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 /* Project Tags, for reading out using the ButtLoad project */
  34 BUTTLOADTAG(ProjName,    "LUFA USB RS232 App");
  35 BUTTLOADTAG(BuildTime,   __TIME__);
  36 BUTTLOADTAG(BuildDate,   __DATE__);
  37 BUTTLOADTAG(LUFAVersion, "LUFA V" LUFA_VERSION_STRING);
  38
  39 /* Scheduler Task List */
  40 TASK_LIST
  41 {
  42         { Task: USB_USBTask          , TaskStatus: TASK_STOP },
  43         { Task: CDC_Task             , TaskStatus: TASK_STOP },
  44 };
  45
  46 /* Globals: */
  47 /** Contains the current baud rate and other settings of the virtual serial port.
  48  *
  49  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the
  50  *  new settings each time they are changed by the host.
  51  */
  52 CDC_Line_Coding_t LineCoding = { BaudRateBPS: 9600,
  53                                  CharFormat:  OneStopBit,
  54                                  ParityType:  Parity_None,
  55                                  DataBits:    8            };
  56
  57 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */
  58 RingBuff_t Rx_Buffer;
  59
  60 /** Ring (circular) buffer to hold the TX data - data from the attached device on the serial port to the host. */
  61 RingBuff_t Tx_Buffer;
  62
  63 /** Flag to indicate if the USART is currently transmitting data from the Rx_Buffer circular buffer. */
  64 volatile bool Transmitting = false;
  65
  66 /** Main program entry point. This routine configures the hardware required by the application, then
  67  *  starts the scheduler to run the application tasks.
  68  */
  69 int main(void)
  70 {
  71         /* Disable watchdog if enabled by bootloader/fuses */
  72         MCUSR &= ~(1 << WDRF);
  73         wdt_disable();
  74
  75         /* Disable clock division */
  76         clock_prescale_set(clock_div_1);
  77
  78         /* Hardware Initialization */
  79         LEDs_Init();
  80         ReconfigureUSART();
  81
  82         /* Ringbuffer Initialization */
  83         Buffer_Initialize(&Rx_Buffer);
  84         Buffer_Initialize(&Tx_Buffer);
  85
  86         /* Indicate USB not ready */
  87         UpdateStatus(Status_USBNotReady);
  88
  89         /* Initialize Scheduler so that it can be used */
  90         Scheduler_Init();
  91
  92         /* Initialize USB Subsystem */
  93         USB_Init();
  94
  95         /* Scheduling - routine never returns, so put this last in the main function */
  96         Scheduler_Start();
  97 }
  98
  99 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs and
 100  *  starts the library USB task to begin the enumeration and USB management process.
 101  */
 102 EVENT_HANDLER(USB_Connect)
 103 {
 104         /* Start USB management task */
 105         Scheduler_SetTaskMode(USB_USBTask, TASK_RUN);
 106
 107         /* Indicate USB enumerating */
 108         UpdateStatus(Status_USBEnumerating);
 109 }
 110
 111 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
 112  *  the status LEDs and stops the USB management and CDC management tasks.
 113  */
 114 EVENT_HANDLER(USB_Disconnect)
 115 {
 116         /* Stop running CDC and USB management tasks */
 117         Scheduler_SetTaskMode(CDC_Task, TASK_STOP);
 118         Scheduler_SetTaskMode(USB_USBTask, TASK_STOP);
 119
 120         /* Reset Tx and Rx buffers, device disconnected */
 121         Buffer_Initialize(&Rx_Buffer);
 122         Buffer_Initialize(&Tx_Buffer);
 123
 124         /* Indicate USB not ready */
 125         UpdateStatus(Status_USBNotReady);
 126 }
 127
 128 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 129  *  of the USB device after enumeration - the device endpoints are configured and the CDC management task started.
