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  • Case ID: 254186
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GATT timeout when reading a characteristic when notify enabled

Nick_RA

I'm using nRF Connect for Windows with a PCA10040 DK to debug my nRF52832 product. Code is using SDK16 & S132

So I currently have one primary GATT service running with one write-only characteristic and one read-only characteristic. Both are working and I can read / write fine.

But, if I set up the read characteristic with notify=1, I get a GATT timeout in nRF Connect. Actually, the read process works initially, but if I click on the characteristic it then times out. I suspect that it's hanging trying to read or set the cccd.

I know that the nRF Connect is working because I can compile the Blinky example which works fine so it's my code at fault but after a couple of days I just can't see why.

This is how I set up the characteristic 

static void status_char_add(ble_mysvc_service_t * p_mysvc_service)
{
    uint32_t              err_code;
    ble_uuid_t            char_status_uuid;
    ble_add_char_params_t add_char_params;
    ble_uuid128_t         char_base_uuid = {BLE_UUID_MYSVC_CHAR_BASE_UUID};

    //Set the UUID
    BLE_UUID_BLE_ASSIGN(char_status_uuid, BLE_MYSVC_STATUS_CHAR);
    char_status_uuid.type = BLE_UUID_TYPE_VENDOR_BEGIN;
    err_code = sd_ble_uuid_vs_add(&char_base_uuid, &char_status_uuid.type);
    
    // Set up then add the characteristic
    memset(&add_char_params, 0, sizeof(add_char_params));
    add_char_params.uuid              = char_status_uuid.uuid;
    add_char_params.uuid_type         = char_status_uuid.type;
    add_char_params.init_len          = 16;
    add_char_params.max_len           = 16;
    add_char_params.char_props.read   = 1;
    add_char_params.char_props.notify = 1; // no problem if this is set to 0 
    add_char_params.read_access       = SEC_OPEN;
    add_char_params.cccd_write_access = SEC_OPEN;
    err_code = characteristic_add(p_mysvc_service->service_handle,
                                  &add_char_params,
                                  &p_mysvc_service->status_char_handles);

}

I'm sure I'm missing something stupid, any suggestions?

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