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         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 143
 144         if (!(CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface)))
 145           LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 146 }
 147
 148 /** Event handler for the library USB Unhandled Control Request event. */
 149 void EVENT_USB_Device_UnhandledControlRequest(void)
 150 {
 151         CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
 152 }
 153
 154 /** ISR to manage the reception of data from the serial port, placing received bytes into a circular buffer
 155  *  for later transmission to the host.
 156  */
 157 ISR(USART1_RX_vect, ISR_BLOCK)
 158 {
 159         uint8_t ReceivedByte = UDR1;
 160
 161         if (USB_DeviceState == DEVICE_STATE_Configured)
 162           RingBuffer_Insert(&USARTtoUSB_Buffer, ReceivedByte);
 163 }
 164
 165 /** Event handler for the CDC Class driver Line Encoding Changed event.
 166  *
 167  *  \param[in] CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
 168  */
 169 void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
 170 {
 171         uint8_t ConfigMask = 0;
 172
 173         switch (CDCInterfaceInfo->State.LineEncoding.ParityType)
 174         {
 175                 case CDC_PARITY_Odd:
 176                         ConfigMask = ((1 << UPM11) | (1 << UPM10));
 177                         break;
 178                 case CDC_PARITY_Even:
 179                         ConfigMask = (1 << UPM11);
 180                         break;
 181         }
 182
 183         if (CDCInterfaceInfo->State.LineEncoding.CharFormat == CDC_LINEENCODING_TwoStopBits)
 184           ConfigMask |= (1 << USBS1);
 185
 186         switch (CDCInterfaceInfo->State.LineEncoding.DataBits)
 187         {
 188                 case 6:
 189                         ConfigMask |= (1 << UCSZ10);
 190                         break;
 191                 case 7:
 192                         ConfigMask |= (1 << UCSZ11);
 193                         break;
 194                 case 8:
 195                         ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 196                         break;
 197         }
 198
 199         /* Must turn off USART before reconfiguring it, otherwise incorrect operation may occur */
 200         UCSR1B = 0;
 201         UCSR1A = 0;
 202         UCSR1C = 0;
 203
 204         /* Set the new baud rate before configuring the USART */
 205         UBRR1  = SERIAL_2X_UBBRVAL(CDCInterfaceInfo->State.LineEncoding.BaudRateBPS);
 206
 207         /* Reconfigure the USART in double speed mode for a wider baud rate range at the expense of accuracy */
 208         UCSR1C = ConfigMask;
 209         UCSR1A = (1 << U2X1);
 210         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 211 }