git.rot13.org Git - simavr/blob - examples/board_usb/at90usb162_cdc_loopback.c

   1 /* vim: set sts=4:sw=4:ts=4:noexpandtab
   2  *
   3  * USB Serial Example for Teensy USB Development Board
   4  * http://www.pjrc.com/teensy/usb_serial.html
   5  * Copyright (c) 2008,2010,2011 PJRC.COM, LLC
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 // Version 1.0: Initial Release
  27 // Version 1.1: support Teensy++
  28 // Version 1.2: fixed usb_serial_available
  29 // Version 1.3: added transmit bandwidth test
  30 // Version 1.4: added usb_serial_write
  31 // Version 1.5: add support for Teensy 2.0
  32 // Version 1.6: fix zero length packet bug
  33 // Version 1.7: fix usb_serial_set_control
  34
  35 #define USB_SERIAL_PRIVATE_INCLUDE
  36 #include "at90usb162_cdc_loopback.h"
  37
  38 /**************************************************************************
  39  *
  40  *  Configurable Options
  41  *
  42  **************************************************************************/
  43
  44 // You can change these to give your code its own name.  On Windows,
  45 // these are only used before an INF file (driver install) is loaded.
  46 #define STR_MANUFACTURER        L"Your Name"
  47 #define STR_PRODUCT             L"USB Serial"
  48
  49 // All USB serial devices are supposed to have a serial number
  50 // (according to Microsoft).  On windows, a new COM port is created
  51 // for every unique serial/vendor/product number combination.  If
  52 // you program 2 identical boards with 2 different serial numbers
  53 // and they are assigned COM7 and COM8, each will always get the
  54 // same COM port number because Windows remembers serial numbers.
  55 //
  56 // On Mac OS-X, a device file is created automatically which
  57 // incorperates the serial number, eg, /dev/cu-usbmodem12341
  58 //
  59 // Linux by default ignores the serial number, and creates device
  60 // files named /dev/ttyACM0, /dev/ttyACM1... in the order connected.
  61 // Udev rules (in /etc/udev/rules.d) can define persistent device
  62 // names linked to this serial number, as well as permissions, owner
  63 // and group settings.
  64 #define STR_SERIAL_NUMBER       L"12345"
  65
  66 // Mac OS-X and Linux automatically load the correct drivers.  On
  67 // Windows, even though the driver is supplied by Microsoft, an
  68 // INF file is needed to load the driver.  These numbers need to
  69 // match the INF file.
  70 #define VENDOR_ID               0x16C0
  71 #define PRODUCT_ID              0x047A
  72
  73 // When you write data, it goes into a USB endpoint buffer, which
  74 // is transmitted to the PC when it becomes full, or after a timeout
  75 // with no more writes.  Even if you write in exactly packet-size
  76 // increments, this timeout is used to send a "zero length packet"
  77 // that tells the PC no more data is expected and it should pass
  78 // any buffered data to the application that may be waiting.  If
  79 // you want data sent immediately, call usb_serial_flush_output().
  80 #define TRANSMIT_FLUSH_TIMEOUT  5   /* in milliseconds */
  81
  82 // If the PC is connected but not "listening", this is the length
  83 // of time before usb_serial_getchar() returns with an error.  This
  84 // is roughly equivilant to a real UART simply transmitting the
  85 // bits on a wire where nobody is listening, except you get an error
  86 // code which you can ignore for serial-like discard of data, or
  87 // use to know your data wasn't sent.
  88 #define TRANSMIT_TIMEOUT        25   /* in milliseconds */
  89
  90 // USB devices are supposed to implment a halt feature, which is
  91 // rarely (if ever) used.  If you comment this line out, the halt
  92 // code will be removed, saving 116 bytes of space (gcc 4.3.0).
  93 // This is not strictly USB compliant, but works with all major
  94 // operating systems.
  95 #define SUPPORT_ENDPOINT_HALT
  96
  97
  98
  99 /**************************************************************************
 100  *
 101  *  Endpoint Buffer Configuration
 102  *
 103  **************************************************************************/
 104
 105 // These buffer sizes are best for most applications, but perhaps if you
 106 // want more buffering on some endpoint at the expense of others, this
 107 // is where you can make such changes.  The AT90USB162 has only 176 bytes
 108 // of DPRAM (USB buffers) and only endpoints 3 & 4 can double buffer.
