USBtoSerial.c

/*
             LUFA Library
     Copyright (C) Dean Camera, 2009.
              
  dean [at] fourwalledcubicle [dot] com
      www.fourwalledcubicle.com
*/

/*
  Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)

  Permission to use, copy, modify, and distribute this software
  and its documentation for any purpose and without fee is hereby
  granted, provided that the above copyright notice appear in all
  copies and that both that the copyright notice and this
  permission notice and warranty disclaimer appear in supporting
  documentation, and that the name of the author not be used in
  advertising or publicity pertaining to distribution of the
  software without specific, written prior permission.

  The author disclaim all warranties with regard to this
  software, including all implied warranties of merchantability
  and fitness.  In no event shall the author be liable for any
  special, indirect or consequential damages or any damages
  whatsoever resulting from loss of use, data or profits, whether
  in an action of contract, negligence or other tortious action,
  arising out of or in connection with the use or performance of
  this software.
*/

/** \file
 *
 *  Main source file for the USBtoSerial demo. This file contains the main tasks of
 *  the demo and is responsible for the initial application hardware configuration.
 */

#include "USBtoSerial.h"

/** Circular buffer to hold data from the host before it is sent to the device via the serial port. */
RingBuff_t Rx_Buffer;

/** Circular buffer to hold data from the serial port before it is sent to the host. */
RingBuff_t Tx_Buffer;

/** LUFA CDC Class driver interface configuration and state information. This structure is
 *  passed to all CDC Class driver functions, so that multiple instances of the same class
 *  within a device can be differentiated from one another.
 */
USB_ClassInfo_CDC_t VirtualSerial_CDC_Interface =
	{
		.ControlInterfaceNumber     = 0,

		.DataINEndpointNumber       = CDC_TX_EPNUM,
		.DataINEndpointSize         = CDC_TXRX_EPSIZE,

		.DataOUTEndpointNumber      = CDC_RX_EPNUM,
		.DataOUTEndpointSize        = CDC_TXRX_EPSIZE,

		.NotificationEndpointNumber = CDC_NOTIFICATION_EPNUM,
		.NotificationEndpointSize   = CDC_NOTIFICATION_EPSIZE,
	};

/** Main program entry point. This routine contains the overall program flow, including initial
 *  setup of all components and the main program loop.
 */
int main(void)
{
	SetupHardware();
	
	Buffer_Initialize(&Rx_Buffer);
	Buffer_Initialize(&Tx_Buffer);

	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);

	for (;;)
	{
		/* Read bytes from the USB OUT endpoint into the USART transmit buffer */
		for (uint8_t DataBytesRem = CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface); DataBytesRem != 0; DataBytesRem--)
		{
			if (!(BUFF_STATICSIZE - Rx_Buffer.Elements))
			  break;
			  
			Buffer_StoreElement(&Rx_Buffer, CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface));
		}
		
		/* Read bytes from the USART receive buffer into the USB IN endpoint */
		if (Tx_Buffer.Elements)
		  CDC_Device_SendByte(&VirtualSerial_CDC_Interface, Buffer_GetElement(&Tx_Buffer));
		
		/* Read bytes from the USART transmit buffer into the USART */
		if (Rx_Buffer.Elements)
		  Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
		
		CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
		USB_USBTask();
	}
}

/** Configures the board hardware and chip peripherals for the demo's functionality. */
void SetupHardware(void)
{
	/* Disable watchdog if enabled by bootloader/fuses */
	MCUSR &= ~(1 << WDRF);
	wdt_disable();

	/* Disable clock division */
	clock_prescale_set(clock_div_1);

	/* Hardware Initialization */
	Joystick_Init();
	LEDs_Init();
	USB_Init();
}

/** Event handler for the library USB Connection event. */
void EVENT_USB_Connect(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
}

/** Event handler for the library USB Disconnection event. */
void EVENT_USB_Disconnect(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
}

/** Event handler for the library USB Configuration Changed event. */
void EVENT_USB_ConfigurationChanged(void)
{
	LEDs_SetAllLEDs(LEDMASK_USB_READY);

	if (!(CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface)))
	  LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
}

/** Event handler for the library USB Unhandled Control Packet event. */
void EVENT_USB_UnhandledControlPacket(void)
{
	CDC_Device_ProcessControlPacket(&VirtualSerial_CDC_Interface);
}

/** ISR to manage the reception of data from the serial port, placing received bytes into a circular buffer
 *  for later transmission to the host.
 */
ISR(USART1_RX_vect, ISR_BLOCK)
{
	if (USB_IsConnected)
	  Buffer_StoreElement(&Tx_Buffer, UDR1);
}

/** Event handler for the CDC Class driver Line Encoding Changed event.
 *
 *  \param CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
 */
void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_t* CDCInterfaceInfo)
{
	uint8_t ConfigMask = 0;

	if (CDCInterfaceInfo->LineEncoding.ParityType == CDC_PARITY_Odd)
	  ConfigMask = ((1 << UPM11) | (1 << UPM10));
	else if (CDCInterfaceInfo->LineEncoding.ParityType == CDC_PARITY_Even)
	  ConfigMask = (1 << UPM11);

	if (CDCInterfaceInfo->LineEncoding.CharFormat == CDC_LINEENCODING_TwoStopBits)
	  ConfigMask |= (1 << USBS1);

	if (CDCInterfaceInfo->LineEncoding.DataBits == 6)
	  ConfigMask |= (1 << UCSZ10);
	else if (CDCInterfaceInfo->LineEncoding.DataBits == 7)
	  ConfigMask |= (1 << UCSZ11);
	else if (CDCInterfaceInfo->LineEncoding.DataBits == 8)
	  ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
	
	UCSR1A = (1 << U2X1);	
	UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
	UCSR1C = ConfigMask;	
	UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)CDCInterfaceInfo->LineEncoding.BaudRateBPS);
}