	
	/* Check if the idle period is set */
	if (IdleCount)
	{
		/* Check if idle period has elapsed */
		if (!(IdleMSRemaining))
		{
			/* Reset the idle time remaining counter, must multiply by 4 to get the duration in milliseconds */
			IdleMSRemaining = (IdleCount << 2);
		}
		else
		{
			/* Idle period not elapsed, indicate that a report must not be sent unless the report has changed */
			SendReport = (memcmp(&PrevKeyboardReportData, &KeyboardReportData, sizeof(USB_KeyboardReport_Data_t)) != 0);
		}
	}
	
	/* Save the current report data for later comparison to check for changes */
	PrevKeyboardReportData = KeyboardReportData;

	/* Select the Keyboard Report Endpoint */
	Endpoint_SelectEndpoint(KEYBOARD_EPNUM);

	/* Check if Keyboard Endpoint Ready for Read/Write, and if we should send a report */
	if (Endpoint_IsReadWriteAllowed() && SendReport)
	{
		/* Write Keyboard Report Data */
		Endpoint_Write_Stream_LE(&KeyboardReportData, sizeof(KeyboardReportData));

		/* Finalize the stream transfer to send the last packet */
		Endpoint_ClearIN();
	}
}

/** Reads the next LED status report from the host from the LED data endpoint, if one has been sent. */
static inline void ReceiveNextReport(void)
{
	/* Select the Keyboard LED Report Endpoint */
	Endpoint_SelectEndpoint(KEYBOARD_LEDS_EPNUM);

	/* Check if Keyboard LED Endpoint contains a packet */
	if (Endpoint_IsOUTReceived())
	{
		/* Check to see if the packet contains data */
		if (Endpoint_IsReadWriteAllowed())
		{
			/* Read in the LED report from the host */
			uint8_t LEDReport = Endpoint_Read_Byte();

			/* Process the read LED report from the host */
			ProcessLEDReport(LEDReport);
		}

		/* Handshake the OUT Endpoint - clear endpoint and ready for next report */
		Endpoint_ClearOUT();
	}
}

/** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 *  log to a serial port, or anything else that is suitable for status updates.
 *
 *  \param CurrentStatus  Current status of the system, from the Keyboard_StatusCodes_t enum
 */
void UpdateStatus(uint8_t CurrentStatus)
{
	uint8_t LEDMask = LEDS_NO_LEDS;
	
	/* Set the LED mask to the appropriate LED mask based on the given status code */
	switch (CurrentStatus)
	{
		case Status_USBNotReady:
			LEDMask = (LEDS_LED1);
			break;
		case Status_USBEnumerating:
			LEDMask = (LEDS_LED1 | LEDS_LED2);
			break;
		case Status_USBReady:
			LEDMask = (LEDS_LED2 | LEDS_LED4);
			break;
	}
	
	/* Set the board LEDs to the new LED mask */
	LEDs_SetAllLEDs(LEDMask);
}

#if !defined(INTERRUPT_DATA_ENDPOINT)
/** Function to manage HID report generation and transmission to the host, when in report mode. */
TASK(USB_Keyboard_Report)
{
	/* Check if the USB system is connected to a host */
	if (USB_IsConnected)
	{
		/* Send the next keypress report to the host */
		SendNextReport();
		
		/* Process the LED report sent from the host */
		ReceiveNextReport();
	}
}
#endif

/** ISR for the general Pipe/Endpoint interrupt vector. This ISR fires when an endpoint's status changes (such as
 *  a packet has been received) on an endpoint with its corresponding ISR enabling bits set. This is used to send
 *  HID packets to the host each time the HID interrupt endpoints polling period elapses, as managed by the USB
 *  controller. It is also used to respond to standard and class specific requests send to the device on the control
 *  endpoint, by handing them off to the LUFA library when they are received.
 */
ISR(ENDPOINT_PIPE_vect, ISR_BLOCK)
{
	#if defined(INTERRUPT_CONTROL_ENDPOINT)
	/* Check if the control endpoint has received a request */
	if (Endpoint_HasEndpointInterrupted(ENDPOINT_CONTROLEP))
	{
		/* Clear the endpoint interrupt */
		Endpoint_ClearEndpointInterrupt(ENDPOINT_CONTROLEP);

		/* Process the control request */
		USB_USBTask();

		/* Handshake the endpoint setup interrupt - must be after the call to USB_USBTask() */
		USB_INT_Clear(ENDPOINT_INT_SETUP);
	}
	#endif

	#if defined(INTERRUPT_DATA_ENDPOINT)
	/* Check if keyboard endpoint has interrupted */
	if (Endpoint_HasEndpointInterrupted(KEYBOARD_EPNUM))
	{
		/* Select the Keyboard Report Endpoint */
		Endpoint_SelectEndpoint(KEYBOARD_EPNUM);

		/* Clear the endpoint IN interrupt flag */
		USB_INT_Clear(ENDPOINT_INT_IN);

		/* Clear the Keyboard Report endpoint interrupt */
		Endpoint_ClearEndpointInterrupt(KEYBOARD_EPNUM);

		/* Send the next keypress report to the host */
		SendNextReport();
	}

	/* Check if Keyboard LED status Endpoint has interrupted */
	if (Endpoint_HasEndpointInterrupted(KEYBOARD_LEDS_EPNUM))
	{
		/* Select the Keyboard LED Report Endpoint */
		Endpoint_SelectEndpoint(KEYBOARD_LEDS_EPNUM);

		/* Clear the endpoint OUT interrupt flag */
		USB_INT_Clear(ENDPOINT_INT_OUT);

		/* Clear the Keyboard LED Report endpoint interrupt */
		Endpoint_ClearEndpointInterrupt(KEYBOARD_LEDS_EPNUM);

		/* Process the LED report sent from the host */
		ReceiveNextReport();
	}
	#endif
}