usb_keyboard.c

/* Big Red Button USB HID
 * https://github.com/andreas23/bigredbutton
 * Copyright (c) 2015 Andreas Bogk
 *
 * Based on:
 * 
 * USB Keyboard Example for Teensy USB Development Board
 * http://www.pjrc.com/teensy/usb_keyboard.html
 * Copyright (c) 2009 PJRC.COM, LLC
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

// Version 1.0: Initial Release
// Version 1.1: Add support for Teensy 2.0

#define USB_SERIAL_PRIVATE_INCLUDE
#include "usb_keyboard.h"

/**************************************************************************
 *
 *  Configurable Options
 *
 **************************************************************************/

// You can change these to give your code its own name.
#define STR_MANUFACTURER L"andreasdotorg"
#define STR_PRODUCT      L"Big Red Button"


// Mac OS-X and Linux automatically load the correct drivers.  On
// Windows, even though the driver is supplied by Microsoft, an
// INF file is needed to load the driver.  These numbers need to
// match the INF file.
#define VENDOR_ID  0x1209
#define PRODUCT_ID 0x2342


// USB devices are supposed to implment a halt feature, which is
// rarely (if ever) used.  If you comment this line out, the halt
// code will be removed, saving 102 bytes of space (gcc 4.3.0).
// This is not strictly USB compliant, but works with all major
// operating systems.
#define SUPPORT_ENDPOINT_HALT



/**************************************************************************
 *
 *  Endpoint Buffer Configuration
 *
 **************************************************************************/

#define ENDPOINT0_SIZE    32

#define KEYBOARD_INTERFACE  0
#define KEYBOARD_ENDPOINT   3
#define KEYBOARD_SIZE       8
#define KEYBOARD_BUFFER     EP_DOUBLE_BUFFER

static const uint8_t PROGMEM endpoint_config_table[] = {
  0,
  0,
  1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(KEYBOARD_SIZE) | KEYBOARD_BUFFER,
  0
};


/**************************************************************************
 *
 *  Descriptor Data
 *
 **************************************************************************/

// Descriptors are the data that your computer reads when it auto-detects
// this USB device (called "enumeration" in USB lingo).  The most commonly
// changed items are editable at the top of this file.  Changing things
// in here should only be done by those who've read chapter 9 of the USB
// spec and relevant portions of any USB class specifications!


static const uint8_t PROGMEM device_descriptor[] = {
  18,                               // bLength
  1,                                // bDescriptorType
  0x00, 0x02,                       // bcdUSB
  0,                                // bDeviceClass
  0,                                // bDeviceSubClass
  0,                                // bDeviceProtocol
  ENDPOINT0_SIZE,                   // bMaxPacketSize0
  LSB(VENDOR_ID), MSB(VENDOR_ID),   // idVendor
  LSB(PRODUCT_ID), MSB(PRODUCT_ID), // idProduct
  0x00, 0x01,                       // bcdDevice
  1,                                // iManufacturer
  2,                                // iProduct
  0,                                // iSerialNumber
  1                                 // bNumConfigurations
};

// Keyboard Protocol 1, HID 1.11 spec, Appendix B, page 59-60
static const uint8_t PROGMEM keyboard_hid_report_desc[] = {
  0x05, 0x01,          // Usage Page (Generic Desktop),
  0x09, 0x06,          // Usage (Keyboard),
  0xA1, 0x01,          // Collection (Application),
  0x75, 0x01,          //   Report Size (1),
  0x95, 0x08,          //   Report Count (8),
  0x05, 0x07,          //   Usage Page (Key Codes),
  0x19, 0xE0,          //   Usage Minimum (224),
  0x29, 0xE7,          //   Usage Maximum (231),
  0x15, 0x00,          //   Logical Minimum (0),
  0x25, 0x01,          //   Logical Maximum (1),
  0x81, 0x02,          //   Input (Data, Variable, Absolute), ;Modifier byte
  0x95, 0x01,          //   Report Count (1),
  0x75, 0x08,          //   Report Size (8),
  0x81, 0x03,          //   Input (Constant),                 ;Reserved byte
  0x95, 0x05,          //   Report Count (5),
  0x75, 0x01,          //   Report Size (1),
  0x05, 0x08,          //   Usage Page (LEDs),
  0x19, 0x01,          //   Usage Minimum (1),
  0x29, 0x05,          //   Usage Maximum (5),
  0x91, 0x02,          //   Output (Data, Variable, Absolute), ;LED report
  0x95, 0x01,          //   Report Count (1),
  0x75, 0x03,          //   Report Size (3),
  0x91, 0x03,          //   Output (Constant),                 ;LED report padding
  0x95, 0x06,          //   Report Count (6),
  0x75, 0x08,          //   Report Size (8),
  0x15, 0x00,          //   Logical Minimum (0),
  0x25, 0x68,          //   Logical Maximum(104),
  0x05, 0x07,          //   Usage Page (Key Codes),
  0x19, 0x00,          //   Usage Minimum (0),
  0x29, 0x68,          //   Usage Maximum (104),
  0x81, 0x00,          //   Input (Data, Array),
  0xc0                 // End Collection
};

