Update BLE Characteristic from ENUM

RE: Update BLE Characteristic from ENUM

aplatts — Wed, 26 Feb 2020 15:25:13 GMT

I have looked at my code and carried out a few modifications and have a better understand how the SoftDevice works.

The following is working, on the following event, it calls handle_ble_char:

case BLE_SRVC_OPT_EVT_CONNECTED:
        t_value = SET;
        handle_ble_char(p_cus_service, &p_cus_service->status_char_handles , &t_value);
        break;

The structure of handle_ble_char is as follows:

static void handle_ble_char (ble_srvc_opt_t *p_service, ble_gatts_char_handles_t *p_char_handle, m_setget *p_type) {

    uint32_t err_code;
    ble_gatts_value_t	t_value;

    //Get & Set for ble_src_opt - Char - Status
    if (p_char_handle->value_handle == m_cus.status_char_handles.value_handle) {
        
        t_value.p_value = &m_srm_state.evt_type;
	    t_value.len      = 1;
	    t_value.offset   = 0;

        switch (*p_type)
        {
        case SET:
            err_code = sd_ble_gatts_value_set(p_service->conn_handle, p_char_handle->value_handle, &t_value);
    	    APP_ERROR_CHECK(err_code);
            break;
        case GET:
            err_code = sd_ble_gatts_value_get(p_service->conn_handle, p_char_handle->value_handle, &t_value);
    	    APP_ERROR_CHECK(err_code);
            break;
        default:
            break;
        }
    }

}

This is a universal bit of code which allows me to tell it which service and characteristic to set or get.

It is working as planned now...thanks for the help on this one.

RE: Update BLE Characteristic from ENUM

Jared — Tue, 25 Feb 2020 15:03:00 GMT

Hi,

Did you try the workaround suggest in the linked case in the previous reply?

You could try setting err_code =sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0) before you call ble_srvc_opt_custom_value_update(). And you should make sure that notifications is enabled.

regards

Jared

RE: Update BLE Characteristic from ENUM

aplatts — Mon, 24 Feb 2020 15:08:25 GMT

I think the issue is that I am attempting to send a Characteristic Value before it being ready (i.e. I'm sending as soon as BLE_SRVC_OPT_EVT_CONNECTED). As this is at the Service level, I assume that the Characteristic could still be being negotiated.

Would this make sense?

RE: Update BLE Characteristic from ENUM

Jared — Fri, 21 Feb 2020 12:31:53 GMT

Hi.

ERROR 13313 is a BLE_ERROR_GATTS_SYS_ATTR_MISSING which is returned by sd_ble_gatts_hvx(). Could you try the solution proposed in this case. Also I can't see that value is a struct member from your definition of the struct m_srm_state. It seems that the struct member is called evt_type.

RE: Update BLE Characteristic from ENUM

aplatts — Thu, 20 Feb 2020 13:26:55 GMT

Hi,

The code won't compile as is, but if I replace the ENUM var with a simple byte of 01 -

ret_code_t err_code;
uint8_t value            = 0;
err_code = ble_srvc_opt_custom_value_update(&m_cus, value);
APP_ERROR_CHECK(err_code);

This code is initiated as soon as the following criteria is met within this static void -

static void on_srvc_opt_evt(ble_srvc_opt_t     * p_cus_service,
                       ble_srvc_opt_evt_t * p_evt)
{

    ret_code_t err_code;
    uint8_t value            = 0;
    
    switch(p_evt->evt_type)
    {

        case BLE_SRVC_OPT_EVT_NOTIFICATION_ENABLED:
            break;

        case BLE_SRVC_OPT_EVT_NOTIFICATION_DISABLED:
            break;

        case BLE_SRVC_OPT_EVT_CONNECTED:
            //Set BLE Characteristics on connection
            err_code = ble_srvc_opt_custom_value_update(&m_cus, value);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_SRVC_OPT_EVT_DISCONNECTED:
            break;

        default:
            // No implementation needed.
            break;
    }
}

I get the following crash:

<info> app: Fast advertising.

<info> app: ble_srvc_data Custom Characteristic - BLE_GAP_EVT_CONNECTED

<info> app: ble_srvc_opt Custom Characteristic - BLE_GAP_EVT_CONNECTED

<info> app: In ble_srvc_opt_custom_value_update. 

<error> app: ERROR 13313 [Unknown error code] at ../../../main.c:206

PC at: 0x0002D141

<error> app: End of error report

Lines 205 and 206 in main.c are:

err_code = ble_srvc_opt_custom_value_update(&m_cus, value);
APP_ERROR_CHECK(err_code);

Value Update Code:-

uint32_t ble_srvc_opt_custom_value_update(ble_srvc_opt_t * p_cus, uint8_t custom_value)
{
    NRF_LOG_INFO("In ble_srvc_opt_custom_value_update. \r\n"); 
    if (p_cus == NULL)
    {
        return NRF_ERROR_NULL;
    }

    uint32_t err_code = NRF_SUCCESS;
    ble_gatts_value_t gatts_value;

    // Initialize value struct.
    memset(&gatts_value, 0, sizeof(gatts_value));

    gatts_value.len     = sizeof(uint8_t);
    gatts_value.offset  = 0;
    gatts_value.p_value = &custom_value;

    // Update database.
    err_code = sd_ble_gatts_value_set(p_cus->conn_handle,
                                      p_cus->custom_value_handles.value_handle,
                                      &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Send value if connected and notifying.
    if ((p_cus->conn_handle != BLE_CONN_HANDLE_INVALID)) 
    {
        ble_gatts_hvx_params_t hvx_params;

        memset(&hvx_params, 0, sizeof(hvx_params));

        hvx_params.handle = p_cus->custom_value_handles.value_handle;
        hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
        hvx_params.offset = gatts_value.offset;
        hvx_params.p_len  = &gatts_value.len;
        hvx_params.p_data = gatts_value.p_value;

        err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
    }
    else
    {
        err_code = NRF_ERROR_INVALID_STATE;
    }


    return err_code;
}

Thanks

RE: Update BLE Characteristic from ENUM

Jared — Thu, 20 Feb 2020 12:16:22 GMT

Hi,

I'm interested in seeing more of your code, specifically the initialization of the service and the ble_srvc_opt_custom_value_update(). Also

[quote user=""]I have the BLE Service and Characteristic running but am struggling to send the ENUM as a single byte (uint8_t).[/quote]

What exactly happens when you run the application? Are you getting any errors? Have you tried debugging your application?

regards

Jared