 109
 110 #define ENDPOINT0_SIZE          16
 111 #define CDC_ACM_ENDPOINT        2
 112 #define CDC_RX_ENDPOINT         3
 113 #define CDC_TX_ENDPOINT         4
 114 #if defined(__AVR_AT90USB162__)
 115 #define CDC_ACM_SIZE            16
 116 #define CDC_ACM_BUFFER          EP_SINGLE_BUFFER
 117 #define CDC_RX_SIZE             32
 118 #define CDC_RX_BUFFER           EP_DOUBLE_BUFFER
 119 #define CDC_TX_SIZE             32
 120 #define CDC_TX_BUFFER           EP_DOUBLE_BUFFER
 121 #else
 122 #define CDC_ACM_SIZE            16
 123 #define CDC_ACM_BUFFER          EP_SINGLE_BUFFER
 124 #define CDC_RX_SIZE             64
 125 #define CDC_RX_BUFFER           EP_DOUBLE_BUFFER
 126 #define CDC_TX_SIZE             64
 127 #define CDC_TX_BUFFER           EP_DOUBLE_BUFFER
 128 #endif
 129
 130 static const uint8_t PROGMEM endpoint_config_table[] = {
 131         0,
 132         1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(CDC_ACM_SIZE) | CDC_ACM_BUFFER,
 133         1, EP_TYPE_BULK_OUT,      EP_SIZE(CDC_RX_SIZE) | CDC_RX_BUFFER,
 134         1, EP_TYPE_BULK_IN,       EP_SIZE(CDC_TX_SIZE) | CDC_TX_BUFFER
 135 };
 136
 137
 138 /**************************************************************************
 139  *
 140  *  Descriptor Data
 141  *
 142  **************************************************************************/
 143
 144 // Descriptors are the data that your computer reads when it auto-detects
 145 // this USB device (called "enumeration" in USB lingo).  The most commonly
 146 // changed items are editable at the top of this file.  Changing things
 147 // in here should only be done by those who've read chapter 9 of the USB
 148 // spec and relevant portions of any USB class specifications!
 149
 150 static uint8_t PROGMEM device_descriptor[] = {
 151         18,                                     // bLength
 152         1,                                      // bDescriptorType
 153         0x00, 0x02,                             // bcdUSB
 154         2,                                      // bDeviceClass
 155         0,                                      // bDeviceSubClass
 156         0,                                      // bDeviceProtocol
 157         ENDPOINT0_SIZE,                         // bMaxPacketSize0
 158         LSB(VENDOR_ID), MSB(VENDOR_ID),         // idVendor
 159         LSB(PRODUCT_ID), MSB(PRODUCT_ID),       // idProduct
 160         0x00, 0x01,                             // bcdDevice
 161         1,                                      // iManufacturer
 162         2,                                      // iProduct
 163         3,                                      // iSerialNumber
 164         1                                       // bNumConfigurations
 165 };
 166
 167 #define CONFIG1_DESC_SIZE (9+9+5+5+4+5+7+9+7+7)
 168 static uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
 169         // configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
 170         9,                                      // bLength;
 171         2,                                      // bDescriptorType;
 172         LSB(CONFIG1_DESC_SIZE),                 // wTotalLength
 173         MSB(CONFIG1_DESC_SIZE),
 174         2,                                      // bNumInterfaces
 175         1,                                      // bConfigurationValue
 176         0,                                      // iConfiguration
 177         0xC0,                                   // bmAttributes
 178         50,                                     // bMaxPower
 179         // interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
 180         9,                                      // bLength
 181         4,                                      // bDescriptorType
 182         0,                                      // bInterfaceNumber
 183         0,                                      // bAlternateSetting
 184         1,                                      // bNumEndpoints
 185         0x02,                                   // bInterfaceClass
 186         0x02,                                   // bInterfaceSubClass
 187         0x01,                                   // bInterfaceProtocol
 188         0,                                      // iInterface
 189         // CDC Header Functional Descriptor, CDC Spec 5.2.3.1, Table 26
 190         5,                                      // bFunctionLength
 191         0x24,                                   // bDescriptorType
 192         0x00,                                   // bDescriptorSubtype
 193         0x10, 0x01,                             // bcdCDC
 194         // Call Management Functional Descriptor, CDC Spec 5.2.3.2, Table 27
 195         5,                                      // bFunctionLength
 196         0x24,                                   // bDescriptorType
 197         0x01,                                   // bDescriptorSubtype
 198         0x01,                                   // bmCapabilities
 199         1,                                      // bDataInterface
 200         // Abstract Control Management Functional Descriptor, CDC Spec 5.2.3.3, Table 28
 201         4,                                      // bFunctionLength
 202         0x24,                                   // bDescriptorType
 203         0x02,                                   // bDescriptorSubtype
 204         0x06,                                   // bmCapabilities
 205         // Union Functional Descriptor, CDC Spec 5.2.3.8, Table 33
 206         5,                                      // bFunctionLength
 207         0x24,                                   // bDescriptorType
 208         0x06,                                   // bDescriptorSubtype
 209         0,                                      // bMasterInterface
 210         1,                                      // bSlaveInterface0
 211         // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
 212         7,                                      // bLength
 213         5,                                      // bDescriptorType
