Demos/Device/USBtoSerial/USBtoSerial.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   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 #include "USBtoSerial.h"
  32
  33 /* Scheduler Task List */
  34 TASK_LIST
  35 {
  36         { .Task = USB_USBTask          , .TaskStatus = TASK_STOP },
  37         { .Task = CDC_Task             , .TaskStatus = TASK_STOP },
  38 };
  39
  40 /* Globals: */
  41 /** Contains the current baud rate and other settings of the virtual serial port.
  42  *
  43  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the
  44  *  new settings each time they are changed by the host.
  45  */
  46 CDC_Line_Coding_t LineCoding = { .BaudRateBPS = 9600,
  47                                  .CharFormat  = OneStopBit,
  48                                  .ParityType  = Parity_None,
  49                                  .DataBits    = 8            };
  50
  51 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */
  52 RingBuff_t Rx_Buffer;
  53
  54 /** Ring (circular) buffer to hold the TX data - data from the attached device on the serial port to the host. */
  55 RingBuff_t Tx_Buffer;
  56
  57 /** Flag to indicate if the USART is currently transmitting data from the Rx_Buffer circular buffer. */
  58 volatile bool Transmitting = false;
  59
  60 /** Main program entry point. This routine configures the hardware required by the application, then
  61  *  starts the scheduler to run the application tasks.
  62  */
  63 int main(void)
  64 {
  65         /* Disable watchdog if enabled by bootloader/fuses */
  66         MCUSR &= ~(1 << WDRF);
  67         wdt_disable();
  68
  69         /* Disable clock division */
  70         clock_prescale_set(clock_div_1);
  71
  72         /* Hardware Initialization */
  73         LEDs_Init();
  74         ReconfigureUSART();
  75
  76         /* Ring buffer Initialization */
  77         Buffer_Initialize(&Rx_Buffer);
  78         Buffer_Initialize(&Tx_Buffer);
  79
  80         /* Indicate USB not ready */
  81         UpdateStatus(Status_USBNotReady);
  82
  83         /* Initialize Scheduler so that it can be used */
  84         Scheduler_Init();
  85
  86         /* Initialize USB Subsystem */
  87         USB_Init();
  88
  89         /* Scheduling - routine never returns, so put this last in the main function */
  90         Scheduler_Start();
  91 }
  92
  93 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs and
  94  *  starts the library USB task to begin the enumeration and USB management process.
  95  */
  96 void EVENT_USB_Connect(void)
  97 {
  98         /* Start USB management task */
  99         Scheduler_SetTaskMode(USB_USBTask, TASK_RUN);
 100
 101         /* Indicate USB enumerating */
 102         UpdateStatus(Status_USBEnumerating);
 103 }
 104
 105 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
 106  *  the status LEDs and stops the USB management and CDC management tasks.
 107  */
 108 void EVENT_USB_Disconnect(void)
 109 {
 110         /* Stop running CDC and USB management tasks */
 111         Scheduler_SetTaskMode(CDC_Task, TASK_STOP);
 112         Scheduler_SetTaskMode(USB_USBTask, TASK_STOP);
 113
 114         /* Reset Tx and Rx buffers, device disconnected */
 115         Buffer_Initialize(&Rx_Buffer);
 116         Buffer_Initialize(&Tx_Buffer);
 117
 118         /* Indicate USB not ready */
 119         UpdateStatus(Status_USBNotReady);
 120 }
 121
 122 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 123  *  of the USB device after enumeration - the device endpoints are configured and the CDC management task started.
