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 project 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                         {
 104                                 /* Try to send the next byte of data to the host, abort if there is an error without dequeuing */
 105                                 if (CDC_Device_SendByte(&VirtualSerial_CDC_Interface,
 106                                                         RingBuffer_Peek(&USARTtoUSB_Buffer)) != ENDPOINT_READYWAIT_NoError)
 107                                 {
 108                                         break;
 109                                 }
 110
 111                                 /* Dequeue the already sent byte from the buffer now we have confirmed that no transmission error occurred */
 112                                 RingBuffer_Remove(&USARTtoUSB_Buffer);
 113                         }
 114                 }
 115
 116                 /* Load the next byte from the USART transmit buffer into the USART */
 117                 if (!(RingBuffer_IsEmpty(&USBtoUSART_Buffer)))
 118                   Serial_TxByte(RingBuffer_Remove(&USBtoUSART_Buffer));
 119
 120                 CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
 121                 USB_USBTask();
 122         }
 123 }
 124
 125 /** Configures the board hardware and chip peripherals for the demo's functionality. */
 126 void SetupHardware(void)
 127 {
 128         /* Disable watchdog if enabled by bootloader/fuses */
 129         MCUSR &= ~(1 << WDRF);
 130         wdt_disable();
 131
 132         /* Disable clock division */
 133         clock_prescale_set(clock_div_1);
 134
 135         /* Hardware Initialization */
 136         LEDs_Init();
 137         USB_Init();
 138
 139         /* Start the flush timer so that overflows occur rapidly to push received bytes to the USB interface */
 140         TCCR0B = (1 << CS02);
 141 }
 142
 143 /** Event handler for the library USB Connection event. */
 144 void EVENT_USB_Device_Connect(void)
 145 {
 146         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
 147 }
 148
 149 /** Event handler for the library USB Disconnection event. */
 150 void EVENT_USB_Device_Disconnect(void)
 151 {
 152         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 153 }
 154
 155 /** Event handler for the library USB Configuration Changed event. */
 156 void EVENT_USB_Device_ConfigurationChanged(void)
 157 {
 158         bool ConfigSuccess = true;
 159
 160         ConfigSuccess &= CDC_Device_ConfigureEndpoints(&VirtualSerial_CDC_Interface);
 161
 162         LEDs_SetAllLEDs(ConfigSuccess ? LEDMASK_USB_READY : LEDMASK_USB_ERROR);
 163 }
 164
 165 /** Event handler for the library USB Control Request reception event. */
 166 void EVENT_USB_Device_ControlRequest(void)
 167 {
 168         CDC_Device_ProcessControlRequest(&VirtualSerial_CDC_Interface);
 169 }
 170
 171 /** ISR to manage the reception of data from the serial port, placing received bytes into a circular buffer
 172  *  for later transmission to the host.
 173  */
 174 ISR(USART1_RX_vect, ISR_BLOCK)
 175 {
 176         uint8_t ReceivedByte = UDR1;
 177
 178         if (USB_DeviceState == DEVICE_STATE_Configured)
 179           RingBuffer_Insert(&USARTtoUSB_Buffer, ReceivedByte);
 180 }
 181
 182 /** Event handler for the CDC Class driver Line Encoding Changed event.
 183  *
 184  *  \param[in] CDCInterfaceInfo  Pointer to the CDC class interface configuration structure being referenced
 185  */
 186 void EVENT_CDC_Device_LineEncodingChanged(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo)
 187 {
 188         uint8_t ConfigMask = 0;
 189
 190         switch (CDCInterfaceInfo->State.LineEncoding.ParityType)
 191         {
 192                 case CDC_PARITY_Odd:
 193                         ConfigMask = ((1 << UPM11) | (1 << UPM10));
 194                         break;
 195                 case CDC_PARITY_Even:
 196                         ConfigMask = (1 << UPM11);
 197                         break;
 198         }
 199
 200         if (CDCInterfaceInfo->State.LineEncoding.CharFormat == CDC_LINEENCODING_TwoStopBits)
 201           ConfigMask |= (1 << USBS1);
 202
 203         switch (CDCInterfaceInfo->State.LineEncoding.DataBits)
 204         {
 205                 case 6:
 206                         ConfigMask |= (1 << UCSZ10);
 207                         break;
 208                 case 7:
 209                         ConfigMask |= (1 << UCSZ11);
 210                         break;
 211                 case 8:
 212                         ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 213                         break;
 214         }
 215
 216         /* Must turn off USART before reconfiguring it, otherwise incorrect operation may occur */
 217         UCSR1B = 0;
 218         UCSR1A = 0;
 219         UCSR1C = 0;
 220
 221         /* Set the new baud rate before configuring the USART */
 222         UBRR1  = SERIAL_2X_UBBRVAL(CDCInterfaceInfo->State.LineEncoding.BaudRateBPS);
 223
 224         /* Reconfigure the USART in double speed mode for a wider baud rate range at the expense of accuracy */
 225         UCSR1C = ConfigMask;
 226         UCSR1A = (1 << U2X1);
 227         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 228 }
 229