 214         CDC_ACM_ENDPOINT | 0x80,                // bEndpointAddress
 215         0x03,                                   // bmAttributes (0x03=intr)
 216         CDC_ACM_SIZE, 0,                        // wMaxPacketSize
 217         64,                                     // bInterval
 218         // interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
 219         9,                                      // bLength
 220         4,                                      // bDescriptorType
 221         1,                                      // bInterfaceNumber
 222         0,                                      // bAlternateSetting
 223         2,                                      // bNumEndpoints
 224         0x0A,                                   // bInterfaceClass
 225         0x00,                                   // bInterfaceSubClass
 226         0x00,                                   // bInterfaceProtocol
 227         0,                                      // iInterface
 228         // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
 229         7,                                      // bLength
 230         5,                                      // bDescriptorType
 231         CDC_RX_ENDPOINT,                        // bEndpointAddress
 232         0x02,                                   // bmAttributes (0x02=bulk)
 233         CDC_RX_SIZE, 0,                         // wMaxPacketSize
 234         0,                                      // bInterval
 235         // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
 236         7,                                      // bLength
 237         5,                                      // bDescriptorType
 238         CDC_TX_ENDPOINT | 0x80,                 // bEndpointAddress
 239         0x02,                                   // bmAttributes (0x02=bulk)
 240         CDC_TX_SIZE, 0,                         // wMaxPacketSize
 241         0                                       // bInterval
 242 };
 243
 244 // If you're desperate for a little extra code memory, these strings
 245 // can be completely removed if iManufacturer, iProduct, iSerialNumber
 246 // in the device desciptor are changed to zeros.
 247 struct usb_string_descriptor_struct {
 248         uint8_t bLength;
 249         uint8_t bDescriptorType;
 250         int16_t wString[];
 251 };
 252 static struct usb_string_descriptor_struct PROGMEM string0 = {
 253         4,
 254         3,
 255         {0x0409}
 256 };
 257 static struct usb_string_descriptor_struct PROGMEM string1 = {
 258         sizeof(STR_MANUFACTURER),
 259         3,
 260         STR_MANUFACTURER
 261 };
 262 static struct usb_string_descriptor_struct PROGMEM string2 = {
 263         sizeof(STR_PRODUCT),
 264         3,
 265         STR_PRODUCT
 266 };
 267 static struct usb_string_descriptor_struct PROGMEM string3 = {
 268         sizeof(STR_SERIAL_NUMBER),
 269         3,
 270         STR_SERIAL_NUMBER
 271 };
 272
 273 // This table defines which descriptor data is sent for each specific
 274 // request from the host (in wValue and wIndex).
 275 static struct descriptor_list_struct {
 276         uint16_t        wValue;
 277         uint16_t        wIndex;
 278         const uint8_t   *addr;
 279         uint8_t         length;
 280 } PROGMEM descriptor_list[] = {
 281         {0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
 282         {0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
 283         {0x0300, 0x0000, (const uint8_t *)&string0, 4},
 284         {0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
 285         {0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)},
 286         {0x0303, 0x0409, (const uint8_t *)&string3, sizeof(STR_SERIAL_NUMBER)}
 287 };
 288 #define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))
 289
 290
 291 /**************************************************************************
 292  *
 293  *  Variables - these are the only non-stack RAM usage
 294  *
 295  **************************************************************************/
 296
 297 // zero when we are not configured, non-zero when enumerated
 298 static volatile uint8_t usb_configuration=0;
 299
 300 // the time remaining before we transmit any partially full
 301 // packet, or send a zero length packet.
 302 static volatile uint8_t transmit_flush_timer=0;
 303 static uint8_t transmit_previous_timeout=0;
 304
 305 // serial port settings (baud rate, control signals, etc) set
 306 // by the PC.  These are ignored, but kept in RAM.
 307 static uint8_t cdc_line_coding[7]={0x00, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x08};
 308 static uint8_t cdc_line_rtsdtr=0;
 309
 310
 311 /**************************************************************************
 312  *
 313  *  Public Functions - these are the API intended for the user
 314  *
 315  **************************************************************************/
 316
 317 // initialize USB serial
 318 void usb_init(void)
 319 {
 320         sei();
 321         HW_CONFIG();
 322                 USB_FREEZE();                           // enable USB
 323                 PLL_CONFIG();                           // config PLL, 16 MHz xtal
 324                 while (!(PLLCSR & (1<<PLOCK))) ;        // wait for PLL lock
 325                 USB_CONFIG();                           // start USB clock
 326                 UDCON = 0;                              // enable attach resistor
 327         usb_configuration = 0;
 328         cdc_line_rtsdtr = 0;
 329                 UDIEN = (1<<EORSTE)|(1<<SOFE);
 330 }
 331
 332 // return 0 if the USB is not configured, or the configuration
 333 // number selected by the HOST
 334 uint8_t usb_configured(void)
 335 {
 336         return usb_configuration;
 337 }
 338
 339 // get the next character, or -1 if nothing received
 340 int16_t usb_serial_getchar(void)
 341 {
 342         uint8_t c, intr_state;
 343
 344         // interrupts are disabled so these functions can be
 345         // used from the main program or interrupt context,
 346         // even both in the same program!
