CODEWITHSUNDEEP
usbreporthidjoystickusb-descriptor
Tomas Gach
Tomas Gach

Reputation: 43

Simple joystick hid report descriptor doesn't work

Using atmega8 chip and V-USB library I made a little bridge to connect my NES gamepad to USB. At first I used one of examples as my hid descriptor and so... I had my device correctly recognized in Windows when I set it to handshake with this HID report descriptor

PROGMEM const char usbHidReportDescriptor[100] = {
    0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
    0x15, 0x00,                    // LOGICAL_MINIMUM (0)
    0x09, 0x04,                    // USAGE (Joystick)
    0xa1, 0x01,                    // COLLECTION (Application)
    0x05, 0x02,                    //   USAGE_PAGE (Simulation Controls)
    0x09, 0xbb,                    //   USAGE (Throttle)
    0x15, 0x81,                    //   LOGICAL_MINIMUM (-127)
    0x25, 0x7f,                    //   LOGICAL_MAXIMUM (127)
    0x75, 0x08,                    //   REPORT_SIZE (8)
    0x95, 0x01,                    //   REPORT_COUNT (1)
    0x81, 0x02,                    //   INPUT (Data,Var,Abs)
    0x05, 0x01,                    //   USAGE_PAGE (Generic Desktop)
    0x09, 0x01,                    //   USAGE (Pointer)
    0xa1, 0x00,                    //   COLLECTION (Physical)
    0x09, 0x30,                    //     USAGE (X)
    0x09, 0x31,                    //     USAGE (Y)
    0x95, 0x02,                    //     REPORT_COUNT (2)
    0x81, 0x02,                    //     INPUT (Data,Var,Abs)
    0xc0,                          //   END_COLLECTION
    0x09, 0x39,                    //   USAGE (Hat switch)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x25, 0x03,                    //   LOGICAL_MAXIMUM (3)
    0x35, 0x00,                    //   PHYSICAL_MINIMUM (0)
    0x46, 0x0e, 0x01,              //   PHYSICAL_MAXIMUM (270)
    0x65, 0x14,                    //   UNIT (Eng Rot:Angular Pos)
    0x75, 0x04,                    //   REPORT_SIZE (4)
    0x95, 0x01,                    //   REPORT_COUNT (1)
    0x81, 0x02,                    //   INPUT (Data,Var,Abs)
    0x05, 0x09,                    //   USAGE_PAGE (Button)
    0x19, 0x01,                    //   USAGE_MINIMUM (Button 1)
    0x29, 0x04,                    //   USAGE_MAXIMUM (Button 4)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
    0x75, 0x01,                    //   REPORT_SIZE (1)
0x95, 0x04,                    //   REPORT_COUNT (4)
0x55, 0x00,                    //   UNIT_EXPONENT (0)
0x65, 0x00,                    //   UNIT (None)
0x81, 0x02,                    //   INPUT (Data,Var,Abs)
0xc0                           // END_COLLECTION
};

and this report type

typedef struct{
    char    throttle;
    char    x;
    char    y;
    uchar    hatSwitchAndButtons;
}report_t;

But when I made it simpler:

PROGMEM const char usbHidReportDescriptor[48] =  {
    0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
    0x09, 0x04,                    // USAGE (Joystick)
    0xa1, 0x01,                    // COLLECTION (Application)
    0x15, 0x81,                    //   LOGICAL_MINIMUM (-127)
    0x25, 0x7f,                    //   LOGICAL_MAXIMUM (127)
    0x05, 0x01,                    //   USAGE_PAGE (Generic Desktop)
    0x09, 0x01,                    //   USAGE (Pointer)
    0xa1, 0x00,                    //   COLLECTION (Physical)
    0x09, 0x30,                    //     USAGE (X)
    0x09, 0x31,                    //     USAGE (Y)
    0x75, 0x08,                    //     REPORT_SIZE (8)
    0x95, 0x02,                    //     REPORT_COUNT (2)
    0x81, 0x02,                    //     INPUT (Data,Var,Abs)
    0xc0,                          //   END_COLLECTION
    0x05, 0x09,                    //   USAGE_PAGE (Button)
    0x19, 0x01,                    //   USAGE_MINIMUM (Button 1)
    0x29, 0x04,                    //   USAGE_MAXIMUM (Button 8)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x25, 0x01,                    //   LOGICAL_MAXIMUM (1)
    0x75, 0x01,                    //   REPORT_SIZE (1)
    0x95, 0x04,                    //   REPORT_COUNT (8)
    0x55, 0x00,                    //   UNIT_EXPONENT (0)
    0x65, 0x00,                    //   UNIT (None)
    0x81, 0x02,                    //   INPUT (Data,Var,Abs)
    0xc0                           // END_COLLECTION
};

typedef struct{
    char    x;
    char    y;
    uchar    buttons;
}report_t;

Windows has not been unable to install my joystick. It will still recognize it's name but will fail to finish installation.

I'm confused because USB Hid Tool validates this report descriptor.

Any idea, please?

Upvotes: 4

Views: 5691

Answers (1)

PickRelated
PickRelated

Reputation: 76

0x29, 0x04,                    //   USAGE_MAXIMUM (Button 8)
0x95, 0x04,                    //   REPORT_COUNT (8)

Ooops, looks like someone programms with comments. :) Change 0x04 to 0x08. And watch so that each report size could be devided by 8 (8,16,24,32 etc.)

Upvotes: 6

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