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 EVENT_HANDLER(USB_Connect)
  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 EVENT_HANDLER(USB_Disconnect)
 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 EVENT_HANDLER(USB_ConfigurationChanged)
 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 EVENT_HANDLER(USB_UnhandledControlPacket)
 152 {
 153         uint8_t* LineCodingData = (uint8_t*)&LineCoding;
 154
 155         /* Process CDC specific control requests */
 156         switch (bRequest)
 157         {
 158                 case REQ_GetLineEncoding:
 159                         if (bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 160                         {
 161                                 /* Acknowledge the SETUP packet, ready for data transfer */
 162                                 Endpoint_ClearControlSETUP();
 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_ClearControlOUT();
 169                         }
 170
 171                         break;
 172                 case REQ_SetLineEncoding:
 173                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 174                         {
 175                                 /* Acknowledge the SETUP packet, ready for data transfer */
 176                                 Endpoint_ClearControlSETUP();
 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_ClearControlIN();
 183
 184                                 /* Reconfigure the USART with the new settings */
 185                                 ReconfigureUSART();
 186                         }
 187
 188                         break;
 189                 case REQ_SetControlLineState:
 190                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 191                         {
 192 #if 0
 193                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 194                                          lines. The mask is read in from the wValue parameter, and can be masked against the CONTROL_LINE_OUT_* masks
 195                                          to determine the RTS and DTR line states using the following code:
 196                                 */
 197
 198                                 uint16_t wIndex = Endpoint_Read_Word_LE();
 199
 200                                 // Do something with the given line states in wIndex
 201 #endif
 202
 203                                 /* Acknowledge the SETUP packet, ready for data transfer */
 204                                 Endpoint_ClearControlSETUP();
 205
 206                                 /* Acknowledge status stage */
 207                                 while (!(Endpoint_IsINReady()));
 208                                 Endpoint_ClearControlIN();
 209                         }
 210
 211                         break;
 212         }
 213 }
 214
 215 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 216 TASK(CDC_Task)
 217 {
 218         if (USB_IsConnected)
 219         {
 220 #if 0
 221                 /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 222                                  handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 223                 */
 224
 225                 USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 226                         {
 227                                 NotificationType: (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 228                                 Notification:     NOTIF_SerialState,
 229                                 wValue:           0,
 230                                 wIndex:           0,
 231                                 wLength:          sizeof(uint16_t),
 232                         };
 233
 234                 uint16_t LineStateMask;
 235
 236                 // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 237
 238                 Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 239                 Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 240                 Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 241                 Endpoint_ClearIN();
 242 #endif
 243
 244                 /* Select the Serial Rx Endpoint */
 245                 Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 246
 247                 if (Endpoint_IsOUTReceived())
 248                 {
 249                         /* Read the bytes in from the endpoint into the buffer while space is available */
 250                         while (Endpoint_BytesInEndpoint() && (BUFF_STATICSIZE - Rx_Buffer.Elements))
 251                         {
 252                                 /* Store each character from the endpoint */
 253                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 254                         }
 255
 256                         /* Check to see if all bytes in the current packet have been read */
 257                         if (!(Endpoint_BytesInEndpoint()))
 258                         {
 259                                 /* Clear the endpoint buffer */
 260                                 Endpoint_ClearOUT();
 261                         }
 262                 }
 263
 264                 /* Check if Rx buffer contains data */
 265                 if (Rx_Buffer.Elements)
 266                 {
 267                         /* Initiate the transmission of the buffer contents if USART idle */
 268                         if (!(Transmitting))
 269                         {
 270                                 Transmitting = true;
 271                                 Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 272                         }
 273                 }
 274
 275                 /* Select the Serial Tx Endpoint */
 276                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 277
 278                 /* Check if the Tx buffer contains anything to be sent to the host */
 279                 if (Tx_Buffer.Elements)
 280                 {
 281                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 282                         while (!(Endpoint_IsReadWriteAllowed()));
 283
 284                         /* Write the bytes from the buffer to the endpoint while space is available */
 285                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 286                         {
 287                                 /* Write each byte retreived from the buffer to the endpoint */
 288                                 Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 289                         }
 290
 291                         /* Remember if the packet to send completely fills the endpoint */
 292                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 293
 294                         /* Send the data */
 295                         Endpoint_ClearIN();
 296
 297                         /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 298                          * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 299                         if (IsFull && !(Tx_Buffer.Elements))
 300                         {
 301                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 302                                 while (!(Endpoint_IsReadWriteAllowed()));
 303
 304                                 /* Send an empty packet to terminate the transfer */
 305                                 Endpoint_ClearIN();
 306                         }
 307                 }
 308         }
 309 }
 310
 311 /** ISR to handle the USART transmit complete interrupt, fired each time the USART has sent a character. This reloads the USART
 312  *  data register with the next byte from the Rx_Buffer circular buffer if a character is available, or stops the transmission if
 313  *  the buffer is currently empty.
