HID get report from a mac not as expected

Question

Hello again,
This time I am trying to read HID reports using bluetooth to get the state of the caps lock.
I know this should be super simple and its explained in the hid keyboard peripheral example using ble_hids_outp_rep_get. I am using a mac as a test machine and the report never becomes 0x02 (caps enabled). 
 Sadly I am unable to test it either using nRF connect due to the following: ˇ github.com/.../4 
 Can anyone confirm that this is the case and if so, assuming it works on windows, explain why mac behaves this way? 
 Thank you,
Yiangos

eekwils · Answer

I know this thread is 3 years old but I think I've found a solution to this issue if anyone else is coming across it. When using the ble_hids_keyboard example from the SDK I was experiencing the same problem, I would receive a report from macOS but the value of the caps lock bit wouldn't change. As I developed my firmware further I added a consumer control report to the hid device descriptor which meant that I needed to explicitly add a report ID to both the keyboard report and consumer control report. After adding the report ID to the keyboard report the capslock functionality started working on macOS. I haven't had time to fully test that this was the change that did it but I pretty sure it was. My report descriptor looks like this: static uint8_t report_map_data[] = { 0x05, 0x01, // Usage Page (Generic Desktop) 0x09, 0x06, // Usage (Keyboard) 0xA1, 0x01, // Collection (Application) 0x85, 0x01, // Report ID (1) <---- !!!!This is the bit I added 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) 0x75, 0x01, // Report Size (1) 0x95, 0x08, // Report Count (8) 0x81, 0x02, // Input (Data, Variable, Absolute) 0x95, 0x01, // Report Count (1) 0x75, 0x08, // Report Size (8) 0x81, 0x01, // Input (Constant) reserved byte(1) 0x95, 0x05, // Report Count (5) 0x75, 0x01, // Report Size (1) 0x05, 0x08, // Usage Page (Page# for 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, 0x01, // Output (Data, Variable, Absolute), Led report padding 0x95, 0x06, // Report Count (6) 0x75, 0x08, // Report Size (8) 0x15, 0x00, // Logical Minimum (0) 0x25, 0x65, // Logical Maximum (101) 0x05, 0x07, // Usage Page (Key codes) 0x19, 0x00, // Usage Minimum (0) 0x29, 0x65, // Usage Maximum (101) 0x81, 0x00, // Input (Data, Array) Key array(6 bytes) 0x09, 0x05, // Usage (Vendor Defined) 0x15, 0x00, // Logical Minimum (0) 0x26, 0xFF, 0x00, // Logical Maximum (255) 0x75, 0x08, // Report Size (8 bit) 0x95, 0x02, // Report Count (2) 0xB1, 0x02, // Feature (Data, Variable, Absolute) 0xC0, // End Collection (Application) //Consumer Control report 0x05, 0x0C, // Usage Page (Consumer Devices) 0x09, 0x01, // Usage (Consumer Control) 0xA1, 0x01, // Collection (Application) 0x85, 0x02, // Report ID (2) 0x15, 0x00, // Logical Minimum (0) 0x25, 0x01, // Logical Maximum (1) 0x75, 0x01, // Report Size (1) 0x95, 0x01, // Report Count (1) 0x09, 0xCD, // Usage (Play/Pause) 0x81, 0x02, // Input (Data, Value, Relative, Bit Field) 0x09, 0xB5, // Usage (Scan Next Track) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0xB6, // Usage (Scan Previous Track) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0xE2, // Usage (Mute) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0xE9, // Usage (Vol Up) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0xEA, // Usage (Vol Down) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0x6F, // Usage (Brightness Up) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0x09, 0x70, // Usage (Brightness Down) 0x81, 0x02, // Input (Data,Value,Relative,Bit Field) 0xC0 }; And my output report now looks like this: #define OUTPUT_REPORT_INDEX 0 #define OUTPUT_REP_REF_ID 1 //<----!!! This must match the report id specified in the descriptor #define OUTPUT_REPORT_MAX_LEN 1 p_output_report = &output_report_array[OUTPUT_REPORT_INDEX]; p_output_report->max_len = OUTPUT_REPORT_MAX_LEN; p_output_report->rep_ref.report_id = OUTPUT_REP_REF_ID; p_output_report->rep_ref.report_type = BLE_HIDS_REP_TYPE_OUTPUT; p_output_report->sec.wr = SEC_JUST_WORKS; p_output_report->sec.rd = SEC_JUST_WORKS; I have no idea why specifying a report id would cause macOS to act differently but it seems it does. I hope this can help anyone who's having this problem!

HID get report from a mac not as expected

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