RE: Ble Service Characteristic - Different Properties On Different Phones

Amanda Hsieh — Wed, 24 Jun 2020 12:29:14 GMT

Hi Ankit,

Great to hear the success and the sharing. 🙂

-Amanda H.

RE: Ble Service Characteristic - Different Properties On Different Phones

Ankit Bhatnagar — Sat, 20 Jun 2020 07:23:54 GMT

Hi Amanda,

Yes. It's the same hardware. We change the device name after provisioning. The screenshots were taken before and after provisioning on the same hardware, that's why the different name.

We managed to the cause of the issue.

In our code, we set the characteristics property notify value to 1, as seen in the code section below

ble_gatts_char_md_t char_metadata;

uint8_t initial_characterstic_value2[BLE_CUSTOM_CHARACTERSTIC2_SIZE] = {0};
char* char2_desc = malloc(BLE_CUSTOM_CHARACTERSTIC_DESC_MAX_SIZE);
char_metadata.char_props.write_wo_resp = 0;
char_metadata.char_props.write = 0;
char_metadata.char_props.read = 1;
char_metadata.char_props.indicate = 1;

adding the line

char_metadata.char_props.notify = 0;

solved the issue.

Now that I think about it, since the variable is a local one, it would be initialized with a garbage value. So the .notify property could be some random value. Why this would work all this while with ble 4 phones and not with newer phones (with ble 5 support) is something of a mystery. Explicitly setting this field to 0 solves the issue.

I checked Nordic official examples, and there also only the required fields are being set (and no memset 0 done on this local variable)

RE: Ble Service Characteristic - Different Properties On Different Phones

Amanda Hsieh — Fri, 19 Jun 2020 11:30:46 GMT

Hi Ankit,

Are you connect to the same device?

Could you try to "Refresh device cache" as the figure? Does it help?

-Amanda H.