 314  */
 315 ISR(USART1_TX_vect, ISR_BLOCK)
 316 {
 317         /* Send next character if available */
 318         if (Rx_Buffer.Elements)
 319           UDR1 = Buffer_GetElement(&Rx_Buffer);
 320         else
 321           Transmitting = false;
 322 }
 323
 324 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 325  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 326  */
 327 ISR(USART1_RX_vect, ISR_BLOCK)
 328 {
 329         /* Only store received characters if the USB interface is connected */
 330         if (USB_IsConnected)
 331         {
 332                 /* Character received, store it into the buffer */
 333                 Buffer_StoreElement(&Tx_Buffer, UDR1);
 334         }
 335 }
 336
 337 /** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 338  *  log to a serial port, or anything else that is suitable for status updates.
 339  *
 340  *  \param CurrentStatus  Current status of the system, from the USBtoSerial_StatusCodes_t enum
 341  */
 342 void UpdateStatus(uint8_t CurrentStatus)
 343 {
 344         uint8_t LEDMask = LEDS_NO_LEDS;
 345
 346         /* Set the LED mask to the appropriate LED mask based on the given status code */
 347         switch (CurrentStatus)
 348         {
 349                 case Status_USBNotReady:
 350                         LEDMask = (LEDS_LED1);
 351                         break;
 352                 case Status_USBEnumerating:
 353                         LEDMask = (LEDS_LED1 | LEDS_LED2);
 354                         break;
 355                 case Status_USBReady:
 356                         LEDMask = (LEDS_LED2 | LEDS_LED4);
 357                         break;
 358         }
 359
 360         /* Set the board LEDs to the new LED mask */
 361         LEDs_SetAllLEDs(LEDMask);
 362 }
 363
 364 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 365 void ReconfigureUSART(void)
 366 {
 367         uint8_t ConfigMask = 0;
 368
 369         /* Determine parity - non odd/even parity mode defaults to no parity */
 370         if (LineCoding.ParityType == Parity_Odd)
 371           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 372         else if (LineCoding.ParityType == Parity_Even)
 373           ConfigMask = (1 << UPM11);
 374
 375         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 376         if (LineCoding.CharFormat == TwoStopBits)
 377           ConfigMask |= (1 << USBS1);
 378
 379         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 380         if (LineCoding.DataBits == 6)
 381           ConfigMask |= (1 << UCSZ10);
 382         else if (LineCoding.DataBits == 7)
 383           ConfigMask |= (1 << UCSZ11);
 384         else if (LineCoding.DataBits == 8)
 385           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 386
 387         /* Enable double speed, gives better error percentages at 8MHz */
 388         UCSR1A = (1 << U2X1);
 389
 390         /* Enable transmit and receive modules and interrupts */
 391         UCSR1B = ((1 << TXCIE1) | (1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 392
 393         /* Set the USART mode to the mask generated by the Line Coding options */
 394         UCSR1C = ConfigMask;
 395
 396         /* Set the USART baud rate register to the desired baud rate value */
 397         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);
 398 }