An input/output controller for virtual pinball machines, with plunger position tracking, accelerometer-based nudge sensing, button input encoding, and feedback device control.

Dependencies:   USBDevice mbed FastAnalogIn FastIO FastPWM SimpleDMA

/media/uploads/mjr/pinscape_no_background_small_L7Miwr6.jpg

The Pinscape Controller is a special-purpose software project that I wrote for my virtual pinball machine.

New version: V2 is now available! The information below is for version 1, which will continue to be available for people who prefer the original setup.

What exactly is a virtual pinball machine? It's basically a video-game pinball emulator built to look like a real pinball machine. (The picture at right is the one I built.) You start with a standard pinball cabinet, either built from scratch or salvaged from a real machine. Inside, you install a PC motherboard to run the software, and install TVs in place of the playfield and backglass. Several Windows pinball programs can take advantage of this setup, including the open-source project Visual Pinball, which has hundreds of tables available. Building one of these makes a great DIY project, and it's a good way to add to your skills at woodworking, computers, and electronics. Check out the Cabinet Builders' Forum on vpforums.org for lots of examples and advice.

This controller project is a key piece in my setup that helps integrate the video game into the pinball cabinet. It handles several input/output tasks that are unique to virtual pinball machines. First, it lets you connect a mechanical plunger to the software, so you can launch the ball like on a real machine. Second, it sends "nudge" data to the software, based on readings from an accelerometer. This lets you interact with the game physically, which makes the playing experience more realistic and immersive. Third, the software can handle button input (for wiring flipper buttons and other cabinet buttons), and fourth, it can control output devices (for tactile feedback, button lights, flashers, and other special effects).

Documentation

The Hardware Build Guide (PDF) has detailed instructions on how to set up a Pinscape Controller for your own virtual pinball cabinet.

Update notes

December 2015 version: This version fully supports the new Expansion Board project, but it'll also run without it. The default configuration settings haven't changed, so existing setups should continue to work as before.

August 2015 version: Be sure to get the latest version of the Config Tool for windows if you're upgrading from an older version of the firmware. This update adds support for TSL1412R sensors (a version of the 1410 sensor with a slightly larger pixel array), and a config option to set the mounting orientation of the board in the firmware rather than in VP (for better support for FP and other pinball programs that don't have VP's flexibility for setting the rotation).

Feb/March 2015 software versions: If you have a CCD plunger that you've been using with the older versions, and the plunger stops working (or doesn't work as well) after you update to the latest version, you might need to increase the brightness of your light source slightly. Check the CCD exposure with the Windows config tool to see if it looks too dark. The new software reads the CCD much more quickly than the old versions did. This makes the "shutter speed" faster, which might require a little more light to get the same readings. The CCD is actually really tolerant of varying light levels, so you probably won't have to change anything for the update - I didn't. But if you do have any trouble, have a look at the exposure meter and try a slightly brighter light source if the exposure looks too dark.

Downloads

  • Config tool for Windows (.exe and C# source): this is a Windows program that lets you view the raw pixel data from the CCD sensor, trigger plunger calibration mode, and configure some of the software options on the controller.
  • Custom VP builds: I created modified versions of Visual Pinball 9.9 and Physmod5 that you might want to use in combination with this controller. The modified versions have special handling for plunger calibration specific to the Pinscape Controller, as well as some enhancements to the nudge physics. If you're not using the plunger, you might still want it for the nudge improvements. The modified version also works with any other input controller, so you can get the enhanced nudging effects even if you're using a different plunger/nudge kit. The big change in the modified versions is a "filter" for accelerometer input that's designed to make the response to cabinet nudges more realistic. It also makes the response more subdued than in the standard VP, so it's not to everyone's taste. The downloads include both the updated executables and the source code changes, in case you want to merge the changes into your own custom version(s).

    Note! These features are now standard in the official VP 9.9.1 and VP 10 releases, so you don't need my custom builds if you're using 9.9.1 or 10 or later. I don't think there's any reason to use my 9.9 instead of the official 9.9.1, but I'm leaving it here just in case. In the official VP releases, look for the checkbox "Enable Nudge Filter" in the Keys preferences dialog. (There's no checkbox in my custom builds, though; the filter is simply always on in those.)
  • Output circuit shopping list: This is a saved shopping cart at mouser.com with the parts needed for each output driver, if you want to use the LedWiz emulator feature. Note that quantities in the cart are for one output channel, so multiply everything by the number of channels you plan to use, except that you only need one of the ULN2803 transistor array chips for each eight output circuits.
  • Lemming77's potentiometer mounting bracket and shooter rod connecter: Sketchup designs for 3D-printable parts for mounting a slide potentiometer as the plunger sensor. These were designed for a particular slide potentiometer that used to be available from an Aliexpress.com seller but is no longer listed. You can probably use this design as a starting point for other similar devices; just check the dimensions before committing the design to plastic.