 347         intr_state = SREG;
 348         cli();
 349         if (!usb_configuration) {
 350                 SREG = intr_state;
 351                 return -1;
 352         }
 353         UENUM = CDC_RX_ENDPOINT;
 354         retry:
 355         c = UEINTX;
 356         if (!(c & (1<<RWAL))) {
 357                 // no data in buffer
 358                 if (c & (1<<RXOUTI)) {
 359                         UEINTX = 0x6B;
 360                         goto retry;
 361                 }
 362                 SREG = intr_state;
 363                 return -1;
 364         }
 365         // take one byte out of the buffer
 366         c = UEDATX;
 367         // if buffer completely used, release it
 368         if (!(UEINTX & (1<<RWAL))) UEINTX = 0x6B;
 369         SREG = intr_state;
 370         return c;
 371 }
 372
 373 // number of bytes available in the receive buffer
 374 uint8_t usb_serial_available(void)
 375 {
 376         uint8_t n=0, i, intr_state;
 377
 378         intr_state = SREG;
 379         cli();
 380         if (usb_configuration) {
 381                 UENUM = CDC_RX_ENDPOINT;
 382                 n = UEBCLX;
 383                 if (!n) {
 384                         i = UEINTX;
 385                         if (i & (1<<RXOUTI) && !(i & (1<<RWAL))) UEINTX = 0x6B;
 386                 }
 387         }
 388         SREG = intr_state;
 389         return n;
 390 }
 391
 392 // discard any buffered input
 393 void usb_serial_flush_input(void)
 394 {
 395         uint8_t intr_state;
 396
 397         if (usb_configuration) {
 398                 intr_state = SREG;
 399                 cli();
 400                 UENUM = CDC_RX_ENDPOINT;
 401                 while ((UEINTX & (1<<RWAL))) {
 402                         UEINTX = 0x6B;
 403                 }
 404                 SREG = intr_state;
 405         }
 406 }
 407
 408 // transmit a character.  0 returned on success, -1 on error
 409 int8_t usb_serial_putchar(uint8_t c)
 410 {
 411         uint8_t timeout, intr_state;
 412
 413         // if we're not online (enumerated and configured), error
 414         if (!usb_configuration) return -1;
 415         // interrupts are disabled so these functions can be
 416         // used from the main program or interrupt context,
 417         // even both in the same program!
 418         intr_state = SREG;
 419         cli();
 420         UENUM = CDC_TX_ENDPOINT;
 421         // if we gave up due to timeout before, don't wait again
 422         if (transmit_previous_timeout) {
 423                 if (!(UEINTX & (1<<RWAL))) {
 424                         SREG = intr_state;
 425                         return -1;
 426                 }
 427                 transmit_previous_timeout = 0;
 428         }
 429         // wait for the FIFO to be ready to accept data
 430         timeout = UDFNUML + TRANSMIT_TIMEOUT;
 431         while (1) {
 432                 // are we ready to transmit?
 433                 if (UEINTX & (1<<RWAL)) break;
 434                 SREG = intr_state;
 435                 // have we waited too long?  This happens if the user
 436                 // is not running an application that is listening
 437                 if (UDFNUML == timeout) {
 438                         transmit_previous_timeout = 1;
 439                         return -1;
 440                 }
 441                 // has the USB gone offline?
 442                 if (!usb_configuration) return -1;
 443                 // get ready to try checking again
 444                 intr_state = SREG;
 445                 cli();
 446                 UENUM = CDC_TX_ENDPOINT;
 447         }
 448         // actually write the byte into the FIFO
 449         UEDATX = c;
 450         // if this completed a packet, transmit it now!
 451         if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
 452         transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
 453         SREG = intr_state;
 454         return 0;
 455 }
 456
 457
 458 // transmit a character, but do not wait if the buffer is full,
 459 //   0 returned on success, -1 on buffer full or error
 460 int8_t usb_serial_putchar_nowait(uint8_t c)
 461 {
 462         uint8_t intr_state;
 463
 464         if (!usb_configuration) return -1;
 465         intr_state = SREG;
 466         cli();
 467         UENUM = CDC_TX_ENDPOINT;
 468         if (!(UEINTX & (1<<RWAL))) {
 469                 // buffer is full
 470                 SREG = intr_state;
 471                 return -1;
 472         }
 473         // actually write the byte into the FIFO
 474         UEDATX = c;
 475                 // if this completed a packet, transmit it now!
