Demos/Device/LowLevel/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 /* Globals: */
  34 /** Contains the current baud rate and other settings of the virtual serial port.
  35  *
  36  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the
  37  *  new settings each time they are changed by the host.
  38  */
  39 CDC_Line_Coding_t LineEncoding = { .BaudRateBPS = 0,
  40                                    .CharFormat  = OneStopBit,
  41                                    .ParityType  = Parity_None,
  42                                    .DataBits    = 8            };
  43
  44 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */
  45 RingBuff_t Rx_Buffer;
  46
  47 /** Ring (circular) buffer to hold the TX data - data from the attached device on the serial port to the host. */
  48 RingBuff_t Tx_Buffer;
  49
  50 /** Flag to indicate if the USART is currently transmitting data from the Rx_Buffer circular buffer. */
  51 volatile bool Transmitting = false;
  52
  53 /** Main program entry point. This routine configures the hardware required by the application, then
  54  *  starts the scheduler to run the application tasks.
  55  */
  56 int main(void)
  57 {
  58         SetupHardware();
  59
  60         /* Ring buffer Initialization */
  61         Buffer_Initialize(&Rx_Buffer);
  62         Buffer_Initialize(&Tx_Buffer);
  63
  64         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  65
  66         for (;;)
  67         {
  68                 CDC_Task();
  69                 USB_USBTask();
  70         }
  71 }
  72
  73 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  74 void SetupHardware(void)
  75 {
  76         /* Disable watchdog if enabled by bootloader/fuses */
  77         MCUSR &= ~(1 << WDRF);
  78         wdt_disable();
  79
  80         /* Disable clock division */
  81         clock_prescale_set(clock_div_1);
  82
  83         /* Hardware Initialization */
  84         LEDs_Init();
  85         ReconfigureUSART();
  86         USB_Init();
  87 }
  88
  89 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs and
  90  *  starts the library USB task to begin the enumeration and USB management process.
  91  */
  92 void EVENT_USB_Connect(void)
  93 {
  94         /* Indicate USB enumerating */
  95         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
  96 }
  97
  98 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
  99  *  the status LEDs and stops the USB management and CDC management tasks.
 100  */
 101 void EVENT_USB_Disconnect(void)
 102 {
 103         /* Reset Tx and Rx buffers, device disconnected */
 104         Buffer_Initialize(&Rx_Buffer);
 105         Buffer_Initialize(&Tx_Buffer);
 106
 107         /* Indicate USB not ready */
 108         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 109 }
 110
 111 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 112  *  of the USB device after enumeration - the device endpoints are configured and the CDC management task started.
 113  */
 114 void EVENT_USB_ConfigurationChanged(void)
 115 {
 116         /* Indicate USB connected and ready */
 117         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 118
 119         /* Setup CDC Notification, Rx and Tx Endpoints */
 120         if (!(Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
 121                                              ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
 122                                          ENDPOINT_BANK_SINGLE)))
 123         {
 124                 LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 125         }
 126
 127         if (!(Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
 128                                              ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
 129                                          ENDPOINT_BANK_SINGLE)))
 130         {
 131                 LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 132         }
 133
 134         if (!(Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
 135                                              ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
 136                                          ENDPOINT_BANK_SINGLE)))
 137         {
 138                 LEDs_SetAllLEDs(LEDMASK_USB_ERROR);
 139         }
 140 }
 141
 142 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 143  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 144  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 145  */
 146 void EVENT_USB_UnhandledControlPacket(void)
 147 {
 148         /* Process CDC specific control requests */
 149         switch (USB_ControlRequest.bRequest)
 150         {
 151                 case REQ_GetLineEncoding:
 152                         if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 153                         {
 154                                 /* Acknowledge the SETUP packet, ready for data transfer */
 155                                 Endpoint_ClearSETUP();
 156
 157                                 /* Write the line coding data to the control endpoint */
 158                                 Endpoint_Write_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));
 159
 160                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 161                                 Endpoint_ClearOUT();
 162                         }
 163
 164                         break;
 165                 case REQ_SetLineEncoding:
 166                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 167                         {
 168                                 /* Acknowledge the SETUP packet, ready for data transfer */
 169                                 Endpoint_ClearSETUP();
 170
 171                                 /* Read the line coding data in from the host into the global struct */
 172                                 Endpoint_Read_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));
 173
 174                                 /* Finalize the stream transfer to clear the last packet from the host */
 175                                 Endpoint_ClearIN();
 176
 177                                 /* Reconfigure the USART with the new settings */
 178                                 ReconfigureUSART();
 179                         }
 180
 181                         break;
 182                 case REQ_SetControlLineState:
 183                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 184                         {
 185                                 /* Acknowledge the SETUP packet, ready for data transfer */
 186                                 Endpoint_ClearSETUP();
 187
 188                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 189                                          lines. The mask is read in from the wValue parameter in USB_ControlRequest, and can be masked against the