Features

  • Plunger position sensing, using a TAOS TSL 1410R CCD linear array sensor. This sensor is a 1280 x 1 pixel array at 400 dpi, which makes it about 3" long - almost exactly the travel distance of a standard pinball plunger. The idea is that you install the sensor just above (within a few mm of) the shooter rod on the inside of the cabinet, with the CCD window facing down, aligned with and centered on the long axis of the shooter rod, and positioned so that the rest position of the tip is about 1/2" from one end of the window. As you pull back the plunger, the tip will travel down the length of the window, and the maximum retraction point will put the tip just about at the far end of the window. Put a light source below, facing the sensor - I'm using two typical 20 mA blue LEDs about 8" away (near the floor of the cabinet) with good results. The principle of operation is that the shooter rod casts a shadow on the CCD, so pixels behind the rod will register lower brightness than pixels that aren't in the shadow. We scan down the length of the sensor for the edge between darker and brighter, and this tells us how far back the rod has been pulled. We can read the CCD at about 25-30 ms intervals, so we can get rapid updates. We pass the readings reports to VP via our USB joystick reports.

    The hardware build guide includes schematics showing how to wire the CCD to the KL25Z. It's pretty straightforward - five wires between the two devices, no external components needed. Two GPIO ports are used as outputs to send signals to the device and one is used as an ADC in to read the pixel brightness inputs. The config tool has a feature that lets you display the raw pixel readings across the array, so you can test that the CCD is working and adjust the light source to get the right exposure level.

    Alternatively, you can use a slide potentiometer as the plunger sensor. This is a cheaper and somewhat simpler option that seems to work quite nicely, as you can see in Lemming77's video of this setup in action. This option is also explained more fully in the build guide.
  • Nudge sensing via the KL25Z's on-board accelerometer. Mounting the board in your cabinet makes it feel the same accelerations the cabinet experiences when you nudge it. Visual Pinball already knows how to interpret accelerometer input as nudging, so we simply feed the acceleration readings to VP via the joystick interface.
  • Cabinet button wiring. Up to 24 pushbuttons and switches can be wired to the controller for input controls (for example, flipper buttons, the Start button, the tilt bob, coin slot switches, and service door buttons). These appear to Windows as joystick buttons. VP can map joystick buttons to pinball inputs via its keyboard preferences dialog. (You can raise the 24-button limit by editing the source code, but since all of the GPIO pins are allocated, you'll have to reassign pins currently used for other functions.)
  • LedWiz emulation (limited). In addition to emulating a joystick, the device emulates the LedWiz USB interface, so controllers on the PC side such as DirectOutput Framework can recognize it and send it commands to control lights, solenoids, and other feedback devices. 22 GPIO ports are assigned by default as feedback device outputs. This feature has some limitations. The big one is that the KL25Z hardware only has 10 PWM channels, which isn't enough for a fully decked-out cabinet. You also need to build some external power driver circuitry to use this feature, because of the paltry 4mA output capacity of the KL25Z GPIO ports. The build guide includes instructions for a simple and robust output circuit, including part numbers for the exact components you need. It's not hard if you know your way around a soldering iron, but just be aware that it'll take a little work.

Warning: This is not replacement software for the VirtuaPin plunger kit. If you bought the VirtuaPin kit, please don't try to install this software. The VP kit happens to use the same microcontroller board, but the rest of its hardware is incompatible. The VP kit uses a different type of sensor for its plunger and has completely different button wiring, so the Pinscape software won't work properly with it.