 476         if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
 477         transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
 478         SREG = intr_state;
 479         return 0;
 480 }
 481
 482 // transmit a buffer.
 483 //  0 returned on success, -1 on error
 484 // This function is optimized for speed!  Each call takes approx 6.1 us overhead
 485 // plus 0.25 us per byte.  12 Mbit/sec USB has 8.67 us per-packet overhead and
 486 // takes 0.67 us per byte.  If called with 64 byte packet-size blocks, this function
 487 // can transmit at full USB speed using 43% CPU time.  The maximum theoretical speed
 488 // is 19 packets per USB frame, or 1216 kbytes/sec.  However, bulk endpoints have the
 489 // lowest priority, so any other USB devices will likely reduce the speed.  Speed
 490 // can also be limited by how quickly the PC-based software reads data, as the host
 491 // controller in the PC will not allocate bandwitdh without a pending read request.
 492 // (thanks to Victor Suarez for testing and feedback and initial code)
 493
 494 int8_t usb_serial_write(const uint8_t *buffer, uint16_t size)
 495 {
 496         uint8_t timeout, intr_state, write_size;
 497
 498         // if we're not online (enumerated and configured), error
 499         if (!usb_configuration) return -1;
 500         // interrupts are disabled so these functions can be
 501         // used from the main program or interrupt context,
 502         // even both in the same program!
 503         intr_state = SREG;
 504         cli();
 505         UENUM = CDC_TX_ENDPOINT;
 506         // if we gave up due to timeout before, don't wait again
 507         if (transmit_previous_timeout) {
 508                 if (!(UEINTX & (1<<RWAL))) {
 509                         SREG = intr_state;
 510                         return -1;
 511                 }
 512                 transmit_previous_timeout = 0;
 513         }
 514         // each iteration of this loop transmits a packet
 515         while (size) {
 516                 // wait for the FIFO to be ready to accept data
 517                 timeout = UDFNUML + TRANSMIT_TIMEOUT;
 518                 while (1) {
 519                         // are we ready to transmit?
 520                         if (UEINTX & (1<<RWAL)) break;
 521                         SREG = intr_state;
 522                         // have we waited too long?  This happens if the user
 523                         // is not running an application that is listening
 524                         if (UDFNUML == timeout) {
 525                                 transmit_previous_timeout = 1;
 526                                 return -1;
 527                         }
 528                         // has the USB gone offline?
 529                         if (!usb_configuration) return -1;
 530                         // get ready to try checking again
 531                         intr_state = SREG;
 532                         cli();
 533                         UENUM = CDC_TX_ENDPOINT;
 534                 }
 535
 536                 // compute how many bytes will fit into the next packet
 537                 write_size = CDC_TX_SIZE - UEBCLX;
 538                 if (write_size > size) write_size = size;
 539                 size -= write_size;
 540
 541                 // write the packet
 542                 switch (write_size) {
 543                         #if (CDC_TX_SIZE == 64)
 544                         case 64: UEDATX = *buffer++;
 545                         case 63: UEDATX = *buffer++;
 546                         case 62: UEDATX = *buffer++;
 547                         case 61: UEDATX = *buffer++;
 548                         case 60: UEDATX = *buffer++;
 549                         case 59: UEDATX = *buffer++;
 550                         case 58: UEDATX = *buffer++;
 551                         case 57: UEDATX = *buffer++;
 552                         case 56: UEDATX = *buffer++;
 553                         case 55: UEDATX = *buffer++;
 554                         case 54: UEDATX = *buffer++;
 555                         case 53: UEDATX = *buffer++;
 556                         case 52: UEDATX = *buffer++;
 557                         case 51: UEDATX = *buffer++;
 558                         case 50: UEDATX = *buffer++;
 559                         case 49: UEDATX = *buffer++;
 560                         case 48: UEDATX = *buffer++;
 561                         case 47: UEDATX = *buffer++;
 562                         case 46: UEDATX = *buffer++;
 563                         case 45: UEDATX = *buffer++;
 564                         case 44: UEDATX = *buffer++;
 565                         case 43: UEDATX = *buffer++;
 566                         case 42: UEDATX = *buffer++;
 567                         case 41: UEDATX = *buffer++;
 568                         case 40: UEDATX = *buffer++;
 569                         case 39: UEDATX = *buffer++;
 570                         case 38: UEDATX = *buffer++;
 571                         case 37: UEDATX = *buffer++;
