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_Device_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_Device_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_Device_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         /* Reset line encoding baud rate so that the host knows to send new values */
 142         LineEncoding.BaudRateBPS = 0;
 143 }
 144
 145 /** Event handler for the USB_UnhandledControlRequest event. This is used to catch standard and class specific
 146  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 147  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 148  */
 149 void EVENT_USB_Device_UnhandledControlRequest(void)
 150 {
 151         /* Process CDC specific control requests */
 152         switch (USB_ControlRequest.bRequest)
 153         {
 154                 case REQ_GetLineEncoding:
 155                         if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 156                         {
 157                                 /* Acknowledge the SETUP packet, ready for data transfer */
 158                                 Endpoint_ClearSETUP();
 159
 160                                 /* Write the line coding data to the control endpoint */
 161                                 Endpoint_Write_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));
 162
 163                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 164                                 Endpoint_ClearOUT();
 165                         }
 166
 167                         break;
 168                 case REQ_SetLineEncoding:
 169                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 170                         {
 171                                 /* Acknowledge the SETUP packet, ready for data transfer */
 172                                 Endpoint_ClearSETUP();
 173
 174                                 /* Read the line coding data in from the host into the global struct */
 175                                 Endpoint_Read_Control_Stream_LE(&LineEncoding, sizeof(LineEncoding));
 176
 177                                 /* Finalize the stream transfer to clear the last packet from the host */
 178                                 Endpoint_ClearIN();
 179
 180                                 /* Reconfigure the USART with the new settings */
 181                                 ReconfigureUSART();
 182                         }
 183
 184                         break;
 185                 case REQ_SetControlLineState:
 186                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 187                         {
 188                                 /* Acknowledge the SETUP packet, ready for data transfer */
 189                                 Endpoint_ClearSETUP();
 190
 191                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 192                                          lines. The mask is read in from the wValue parameter in USB_ControlRequest, and can be masked against the
 193                                                  CONTROL_LINE_OUT_* masks to determine the RTS and DTR line states using the following code:
 194                                 */
 195
 196                                 Endpoint_ClearStatusStage();
 197                         }
 198
 199                         break;
 200         }
 201 }
 202
 203 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 204 void CDC_Task(void)
 205 {
 206         /* Device must be connected and configured for the task to run */
 207         if (USB_DeviceState != DEVICE_STATE_Configured)
 208           return;
 209
 210 #if 0
 211         /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 212                          handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 213         */
 214
 215         USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 216                 {
 217                         .NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 218                         .Notification     = NOTIF_SerialState,
 219                         .wValue           = 0,
 220                         .wIndex           = 0,
 221                         .wLength          = sizeof(uint16_t),
 222                 };
 223
 224         uint16_t LineStateMask;
 225
 226         // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 227
 228         Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 229         Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 230         Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 231         Endpoint_ClearIN();
 232 #endif
 233
 234         /* Select the Serial Rx Endpoint */
 235         Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 236
 237         /* Check to see if a packet has been received from the host */
 238         if (Endpoint_IsOUTReceived())
 239         {
 240                 /* Read the bytes in from the endpoint into the buffer while space is available */
 241                 while (Endpoint_BytesInEndpoint() && (Rx_Buffer.Elements != BUFF_STATICSIZE))
 242                 {
 243                         /* Store each character from the endpoint */
 244                         Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 245                 }
 246
 247                 /* Check to see if all bytes in the current packet have been read */
 248                 if (!(Endpoint_BytesInEndpoint()))
 249                 {
 250                         /* Clear the endpoint buffer */
 251                         Endpoint_ClearOUT();
 252                 }
 253         }
 254
 255         /* Check if Rx buffer contains data - if so, send it */
 256         if (Rx_Buffer.Elements)
 257           Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 258
 259         /* Select the Serial Tx Endpoint */
 260         Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 261
 262         /* Check if the Tx buffer contains anything to be sent to the host */
 263         if ((Tx_Buffer.Elements) && LineEncoding.BaudRateBPS)
 264         {
 265                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 266                 Endpoint_WaitUntilReady();
 267
 268                 /* Write the bytes from the buffer to the endpoint while space is available */
 269                 while (Tx_Buffer.Elements && Endpoint_IsReadWriteAllowed())
 270                 {
 271                         /* Write each byte retreived from the buffer to the endpoint */
 272                         Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 273                 }
 274
 275                 /* Remember if the packet to send completely fills the endpoint */
 276                 bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 277
 278                 /* Send the data */
 279                 Endpoint_ClearIN();
 280
 281                 /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 282                  * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 283                 if (IsFull && !(Tx_Buffer.Elements))
 284                 {
 285                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 286                         Endpoint_WaitUntilReady();
 287
 288                         /* Send an empty packet to terminate the transfer */
 289                         Endpoint_ClearIN();
 290                 }
 291         }
 292 }
 293
 294 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 295  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 296  */
 297 ISR(USART1_RX_vect, ISR_BLOCK)
 298 {
 299         /* Only store received characters if the USB interface is connected */
 300         if ((USB_DeviceState != DEVICE_STATE_Configured) && LineEncoding.BaudRateBPS)
 301           Buffer_StoreElement(&Tx_Buffer, UDR1);
 302 }
 303
 304 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 305 void ReconfigureUSART(void)
 306 {
 307         uint8_t ConfigMask = 0;
 308
 309         /* Determine parity - non odd/even parity mode defaults to no parity */
 310         if (LineEncoding.ParityType == Parity_Odd)
 311           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 312         else if (LineEncoding.ParityType == Parity_Even)
 313           ConfigMask = (1 << UPM11);
 314
 315         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 316         if (LineEncoding.CharFormat == TwoStopBits)
 317           ConfigMask |= (1 << USBS1);
 318
 319         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 320         if (LineEncoding.DataBits == 6)
 321           ConfigMask |= (1 << UCSZ10);
 322         else if (LineEncoding.DataBits == 7)
 323           ConfigMask |= (1 << UCSZ11);
 324         else if (LineEncoding.DataBits == 8)
 325           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 326
 327         /* Enable double speed, gives better error percentages at 8MHz */
 328         UCSR1A = (1 << U2X1);
 329
 330         /* Enable transmit and receive modules and interrupts */
 331         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 332
 333         /* Set the USART mode to the mask generated by the Line Coding options */
 334         UCSR1C = ConfigMask;
 335
 336         /* Set the USART baud rate register to the desired baud rate value */
 337         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineEncoding.BaudRateBPS);
 338 }