 130  */
 131 EVENT_HANDLER(USB_ConfigurationChanged)
 132 {
 133         /* Setup CDC Notification, Rx and Tx Endpoints */
 134         Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
 135                                        ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
 136                                    ENDPOINT_BANK_SINGLE);
 137
 138         Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
 139                                        ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
 140                                    ENDPOINT_BANK_SINGLE);
 141
 142         Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
 143                                        ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
 144                                    ENDPOINT_BANK_SINGLE);
 145
 146         /* Indicate USB connected and ready */
 147         UpdateStatus(Status_USBReady);
 148
 149         /* Start CDC task */
 150         Scheduler_SetTaskMode(CDC_Task, TASK_RUN);
 151 }
 152
 153 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 154  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 155  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 156  */
 157 EVENT_HANDLER(USB_UnhandledControlPacket)
 158 {
 159         uint8_t* LineCodingData = (uint8_t*)&LineCoding;
 160
 161         /* Process CDC specific control requests */
 162         switch (bRequest)
 163         {
 164                 case REQ_GetLineEncoding:
 165                         if (bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 166                         {
 167                                 /* Acknowledge the SETUP packet, ready for data transfer */
 168                                 Endpoint_ClearSetupReceived();
 169
 170                                 /* Write the line coding data to the control endpoint */
 171                                 Endpoint_Write_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 172
 173                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 174                                 Endpoint_ClearSetupOUT();
 175                         }
 176
 177                         break;
 178                 case REQ_SetLineEncoding:
 179                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 180                         {
 181                                 /* Acknowledge the SETUP packet, ready for data transfer */
 182                                 Endpoint_ClearSetupReceived();
 183
 184                                 /* Read the line coding data in from the host into the global struct */
 185                                 Endpoint_Read_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 186
 187                                 /* Finalize the stream transfer to clear the last packet from the host */
 188                                 Endpoint_ClearSetupIN();
 189
 190                                 /* Reconfigure the USART with the new settings */
 191                                 ReconfigureUSART();
 192                         }
 193
 194                         break;
 195                 case REQ_SetControlLineState:
 196                         if (bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 197                         {
 198 #if 0
 199                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 200                                          lines. The mask is read in from the wValue parameter, and can be masked against the CONTROL_LINE_OUT_* masks
 201                                          to determine the RTS and DTR line states using the following code:
 202                                 */
 203
 204                                 uint16_t wIndex = Endpoint_Read_Word_LE();
 205
 206                                 // Do something with the given line states in wIndex
 207 #endif
 208
 209                                 /* Acknowledge the SETUP packet, ready for data transfer */
 210                                 Endpoint_ClearSetupReceived();
 211
 212                                 /* Acknowledge status stage */
 213                                 while (!(Endpoint_IsSetupINReady()));
 214                                 Endpoint_ClearSetupIN();
 215                         }
 216
 217                         break;
 218         }
 219 }
 220
 221 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 222 TASK(CDC_Task)
 223 {
 224         if (USB_IsConnected)
 225         {
 226 #if 0
 227                 /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 228                                  handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 229                 */
 230
 231                 USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 232                         {
 233                                 NotificationType: (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 234                                 Notification:     NOTIF_SerialState,
 235                                 wValue:           0,
 236                                 wIndex:           0,
 237                                 wLength:          sizeof(uint16_t),
 238                         };
 239
 240                 uint16_t LineStateMask;
 241
 242                 // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 243
 244                 Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 245                 Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 246                 Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 247                 Endpoint_ClearCurrentBank();
 248 #endif
 249
 250                 /* Select the Serial Rx Endpoint */
 251                 Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 252
 253                 if (Endpoint_ReadWriteAllowed())
 254                 {
 255                         /* Read the received data endpoint into the transmission buffer */
 256                         while (Endpoint_BytesInEndpoint())
 257                         {
 258                                 /* Wait until the buffer has space for a new character */
 259                                 while (!((BUFF_STATICSIZE - Rx_Buffer.Elements)));
 260
 261                                 /* Store each character from the endpoint */
 262                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 263                         }
 264
 265                         /* Clear the endpoint buffer */
 266                         Endpoint_ClearCurrentBank();
 267                 }
 268
 269                 /* Check if Rx buffer contains data */
 270                 if (Rx_Buffer.Elements)
 271                 {
 272                         /* Initiate the transmission of the buffer contents if USART idle */
 273                         if (!(Transmitting))
 274                         {
 275                                 Transmitting = true;
 276                                 Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 277                         }
 278                 }
 279
 280                 /* Select the Serial Tx Endpoint */
 281                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 282
 283                 /* Check if the Tx buffer contains anything to be sent to the host */
 284                 if (Tx_Buffer.Elements)
 285                 {
 286                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 287                         while (!(Endpoint_ReadWriteAllowed()));
 288
 289                         /* Check before sending the data if the endpoint is completely full */
 290                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 291
 292                         /* Write the transmission buffer contents to the received data endpoint */
 293                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 294                           Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 295
 296                         /* Send the data */
 297                         Endpoint_ClearCurrentBank();
 298
 299                         /* If a full endpoint was sent, we need to send an empty packet afterwards to terminate the transfer */
 300                         if (IsFull)
 301                         {
 302                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 303                                 while (!(Endpoint_ReadWriteAllowed()));
 304
 305                                 /* Send an empty packet to terminate the transfer */
 306                                 Endpoint_ClearCurrentBank();
 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 }