USBJoystick/USBJoystick.cpp

Committer:
mjr
Date:
2015-12-19
Revision:
35:e959ffba78fd
Parent:
33:d832bcab089e
Child:
37:ed52738445fc

File content as of revision 35:e959ffba78fd:

/* Copyright (c) 2010-2011 mbed.org, MIT License
* Modified Mouse code for Joystick - WH 2012
*
* 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 "USBJoystick.h"

#include "config.h"  // Pinscape configuration



// Length of our joystick reports.  Important: This must be kept in sync 
// with the actual joystick report format sent in update().
const int reportLen = 14;

bool USBJoystick::update(int16_t x, int16_t y, int16_t z, uint32_t buttons, uint16_t status) 
{
   _x = x;
   _y = y;
   _z = z;
   _buttonsLo = (uint16_t)(buttons & 0xffff);
   _buttonsHi = (uint16_t)((buttons >> 16) & 0xffff);
   _status = status;
 
   // send the report
   return update();
}

bool USBJoystick::update() 
{
   HID_REPORT report;

   // Fill the report according to the Joystick Descriptor
#define put(idx, val) (report.data[idx] = (val) & 0xff, report.data[(idx)+1] = ((val) >> 8) & 0xff)
   put(0, _status);
   put(2, 0);  // second byte of status isn't used in normal reports
   put(4, _buttonsLo);
   put(6, _buttonsHi);
   put(8, _x);
   put(10, _y);
   put(12, _z);
   
   // important: keep reportLen in sync with the actual byte length of
   // the reports we build here
   report.length = reportLen;
 
   // send the report
   return sendTO(&report, 100);
}

bool USBJoystick::kbUpdate(uint8_t data[8])
{
    // set up the report
    HID_REPORT report;
    report.data[0] = REPORT_ID_KB;      // report ID = keyboard
    memcpy(&report.data[1], data, 8);   // copy the kb report data
    report.length = 9;                  // length = ID prefix + kb report length
    
    // send it to endpoint 4 (the keyboard interface endpoint)
    return writeTO(EP4IN, report.data, report.length, MAX_PACKET_SIZE_EPINT, 100);
}

bool USBJoystick::mediaUpdate(uint8_t data)
{
    // set up the report
    HID_REPORT report;
    report.data[0] = REPORT_ID_MEDIA;   // report ID = media
    report.data[1] = data;              // key pressed bits
    report.length = 2;
    
    // send it
    return writeTO(EP4IN, report.data, report.length, MAX_PACKET_SIZE_EPINT, 100);
}
 
bool USBJoystick::updateExposure(int &idx, int npix, const uint16_t *pix)
{
    HID_REPORT report;
    
    // Set the special status bits to indicate it's an exposure report.
    // The high 5 bits of the status word are set to 10000, and the
    // low 11 bits are the current pixel index.
    uint16_t s = idx | 0x8000;
    put(0, s);
    
    // start at the second byte
    int ofs = 2;
    
    // in the first report, add the total pixel count as the next two bytes
    if (idx == 0)
    {
        put(ofs, npix);
        ofs += 2;
    }
        
    // now fill out the remaining words with exposure values
    report.length = reportLen;
    for ( ; ofs + 1 < report.length ; ofs += 2)
    {
        uint16_t p = (idx < npix ? pix[idx++] : 0);
        put(ofs, p);
    }
    
    // send the report
    return sendTO(&report, 100);
}

bool USBJoystick::reportConfig(int numOutputs, int unitNo, int plungerZero, int plungerMax)
{
    HID_REPORT report;

    // initially fill the report with zeros
    memset(report.data, 0, sizeof(report.data));
    
    // Set the special status bits to indicate that it's a config report.
    uint16_t s = 0x8800;
    put(0, s);
    
    // write the number of configured outputs
    put(2, numOutputs);
    
    // write the unit number
    put(4, unitNo);
    
    // write the plunger zero and max values
    put(6, plungerZero);
    put(8, plungerMax);
    
    // send the report
    report.length = reportLen;
    return sendTO(&report, 100);
}

bool USBJoystick::move(int16_t x, int16_t y) 
{
     _x = x;
     _y = y;
     return update();
}

bool USBJoystick::setZ(int16_t z) 
{
    _z = z;
    return update();
}
 
bool USBJoystick::buttons(uint32_t buttons) 
{
     _buttonsLo = (uint16_t)(buttons & 0xffff);
     _buttonsHi = (uint16_t)((buttons >> 16) & 0xffff);
     return update();
}

bool USBJoystick::updateStatus(uint32_t status)
{
   HID_REPORT report;

   // Fill the report according to the Joystick Descriptor
#define put(idx, val) (report.data[idx] = (val) & 0xff, report.data[(idx)+1] = ((val) >> 8) & 0xff)
   memset(report.data, 0, reportLen);
   put(0, status);
   report.length = reportLen;
 
   // send the report
   return sendTO(&report, 100);
}

void USBJoystick::_init() {
 
   _x = 0;                       
   _y = 0;     
   _z = 0;
   _buttonsLo = 0x0000;
   _buttonsHi = 0x0000;
   _status = 0;
}
 