 572                         case 36: UEDATX = *buffer++;
 573                         case 35: UEDATX = *buffer++;
 574                         case 34: UEDATX = *buffer++;
 575                         case 33: UEDATX = *buffer++;
 576                         #endif
 577                         #if (CDC_TX_SIZE >= 32)
 578                         case 32: UEDATX = *buffer++;
 579                         case 31: UEDATX = *buffer++;
 580                         case 30: UEDATX = *buffer++;
 581                         case 29: UEDATX = *buffer++;
 582                         case 28: UEDATX = *buffer++;
 583                         case 27: UEDATX = *buffer++;
 584                         case 26: UEDATX = *buffer++;
 585                         case 25: UEDATX = *buffer++;
 586                         case 24: UEDATX = *buffer++;
 587                         case 23: UEDATX = *buffer++;
 588                         case 22: UEDATX = *buffer++;
 589                         case 21: UEDATX = *buffer++;
 590                         case 20: UEDATX = *buffer++;
 591                         case 19: UEDATX = *buffer++;
 592                         case 18: UEDATX = *buffer++;
 593                         case 17: UEDATX = *buffer++;
 594                         #endif
 595                         #if (CDC_TX_SIZE >= 16)
 596                         case 16: UEDATX = *buffer++;
 597                         case 15: UEDATX = *buffer++;
 598                         case 14: UEDATX = *buffer++;
 599                         case 13: UEDATX = *buffer++;
 600                         case 12: UEDATX = *buffer++;
 601                         case 11: UEDATX = *buffer++;
 602                         case 10: UEDATX = *buffer++;
 603                         case  9: UEDATX = *buffer++;
 604                         #endif
 605                         case  8: UEDATX = *buffer++;
 606                         case  7: UEDATX = *buffer++;
 607                         case  6: UEDATX = *buffer++;
 608                         case  5: UEDATX = *buffer++;
 609                         case  4: UEDATX = *buffer++;
 610                         case  3: UEDATX = *buffer++;
 611                         case  2: UEDATX = *buffer++;
 612                         default:
 613                         case  1: UEDATX = *buffer++;
 614                         case  0: break;
 615                 }
 616                 // if this completed a packet, transmit it now!
 617                 if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
 618                 transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
 619                 SREG = intr_state;
 620         }
 621         return 0;
 622 }
 623
 624
 625 // immediately transmit any buffered output.
 626 // This doesn't actually transmit the data - that is impossible!
 627 // USB devices only transmit when the host allows, so the best
 628 // we can do is release the FIFO buffer for when the host wants it
 629 void usb_serial_flush_output(void)
 630 {
 631         uint8_t intr_state;
 632
 633         intr_state = SREG;
 634         cli();
 635         if (transmit_flush_timer) {
 636                 UENUM = CDC_TX_ENDPOINT;
 637                 UEINTX = 0x3A;
 638                 transmit_flush_timer = 0;
 639         }
 640         SREG = intr_state;
 641 }
 642
 643 // functions to read the various async serial settings.  These
 644 // aren't actually used by USB at all (communication is always
 645 // at full USB speed), but they are set by the host so we can
 646 // set them properly if we're converting the USB to a real serial
 647 // communication
 648 // uint32_t usb_serial_get_baud(void)
 649 // {
 650 //      return *(uint32_t *)cdc_line_coding;
 651 // }
 652 uint8_t usb_serial_get_stopbits(void)
 653 {
 654         return cdc_line_coding[4];
 655 }
 656 uint8_t usb_serial_get_paritytype(void)
 657 {
 658         return cdc_line_coding[5];
 659 }
 660 uint8_t usb_serial_get_numbits(void)
 661 {
 662         return cdc_line_coding[6];
 663 }
 664 uint8_t usb_serial_get_control(void)
 665 {
 666         return cdc_line_rtsdtr;
 667 }
 668 // write the control signals, DCD, DSR, RI, etc
 669 // There is no CTS signal.  If software on the host has transmitted
 670 // data to you but you haven't been calling the getchar function,
 671 // it remains buffered (either here or on the host) and can not be
 672 // lost because you weren't listening at the right time, like it
 673 // would in real serial communication.
 674 int8_t usb_serial_set_control(uint8_t signals)
 675 {
 676         uint8_t intr_state;
 677
 678         intr_state = SREG;
 679         cli();
 680         if (!usb_configuration) {
 681                 // we're not enumerated/configured
 682                 SREG = intr_state;
 683                 return -1;
 684         }
 685
 686         UENUM = CDC_ACM_ENDPOINT;
 687         if (!(UEINTX & (1<<RWAL))) {
 688                 // unable to write
 689                 // TODO; should this try to abort the previously
 690                 // buffered message??
