Tomas Cerskus / USBDevice

USB device stack with Nucleo F401RE support. NOTE: the default clock config needs to be changed to in order for USB to work.

Fork of USBDevice by Tomas Cerskus

Slightly modified original USBDevice library to support F401RE.

On F401RE the data pins of your USB connector should be attached to PA12 (D+) and PA11(D-). It is also required to connect the +5V USB line to PA9.

F401RE requires 48MHz clock for USB. Therefore in order for this to work you will need to change the default clock settings:

Clock settings for USB

#include "stm32f4xx_hal.h"

RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = 16;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = 16;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 7;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
    error("RTC error: LSI clock initialization failed."); 
}

NOTE: Changing the clock frequency might affect the behavior of other libraries. I only tested the Serial library.

UPDATE: Clock settings should not to be changed anymore! Looks like the newer mbed library has the required clock enabled.

USBHID/USBKeyboard.cpp

Committer:
tolaipner
Date:
2014-03-30
Revision:
24:4ed3e25c3edc
Parent:
11:eeb3cbbaa996

File content as of revision 24:4ed3e25c3edc:

/* Copyright (c) 2010-2011 mbed.org, MIT License
*
* 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.
*/

#include "stdint.h"

#include "USBKeyboard.h"

#define REPORT_ID_KEYBOARD 1
#define REPORT_ID_VOLUME   3


typedef struct {
    unsigned char usage;
    unsigned char modifier;
} KEYMAP;