 
// --------------------------------------------------------------------------
//
// USB HID Report Descriptor - Joystick
//
static uint8_t reportDescriptorJS[] = 
{         
    USAGE_PAGE(1), 0x01,            // Generic desktop
    USAGE(1), 0x04,                 // Joystick
    COLLECTION(1), 0x01,            // Application
     
        // input report (device to host)

        USAGE_PAGE(1), 0x06,        // generic device controls - for config status
        USAGE(1), 0x00,             // undefined device control
        LOGICAL_MINIMUM(1), 0x00,   // 8-bit values
        LOGICAL_MAXIMUM(1), 0xFF,
        REPORT_SIZE(1), 0x08,       // 8 bits per report
        REPORT_COUNT(1), 0x04,      // 4 reports (4 bytes)
        INPUT(1), 0x02,             // Data, Variable, Absolute

        USAGE_PAGE(1), 0x09,        // Buttons
        USAGE_MINIMUM(1), 0x01,     // { buttons }
        USAGE_MAXIMUM(1), 0x20,     // {  1-32   }
        LOGICAL_MINIMUM(1), 0x00,   // 1-bit buttons - 0...
        LOGICAL_MAXIMUM(1), 0x01,   // ...to 1
        REPORT_SIZE(1), 0x01,       // 1 bit per report
        REPORT_COUNT(1), 0x20,      // 32 reports
        UNIT_EXPONENT(1), 0x00,     // Unit_Exponent (0)
        UNIT(1), 0x00,              // Unit (None)                                           
        INPUT(1), 0x02,             // Data, Variable, Absolute
       
        USAGE_PAGE(1), 0x01,        // Generic desktop
        USAGE(1), 0x30,             // X axis
        USAGE(1), 0x31,             // Y axis
        USAGE(1), 0x32,             // Z axis
        LOGICAL_MINIMUM(2), 0x00,0xF0,   // each value ranges -4096
        LOGICAL_MAXIMUM(2), 0x00,0x10,   // ...to +4096
        REPORT_SIZE(1), 0x10,       // 16 bits per report
        REPORT_COUNT(1), 0x03,      // 3 reports (X, Y, Z)
        INPUT(1), 0x02,             // Data, Variable, Absolute
         
        // output report (host to device)
        REPORT_SIZE(1), 0x08,       // 8 bits per report
        REPORT_COUNT(1), 0x08,      // output report count - 8-byte LedWiz format
        0x09, 0x01,                 // usage
        0x91, 0x01,                 // Output (array)

    END_COLLECTION(0)
};

// 
// USB HID Report Descriptor - Keyboard/Media Control
//
static uint8_t reportDescriptorKB[] = 
{
    USAGE_PAGE(1), 0x01,                    // Generic Desktop
    USAGE(1), 0x06,                         // Keyboard
    COLLECTION(1), 0x01,                    // Application
        REPORT_ID(1), REPORT_ID_KB,

        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_MEDIA,
        USAGE_PAGE(1), 0x0C,
        LOGICAL_MINIMUM(1), 0x00,
        LOGICAL_MAXIMUM(1), 0x01,
        REPORT_SIZE(1), 0x01,
        REPORT_COUNT(1), 0x07,
        USAGE(1), 0xE9,             // Volume Up
        USAGE(1), 0xEA,             // Volume Down
        USAGE(1), 0xE2,             // Mute
        USAGE(1), 0xB5,             // Next Track
        USAGE(1), 0xB6,             // Previous Track
        USAGE(1), 0xB7,             // Stop
        USAGE(1), 0xCD,             // Play / Pause
        INPUT(1), 0x02,             // Input (Data, Variable, Absolute)
        REPORT_COUNT(1), 0x01,
        INPUT(1), 0x01,
    END_COLLECTION(0),
};

// 
// USB HID Report Descriptor - LedWiz only, with no joystick or keyboard
// input reporting
//
static uint8_t reportDescriptorLW[] = 
{         
    USAGE_PAGE(1), 0x01,            // Generic desktop
    USAGE(1), 0x00,                 // Undefined

    COLLECTION(1), 0x01,            // Application
     
        // input report (device to host)
        USAGE_PAGE(1), 0x06,        // generic device controls - for config status
        USAGE(1), 0x00,             // undefined device control
        LOGICAL_MINIMUM(1), 0x00,   // 8-bit values
        LOGICAL_MAXIMUM(1), 0xFF,
        REPORT_SIZE(1), 0x08,       // 8 bits per report
        REPORT_COUNT(1), reportLen, // standard report length (same as if we were in joystick mode)
        INPUT(1), 0x02,             // Data, Variable, Absolute

