Difference in characteristics display between nRF Connect App on PC and App on MOBILE

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Stefan Wyss — Thu, 17 Jan 2019 16:00:39 GMT

Ok, I tested your proof_of_concept_pca10040_s132.hex on my custom board with my iPhone7. It still shows garbage as you can see in the following screenshot.

Please forwart this to the APP developers. I also think it is an iPhone 7 specific problem and I consider this case as closed.

Thank you very much for your excellent support!

Cu, Stefan

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Jørgen Holmefjord — Thu, 17 Jan 2019 14:00:06 GMT

My colleague tested with iPhone 7 and same version of nRF Connect, and we are not able to reproduce the issue. Can you try this hex-file that I compiled (does not include softdevice), to check if there are any issues in your project/SDK setup? devzone.nordicsemi.com/.../proof_5F00_of_5F00_concept_5F00_pca10040_5F00_s132.hex

If this also does not work, I will forward the issue to our app developers.

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Stefan Wyss — Thu, 17 Jan 2019 10:34:25 GMT

iPhone 7, nRF Connect 1.8.8 APP

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Jørgen Holmefjord — Thu, 17 Jan 2019 10:30:44 GMT

I'm not able to reproduce this on my phone (Samsung Galaxy S7). Which phone are you using, and what version of nRF Connect are you running?

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Stefan Wyss — Wed, 16 Jan 2019 16:27:26 GMT

I don't know how to upload to devzone, so here is an external link for downloading my project: https://drive.google.com/file/d/1_p5jeaIHz33PLexP4xDLm0mKe_gONNPr/view?usp=sharing

Please note that this is an IAR project and must follow a special folder structure for the relative SDK path:

.\nrf52_3100-1_fw
.\nrf5_sdk\nRF5_SDK_14.2.0_17b948a

Although it's for a custom board, it should run fine on the nRF52 DK (with internal RC LFCLK).

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Jørgen Holmefjord — Wed, 16 Jan 2019 15:33:37 GMT

If you can upload your entire project, I can debug it and see if I can figure out why this is happening.

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Stefan Wyss — Wed, 16 Jan 2019 14:51:42 GMT

Yes, I did the following, without success:

[...]
static uint8_t value[] = "1234";
attr_char_value.p_value   = value;           // was NULL before
[...]

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Jørgen Holmefjord — Wed, 16 Jan 2019 14:16:06 GMT

Have you tried setting attr_char_value.p_value to something else than NULL?

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Stefan Wyss — Wed, 16 Jan 2019 13:06:23 GMT

Hi Jorgen, and thanks for your help.

1. Ok, sounds reasonable.

2. I pressed the read button and enabled notifications, but this does not change anything. Below I send you the init code for my second characteristic. Thanks for checking...

/**@brief Function for adding the Sensor Value Characteristic.
 *
 * @param[in] p_doss      DOSS Service structure.
 * @param[in] p_doss_init DOSS Service initialization structure.
 *
 * @retval NRF_SUCCESS on success, else an error value from the SoftDevice
 */
static uint32_t sensor_value_char_add(ble_doss_t * p_doss, const ble_doss_init_t * p_doss_init)
{
    ble_gatts_char_md_t char_md;
    ble_gatts_attr_md_t cccd_md;
    ble_gatts_attr_t    attr_char_value;
    ble_uuid_t          ble_uuid;
    ble_gatts_attr_md_t attr_md;

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

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
    cccd_md.vloc = BLE_GATTS_VLOC_STACK;

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

    char_md.char_props.read   = 1;
    char_md.char_props.notify = 1;
    
    // char_md.p_char_user_desc  = "NULL";
    
    static char user_desc[] = "Sensor Value";
    char_md.p_char_user_desc  = (uint8_t *) user_desc;
    char_md.char_user_desc_size = strlen(user_desc);
    char_md.char_user_desc_max_size = strlen(user_desc);	
    
    
    char_md.p_char_pf         = NULL;
    char_md.p_user_desc_md    = NULL;
    char_md.p_cccd_md         = &cccd_md;
    char_md.p_sccd_md         = NULL;

    ble_uuid.type = p_doss->uuid_type;
    ble_uuid.uuid = DOSS_UUID_SENSOR_VALUE;

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

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
    BLE_GAP_CONN_SEC_MODE_SET_NO_ACCESS(&attr_md.write_perm);
    attr_md.vloc    = BLE_GATTS_VLOC_STACK;
    attr_md.rd_auth = 0;
    attr_md.wr_auth = 0;
    attr_md.vlen    = 0;

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

    attr_char_value.p_uuid    = &ble_uuid;
    attr_char_value.p_attr_md = &attr_md;
    attr_char_value.init_len  = sizeof(uint8_t); // already tried 4, but nRF Connect APP still display garbage 
    attr_char_value.init_offs = 0;
    attr_char_value.max_len   = 4;               // sensor value size is 4 bytes
    attr_char_value.p_value   = NULL;

    return sd_ble_gatts_characteristic_add(p_doss->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_doss->sensor_value_char_handles);
}

RE: Difference in characteristics display between nRF Connect App on PC and App on MOBILE

Jørgen Holmefjord — Wed, 16 Jan 2019 12:46:43 GMT

Hi,

The characteristics name is gathered from comparing the UUID towards know UUIDs. If your UUID is not found in this list, it will show Unknown Characteristics.
It seems that notifications have been enabled on desktop side. Have you pressed the read button or tried enabling notifications (by pressing three arrows button) in mobile as well? It could be some garbage data if the characteristics is not properly initialized. Note that the max/init length can be larger than the "normal length" that you send in notifications. Can you post the initialization code for this characteristics?
See point 2.

Best regards,
Jørgen