#ifdef US_KEYBOARD
/* US keyboard (as HID standard) */
#define KEYMAP_SIZE (152)
const KEYMAP keymap[KEYMAP_SIZE] = {
    {0, 0},             /* NUL */
    {0, 0},             /* SOH */
    {0, 0},             /* STX */
    {0, 0},             /* ETX */
    {0, 0},             /* EOT */
    {0, 0},             /* ENQ */
    {0, 0},             /* ACK */
    {0, 0},             /* BEL */
    {0x2a, 0},          /* BS  */  /* Keyboard Delete (Backspace) */
    {0x2b, 0},          /* TAB */  /* Keyboard Tab */
    {0x28, 0},          /* LF  */  /* Keyboard Return (Enter) */
    {0, 0},             /* VT  */
    {0, 0},             /* FF  */
    {0, 0},             /* CR  */
    {0, 0},             /* SO  */
    {0, 0},             /* SI  */
    {0, 0},             /* DEL */
    {0, 0},             /* DC1 */
    {0, 0},             /* DC2 */
    {0, 0},             /* DC3 */
    {0, 0},             /* DC4 */
    {0, 0},             /* NAK */
    {0, 0},             /* SYN */
    {0, 0},             /* ETB */
    {0, 0},             /* CAN */
    {0, 0},             /* EM  */
    {0, 0},             /* SUB */
    {0, 0},             /* ESC */
    {0, 0},             /* FS  */
    {0, 0},             /* GS  */
    {0, 0},             /* RS  */
    {0, 0},             /* US  */
    {0x2c, 0},          /*   */
    {0x1e, KEY_SHIFT},      /* ! */
    {0x34, KEY_SHIFT},      /* " */
    {0x20, KEY_SHIFT},      /* # */
    {0x21, KEY_SHIFT},      /* $ */
    {0x22, KEY_SHIFT},      /* % */
    {0x24, KEY_SHIFT},      /* & */
    {0x34, 0},          /* ' */
    {0x26, KEY_SHIFT},      /* ( */
    {0x27, KEY_SHIFT},      /* ) */
    {0x25, KEY_SHIFT},      /* * */
    {0x2e, KEY_SHIFT},      /* + */
    {0x36, 0},          /* , */
    {0x2d, 0},          /* - */
    {0x37, 0},          /* . */
    {0x38, 0},          /* / */
    {0x27, 0},          /* 0 */
    {0x1e, 0},          /* 1 */
    {0x1f, 0},          /* 2 */
    {0x20, 0},          /* 3 */
    {0x21, 0},          /* 4 */
    {0x22, 0},          /* 5 */
    {0x23, 0},          /* 6 */
    {0x24, 0},          /* 7 */
    {0x25, 0},          /* 8 */
    {0x26, 0},          /* 9 */
    {0x33, KEY_SHIFT},      /* : */
    {0x33, 0},          /* ; */
    {0x36, KEY_SHIFT},      /* < */
    {0x2e, 0},          /* = */
    {0x37, KEY_SHIFT},      /* > */
    {0x38, KEY_SHIFT},      /* ? */
    {0x1f, KEY_SHIFT},      /* @ */
    {0x04, KEY_SHIFT},      /* A */
    {0x05, KEY_SHIFT},      /* B */
    {0x06, KEY_SHIFT},      /* C */
    {0x07, KEY_SHIFT},      /* D */
    {0x08, KEY_SHIFT},      /* E */
    {0x09, KEY_SHIFT},      /* F */
    {0x0a, KEY_SHIFT},      /* G */
    {0x0b, KEY_SHIFT},      /* H */
    {0x0c, KEY_SHIFT},      /* I */
    {0x0d, KEY_SHIFT},      /* J */
    {0x0e, KEY_SHIFT},      /* K */
    {0x0f, KEY_SHIFT},      /* L */
    {0x10, KEY_SHIFT},      /* M */
    {0x11, KEY_SHIFT},      /* N */
    {0x12, KEY_SHIFT},      /* O */
    {0x13, KEY_SHIFT},      /* P */
    {0x14, KEY_SHIFT},      /* Q */
    {0x15, KEY_SHIFT},      /* R */
    {0x16, KEY_SHIFT},      /* S */
    {0x17, KEY_SHIFT},      /* T */
    {0x18, KEY_SHIFT},      /* U */
    {0x19, KEY_SHIFT},      /* V */
    {0x1a, KEY_SHIFT},      /* W */
    {0x1b, KEY_SHIFT},      /* X */
    {0x1c, KEY_SHIFT},      /* Y */
    {0x1d, KEY_SHIFT},      /* Z */
    {0x2f, 0},          /* [ */
    {0x31, 0},          /* \ */
    {0x30, 0},          /* ] */
    {0x23, KEY_SHIFT},      /* ^ */
    {0x2d, KEY_SHIFT},      /* _ */
    {0x35, 0},          /* ` */
    {0x04, 0},          /* a */
    {0x05, 0},          /* b */
    {0x06, 0},          /* c */
    {0x07, 0},          /* d */
    {0x08, 0},          /* e */
    {0x09, 0},          /* f */
    {0x0a, 0},          /* g */
    {0x0b, 0},          /* h */
    {0x0c, 0},          /* i */
    {0x0d, 0},          /* j */
    {0x0e, 0},          /* k */
    {0x0f, 0},          /* l */
    {0x10, 0},          /* m */
    {0x11, 0},          /* n */
    {0x12, 0},          /* o */
    {0x13, 0},          /* p */
    {0x14, 0},          /* q */
    {0x15, 0},          /* r */
    {0x16, 0},          /* s */
    {0x17, 0},          /* t */
    {0x18, 0},          /* u */
    {0x19, 0},          /* v */
    {0x1a, 0},          /* w */
    {0x1b, 0},          /* x */
    {0x1c, 0},          /* y */
    {0x1d, 0},          /* z */
    {0x2f, KEY_SHIFT},      /* { */
    {0x31, KEY_SHIFT},      /* | */
    {0x30, KEY_SHIFT},      /* } */
    {0x35, KEY_SHIFT},      /* ~ */
    {0,0},              /* DEL */

    {0x3a, 0},          /* F1 */
    {0x3b, 0},          /* F2 */
    {0x3c, 0},          /* F3 */
    {0x3d, 0},          /* F4 */
    {0x3e, 0},          /* F5 */
    {0x3f, 0},          /* F6 */
    {0x40, 0},          /* F7 */
    {0x41, 0},          /* F8 */
    {0x42, 0},          /* F9 */
    {0x43, 0},          /* F10 */
    {0x44, 0},          /* F11 */
    {0x45, 0},          /* F12 */

