I have problem when i use nRF52840 to make a touchpad

[Harvey.Zhang]

Hello,

I have made a PCB has 4 buttons and touchpad, now I want to drive all of them.

1. one button for left button of mouse.
2. one button for right button of mouse.
3. one button for copy compose key(CTRL + C) of keyboard.
4. the last button for paste compose key (CTRL + V) of keyboard.
5. touchpad

So I make a report descriptor to mix all of them, this report descriptor is total 615 bytes. I show it in the end. 
However, it couldn't run. I tracked that it returned an error code [12] after executing ble_hids_init();
So is it the report descriptor is too bit to cause the above problems? And what should I do to solve this problems?

Thanks!

#define APP_USBD_HID_DEVICE_REPORT_DSC() { \
/** TOUCH PAD input TLC  +8 */ \
    0x05, 0x0d,                         /** USAGE_PAGE (Digitizers) */ \
    0x09, 0x05,                         /** USAGE (Touch Pad) */ \
    0xa1, 0x01,                         /** COLLECTION (Application) */ \
    0x85, REPORT_ID_PTP,               /**   REPORT_ID (Touch pad) */ \
 \
	/** 1st finger  73 */  \
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */  \
    0x09, 0x22,                         /**   USAGE (Finger) */  \
    0xa1, 0x02,                         /**   COLLECTION (Logical)  */  \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */  \
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */  \
    0x09, 0x47,                         /**       USAGE (Confidence) */  \
    0x09, 0x42,                         /**       USAGE (Tip switch) */  \
    0x95, 0x02,                         /**       REPORT_COUNT (2) */  \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */  \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ \
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ \
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ \
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095)  //3859 */ \
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ \
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ \
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ \
    0x09, 0x30,                         /**       USAGE (X) */ \
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ \
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0xe3, 0x07,                   /**       LOGICAL_MAXIMUM (2019) */ \
    0x09, 0x31,                         /**       USAGE (Y) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0xc0,                               /**    END_COLLECTION */ \
     \
   /** 2nd   73 */ \
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x02,                         /**   COLLECTION (Logical)  */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */ \
    0x09, 0x47,                         /**       USAGE (Confidence) */ \
    0x09, 0x42,                         /**       USAGE (Tip switch) */ \
    0x95, 0x02,                         /**       REPORT_COUNT (2) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ \
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ \
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ \
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095) */ \
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ \
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ \
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ \
    0x09, 0x30,                         /**       USAGE (X) */ \
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ \
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0xa0, 0x07,                   /**       LOGICAL_MAXIMUM (1952) */ \
    0x09, 0x31,                         /**       USAGE (Y) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
	0xc0,								/**       END_COLLECTION */ \
 \
    /** 3   73  */ \
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x02,                         /**   COLLECTION (Logical)  */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */ \
    0x09, 0x47,                         /**       USAGE (Confidence) */ \
    0x09, 0x42,                         /**       USAGE (Tip switch) */ \
    0x95, 0x02,                         /**       REPORT_COUNT (2) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ \
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ \
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ \
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095) */ \
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ \
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ \
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ \
    0x09, 0x30,                         /**       USAGE (X) */ \
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ \
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0xa0, 0x07,                   /**       LOGICAL_MAXIMUM (1952) */ \
    0x09, 0x31,                         /**       USAGE (Y) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0xc0,								/**       END_COLLECTION */ \
     \
    /** 4    73 */ \
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x02,                         /**   COLLECTION (Logical)      */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */ \
    0x09, 0x47,                         /**       USAGE (Confidence) */ \
    0x09, 0x42,                         /**       USAGE (Tip switch) */ \