 124  */
 125 void EVENT_USB_ConfigurationChanged(void)
 126 {
 127         /* Setup CDC Notification, Rx and Tx Endpoints */
 128         Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
 129                                        ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
 130                                    ENDPOINT_BANK_SINGLE);
 131
 132         Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
 133                                        ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
 134                                    ENDPOINT_BANK_SINGLE);
 135
 136         Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
 137                                        ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
 138                                    ENDPOINT_BANK_SINGLE);
 139
 140         /* Indicate USB connected and ready */
 141         UpdateStatus(Status_USBReady);
 142
 143         /* Start CDC task */
 144         Scheduler_SetTaskMode(CDC_Task, TASK_RUN);
 145 }
 146
 147 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 148  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 149  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 150  */
 151 void EVENT_USB_UnhandledControlPacket(void)
 152 {
 153         uint8_t* LineCodingData = (uint8_t*)&LineCoding;
 154
 155         /* Process CDC specific control requests */
 156         switch (USB_ControlRequest.bRequest)
 157         {
 158                 case REQ_GetLineEncoding:
 159                         if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 160                         {
 161                                 /* Acknowledge the SETUP packet, ready for data transfer */
 162                                 Endpoint_ClearSETUP();
 163
 164                                 /* Write the line coding data to the control endpoint */
 165                                 Endpoint_Write_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 166
 167                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 168                                 Endpoint_ClearOUT();
 169                         }
 170
 171                         break;
 172                 case REQ_SetLineEncoding:
 173                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 174                         {
 175                                 /* Acknowledge the SETUP packet, ready for data transfer */
 176                                 Endpoint_ClearSETUP();
 177
 178                                 /* Read the line coding data in from the host into the global struct */
 179                                 Endpoint_Read_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 180
 181                                 /* Finalize the stream transfer to clear the last packet from the host */
 182                                 Endpoint_ClearIN();
 183
 184                                 /* Reconfigure the USART with the new settings */
 185                                 ReconfigureUSART();
 186                         }
 187
 188                         break;
 189                 case REQ_SetControlLineState:
 190                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 191                         {
 192                                 /* Acknowledge the SETUP packet, ready for data transfer */
 193                                 Endpoint_ClearSETUP();
 194
 195                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 196                                          lines. The mask is read in from the wValue parameter in USB_ControlRequest, and can be masked against the
 197                                                  CONTROL_LINE_OUT_* masks to determine the RTS and DTR line states using the following code:
 198                                 */
 199
 200                                 /* Acknowledge status stage */
 201                                 while (!(Endpoint_IsINReady()));
 202                                 Endpoint_ClearIN();
 203                         }
 204
 205                         break;
 206         }
 207 }
 208
 209 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 210 TASK(CDC_Task)
 211 {
 212         if (USB_IsConnected)
 213         {
 214 #if 0
 215                 /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 216                                  handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 217                 */
 218
 219                 USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 220                         {
 221                                 .NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 222                                 .Notification     = NOTIF_SerialState,
 223                                 .wValue           = 0,
 224                                 .wIndex           = 0,
 225                                 .wLength          = sizeof(uint16_t),
 226                         };
 227
 228                 uint16_t LineStateMask;
 229
 230                 // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 231
 232                 Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 233                 Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 234                 Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 235                 Endpoint_ClearIN();
 236 #endif
 237
 238                 /* Select the Serial Rx Endpoint */
 239                 Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 240
 241                 /* Check to see if a packet has been received from the host */
 242                 if (Endpoint_IsOUTReceived())
 243                 {
 244                         /* Read the bytes in from the endpoint into the buffer while space is available */
 245                         while (Endpoint_BytesInEndpoint() && (BUFF_STATICSIZE - Rx_Buffer.Elements))
 246                         {
 247                                 /* Store each character from the endpoint */
 248                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 249                         }
 250
 251                         /* Check to see if all bytes in the current packet have been read */
 252                         if (!(Endpoint_BytesInEndpoint()))
 253                         {
 254                                 /* Clear the endpoint buffer */
 255                                 Endpoint_ClearOUT();
 256                         }
 257                 }
 258
 259                 /* Check if Rx buffer contains data */
 260                 if (Rx_Buffer.Elements)
 261                 {
 262                         /* Initiate the transmission of the buffer contents if USART idle */
 263                         if (!(Transmitting))
 264                         {
 265                                 Transmitting = true;
 266                                 Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 267                         }
 268                 }
 269
 270                 /* Select the Serial Tx Endpoint */
 271                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 272
 273                 /* Check if the Tx buffer contains anything to be sent to the host */
 274                 if (Tx_Buffer.Elements)
 275                 {
 276                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 277                         while (!(Endpoint_IsReadWriteAllowed()));
 278
 279                         /* Write the bytes from the buffer to the endpoint while space is available */
 280                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 281                         {
 282                                 /* Write each byte retreived from the buffer to the endpoint */
 283                                 Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 284                         }
 285
 286                         /* Remember if the packet to send completely fills the endpoint */
 287                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 288
 289                         /* Send the data */
 290                         Endpoint_ClearIN();
 291
 292                         /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 293                          * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 294                         if (IsFull && !(Tx_Buffer.Elements))
 295                         {
 296                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 297                                 while (!(Endpoint_IsReadWriteAllowed()));
 298
 299                                 /* Send an empty packet to terminate the transfer */
 300                                 Endpoint_ClearIN();
 301                         }
 302                 }
 303         }
 304 }
 305
 306 /** ISR to handle the USART transmit complete interrupt, fired each time the USART has sent a character. This reloads the USART
 307  *  data register with the next byte from the Rx_Buffer circular buffer if a character is available, or stops the transmission if
 308  *  the buffer is currently empty.