    {0x46, 0},          /* PRINT_SCREEN */
    {0x47, 0},          /* SCROLL_LOCK */
    {0x39, 0},          /* CAPS_LOCK */
    {0x53, 0},          /* NUM_LOCK */
    {0x49, 0},          /* INSERT */
    {0x4a, 0},          /* HOME */
    {0x4b, 0},          /* PAGE_UP */
    {0x4e, 0},          /* PAGE_DOWN */
    
    {0x4f, 0},          /* RIGHT_ARROW */
    {0x50, 0},          /* LEFT_ARROW */
    {0x51, 0},          /* DOWN_ARROW */
    {0x52, 0},          /* UP_ARROW */
};

#else
/* UK keyboard */
#define KEYMAP_SIZE (152)
const KEYMAP keymap[KEYMAP_SIZE] = {
    {0, 0},             /* NUL */
    {0, 0},             /* SOH */
    {0, 0},             /* STX */
    {0, 0},             /* ETX */
    {0, 0},             /* EOT */
    {0, 0},             /* ENQ */
    {0, 0},             /* ACK */
    {0, 0},             /* BEL */
    {0x2a, 0},          /* BS  */  /* Keyboard Delete (Backspace) */
    {0x2b, 0},          /* TAB */  /* Keyboard Tab */
    {0x28, 0},          /* LF  */  /* Keyboard Return (Enter) */
    {0, 0},             /* VT  */
    {0, 0},             /* FF  */
    {0, 0},             /* CR  */
    {0, 0},             /* SO  */
    {0, 0},             /* SI  */
    {0, 0},             /* DEL */
    {0, 0},             /* DC1 */
    {0, 0},             /* DC2 */
    {0, 0},             /* DC3 */
    {0, 0},             /* DC4 */
    {0, 0},             /* NAK */
    {0, 0},             /* SYN */
    {0, 0},             /* ETB */
    {0, 0},             /* CAN */
    {0, 0},             /* EM  */
    {0, 0},             /* SUB */
    {0, 0},             /* ESC */
    {0, 0},             /* FS  */
    {0, 0},             /* GS  */
    {0, 0},             /* RS  */
    {0, 0},             /* US  */
    {0x2c, 0},          /*   */
    {0x1e, KEY_SHIFT},      /* ! */
    {0x1f, KEY_SHIFT},      /* " */
    {0x32, 0},          /* # */
    {0x21, KEY_SHIFT},      /* $ */
    {0x22, KEY_SHIFT},      /* % */
    {0x24, KEY_SHIFT},      /* & */
    {0x34, 0},          /* ' */
    {0x26, KEY_SHIFT},      /* ( */
    {0x27, KEY_SHIFT},      /* ) */
    {0x25, KEY_SHIFT},      /* * */
    {0x2e, KEY_SHIFT},      /* + */
    {0x36, 0},          /* , */
    {0x2d, 0},          /* - */
    {0x37, 0},          /* . */
    {0x38, 0},          /* / */
    {0x27, 0},          /* 0 */
    {0x1e, 0},          /* 1 */
    {0x1f, 0},          /* 2 */
    {0x20, 0},          /* 3 */
    {0x21, 0},          /* 4 */
    {0x22, 0},          /* 5 */