 190                                                  CONTROL_LINE_OUT_* masks to determine the RTS and DTR line states using the following code:
 191                                 */
 192
 193                                 Endpoint_ClearStatusStage();
 194                         }
 195
 196                         break;
 197         }
 198 }
 199
 200 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 201 void CDC_Task(void)
 202 {
 203         /* Device must be connected and configured for the task to run */
 204         if (USB_DeviceState != DEVICE_STATE_Configured)
 205           return;
 206
 207 #if 0
 208         /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 209                          handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 210         */
 211
 212         USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 213                 {
 214                         .NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 215                         .Notification     = NOTIF_SerialState,
 216                         .wValue           = 0,
 217                         .wIndex           = 0,
 218                         .wLength          = sizeof(uint16_t),
 219                 };
 220
 221         uint16_t LineStateMask;
 222
 223         // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 224
 225         Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 226         Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 227         Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 228         Endpoint_ClearIN();
 229 #endif
 230
 231         /* Select the Serial Rx Endpoint */
 232         Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 233
 234         /* Check to see if a packet has been received from the host */
 235         if (Endpoint_IsOUTReceived())
 236         {
 237                 /* Read the bytes in from the endpoint into the buffer while space is available */
 238                 while (Endpoint_BytesInEndpoint() && (Rx_Buffer.Elements != BUFF_STATICSIZE))
 239                 {
 240                         /* Store each character from the endpoint */
 241                         Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 242                 }
 243
 244                 /* Check to see if all bytes in the current packet have been read */
 245                 if (!(Endpoint_BytesInEndpoint()))
 246                 {
 247                         /* Clear the endpoint buffer */
 248                         Endpoint_ClearOUT();
 249                 }
 250         }
 251
 252         /* Check if Rx buffer contains data - if so, send it */
 253         if (Rx_Buffer.Elements)
 254           Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 255
 256         /* Select the Serial Tx Endpoint */
 257         Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 258
 259         /* Check if the Tx buffer contains anything to be sent to the host */
 260         if ((Tx_Buffer.Elements) && LineEncoding.BaudRateBPS)
 261         {
 262                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 263                 while (!(Endpoint_IsReadWriteAllowed()))
 264                 {
 265                         if (USB_DeviceState == DEVICE_STATE_Unattached)
 266                           return;
 267                 }
 268
 269                 /* Write the bytes from the buffer to the endpoint while space is available */
 270                 while (Tx_Buffer.Elements && Endpoint_IsReadWriteAllowed())
 271                 {
 272                         /* Write each byte retreived from the buffer to the endpoint */
 273                         Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 274                 }
 275
 276                 /* Remember if the packet to send completely fills the endpoint */
 277                 bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 278
 279                 /* Send the data */
 280                 Endpoint_ClearIN();
 281
 282                 /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 283                  * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 284                 if (IsFull && !(Tx_Buffer.Elements))
 285                 {
 286                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 287                         while (!(Endpoint_IsReadWriteAllowed()))
 288                         {
 289                                 if (USB_DeviceState == DEVICE_STATE_Unattached)
 290                                   return;
 291                         }
 292
 293                         /* Send an empty packet to terminate the transfer */
 294                         Endpoint_ClearIN();
 295                 }
 296         }
 297 }
 298
 299 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 300  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 301  */
 302 ISR(USART1_RX_vect, ISR_BLOCK)
 303 {
 304         /* Only store received characters if the USB interface is connected */
 305         if ((USB_DeviceState != DEVICE_STATE_Configured) && LineEncoding.BaudRateBPS)
 306           Buffer_StoreElement(&Tx_Buffer, UDR1);
 307 }
 308
 309 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 310 void ReconfigureUSART(void)
 311 {
 312         uint8_t ConfigMask = 0;
 313
 314         /* Determine parity - non odd/even parity mode defaults to no parity */
 315         if (LineEncoding.ParityType == Parity_Odd)
 316           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 317         else if (LineEncoding.ParityType == Parity_Even)
 318           ConfigMask = (1 << UPM11);
 319
 320         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 321         if (LineEncoding.CharFormat == TwoStopBits)
 322           ConfigMask |= (1 << USBS1);
 323
 324         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 325         if (LineEncoding.DataBits == 6)
 326           ConfigMask |= (1 << UCSZ10);
 327         else if (LineEncoding.DataBits == 7)
 328           ConfigMask |= (1 << UCSZ11);
 329         else if (LineEncoding.DataBits == 8)
 330           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 331
 332         /* Enable double speed, gives better error percentages at 8MHz */
 333         UCSR1A = (1 << U2X1);
 334
 335         /* Enable transmit and receive modules and interrupts */
 336         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 337
 338         /* Set the USART mode to the mask generated by the Line Coding options */
 339         UCSR1C = ConfigMask;
 340
 341         /* Set the USART baud rate register to the desired baud rate value */
 342         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineEncoding.BaudRateBPS);
 343 }