        // output report (host to device)
        REPORT_SIZE(1), 0x08,       // 8 bits per report
        REPORT_COUNT(1), 0x08,      // output report count (LEDWiz messages)
        0x09, 0x01,                 // usage
        0x91, 0x01,                 // Output (array)

    END_COLLECTION(0)
};


uint8_t * USBJoystick::reportDescN(int idx) 
{    
    if (enableJoystick)
    {
        // Joystick reports are enabled.  Use the full joystick report
        // format, or full keyboard report format, depending on which
        // interface is being requested.
        switch (idx)
        {
        case 0:
            // joystick interface
            reportLength = sizeof(reportDescriptorJS);
            return reportDescriptorJS;
            
        case 1:
            // keyboard interface
            reportLength = sizeof(reportDescriptorKB);
            return reportDescriptorKB;
            
        default:
            // unknown interface
            reportLength = 0;
            return 0;
        }
    }
    else
    {
        // Joystick reports are disabled.  Use the LedWiz-only format.
        reportLength = sizeof(reportDescriptorLW);
        return reportDescriptorLW;
    }
} 
 
 uint8_t * USBJoystick::stringImanufacturerDesc() {
    static uint8_t stringImanufacturerDescriptor[] = {
        0x10,                                            /*bLength*/
        STRING_DESCRIPTOR,                               /*bDescriptorType 0x03*/
        'm',0,'j',0,'r',0,'c',0,'o',0,'r',0,'p',0        /*bString iManufacturer - mjrcorp*/
    };
    return stringImanufacturerDescriptor;
}

uint8_t * USBJoystick::stringIserialDesc() {
    static uint8_t stringIserialDescriptor[] = {
        0x16,                                                           /*bLength*/
        STRING_DESCRIPTOR,                                              /*bDescriptorType 0x03*/
        '0',0,'1',0,'2',0,'3',0,'4',0,'5',0,'6',0,'7',0,'8',0,'9',0,    /*bString iSerial - 0123456789*/
    };
    return stringIserialDescriptor;
}

uint8_t * USBJoystick::stringIproductDesc() {
    static uint8_t stringIproductDescriptor[] = {
        0x28,                                                       /*bLength*/
        STRING_DESCRIPTOR,                                          /*bDescriptorType 0x03*/
        'P',0,'i',0,'n',0,'s',0,'c',0,'a',0,'p',0,'e',0,
        ' ',0,'C',0,'o',0,'n',0,'t',0,'r',0,'o',0,'l',0,
        'l',0,'e',0,'r',0                                           /*String iProduct */
    };
    return stringIproductDescriptor;
}

#define DEFAULT_CONFIGURATION (1)

uint8_t * USBJoystick::configurationDesc() 
{
    int rptlen0 = reportDescLengthN(0);
    int rptlen1 = reportDescLengthN(1);
    if (useKB)
    {
        int cfglenKB = ((1 * CONFIGURATION_DESCRIPTOR_LENGTH)
                        + (2 * INTERFACE_DESCRIPTOR_LENGTH)
                        + (2 * HID_DESCRIPTOR_LENGTH)
                        + (4 * ENDPOINT_DESCRIPTOR_LENGTH));
        static uint8_t configurationDescriptorWithKB[] = 
        {
            CONFIGURATION_DESCRIPTOR_LENGTH,// bLength
            CONFIGURATION_DESCRIPTOR,       // bDescriptorType
            LSB(cfglenKB),                  // wTotalLength (LSB)
            MSB(cfglenKB),                  // wTotalLength (MSB)
            0x02,                           // bNumInterfaces - TWO INTERFACES (JOYSTICK + KEYBOARD)
            DEFAULT_CONFIGURATION,          // bConfigurationValue
            0x00,                           // iConfiguration
            C_RESERVED | C_SELF_POWERED,    // bmAttributes
            C_POWER(0),                     // bMaxPowerHello World from Mbed
        
            // INTERFACE 0 - JOYSTICK/LEDWIZ
            INTERFACE_DESCRIPTOR_LENGTH,    // bLength
            INTERFACE_DESCRIPTOR,           // bDescriptorType
            0x00,                           // bInterfaceNumber - first interface = 0
            0x00,                           // bAlternateSetting
            0x02,                           // bNumEndpoints
            HID_CLASS,                      // bInterfaceClass
            HID_SUBCLASS_NONE,              // bInterfaceSubClass
            HID_PROTOCOL_NONE,              // bInterfaceProtocol
            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
            LSB(rptlen0),                   // wDescriptorLength (LSB)
            MSB(rptlen0),                   // wDescriptorLength (MSB)
        