#define CONFIG1_DESC_SIZE        (9+9+9+7)
#define KEYBOARD_HID_DESC_OFFSET (9+9)
static const uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
  // configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
  9,                                 // bLength;
  2,                                 // bDescriptorType;
  LSB(CONFIG1_DESC_SIZE),            // wTotalLength
  MSB(CONFIG1_DESC_SIZE),
  1,                                 // bNumInterfaces
  1,                                 // bConfigurationValue
  0,                                 // iConfiguration
  0xC0,                              // bmAttributes
  50,                                // bMaxPower
  // interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
  9,                                 // bLength
  4,                                 // bDescriptorType
  KEYBOARD_INTERFACE,                // bInterfaceNumber
  0,                                 // bAlternateSetting
  1,                                 // bNumEndpoints
  0x03,                              // bInterfaceClass (0x03 = HID)
  0x01,                              // bInterfaceSubClass (0x01 = Boot)
  0x01,                              // bInterfaceProtocol (0x01 = Keyboard)
  0,                                 // iInterface
  // HID interface descriptor, HID 1.11 spec, section 6.2.1
  9,                                 // bLength
  0x21,                              // bDescriptorType
  0x11, 0x01,                        // bcdHID
  0,                                 // bCountryCode
  1,                                 // bNumDescriptors
  0x22,                              // bDescriptorType
  sizeof(keyboard_hid_report_desc),  // wDescriptorLength
  0,
  // endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
  7,                                 // bLength
  5,                                 // bDescriptorType
  KEYBOARD_ENDPOINT | 0x80,          // bEndpointAddress
  0x03,                              // bmAttributes (0x03=intr)
  KEYBOARD_SIZE, 0,                  // wMaxPacketSize
  1                                  // bInterval
};

// If you're desperate for a little extra code memory, these strings
// can be completely removed if iManufacturer, iProduct, iSerialNumber
// in the device desciptor are changed to zeros.
struct usb_string_descriptor_struct {
  uint8_t bLength;
  uint8_t bDescriptorType;
  int16_t wString[];
};
static const struct usb_string_descriptor_struct PROGMEM string0 = {
  4,
  3,
  {0x0409}
};
static const struct usb_string_descriptor_struct PROGMEM string1 = {
  sizeof(STR_MANUFACTURER),
  3,
  STR_MANUFACTURER
};
static const struct usb_string_descriptor_struct PROGMEM string2 = {
  sizeof(STR_PRODUCT),
  3,
  STR_PRODUCT
};

// This table defines which descriptor data is sent for each specific
// request from the host (in wValue and wIndex).
static const struct descriptor_list_struct {
  uint16_t  wValue;
  uint16_t  wIndex;
  const uint8_t  *addr;
  uint8_t    length;
} PROGMEM descriptor_list[] = {
  {0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
  {0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
  {0x2200, KEYBOARD_INTERFACE, keyboard_hid_report_desc, sizeof(keyboard_hid_report_desc)},
  {0x2100, KEYBOARD_INTERFACE, config1_descriptor+KEYBOARD_HID_DESC_OFFSET, 9},
  {0x0300, 0x0000, (const uint8_t *)&string0, 4},
  {0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
  {0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)}
};
#define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))


/**************************************************************************
 *
 *  Variables - these are the only non-stack RAM usage
 *
 **************************************************************************/

// zero when we are not configured, non-zero when enumerated
static volatile uint8_t usb_configuration=0;

// which modifier keys are currently pressed
// 1=left ctrl,    2=left shift,   4=left alt,    8=left gui
// 16=right ctrl, 32=right shift, 64=right alt, 128=right gui
uint8_t keyboard_modifier_keys=0;

// which keys are currently pressed, up to 6 keys may be down at once
uint8_t keyboard_keys[6]={0,0,0,0,0,0};

// protocol setting from the host.  We use exactly the same report
// either way, so this variable only stores the setting since we
// are required to be able to report which setting is in use.
static uint8_t keyboard_protocol=1;

// the idle configuration, how often we send the report to the
// host (ms * 4) even when it hasn't changed
static uint8_t keyboard_idle_config=125;

// count until idle timeout
static uint8_t keyboard_idle_count=0;