 691                 SREG = intr_state;
 692                 return -1;
 693         }
 694         UEDATX = 0xA1;
 695         UEDATX = 0x20;
 696         UEDATX = 0;
 697         UEDATX = 0;
 698         UEDATX = 0; // 0 seems to work nicely.  what if this is 1??
 699         UEDATX = 0;
 700         UEDATX = 1;
 701         UEDATX = 0;
 702         UEDATX = signals;
 703         UEINTX = 0x3A;
 704         SREG = intr_state;
 705         return 0;
 706 }
 707
 708
 709
 710 /**************************************************************************
 711  *
 712  *  Private Functions - not intended for general user consumption....
 713  *
 714  **************************************************************************/
 715
 716
 717 // USB Device Interrupt - handle all device-level events
 718 // the transmit buffer flushing is triggered by the start of frame
 719 //
 720 ISR(USB_GEN_vect, ISR_BLOCK)
 721 {
 722         uint8_t intbits, t;
 723                 intbits = UDINT;
 724                 UDINT = 0;
 725         if (intbits & (1<<EORSTI)) {
 726                 UENUM = 0;
 727                 UECONX = 1;
 728                 UECFG0X = EP_TYPE_CONTROL;
 729                 UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
 730                 UEIENX = (1<<RXSTPE);
 731                 usb_configuration = 0;
 732                 cdc_line_rtsdtr = 0;
 733         }
 734         if (intbits & (1<<SOFI)) {
 735                 if (usb_configuration) {
 736                         t = transmit_flush_timer;
 737                         if (t) {
 738                                 transmit_flush_timer = --t;
 739                                 if (!t) {
 740                                         UENUM = CDC_TX_ENDPOINT;
 741                                         UEINTX = 0x3A;
 742                                 }
 743                         }
 744                 }
 745         }
 746 }
 747
 748
 749 // Misc functions to wait for ready and send/receive packets
 750 static inline void usb_wait_in_ready(void)
 751 {
 752         while (!(UEINTX & (1<<TXINI))) ;
 753 }
 754 static inline void usb_send_in(void)
 755 {
 756         UEINTX = ~(1<<TXINI);
 757 }
 758 static inline void usb_wait_receive_out(void)
 759 {
 760         while (!(UEINTX & (1<<RXOUTI))) ;
 761 }
 762 static inline void usb_ack_out(void)
 763 {
 764         UEINTX = ~(1<<RXOUTI);
 765 }
 766
 767
 768
 769 // USB Endpoint Interrupt - endpoint 0 is handled here.  The
 770 // other endpoints are manipulated by the user-callable
 771 // functions, and the start-of-frame interrupt.
 772 //
 773 ISR(USB_COM_vect, ISR_BLOCK)
 774 {
 775         uint8_t intbits;
 776         const uint8_t *list;
 777         const uint8_t *cfg;
 778         uint8_t i, n, len, en;
 779         uint8_t *p;
 780         uint8_t bmRequestType;
 781         uint8_t bRequest;
 782         uint16_t wValue;
 783         uint16_t wIndex;
 784         uint16_t wLength;
 785         uint16_t desc_val;
 786         const uint8_t *desc_addr;
 787         uint8_t desc_length;
 788
 789         UENUM = 0;
 790         intbits = UEINTX;
 791         if (intbits & (1<<RXSTPI)) {
 792                 bmRequestType = UEDATX;
 793                 bRequest = UEDATX;
 794                 wValue = UEDATX;
 795                 wValue |= (UEDATX << 8);
 796                 wIndex = UEDATX;
 797                 wIndex |= (UEDATX << 8);
 798                 wLength = UEDATX;
 799                 wLength |= (UEDATX << 8);
 800                 UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
 801                 if (bRequest == GET_DESCRIPTOR) {
 802                         list = (const uint8_t *)descriptor_list;
 803                         for (i=0; ; i++) {
 804                                 if (i >= NUM_DESC_LIST) {
 805                                         UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
 806                                         return;
 807                                 }
 808                                 desc_val = pgm_read_word(list);
 809                                 if (desc_val != wValue) {
 810                                         list += sizeof(struct descriptor_list_struct);
 811                                         continue;
 812                                 }
 813                                 list += 2;
 814                                 desc_val = pgm_read_word(list);
 815                                 if (desc_val != wIndex) {
 816                                         list += sizeof(struct descriptor_list_struct)-2;
 817                                         continue;
 818                                 }
 819                                 list += 2;
 820                                 desc_addr = (const uint8_t *)pgm_read_word(list);
 821                                 list += 2;
 822                                 desc_length = pgm_read_byte(list);
 823                                 break;
 824                         }
 825                         len = (wLength < 256) ? wLength : 255;
 826                         if (len > desc_length) len = desc_length;
 827                         do {
 828                                 // wait for host ready for IN packet
 829                                 do {
 830                                         i = UEINTX;
 831                                 } while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
 832                                 if (i & (1<<RXOUTI))
 833                                 {
 834                                         return; // abort
 835                                 }