            ENDPOINT_DESCRIPTOR_LENGTH,     // bLength
            ENDPOINT_DESCRIPTOR,            // bDescriptorType
            PHY_TO_DESC(EPINT_IN),          // bEndpointAddress - EPINT == EP1
            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 - EPINT == EP1
            E_INTERRUPT,                    // bmAttributes
            LSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (LSB)
            MSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (MSB)
            1,                              // bInterval (milliseconds)
            
            // INTERFACE 1 - KEYBOARD
            INTERFACE_DESCRIPTOR_LENGTH,    // bLength
            INTERFACE_DESCRIPTOR,           // bDescriptorType
            0x01,                           // bInterfaceNumber - second interface = 1
            0x00,                           // bAlternateSetting
            0x02,                           // bNumEndpoints
            HID_CLASS,                      // bInterfaceClass
            1,                              // bInterfaceSubClass - KEYBOARD
            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
            LSB(rptlen1),                   // wDescriptorLength (LSB)
            MSB(rptlen1),                   // wDescriptorLength (MSB)
        
            ENDPOINT_DESCRIPTOR_LENGTH,     // bLength
            ENDPOINT_DESCRIPTOR,            // bDescriptorType
            PHY_TO_DESC(EP4IN),             // 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(EP4OUT),            // bEndpointAddress
            E_INTERRUPT,                    // bmAttributes
            LSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (LSB)
            MSB(MAX_PACKET_SIZE_EPINT),     // wMaxPacketSize (MSB)
            1,                              // bInterval (milliseconds)
        };

        // Keyboard + joystick interfaces
        return configurationDescriptorWithKB;
    }
    else
    {
        // No keyboard - joystick interface only
        int cfglenNoKB = ((1 * CONFIGURATION_DESCRIPTOR_LENGTH)
                          + (1 * INTERFACE_DESCRIPTOR_LENGTH)
                          + (1 * HID_DESCRIPTOR_LENGTH)
                          + (2 * ENDPOINT_DESCRIPTOR_LENGTH));
        static uint8_t configurationDescriptorNoKB[] = 
        {
            CONFIGURATION_DESCRIPTOR_LENGTH,// bLength
            CONFIGURATION_DESCRIPTOR,       // bDescriptorType
            LSB(cfglenNoKB),                // wTotalLength (LSB)
            MSB(cfglenNoKB),                // 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(rptlen0)),        // wDescriptorLength (LSB)
            (uint8_t)(MSB(rptlen0)),        // 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 configurationDescriptorNoKB;
    }
}

// Set the configuration.  We need to set up the endpoints for
// our active interfaces.
bool USBJoystick::USBCallback_setConfiguration(uint8_t configuration) 
{
    // we only have one valid configuration
    if (configuration != DEFAULT_CONFIGURATION)
        return false;
        
    // Configure endpoint 1 - we use this in all cases, for either
    // the combined joystick/ledwiz interface or just the ledwiz interface
    addEndpoint(EPINT_IN, MAX_PACKET_SIZE_EPINT);
    addEndpoint(EPINT_OUT, MAX_PACKET_SIZE_EPINT);
    readStart(EPINT_OUT, MAX_HID_REPORT_SIZE);
    
    // if the keyboard is enabled, configure endpoint 4 for the kb interface
    if (useKB)
    {
        addEndpoint(EP4IN, MAX_PACKET_SIZE_EPINT);
        addEndpoint(EP4OUT, MAX_PACKET_SIZE_EPINT);
        readStart(EP4OUT, MAX_PACKET_SIZE_EPINT);
    }

    // success
    return true;
}

// Handle messages on endpoint 4 - this is the keyboard interface.
// The host uses this to send updates for the keyboard indicator LEDs
// (caps lock, num lock, etc).  We don't do anything with these, but
// we at least need to read them to keep the pipe from clogging up.
bool USBJoystick::EP4_OUT_callback() 
{
    // read this message
    uint32_t bytesRead = 0;
    uint8_t led[65];
    USBDevice::readEP(EP4OUT, led, &bytesRead, MAX_HID_REPORT_SIZE);

    // start the next read
    return readStart(EP4OUT, MAX_HID_REPORT_SIZE);
}