Projects/USBtoSerial/USBtoSerial.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Main source file for the USBtoSerial project. This file contains the main tasks of
  34  *  the demo and is responsible for the initial application hardware configuration.
  35  */
  36
  37 #include "USBtoSerial.h"
  38
  39 /** Circular buffer to hold data from the host before it is sent to the device via the serial port. */
  40 RingBuff_t USBtoUSART_Buffer;
  41
  42 /** Circular buffer to hold data from the serial port before it is sent to the host. */
  43 RingBuff_t USARTtoUSB_Buffer;
  44
  45 /** LUFA CDC Class driver interface configuration and state information. This structure is
  46  *  passed to all CDC Class driver functions, so that multiple instances of the same class
  47  *  within a device can be differentiated from one another.
  48  */
  49 USB_ClassInfo_CDC_Device_t VirtualSerial_CDC_Interface =
  50         {
  51                 .Config =
  52                         {
  53                                 .ControlInterfaceNumber         = 0,
  54
  55                                 .DataINEndpointNumber           = CDC_TX_EPNUM,
  56                                 .DataINEndpointSize             = CDC_TXRX_EPSIZE,
  57                                 .DataINEndpointDoubleBank       = false,
  58
  59                                 .DataOUTEndpointNumber          = CDC_RX_EPNUM,
  60                                 .DataOUTEndpointSize            = CDC_TXRX_EPSIZE,
  61                                 .DataOUTEndpointDoubleBank      = false,
  62
  63                                 .NotificationEndpointNumber     = CDC_NOTIFICATION_EPNUM,
  64                                 .NotificationEndpointSize       = CDC_NOTIFICATION_EPSIZE,
  65                                 .NotificationEndpointDoubleBank = false,
  66                         },
  67         };
  68
  69 /** Main program entry point. This routine contains the overall program flow, including initial
  70  *  setup of all components and the main program loop.
  71  */
  72 int main(void)
  73 {
  74         SetupHardware();
  75
  76         RingBuffer_InitBuffer(&USBtoUSART_Buffer);
  77         RingBuffer_InitBuffer(&USARTtoUSB_Buffer);
  78
  79         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  80         sei();
  81
  82         for (;;)
  83         {
  84                 /* Read bytes from the USB OUT endpoint into the USART transmit buffer */
  85                 int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
  86                 if (!(ReceivedByte < 0) && !(RingBuffer_IsFull(&USBtoUSART_Buffer)))
  87                   RingBuffer_Insert(&USBtoUSART_Buffer, ReceivedByte);
  88
  89                 /* Check if the UART receive buffer flush timer has expired or the buffer is nearly full */
  90                 RingBuff_Count_t BufferCount = RingBuffer_GetCount(&USARTtoUSB_Buffer);
  91                 if ((TIFR0 & (1 << TOV0)) || (BufferCount > 200))
  92                 {
  93                         TIFR0 |= (1 << TOV0);
  94
  95                         /* Read bytes from the USART receive buffer into the USB IN endpoint */
  96                         while (BufferCount--)
  97                           CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&USARTtoUSB_Buffer));
  98                 }
  99
 100                 /* Load the next byte from the USART transmit buffer into the USART */
 101                 if (!(RingBuffer_IsEmpty(&USBtoUSART_Buffer)))
 102                   Serial_TxByte(RingBuffer_Remove(&USBtoUSART_Buffer));
 103
 104                 CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
 105                 USB_USBTask();
 106         }
 107 }
 108
 109 /** Configures the board hardware and chip peripherals for the demo's functionality. */
 110 void SetupHardware(void)
 111 {
 112         /* Disable watchdog if enabled by bootloader/fuses */
 113         MCUSR &= ~(1 << WDRF);
 114         wdt_disable();
 115
 116         /* Disable clock division */
 117         clock_prescale_set(clock_div_1);
 118
 119         /* Hardware Initialization */
 120         LEDs_Init();
 121         USB_Init();
 122
 123         /* Start the flush timer so that overflows occur rapidly to push received bytes to the USB interface */
 124         TCCR0B = (1 << CS02);
 125 }
 126
 127 /** Event handler for the library USB Connection event. */
 128 void EVENT_USB_Device_Connect(void)
 129 {
 130         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 131 }
 132
 133 /** Event handler for the library USB Disconnection event. */
 134 void EVENT_USB_Device_Disconnect(void)
 135 {
 136         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 137 }
 138
 139 /** Event handler for the library USB Configuration Changed event. */
 140 void EVENT_USB_Device_ConfigurationChanged(void)
 141 {
 142         bool ConfigSuccess = true;
 143
 144         ConfigSuccess &= CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface);
 145
 146         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 147 }
 148
 149 /** Event handler for the library USB Unhandled Control Request event. */
 150 void EVENT_USB_Device_UnhandledControlRequest(void)
 151 {
 152         CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
 153 }
 154
 155 /** ISR to manage the reception of data from the serial port, placing received bytes into a circular buffer
 156  *  for later transmission to the host.
 157  */
 158 ISR(USART1_RX_vect, ISR_BLOCK)
 159 {
 160         uint8_t ReceivedByte = UDR1;
 161
 162         if (USB_DeviceState == DEVICE_STATE_Configured)
 163           RingBuffer_Insert(&USARTtoUSB_Buffer, ReceivedByte);
 164 }
 165
 166 /** Event handler for the CDC Class driver Line Encoding Changed event.
 167  *
 168  *  \param[in] CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
 169  */
 170 void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
 171 {
 172         uint8_t ConfigMask = 0;
 173
 174         switch (CDCInterfaceInfo->State.LineEncoding.ParityType)
 175         {
 176                 case CDC_PARITY_Odd:
 177                         ConfigMask = ((1 << UPM11) | (1 << UPM10));
 178                         break;
 179                 case CDC_PARITY_Even:
 180                         ConfigMask = (1 << UPM11);
 181                         break;
 182         }
 183
 184         if (CDCInterfaceInfo->State.LineEncoding.CharFormat == CDC_LINEENCODING_TwoStopBits)
 185           ConfigMask |= (1 << USBS1);
 186
 187         switch (CDCInterfaceInfo->State.LineEncoding.DataBits)
 188         {
 189                 case 6:
 190                         ConfigMask |= (1 << UCSZ10);
 191                         break;
 192                 case 7:
 193                         ConfigMask |= (1 << UCSZ11);
 194                         break;
 195                 case 8:
 196                         ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 197                         break;
 198         }
 199
 200         /* Must turn off USART before reconfiguring it, otherwise incorrect operation may occur */
 201         UCSR1B = 0;
 202         UCSR1A = 0;
 203         UCSR1C = 0;
 204
 205         /* Set the new baud rate before configuring the USART */
 206         UBRR1  = SERIAL_2X_UBBRVAL(CDCInterfaceInfo->State.LineEncoding.BaudRateBPS);
 207
 208         /* Reconfigure the USART in double speed mode for a wider baud rate range at the expense of accuracy */
 209         UCSR1C = ConfigMask;
 210         UCSR1A = (1 << U2X1);
 211         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 212 }