    {0x23, 0},          /* 6 */
    {0x24, 0},          /* 7 */
    {0x25, 0},          /* 8 */
    {0x26, 0},          /* 9 */
    {0x33, KEY_SHIFT},      /* : */
    {0x33, 0},          /* ; */
    {0x36, KEY_SHIFT},      /* < */
    {0x2e, 0},          /* = */
    {0x37, KEY_SHIFT},      /* > */
    {0x38, KEY_SHIFT},      /* ? */
    {0x34, KEY_SHIFT},      /* @ */
    {0x04, KEY_SHIFT},      /* A */
    {0x05, KEY_SHIFT},      /* B */
    {0x06, KEY_SHIFT},      /* C */
    {0x07, KEY_SHIFT},      /* D */
    {0x08, KEY_SHIFT},      /* E */
    {0x09, KEY_SHIFT},      /* F */
    {0x0a, KEY_SHIFT},      /* G */
    {0x0b, KEY_SHIFT},      /* H */
    {0x0c, KEY_SHIFT},      /* I */
    {0x0d, KEY_SHIFT},      /* J */
    {0x0e, KEY_SHIFT},      /* K */
    {0x0f, KEY_SHIFT},      /* L */
    {0x10, KEY_SHIFT},      /* M */
    {0x11, KEY_SHIFT},      /* N */
    {0x12, KEY_SHIFT},      /* O */
    {0x13, KEY_SHIFT},      /* P */
    {0x14, KEY_SHIFT},      /* Q */
    {0x15, KEY_SHIFT},      /* R */
    {0x16, KEY_SHIFT},      /* S */
    {0x17, KEY_SHIFT},      /* T */
    {0x18, KEY_SHIFT},      /* U */
    {0x19, KEY_SHIFT},      /* V */
    {0x1a, KEY_SHIFT},      /* W */
    {0x1b, KEY_SHIFT},      /* X */
    {0x1c, KEY_SHIFT},      /* Y */
    {0x1d, KEY_SHIFT},      /* Z */
    {0x2f, 0},          /* [ */
    {0x64, 0},          /* \ */
    {0x30, 0},          /* ] */
    {0x23, KEY_SHIFT},      /* ^ */
    {0x2d, KEY_SHIFT},      /* _ */
    {0x35, 0},          /* ` */
    {0x04, 0},          /* a */
    {0x05, 0},          /* b */
    {0x06, 0},          /* c */
    {0x07, 0},          /* d */
    {0x08, 0},          /* e */
    {0x09, 0},          /* f */
    {0x0a, 0},          /* g */
    {0x0b, 0},          /* h */
    {0x0c, 0},          /* i */
    {0x0d, 0},          /* j */
    {0x0e, 0},          /* k */
    {0x0f, 0},          /* l */
    {0x10, 0},          /* m */
    {0x11, 0},          /* n */
    {0x12, 0},          /* o */
    {0x13, 0},          /* p */
    {0x14, 0},          /* q */
    {0x15, 0},          /* r */
    {0x16, 0},          /* s */
    {0x17, 0},          /* t */
    {0x18, 0},          /* u */
    {0x19, 0},          /* v */
    {0x1a, 0},          /* w */
    {0x1b, 0},          /* x */
    {0x1c, 0},          /* y */
    {0x1d, 0},          /* z */
    {0x2f, KEY_SHIFT},      /* { */
    {0x64, KEY_SHIFT},      /* | */
    {0x30, KEY_SHIFT},      /* } */
    {0x32, KEY_SHIFT},      /* ~ */
    {0,0},             /* DEL */