// 1=num lock, 2=caps lock, 4=scroll lock, 8=compose, 16=kana
volatile uint8_t keyboard_leds=0;


/**************************************************************************
 *
 *  Public Functions - these are the API intended for the user
 *
 **************************************************************************/


// initialize USB
void usb_init(void)
{
  HW_CONFIG();
  USB_FREEZE();                     // enable USB
  PLL_CONFIG();                     // config PLL
  while (!(PLLCSR & (1<<PLOCK))) ;  // wait for PLL lock
  USB_CONFIG();                     // start USB clock
  UDCON = 0;                        // enable attach resistor
  usb_configuration = 0;
  UDIEN = (1<<EORSTE)|(1<<SOFE);
  sei();
}

// return 0 if the USB is not configured, or the configuration
// number selected by the HOST
uint8_t usb_configured(void)
{
  return usb_configuration;
}


// perform a single keystroke
int8_t usb_keyboard_press(uint8_t key, uint8_t modifier)
{
  int8_t r;

  keyboard_modifier_keys = modifier;
  keyboard_keys[0] = key;
  r = usb_keyboard_send();
  if (r) return r;
  keyboard_modifier_keys = 0;
  keyboard_keys[0] = 0;
  return usb_keyboard_send();
}

// send the contents of keyboard_keys and keyboard_modifier_keys
int8_t usb_keyboard_send(void)
{
  uint8_t i, intr_state, timeout;

  if (!usb_configuration) return -1;
  intr_state = SREG;
  cli();
  UENUM = KEYBOARD_ENDPOINT;
  timeout = UDFNUML + 50;
  while (1) {
    // are we ready to transmit?
    if (UEINTX & (1<<RWAL)) break;
    SREG = intr_state;
    // has the USB gone offline?
    if (!usb_configuration) return -1;
    // have we waited too long?
    if (UDFNUML == timeout) return -1;
    // get ready to try checking again
    intr_state = SREG;
    cli();
    UENUM = KEYBOARD_ENDPOINT;
  }
  UEDATX = keyboard_modifier_keys;
  UEDATX = 0;
  for (i=0; i<6; i++) {
    UEDATX = keyboard_keys[i];
  }
  UEINTX = 0x3A;
  keyboard_idle_count = 0;
  SREG = intr_state;
  return 0;
}

/**************************************************************************
 *
 *  Private Functions - not intended for general user consumption....
 *
 **************************************************************************/



// USB Device Interrupt - handle all device-level events
// the transmit buffer flushing is triggered by the start of frame
//
ISR(USB_GEN_vect)
{
  uint8_t intbits, i;
  static uint8_t div4=0;

  intbits = UDINT;
  UDINT = 0;
  if (intbits & (1<<EORSTI)) {
    UENUM = 0;
    UECONX = 1;
    UECFG0X = EP_TYPE_CONTROL;
    UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
    UEIENX = (1<<RXSTPE);
    usb_configuration = 0;
  }
  if ((intbits & (1<<SOFI)) && usb_configuration) {
    if (keyboard_idle_config && (++div4 & 3) == 0) {
      UENUM = KEYBOARD_ENDPOINT;
      if (UEINTX & (1<<RWAL)) {
        keyboard_idle_count++;
        if (keyboard_idle_count == keyboard_idle_config) {
          keyboard_idle_count = 0;
          UEDATX = keyboard_modifier_keys;
          UEDATX = 0;
          for (i=0; i<6; i++) {
            UEDATX = keyboard_keys[i];
          }
          UEINTX = 0x3A;
        }
      }
    }
  }
}



// Misc functions to wait for ready and send/receive packets
static inline void usb_wait_in_ready(void)
{
  while (!(UEINTX & (1<<TXINI))) ;
}
static inline void usb_send_in(void)
{
  UEINTX = ~(1<<TXINI);
}
static inline void usb_wait_receive_out(void)
{
  while (!(UEINTX & (1<<RXOUTI))) ;
}
static inline void usb_ack_out(void)
{
  UEINTX = ~(1<<RXOUTI);
}



// USB Endpoint Interrupt - endpoint 0 is handled here.  The
// other endpoints are manipulated by the user-callable
// functions, and the start-of-frame interrupt.
//
ISR(USB_COM_vect)
{
  uint8_t intbits;
  const uint8_t *list;
  const uint8_t *cfg;
  uint8_t i, n, len, en;
  uint8_t bmRequestType;
  uint8_t bRequest;
  uint16_t wValue;
  uint16_t wIndex;
  uint16_t wLength;
  uint16_t desc_val;
  const uint8_t *desc_addr;
  uint8_t  desc_length;