 836                                 // send IN packet
 837                                 n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
 838                                 for (i = n; i; i--) {
 839                                         UEDATX = pgm_read_byte(desc_addr++);
 840                                 }
 841                                 len -= n;
 842                                 usb_send_in();
 843                         } while (len || n == ENDPOINT0_SIZE);
 844                         return;
 845                 }
 846                 if (bRequest == SET_ADDRESS) {
 847                         usb_send_in();
 848                         usb_wait_in_ready();
 849                         UDADDR = wValue | (1<<ADDEN);
 850                         return;
 851                 }
 852                 if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
 853                         usb_configuration = wValue;
 854                         cdc_line_rtsdtr = 0;
 855                         transmit_flush_timer = 0;
 856                         usb_send_in();
 857                         cfg = endpoint_config_table;
 858                         for (i=1; i<5; i++) {
 859                                 UENUM = i;
 860                                 en = pgm_read_byte(cfg++);
 861                                 UECONX = en;
 862                                 if (en) {
 863                                         UECFG0X = pgm_read_byte(cfg++);
 864                                         UECFG1X = pgm_read_byte(cfg++);
 865                                 }
 866                         }
 867                                 UERST = 0x1E;
 868                                 UERST = 0;
 869                         return;
 870                 }
 871                 if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
 872                         usb_wait_in_ready();
 873                         UEDATX = usb_configuration;
 874                         usb_send_in();
 875                         return;
 876                 }
 877                 if (bRequest == CDC_GET_LINE_CODING && bmRequestType == 0xA1) {
 878                         usb_wait_in_ready();
 879                         p = cdc_line_coding;
 880                         for (i=0; i<7; i++) {
 881                                 UEDATX = *p++;
 882                         }
 883                         usb_send_in();
 884                         return;
 885                 }
 886                 if (bRequest == CDC_SET_LINE_CODING && bmRequestType == 0x21) {
 887                         usb_wait_receive_out();
 888                         p = cdc_line_coding;
 889                         for (i=0; i<7; i++) {
 890                                 *p++ = UEDATX;
 891                         }
 892                         usb_ack_out();
 893                         usb_send_in();
 894                         return;
 895                 }
 896                 if (bRequest == CDC_SET_CONTROL_LINE_STATE && bmRequestType == 0x21) {
 897                         cdc_line_rtsdtr = wValue;
 898                         usb_wait_in_ready();
 899                         usb_send_in();
 900                         return;
 901                 }
 902                 if (bRequest == GET_STATUS) {
 903                         usb_wait_in_ready();
 904                         i = 0;
 905                         #ifdef SUPPORT_ENDPOINT_HALT
 906                         if (bmRequestType == 0x82) {
 907                                 UENUM = wIndex;
 908                                 if (UECONX & (1<<STALLRQ)) i = 1;
 909                                 UENUM = 0;
 910                         }
 911                         #endif
 912                         UEDATX = i;
 913                         UEDATX = 0;
 914                         usb_send_in();
 915                         return;
 916                 }
 917                 #ifdef SUPPORT_ENDPOINT_HALT
 918                 if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
 919                   && bmRequestType == 0x02 && wValue == 0) {
 920                         i = wIndex & 0x7F;
 921                         if (i >= 1 && i <= MAX_ENDPOINT) {
 922                                 usb_send_in();
 923                                 UENUM = i;
 924                                 if (bRequest == SET_FEATURE) {
 925                                         UECONX = (1<<STALLRQ)|(1<<EPEN);
 926                                 } else {
 927                                         UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
 928                                         UERST = (1 << i);
 929                                         UERST = 0;
 930                                 }
 931                                 return;
 932                         }
 933                 }
 934                 #endif
 935         }
 936         UECONX = (1<<STALLRQ) | (1<<EPEN);      // stall
 937 }
 938
 939
 940 #define CPU_PRESCALE(n) (CLKPR = 0x80, CLKPR = (n))
 941
 942 #if 0
 943 #include <stdio.h>
 944 static int dw_putchar(char __c, FILE *__stream) { DWDR = __c;(void)__stream; return __c;}
 945 FILE dwout = FDEV_SETUP_STREAM(dw_putchar, NULL, _FDEV_SETUP_WRITE);
 946 stdout=&dwout;
 947 #endif
 948
 949 // Very simple character echo test
 950 int main(void)
 951 {
 952         CPU_PRESCALE(0);
 953         usb_init();
 954         while(usb_configured()==0);
 955         while (1) {
 956                 int n = usb_serial_getchar();
 957                 if (n >= 0) usb_serial_putchar(n);
 958         }
 959 }