    {0x3a, 0},          /* F1 */
    {0x3b, 0},          /* F2 */
    {0x3c, 0},          /* F3 */
    {0x3d, 0},          /* F4 */
    {0x3e, 0},          /* F5 */
    {0x3f, 0},          /* F6 */
    {0x40, 0},          /* F7 */
    {0x41, 0},          /* F8 */
    {0x42, 0},          /* F9 */
    {0x43, 0},          /* F10 */
    {0x44, 0},          /* F11 */
    {0x45, 0},          /* F12 */

    {0x46, 0},          /* PRINT_SCREEN */
    {0x47, 0},          /* SCROLL_LOCK */
    {0x39, 0},          /* CAPS_LOCK */
    {0x53, 0},          /* NUM_LOCK */
    {0x49, 0},          /* INSERT */
    {0x4a, 0},          /* HOME */
    {0x4b, 0},          /* PAGE_UP */
    {0x4e, 0},          /* PAGE_DOWN */
    
    {0x4f, 0},          /* RIGHT_ARROW */
    {0x50, 0},          /* LEFT_ARROW */
    {0x51, 0},          /* DOWN_ARROW */
    {0x52, 0},          /* UP_ARROW */
};
#endif

uint8_t * USBKeyboard::reportDesc() {
    static uint8_t reportDescriptor[] = {
        USAGE_PAGE(1), 0x01,                    // Generic Desktop
        USAGE(1), 0x06,                         // Keyboard
        COLLECTION(1), 0x01,                    // Application
        REPORT_ID(1),       REPORT_ID_KEYBOARD,

        USAGE_PAGE(1), 0x07,                    // Key Codes
        USAGE_MINIMUM(1), 0xE0,
        USAGE_MAXIMUM(1), 0xE7,
        LOGICAL_MINIMUM(1), 0x00,
        LOGICAL_MAXIMUM(1), 0x01,
        REPORT_SIZE(1), 0x01,
        REPORT_COUNT(1), 0x08,
        INPUT(1), 0x02,                         // Data, Variable, Absolute
        REPORT_COUNT(1), 0x01,
        REPORT_SIZE(1), 0x08,
        INPUT(1), 0x01,                         // Constant


        REPORT_COUNT(1), 0x05,
        REPORT_SIZE(1), 0x01,
        USAGE_PAGE(1), 0x08,                    // LEDs
        USAGE_MINIMUM(1), 0x01,
        USAGE_MAXIMUM(1), 0x05,
        OUTPUT(1), 0x02,                        // Data, Variable, Absolute
        REPORT_COUNT(1), 0x01,
        REPORT_SIZE(1), 0x03,
        OUTPUT(1), 0x01,                        // Constant


        REPORT_COUNT(1), 0x06,
        REPORT_SIZE(1), 0x08,
        LOGICAL_MINIMUM(1), 0x00,
        LOGICAL_MAXIMUM(1), 0x65,
        USAGE_PAGE(1), 0x07,                    // Key Codes
        USAGE_MINIMUM(1), 0x00,
        USAGE_MAXIMUM(1), 0x65,
        INPUT(1), 0x00,                         // Data, Array
        END_COLLECTION(0),

        // Media Control
        USAGE_PAGE(1), 0x0C,
        USAGE(1), 0x01,
        COLLECTION(1), 0x01,
        REPORT_ID(1), REPORT_ID_VOLUME,
        USAGE_PAGE(1), 0x0C,
        LOGICAL_MINIMUM(1), 0x00,
        LOGICAL_MAXIMUM(1), 0x01,
        REPORT_SIZE(1), 0x01,
        REPORT_COUNT(1), 0x07,
        USAGE(1), 0xB5,             // Next Track
        USAGE(1), 0xB6,             // Previous Track
        USAGE(1), 0xB7,             // Stop
        USAGE(1), 0xCD,             // Play / Pause
        USAGE(1), 0xE2,             // Mute
        USAGE(1), 0xE9,             // Volume Up
        USAGE(1), 0xEA,             // Volume Down
        INPUT(1), 0x02,             // Input (Data, Variable, Absolute)
        REPORT_COUNT(1), 0x01,
        INPUT(1), 0x01,
        END_COLLECTION(0),
    };
    reportLength = sizeof(reportDescriptor);
    return reportDescriptor;
}


bool USBKeyboard::EP1_OUT_callback() {
    uint32_t bytesRead = 0;
    uint8_t led[65];
    USBDevice::readEP(EPINT_OUT, led, &bytesRead, MAX_HID_REPORT_SIZE);
    
    // we take led[1] because led[0] is the report ID
    lock_status = led[1] & 0x07;
    