 309  */
 310 ISR(USART1_TX_vect, ISR_BLOCK)
 311 {
 312         /* Send next character if available */
 313         if (Rx_Buffer.Elements)
 314           UDR1 = Buffer_GetElement(&Rx_Buffer);
 315         else
 316           Transmitting = false;
 317 }
 318
 319 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 320  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 321  */
 322 ISR(USART1_RX_vect, ISR_BLOCK)
 323 {
 324         /* Only store received characters if the USB interface is connected */
 325         if (USB_IsConnected)
 326         {
 327                 /* Character received, store it into the buffer */
 328                 Buffer_StoreElement(&Tx_Buffer, UDR1);
 329         }
 330 }
 331
 332 /** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 333  *  log to a serial port, or anything else that is suitable for status updates.
 334  *
 335  *  \param CurrentStatus  Current status of the system, from the USBtoSerial_StatusCodes_t enum
 336  */
 337 void UpdateStatus(uint8_t CurrentStatus)
 338 {
 339         uint8_t LEDMask = LEDS_NO_LEDS;
 340
 341         /* Set the LED mask to the appropriate LED mask based on the given status code */
 342         switch (CurrentStatus)
 343         {
 344                 case Status_USBNotReady:
 345                         LEDMask = (LEDS_LED1);
 346                         break;
 347                 case Status_USBEnumerating:
 348                         LEDMask = (LEDS_LED1 | LEDS_LED2);
 349                         break;
 350                 case Status_USBReady:
 351                         LEDMask = (LEDS_LED2 | LEDS_LED4);
 352                         break;
 353         }
 354
 355         /* Set the board LEDs to the new LED mask */
 356         LEDs_SetAllLEDs(LEDMask);
 357 }
 358
 359 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 360 void ReconfigureUSART(void)
 361 {
 362         uint8_t ConfigMask = 0;
 363
 364         /* Determine parity - non odd/even parity mode defaults to no parity */
 365         if (LineCoding.ParityType == Parity_Odd)
 366           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 367         else if (LineCoding.ParityType == Parity_Even)
 368           ConfigMask = (1 << UPM11);
 369
 370         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 371         if (LineCoding.CharFormat == TwoStopBits)
 372           ConfigMask |= (1 << USBS1);
 373
 374         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 375         if (LineCoding.DataBits == 6)
 376           ConfigMask |= (1 << UCSZ10);
 377         else if (LineCoding.DataBits == 7)
 378           ConfigMask |= (1 << UCSZ11);
 379         else if (LineCoding.DataBits == 8)
 380           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 381
 382         /* Enable double speed, gives better error percentages at 8MHz */
 383         UCSR1A = (1 << U2X1);
 384
 385         /* Enable transmit and receive modules and interrupts */
 386         UCSR1B = ((1 << TXCIE1) | (1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 387
 388         /* Set the USART mode to the mask generated by the Line Coding options */
 389         UCSR1C = ConfigMask;
 390
 391         /* Set the USART baud rate register to the desired baud rate value */
 392         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);
 393 }