    0x95, 0x02,                         /**       REPORT_COUNT (2) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ \
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ \
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ \
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095) */ \
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ \
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ \
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ \
    0x09, 0x30,                         /**       USAGE (X) */ \
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ \
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0xa0, 0x07,                   /**       LOGICAL_MAXIMUM (1952) */ \
    0x09, 0x31,                         /**       USAGE (Y) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0xc0,								/**    END_COLLECTION */ \
     \
    /** 5  73 */ \
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x02,                         /**   COLLECTION (Logical)     */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */ \
    0x09, 0x47,                         /**       USAGE (Confidence) */ \
    0x09, 0x42,                         /**       USAGE (Tip switch) */ \
    0x95, 0x02,                         /**       REPORT_COUNT (2) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ \
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ \
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ \
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ \
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095) */ \
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ \
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ \
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ \
    0x09, 0x30,                         /**       USAGE (X) */ \
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ \
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ \
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ \
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ \
    0x26, 0xa0, 0x07,                   /**       LOGICAL_MAXIMUM (1952) */ \
    0x09, 0x31,                         /**       USAGE (Y) */ \
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ \
	0xc0,								/**    END_COLLECTION */ \
 \
/**  scan time& buttons. end input. +57 */ \
    0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ \
    0x55, 0x0C,                         /**    UNIT_EXPONENT (-4) */ \
    0x66, 0x01, 0x10,                   /**    UNIT (Seconds) */ \
    0x47, 0xff, 0xff, 0x00, 0x00,      /**     PHYSICAL_MAXIMUM (65535) */ \
    0x27, 0xff, 0xff, 0x00, 0x00,         /**  LOGICAL_MAXIMUM (65535) */ \
    0x75, 0x10,                           /**  REPORT_SIZE (16) */ \
    0x95, 0x01,                           /**  REPORT_COUNT (1) */ \
    0x05, 0x0d,                         /**    USAGE_PAGE (Digitizers) */ \
    0x09, 0x56,                         /**    USAGE (Scan Time) */ \
    0x81, 0x02,                           /**  INPUT (Data,Var,Abs) */ \
    0x09, 0x54,                         /**    USAGE (Contact count) */ \
    0x25, 0x7f,                           /**  LOGICAL_MAXIMUM (127) */ \
    0x95, 0x01,                         /**    REPORT_COUNT (1) */ \
    0x75, 0x08,                         /**    REPORT_SIZE (8) */ \
    0x81, 0x02,                         /**    INPUT (Data,Var,Abs) */ \
    0x05, 0x09,                         /**    USAGE_PAGE (Button) */ \
    0x09, 0x01,                         /**    USAGE_(Button 1) */ \
    0x09, 0x02,                         /**    USAGE_(Button 2) */ \
    0x09, 0x03,                         /**    USAGE_(Button 3) */ \
    0x25, 0x01,                         /**    LOGICAL_MAXIMUM (1) */ \
    0x75, 0x01,                         /**    REPORT_SIZE (1) */ \
    0x95, 0x03,                         /**    REPORT_COUNT (3) */ \
    0x81, 0x02,                         /**    INPUT (Data,Var,Abs) */ \
    0x95, 0x05,                          /**   REPORT_COUNT (5) */ \
    0x81, 0x03,                         /**    INPUT (Cnst,Var,Abs) */ \
 \
/**  PTPHQA.  Feature reprot. +36 */ \
    0x05, 0x0d,                         /**    USAGE_PAGE (Digitizer) */ \
    0x85, REPORT_ID_CONTACT_NUM,            /**   REPORT_ID (Feature) */ \
    0x09, 0x55,                         /**    USAGE (Contact Count Maximum) */ \
    0x09, 0x59,                         /**    USAGE (Pad TYpe) */ \
    0x75, 0x04,                         /**    REPORT_SIZE (4) */ \
    0x95, 0x02,                         /**    REPORT_COUNT (2) */ \
    0x25, 0x0f,                         /**    LOGICAL_MAXIMUM (15) */ \
    0xb1, 0x02,                         /**    FEATURE (Data,Var,Abs) */ \
    0x06, 0x00, 0xff,                   /**    USAGE_PAGE (Vendor Defined) */ \
    0x85, REPORT_ID_PTPHQA,               /**    REPORT_ID (PTPHQA) */ \
    0x09, 0xC5,                         /**    USAGE (Vendor Usage 0xC5) */ \
    0x15, 0x00,                         /**    LOGICAL_MINIMUM (0) */ \
    0x26, 0xff, 0x00,                   /**    LOGICAL_MAXIMUM (0xff) */ \
    0x75, 0x08,                         /**    REPORT_SIZE (8) */ \
    0x96, 0x00, 0x01,                   /**    REPORT_COUNT (0x100 (256)) */ \
    0xb1, 0x02,                         /**    FEATURE (Data,Var,Abs) */ \
    0xc0,                               /** END_COLLECTION */ \
 \
    /** CONFIG TLC  +49 */ \
