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_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 (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 (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_ClearSETUP();
 205
 206                                 /* Acknowledge status stage */
 207                                 while (!(Endpoint_IsINReady()));
 208                                 Endpoint_ClearIN();
 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                 /* Check to see if a packet has been received from the host */
 248                 if (Endpoint_IsOUTReceived())
 249                 {
 250                         /* Read the bytes in from the endpoint into the buffer while space is available */
 251                         while (Endpoint_BytesInEndpoint() && (BUFF_STATICSIZE - Rx_Buffer.Elements))
 252                         {
 253                                 /* Store each character from the endpoint */
 254                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 255                         }
 256
 257                         /* Check to see if all bytes in the current packet have been read */
 258                         if (!(Endpoint_BytesInEndpoint()))
 259                         {
 260                                 /* Clear the endpoint buffer */
 261                                 Endpoint_ClearOUT();
 262                         }
 263                 }
 264
 265                 /* Check if Rx buffer contains data */
 266                 if (Rx_Buffer.Elements)
 267                 {
 268                         /* Initiate the transmission of the buffer contents if USART idle */
 269                         if (!(Transmitting))
 270                         {
 271                                 Transmitting = true;
 272                                 Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 273                         }
 274                 }
 275
 276                 /* Select the Serial Tx Endpoint */
 277                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 278
 279                 /* Check if the Tx buffer contains anything to be sent to the host */
 280                 if (Tx_Buffer.Elements)
 281                 {
 282                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 283                         while (!(Endpoint_IsReadWriteAllowed()));
 284
 285                         /* Write the bytes from the buffer to the endpoint while space is available */
 286                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 287                         {
 288                                 /* Write each byte retreived from the buffer to the endpoint */
 289                                 Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 290                         }
 291
 292                         /* Remember if the packet to send completely fills the endpoint */
 293                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 294
 295                         /* Send the data */
 296                         Endpoint_ClearIN();
 297
 298                         /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 299                          * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 300                         if (IsFull && !(Tx_Buffer.Elements))
 301                         {
 302                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 303                                 while (!(Endpoint_IsReadWriteAllowed()));
 304
 305                                 /* Send an empty packet to terminate the transfer */
 306                                 Endpoint_ClearIN();
 307                         }
 308                 }
 309         }
 310 }
 311
 312 /** ISR to handle the USART transmit complete interrupt, fired each time the USART has sent a character. This reloads the USART
 313  *  data register with the next byte from the Rx_Buffer circular buffer if a character is available, or stops the transmission if
 314  *  the buffer is currently empty.
 315  */
 316 ISR(USART1_TX_vect, ISR_BLOCK)
 317 {
 318         /* Send next character if available */
 319         if (Rx_Buffer.Elements)
 320           UDR1 = Buffer_GetElement(&Rx_Buffer);
 321         else
 322           Transmitting = false;
 323 }
 324
 325 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 326  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 327  */
 328 ISR(USART1_RX_vect, ISR_BLOCK)
 329 {
 330         /* Only store received characters if the USB interface is connected */
 331         if (USB_IsConnected)
 332         {
 333                 /* Character received, store it into the buffer */
 334                 Buffer_StoreElement(&Tx_Buffer, UDR1);
 335         }
 336 }
 337
 338 /** Function to manage status updates to the user. This is done via LEDs on the given board, if available, but may be changed to
 339  *  log to a serial port, or anything else that is suitable for status updates.
 340  *
 341  *  \param CurrentStatus  Current status of the system, from the USBtoSerial_StatusCodes_t enum
 342  */
 343 void UpdateStatus(uint8_t CurrentStatus)
 344 {
 345         uint8_t LEDMask = LEDS_NO_LEDS;
 346
 347         /* Set the LED mask to the appropriate LED mask based on the given status code */
 348         switch (CurrentStatus)
 349         {
 350                 case Status_USBNotReady:
 351                         LEDMask = (LEDS_LED1);
 352                         break;
 353                 case Status_USBEnumerating:
 354                         LEDMask = (LEDS_LED1 | LEDS_LED2);
 355                         break;
 356                 case Status_USBReady:
 357                         LEDMask = (LEDS_LED2 | LEDS_LED4);
 358                         break;
 359         }
 360
 361         /* Set the board LEDs to the new LED mask */
 362         LEDs_SetAllLEDs(LEDMask);
 363 }
 364
 365 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 366 void ReconfigureUSART(void)
 367 {
 368         uint8_t ConfigMask = 0;
 369
 370         /* Determine parity - non odd/even parity mode defaults to no parity */
 371         if (LineCoding.ParityType == Parity_Odd)
 372           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 373         else if (LineCoding.ParityType == Parity_Even)
 374           ConfigMask = (1 << UPM11);
 375
 376         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 377         if (LineCoding.CharFormat == TwoStopBits)
 378           ConfigMask |= (1 << USBS1);
 379
 380         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 381         if (LineCoding.DataBits == 6)
 382           ConfigMask |= (1 << UCSZ10);
 383         else if (LineCoding.DataBits == 7)
 384           ConfigMask |= (1 << UCSZ11);
 385         else if (LineCoding.DataBits == 8)
 386           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 387
 388         /* Enable double speed, gives better error percentages at 8MHz */
 389         UCSR1A = (1 << U2X1);
 390
 391         /* Enable transmit and receive modules and interrupts */
 392         UCSR1B = ((1 << TXCIE1) | (1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 393
 394         /* Set the USART mode to the mask generated by the Line Coding options */
 395         UCSR1C = ConfigMask;
 396
 397         /* Set the USART baud rate register to the desired baud rate value */
 398         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);
 399 }