    // We activate the endpoint to be able to recceive data
    if (!readStart(EPINT_OUT, MAX_HID_REPORT_SIZE))
        return false;
    return true;
}

uint8_t USBKeyboard::lockStatus() {
    return lock_status;
}

int USBKeyboard::_putc(int c) {
    return keyCode(c, keymap[c].modifier);
}

bool USBKeyboard::keyCode(uint8_t key, uint8_t modifier) {
    // Send a simulated keyboard keypress. Returns true if successful.
    HID_REPORT report;

    report.data[0] = REPORT_ID_KEYBOARD;
    report.data[1] = modifier;
    report.data[2] = 0;
    report.data[3] = keymap[key].usage;
    report.data[4] = 0;
    report.data[5] = 0;
    report.data[6] = 0;
    report.data[7] = 0;
    report.data[8] = 0;

    report.length = 9;

    if (!send(&report)) {
        return false;
    }

    report.data[1] = 0;
    report.data[3] = 0;

    if (!send(&report)) {
        return false;
    }

    return true;

}


bool USBKeyboard::mediaControl(MEDIA_KEY key) {
    HID_REPORT report;

    report.data[0] = REPORT_ID_VOLUME;
    report.data[1] = (1 << key) & 0x7f;

    report.length = 2;

    if (!send(&report)) {
        return false;
    }

    report.data[0] = REPORT_ID_VOLUME;
    report.data[1] = 0;

    report.length = 2;

    return send(&report);
}


#define DEFAULT_CONFIGURATION (1)
#define TOTAL_DESCRIPTOR_LENGTH ((1 * CONFIGURATION_DESCRIPTOR_LENGTH) \
                               + (1 * INTERFACE_DESCRIPTOR_LENGTH) \
                               + (1 * HID_DESCRIPTOR_LENGTH) \
                               + (2 * ENDPOINT_DESCRIPTOR_LENGTH))

uint8_t * USBKeyboard::configurationDesc() {
    static uint8_t configurationDescriptor[] = {
        CONFIGURATION_DESCRIPTOR_LENGTH,// bLength
        CONFIGURATION_DESCRIPTOR,       // bDescriptorType
        LSB(TOTAL_DESCRIPTOR_LENGTH),   // wTotalLength (LSB)
        MSB(TOTAL_DESCRIPTOR_LENGTH),   // wTotalLength (MSB)
        0x01,                           // bNumInterfaces
        DEFAULT_CONFIGURATION,          // bConfigurationValue
        0x00,                           // iConfiguration
        C_RESERVED | C_SELF_POWERED,    // bmAttributes
        C_POWER(0),                     // bMaxPowerHello World from Mbed

        INTERFACE_DESCRIPTOR_LENGTH,    // bLength
        INTERFACE_DESCRIPTOR,           // bDescriptorType
        0x00,                           // bInterfaceNumber
        0x00,                           // bAlternateSetting
        0x02,                           // bNumEndpoints
        HID_CLASS,                      // bInterfaceClass
        1,                              // bInterfaceSubClass
        1,                              // bInterfaceProtocol (keyboard)
        0x00,                           // iInterface

        HID_DESCRIPTOR_LENGTH,          // bLength
        HID_DESCRIPTOR,                 // bDescriptorType
        LSB(HID_VERSION_1_11),          // bcdHID (LSB)
        MSB(HID_VERSION_1_11),          // bcdHID (MSB)
        0x00,                           // bCountryCode
        0x01,                           // bNumDescriptors
        REPORT_DESCRIPTOR,              // bDescriptorType
        (uint8_t)(LSB(reportDescLength())),  // wDescriptorLength (LSB)
        (uint8_t)(MSB(reportDescLength())),  // wDescriptorLength (MSB)

        ENDPOINT_DESCRIPTOR_LENGTH,     // bLength
        ENDPOINT_DESCRIPTOR,            // bDescriptorType
        PHY_TO_DESC(EPINT_IN),          // bEndpointAddress
        E_INTERRUPT,                    // bmAttributes
        LSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (LSB)
        MSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (MSB)
        1,                             // bInterval (milliseconds)

        ENDPOINT_DESCRIPTOR_LENGTH,     // bLength
        ENDPOINT_DESCRIPTOR,            // bDescriptorType
        PHY_TO_DESC(EPINT_OUT),          // bEndpointAddress
        E_INTERRUPT,                    // bmAttributes
        LSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (LSB)
        MSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (MSB)
        1,                             // bInterval (milliseconds)
    };
    return configurationDescriptor;
}