How to get full Service UUID from given BASE UUID

[davidm]

Hi all

I am trying to pair nrf52840 (as a central) with ESP32 (as peripheral).

 Now I want to get the service uuid so that i can pass to advertising service in ESP32 code.How do I get the full-service UUID, I see that in the ble_lbs_c service  UUID is declared as 0x1523 characteristic  UUID as 0x1525 and LBS_UUID_BASE {0x23, 0xD1, 0xBC, 0xEA, 0x5F, 0x78, 0x23, 0x15, 0xDE, 0xEF, 0x12, 0x12, 0x00, 0x00, 0x00, 0x00}

I tried to pass the service uuid as #define SERVICE_UUID   "23151212EFDE1523785FEABCD1" on ESP32 program but that didnt work. What is the exact order of the UUID? If you need  details on esp32 code here is the example esp32 program

I am using ble_app_blinky_c example on nrf52840.

Thank you in advance

[davidm]

Hi Edvin

I am using 15.3.0 and to be exact, I am using ble_app_blinky_c central example.

[Edvin]

Please look at the scan_init in ble_app_uart_c, as this is looking for a specific UUID, which you can try to modify to match your UUID. Remember to also set NRF_BLE_SCAN_UUID_CNT to 1 in sdk_config.h.

If you insert the correct UUID, does nrf_ble_scan_connect_with_target() get called inside the nrf_ble_scan_on_adv_report() in nrf_ble_scan.c?

[davidm]

Hi Edvin

I did some digging a bit. It seems like adv_name_compare() in nrf_ble_scan.c returns false. To be specific i think ble_advdata_name_find returns false. I tried to log NRF_LOG_DEBUG("adv_data %s",p_adv_report->data.p_data) it prints out  "ESP32  #N_x...." with some strange characters after that.

I have tried with NRF52 peripheral board which connects successfully, but the log above doesn't print anything, and ble_advdata_name_find returns true. 

What could be the cause of returning false (in esp32 peripheral case) ?

static bool adv_name_compare(ble_gap_evt_adv_report_t const * p_adv_report,
                             nrf_ble_scan_t     const * const p_scan_ctx)
{
    nrf_ble_scan_name_filter_t const * p_name_filter = &p_scan_ctx->scan_filters.name_filter;
    uint8_t                            counter       =
        p_scan_ctx->scan_filters.name_filter.name_cnt;
    uint8_t  index;
    uint16_t data_len;

    data_len = p_adv_report->data.len;

    // Compare the name found with the name filter.
    for (index = 0; index < counter; index++)
    {
        if (ble_advdata_name_find(p_adv_report->data.p_data,
                                  data_len,
                                  p_name_filter->target_name[index]))
        {
            return true;
        }
    }

    return false;
}

[Edvin]

Can you show me what the entire advertising pack looks like?

for(uint i=0; i<data_len; i++)
{
    NRF_LOG_RAW_INFO("%02x:", p_adv_report->data.p_data);
}

 

davidm said:

What could be the cause of returning false (in esp32 peripheral case) ?

 The obvious answer is that ble_advdata_name_find returns false. 

Try to print out the entire p_data, and see what it looks like, then you can analyze ble_advdata_name find, to see why it returns false. 

But let me see the entire advertising data packet that contains "ESP32 #N_x...".

BR,
Edvin

[davidm]

Edvin,

NRF_LOG_DEBUG("%s",  p_adv_report->data.p_data); prints -> ESP32
#Ѽê_x#Þï# 

NRF_LOG_RAW_INFO("raw data %s:", p_adv_report->data.p_data);prints -> ESP32

NRF_LOG_RAW_INFO("%02x:", p_adv_report->data.p_data); prints-> 20002C28
By the way "ESP32" you see in the logs, is the name I configured on esp32 peripheral board to be the name of the device.