    0x05, 0x0d,                         /**    USAGE_PAGE (Digitizer) */ \
    0x09, 0x0E,                         /**    USAGE (Configuration) */ \
    0xa1, 0x01,                         /**   COLLECTION (Application) */ \
    0x85, REPORT_ID_CONFIG,             /**   REPORT_ID (Feature) from host to device.  3:touchpad.  0:mouse.  */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x02,                         /**   COLLECTION (logical) */ \
    0x09, 0x52,                         /**    USAGE (Input Mode) */ \
    0x15, 0x00,                         /**    LOGICAL_MINIMUM (0) */ \
    0x25, 0x0a,                         /**    LOGICAL_MAXIMUM (10) */ \
    0x75, 0x08,                         /**    REPORT_SIZE (8) */ \
    0x95, 0x01,                         /**    REPORT_COUNT (1) */ \
    0xb1, 0x02,                         /**    FEATURE (Data,Var,Abs */ \
    0xc0,                               /**   END_COLLECTION */ \
    0x09, 0x22,                         /**   USAGE (Finger) */ \
    0xa1, 0x00,                         /**   COLLECTION (physical) */ \
    0x85, REPORT_ID_SWITCH,     /**     REPORT_ID (Feature) */ \
    0x09, 0x57,                         /**     USAGE(Surface switch) */ \
    0x09, 0x58,                         /**     USAGE(Button switch) */ \
    0x75, 0x01,                         /**     REPORT_SIZE (1) */ \
    0x95, 0x02,                         /**     REPORT_COUNT (2) */ \
    0x25, 0x01,                         /**     LOGICAL_MAXIMUM (1) */ \
    0xb1, 0x02,                         /**     FEATURE (Data,Var,Abs) */ \
    0x95, 0x06,                         /**     REPORT_COUNT (6) */ \
    0xb1, 0x03,                         /**     FEATURE (Cnst,Var,Abs) */ \
    0xc0,                               /**   END_COLLECTION */ \
    0xc0,                               /** END_COLLECTION */ \
 \
    /** MOUSE TLC-------------48. */ \
    0x05, 0x01,                         /** USAGE_PAGE (Generic Desktop) */ \
    0x09, 0x02,                         /** USAGE (Mouse) */ \
    0xa1, 0x01,                         /** COLLECTION (Application) */ \
    0x85, REPORT_ID_MOUSE,               /**   REPORT_ID (Mouse) */ \
    0x09, 0x01,                         /**   USAGE (Pointer) */ \
    0xa1, 0x00,                         /**   COLLECTION (Physical) */ \
    0x05, 0x09,                         /**     USAGE_PAGE (Button) */ \
    0x19, 0x01,                         /**     USAGE_MINIMUM (Button 1) */ \
    0x29, 0x05,                         /**     USAGE_MAXIMUM (Button 2)  */ \
    0x25, 0x01,                         /**     LOGICAL_MAXIMUM (1) */ \
    0x75, 0x01,                         /**     REPORT_SIZE (1) */ \
    0x95, 0x05,                         /**     REPORT_COUNT (5) */ \
    0x81, 0x02,                         /**     INPUT (Data,Var,Abs) */ \
    0x75, 0x01,                         /**     REPORT_SIZE (1) */ \
    0x95, 0x03,                         /**     REPORT_COUNT (3) */ \
    0x81, 0x03,                         /**     INPUT (Data,Var,Abs)   */ \
    0x05, 0x01,                         /**     USAGE_PAGE (Generic Desktop) */ \
    0x09, 0x30,                         /**     USAGE (X) */ \
    0x09, 0x31,                         /**     USAGE (Y) */ \
    0x75, 0x10,                         /**     REPORT_SIZE (16) */ \
    0x95, 0x02,                         /**     REPORT_COUNT (2) */ \
    0x25, 0x0a,                          /**    LOGICAL_MAXIMUM (10) */ \
    0x81, 0x06,                         /**     INPUT (Data,Var,Rel) */ \
    0xc0,                               /**   END_COLLECTION */ \
    0xc0,                                /** END_COLLECTION */ \
 \
/** ---------FOR KEYBOARD----52 */ \
/* USAGE_PAGE                              */ 0x05u, 0x01u,  \
/* USAGE                                   */ 0x09u, 0x06u,  \
/* COLLECTION                              */ 0xA1u, 0x01u,  \
/* REPORT_ID                               */ 0x85u, REPORT_ID_KEYBOARD,  \
/* USAGE_PAGE                              */ 0x05u, 0x07u,  \
/* USAGE_MINIMUM                           */ 0x19u, 0xE0u,  \
/* USAGE_MAXIMUM                           */ 0x29u, 0xE7u,  \
/* LOGICAL_MINIMUM                         */ 0x15u, 0x00u,  \
/* LOGICAL_MAXIMUM                         */ 0x25u, 0x01u,  \
/* REPORT_SIZE                             */ 0x75u, 0x01u,  \
/* REPORT_COUNT                            */ 0x95u, 0x08u,  \
/* INPUT                                   */ 0x81u, 0x02u,  \
/* USAGE_PAGE                              */ 0x06u, 0x00u, 0xFFu,  \
/* USAGE                                   */ 0x09u, 0x02u,  \
/* REPORT_SIZE                             */ 0x75u, 0x08u,  \
/* REPORT_COUNT                            */ 0x95u, 0x01u,  \
/* INPUT                                   */ 0x81u, 0x02u,  \
/* USAGE_PAGE                              */ 0x05u, 0x07u,  \
/* USAGE_MINIMUM                           */ 0x19u, 0x00u,  \
/* USAGE_MAXIMUM                           */ 0x29u, 0x7Fu,  \
/* LOGICAL_MINIMUM                         */ 0x15u, 0x00u,  \
/* LOGICAL_MAXIMUM                         */ 0x25u, 0x7Fu,  \
/* REPORT_SIZE                             */ 0x75u, 0x08u,  \
/* REPORT_COUNT                            */ 0x95u, 0x05u,  \
/* INPUT                                   */ 0x81u, 0x00u,  \
/* END_COLLECTION                          */ 0xC0u \
}

