Projects/USBtoSerial/USBtoSerial.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   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                 /* Only try to read in bytes from the CDC interface if the transmit buffer is not full */
  85                 if (!(RingBuffer_IsFull(&USBtoUSART_Buffer)))
  86                 {
  87                         int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
  88
  89                         /* Read bytes from the USB OUT endpoint into the USART transmit buffer */
  90                         if (!(ReceivedByte < 0))
  91                           RingBuffer_Insert(&USBtoUSART_Buffer, ReceivedByte);
  92                 }
  93
  94                 /* Check if the UART receive buffer flush timer has expired or the buffer is nearly full */
  95                 RingBuff_Count_t BufferCount = RingBuffer_GetCount(&USARTtoUSB_Buffer);
  96                 if ((TIFR0 & (1 << TOV0)) || (BufferCount > 200))
  97                 {
  98                         /* Clear flush timer expiry flag */
  99                         TIFR0 |= (1 << TOV0);
 100
 101                         /* Read bytes from the USART receive buffer into the USB IN endpoint */
 102                         while (BufferCount--)
 103                           CDC_Device_SendByte(&VirtualSerial_CDC_Interface, RingBuffer_Remove(&USARTtoUSB_Buffer));
 104                 }
 105
 106                 /* Load the next byte from the USART transmit buffer into the USART */
 107                 if (!(RingBuffer_IsEmpty(&USBtoUSART_Buffer)))
 108                   Serial_TxByte(RingBuffer_Remove(&USBtoUSART_Buffer));
 109
 110                 CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
 111                 USB_USBTask();
 112         }
 113 }
 114
 115 /** Configures the board hardware and chip peripherals for the demo's functionality. */
 116 void SetupHardware(void)
 117 {
 118         /* Disable watchdog if enabled by bootloader/fuses */
 119         MCUSR &= ~(1 << WDRF);
 120         wdt_disable();
 121
 122         /* Disable clock division */
 123         clock_prescale_set(clock_div_1);
 124
 125         /* Hardware Initialization */
 126         LEDs_Init();
 127         USB_Init();
 128
 129         /* Start the flush timer so that overflows occur rapidly to push received bytes to the USB interface */
 130         TCCR0B = (1 << CS02);
 131 }
 132
 133 /** Event handler for the library USB Connection event. */
 134 void EVENT_USB_Device_Connect(void)
 135 {
 136         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 137 }
 138
 139 /** Event handler for the library USB Disconnection event. */
 140 void EVENT_USB_Device_Disconnect(void)
 141 {
 142         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 143 }
 144
 145 /** Event handler for the library USB Configuration Changed event. */
 146 void EVENT_USB_Device_ConfigurationChanged(void)
 147 {
 148         bool ConfigSuccess = true;
 149
 150         ConfigSuccess &= CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface);
 151
 152         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 153 }
 154
 155 /** Event handler for the library USB Unhandled Control Request event. */
 156 void EVENT_USB_Device_UnhandledControlRequest(void)
 157 {
 158         CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
 159 }
 160
 161 /** ISR to manage the reception of data from the serial port, placing received bytes into a circular buffer
 162  *  for later transmission to the host.
 163  */
 164 ISR(USART1_RX_vect, ISR_BLOCK)
 165 {
 166         uint8_t ReceivedByte = UDR1;
 167
 168         if (USB_DeviceState == DEVICE_STATE_Configured)
 169           RingBuffer_Insert(&USARTtoUSB_Buffer, ReceivedByte);
 170 }
 171
 172 /** Event handler for the CDC Class driver Line Encoding Changed event.
 173  *
 174  *  \param[in] CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
 175  */
 176 void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
 177 {
 178         uint8_t ConfigMask = 0;
 179
 180         switch (CDCInterfaceInfo->State.LineEncoding.ParityType)
 181         {
 182                 case CDC_PARITY_Odd:
 183                         ConfigMask = ((1 << UPM11) | (1 << UPM10));
 184                         break;
 185                 case CDC_PARITY_Even:
 186                         ConfigMask = (1 << UPM11);
 187                         break;
 188         }
 189
 190         if (CDCInterfaceInfo->State.LineEncoding.CharFormat == CDC_LINEENCODING_TwoStopBits)
 191           ConfigMask |= (1 << USBS1);
 192
 193         switch (CDCInterfaceInfo->State.LineEncoding.DataBits)
 194         {
 195                 case 6:
 196                         ConfigMask |= (1 << UCSZ10);
 197                         break;
 198                 case 7:
 199                         ConfigMask |= (1 << UCSZ11);
 200                         break;
 201                 case 8:
 202                         ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 203                         break;
 204         }
 205
 206         /* Must turn off USART before reconfiguring it, otherwise incorrect operation may occur */
 207         UCSR1B = 0;
 208         UCSR1A = 0;
 209         UCSR1C = 0;
 210
 211         /* Set the new baud rate before configuring the USART */
 212         UBRR1  = SERIAL_2X_UBBRVAL(CDCInterfaceInfo->State.LineEncoding.BaudRateBPS);
 213
 214         /* Reconfigure the USART in double speed mode for a wider baud rate range at the expense of accuracy */
 215         UCSR1C = ConfigMask;
 216         UCSR1A = (1 << U2X1);
 217         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 218 }
 219