  UENUM = 0;
  intbits = UEINTX;
  if (intbits & (1<<RXSTPI)) {
    bmRequestType = UEDATX;
    bRequest = UEDATX;
    wValue = UEDATX;
    wValue |= (UEDATX << 8);
    wIndex = UEDATX;
    wIndex |= (UEDATX << 8);
    wLength = UEDATX;
    wLength |= (UEDATX << 8);
    UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
    if (bRequest == GET_DESCRIPTOR) {
      list = (const uint8_t *)descriptor_list;
      for (i=0; ; i++) {
        if (i >= NUM_DESC_LIST) {
          UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
          return;
        }
        desc_val = pgm_read_word(list);
        if (desc_val != wValue) {
          list += sizeof(struct descriptor_list_struct);
          continue;
        }
        list += 2;
        desc_val = pgm_read_word(list);
        if (desc_val != wIndex) {
          list += sizeof(struct descriptor_list_struct)-2;
          continue;
        }
        list += 2;
        desc_addr = (const uint8_t *)pgm_read_word(list);
        list += 2;
        desc_length = pgm_read_byte(list);
        break;
      }
      len = (wLength < 256) ? wLength : 255;
      if (len > desc_length) len = desc_length;
      do {
        // wait for host ready for IN packet
        do {
          i = UEINTX;
        } while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
        if (i & (1<<RXOUTI)) return;  // abort
        // send IN packet
        n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
        for (i = n; i; i--) {
          UEDATX = pgm_read_byte(desc_addr++);
        }
        len -= n;
        usb_send_in();
      } while (len || n == ENDPOINT0_SIZE);
      return;
    }
    if (bRequest == SET_ADDRESS) {
      usb_send_in();
      usb_wait_in_ready();
      UDADDR = wValue | (1<<ADDEN);
      return;
    }
    if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
      usb_configuration = wValue;
      usb_send_in();
      cfg = endpoint_config_table;
      for (i=1; i<5; i++) {
        UENUM = i;
        en = pgm_read_byte(cfg++);
        UECONX = en;
        if (en) {
          UECFG0X = pgm_read_byte(cfg++);
          UECFG1X = pgm_read_byte(cfg++);
        }
      }
      UERST = 0x1E;
      UERST = 0;
      return;
    }
    if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
      usb_wait_in_ready();
      UEDATX = usb_configuration;
      usb_send_in();
      return;
    }

    if (bRequest == GET_STATUS) {
      usb_wait_in_ready();
      i = 0;
#ifdef SUPPORT_ENDPOINT_HALT
      if (bmRequestType == 0x82) {
        UENUM = wIndex;
        if (UECONX & (1<<STALLRQ)) i = 1;
        UENUM = 0;
      }
#endif
      UEDATX = i;
      UEDATX = 0;
      usb_send_in();
      return;
    }
#ifdef SUPPORT_ENDPOINT_HALT
    if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
	&& bmRequestType == 0x02 && wValue == 0) {
      i = wIndex & 0x7F;
      if (i >= 1 && i <= MAX_ENDPOINT) {
        usb_send_in();
        UENUM = i;
        if (bRequest == SET_FEATURE) {
          UECONX = (1<<STALLRQ)|(1<<EPEN);
        } else {
          UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
          UERST = (1 << i);
          UERST = 0;
        }
        return;
      }
    }
#endif
    if (wIndex == KEYBOARD_INTERFACE) {
      if (bmRequestType == 0xA1) {
        if (bRequest == HID_GET_REPORT) {
          usb_wait_in_ready();
          UEDATX = keyboard_modifier_keys;
          UEDATX = 0;
          for (i=0; i<6; i++) {
            UEDATX = keyboard_keys[i];
          }
          usb_send_in();
          return;
        }
        if (bRequest == HID_GET_IDLE) {
          usb_wait_in_ready();
          UEDATX = keyboard_idle_config;
          usb_send_in();
          return;
        }
        if (bRequest == HID_GET_PROTOCOL) {
          usb_wait_in_ready();
          UEDATX = keyboard_protocol;
          usb_send_in();
          return;
        }
      }
      if (bmRequestType == 0x21) {
        if (bRequest == HID_SET_REPORT) {
          usb_wait_receive_out();
          keyboard_leds = UEDATX;
          usb_ack_out();
          usb_send_in();
          return;
        }
        if (bRequest == HID_SET_IDLE) {
          keyboard_idle_config = (wValue >> 8);
          keyboard_idle_count = 0;
          usb_send_in();
          return;
        }
        if (bRequest == HID_SET_PROTOCOL) {
          keyboard_protocol = wValue;
          usb_send_in();
          return;
        }
      }
    }
  }
  UECONX = (1<<STALLRQ) | (1<<EPEN);  // stall
}