[Hieu]

Hello Harvey.Zhang,

615 bytes is longer than 512, which is the maximum length of a HID Service. In this case, you need to split your record into two half, and support two HIDS instances. Refer to section 2.5 of the HID over GATT Profile Specification.

However, I experimented with it a little bit 2 years ago and found that Android devices don't handle two HIDS instances very well. It might be safer to see if you can minimize the descriptor further.

I am not familiar with a touchpad report descriptor, but I know for sure there have been mouse and keyboard report descriptor done successfully. Does a touchpad require far more reports than a mouse?

Hieu

[Harvey.Zhang]

Oh! thank you very much.

Do you mean to use an endpoint using touchpad ID and another endpoint for rest?

It looks can reduce the size of a single endpoint.

This is the descriptor of one finger.

	/** 1st finger  73 */  
	0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */  
    0x09, 0x22,                         /**   USAGE (Finger) */  
    0xa1, 0x02,                         /**   COLLECTION (Logical)  */  
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */  
    0x25, 0x01,                         /**       LOGICAL_MAXIMUM (1) */  
    0x09, 0x47,                         /**       USAGE (Confidence) */  
    0x09, 0x42,                         /**       USAGE (Tip switch) */  
    0x95, 0x02,                         /**       REPORT_COUNT (2) */  
    0x75, 0x01,                         /**       REPORT_SIZE (1) */  
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ 
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ 
    0x75, 0x02,                         /**       REPORT_SIZE (3) */ 
    0x25, 0x02,                         /**       LOGICAL_MAXIMUM (2) */ 
    0x09, 0x51,                         /**       USAGE (Contact Identifier) */ 
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ 
    0x75, 0x01,                         /**       REPORT_SIZE (1) */ 
    0x95, 0x04,                         /**       REPORT_COUNT (3) */ 
    0x81, 0x03,                         /**       INPUT (Cnst,Var,Abs) */ 
    0x05, 0x01,                         /**       USAGE_PAGE (Generic Desk.. */ 
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ 
    0x26, 0x13, 0x0f,                   /**       LOGICAL_MAXIMUM (4095)  //3859 */ 
    0x75, 0x10,                         /**       REPORT_SIZE (16) */ 
    0x55, 0x0e,                         /**       UNIT_EXPONENT (-2) */ 
    0x65, 0x13,                         /**       UNIT(Inch,EngLinear) */ 
    0x09, 0x30,                         /**       USAGE (X) */ 
    0x35, 0x00,                         /**       PHYSICAL_MINIMUM (0) */ 
    0x46, 0xad, 0x01,                   /**       PHYSICAL_MAXIMUM (429,4.29inch)   800=0x0320 */ 
    0x95, 0x01,                         /**       REPORT_COUNT (1) */ 
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ 
    0x46, 0xD8, 0x00,                   /**       PHYSICAL_MAXIMUM (216,2.16inch)  0x0226 */ 
    0x15, 0x00,                         /**       LOGICAL_MINIMUM (0) */ 
    0x26, 0xe3, 0x07,                   /**       LOGICAL_MAXIMUM (2019) */ 
    0x09, 0x31,                         /**       USAGE (Y) */ 
    0x81, 0x02,                         /**       INPUT (Data,Var,Abs) */ 
    0xc0,                               /**    END_COLLECTION */ 

We have five finger and touchpad report id, this is total 373 bytes.

And that need to be added for the scanning time, keys and the number of contacts, as follow,

/**  scan time& buttons. end input. +57 */ 
    0x05, 0x0d, 						/** USAGE_PAGE (Digitizers) */ 
    0x55, 0x0C,                         /**    UNIT_EXPONENT (-4) */ 
    0x66, 0x01, 0x10,                   /**    UNIT (Seconds) */ 
    0x47, 0xff, 0xff, 0x00, 0x00,      /**     PHYSICAL_MAXIMUM (65535) */ 
    0x27, 0xff, 0xff, 0x00, 0x00,         /**  LOGICAL_MAXIMUM (65535) */ 
    0x75, 0x10,                           /**  REPORT_SIZE (16) */ 
    0x95, 0x01,                           /**  REPORT_COUNT (1) */ 
    0x05, 0x0d,                         /**    USAGE_PAGE (Digitizers) */ 
    0x09, 0x56,                         /**    USAGE (Scan Time) */ 
    0x81, 0x02,                           /**  INPUT (Data,Var,Abs) */ 
    0x09, 0x54,                         /**    USAGE (Contact count) */ 
    0x25, 0x7f,                           /**  LOGICAL_MAXIMUM (127) */ 
    0x95, 0x01,                         /**    REPORT_COUNT (1) */ 
    0x75, 0x08,                         /**    REPORT_SIZE (8) */ 
    0x81, 0x02,                         /**    INPUT (Data,Var,Abs) */ 
    0x05, 0x09,                         /**    USAGE_PAGE (Button) */ 
    0x09, 0x01,                         /**    USAGE_(Button 1) */ 
    0x09, 0x02,                         /**    USAGE_(Button 2) */ 
    0x09, 0x03,                         /**    USAGE_(Button 3) */ 
    0x25, 0x01,                         /**    LOGICAL_MAXIMUM (1) */ 
    0x75, 0x01,                         /**    REPORT_SIZE (1) */ 
    0x95, 0x03,                         /**    REPORT_COUNT (3) */ 
    0x81, 0x02,                         /**    INPUT (Data,Var,Abs) */ 
    0x95, 0x05,                          /**   REPORT_COUNT (5) */ 
    0x81, 0x03,                         /**    INPUT (Cnst,Var,Abs) */ 

This is total 53 bytes.

So we need 426 bytes for whole touchpad report descriptor.

It seems need to simplify the report descriptor.

[Hieu]

Harvey.Zhang said:

Do you mean to use an endpoint using touchpad ID and another endpoint for rest?

We are working with HID Service over GATT, a BLE feature, and not USB HID, right? Unlike USB with endpoints, in BLE GATT, we are working with HID Service. What I mean is creating two HID Service instances, in a way that if you would perform service discovery on the device, you will see two HID Services.

Harvey.Zhang said:

So we need 426 bytes for whole touchpad report descriptor.

It seems need to simplify the report descriptor.

If you can optimize the descriptor size to under 512, that would be the best solution.