Dynamically changing Advertisement name when using PHY ENCODED

RE: Dynamically changing Advertisement name when using PHY ENCODED

CktDesigner — Sun, 11 Sep 2022 00:09:14 GMT

OK... Now I see what is happening...

When I changed from "normal" to "coded" BLE modes, I had to move the advertised name from the sd[] array to the ad[] array.

When changing the advertised name, I failed to change the "index" (using the index of the advertised name in sd[] when modifying the (now moved) advertised name in ad[]) when making the modification.

The modified values made it into the ad[] array, but the old name was also still there and was used by BLE when advertising. Using the proper index fixed things.

Thanks

RE: Dynamically changing Advertisement name when using PHY ENCODED

Einarh — Fri, 09 Sep 2022 14:27:04 GMT

Can you please share the contents of your ad array before and after you try to set the new name using coded phy?

RE: Dynamically changing Advertisement name when using PHY ENCODED

CktDesigner — Thu, 08 Sep 2022 14:42:13 GMT

Thanks... But I don't think this is set. Here is the code used to start advertising:

static void btAdvertisingStart(void) {
  int err;
printk("Start Avertisement\n");

  struct bt_le_adv_param param =
  BT_LE_ADV_PARAM_INIT(BT_LE_ADV_OPT_CONNECTABLE |
                        BT_LE_ADV_OPT_EXT_ADV |
                        BT_LE_ADV_OPT_CODED,
                        BT_GAP_ADV_FAST_INT_MIN_2,
                        BT_GAP_ADV_FAST_INT_MAX_2,
                        NULL);

	err = bt_le_ext_adv_create(&param, NULL, &adv);
	if (err) {
		printk("Failed to create advertiser set (%d)\n", err);
		return err;
	}

printk("Created adv: %p\n", adv);

	//err = bt_le_ext_adv_set_data(adv, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
  err = bt_le_ext_adv_set_data(adv, ad, ARRAY_SIZE(ad), NULL, 0);
	if (err) {
		printk("Failed to set advertising data (%d)\n", err);
		return err;
	}

  err = bt_le_ext_adv_start(adv, NULL);
	if (err) {
		printk("Failed to start advertising set (%d)\n", err);
		return;
	} else {
    printk("Advertising successfully started\n");
  }

    // Change the name of the module
#if 1
  printf("After bt ready: Setting name to %s\n",telemetry1Name.name.chars);
      err= newBleAdvName(telemetry1Name.name.chars);
      if(err < 0) {
  printk("Error setting device name at startup: %d\n",err);
      }
#endif
}

RE: Dynamically changing Advertisement name when using PHY ENCODED

Einarh — Thu, 08 Sep 2022 14:29:54 GMT

The "defines" are advertising options, part of the bt_le_adv_param struct passed into bt_le_ext_adv_update_param().

Sounds like BT_LE_ADV_OPT_SCANNABLE should be disabled to let you update your advertising data.

RE: Dynamically changing Advertisement name when using PHY ENCODED

CktDesigner — Thu, 08 Sep 2022 13:43:52 GMT

In prj.conf:

CONFIG_BT_DEVICE_NAME_DYNAMIC=y

Where are the "defines" you mention set?

I set the device name via bt_set_name(). But to change the advertising name:

for "normal" BLE, the advertised name is in the sd[] array and bt_le_adv_update_data() is used to change it. This works.

for "coded" BLE , the advertised name is in the ad[] array and I've tried both bt_le_ext_adv_set_data() and bt_le_adv_update_data() to change the name. As mentioned above, using bt_le_adv_update_data() fails. Using bt_le_ext_adv_set_data() does not return an error, but the advertised name doesn't change.

Here is the code for assigning a new name... Lots of debugging printk statements... A #ifdef is used to select one set of code.

For "normal" BLE:

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
        BT_DATA_BYTES(BT_DATA_UUID128_ALL, UUID_VLSI_TELEMETRY1_SERVICE_VAL),
};

static struct bt_data sd[] = {
        BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

int newBleAdvName(char *newName) {
  int err;

  // Update the device name
  printk("Set new name: %s\n",newName);
  err = bt_set_name(newName);
  if(err) {
    printk("Error setting device name variable: %d\n", err);
  } else {
printk("Changed device name to: %s\n", newName);
    // Update the advertising and scan response data needed to update the advertised device name
    // Only need to modify the scan response data in this example as name is in scan response here.
    sd->data = newName;
    sd->data_len = strlen(newName);
    err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
    if(err) {
      printk("Error updating advertised name: %d\n", err);
    } else {
printk("Changed advertised name to: %s\n", newName);
    }
  }
  return err;
}

For "coded" BLE:

static struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
        BT_DATA_BYTES(BT_DATA_UUID128_ALL, UUID_VLSI_TELEMETRY1_SERVICE_VAL),
        BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

int newBleAdvName(char *newName) {
  int err;

  // Update the device name
  printk("Set new name: %s\n",newName);
  err = bt_set_name(newName);
  if(err) {
    printk("Error setting device name variable: %d\n", err);
  } else {
printk("Changed device name to: %s\n", newName);

btAdvertisingStop();

    // Update the advertising and scan response data needed to update the advertised device name
    //// Only need to modify the scan response data in this example as name is in scan response here.
    ad->data = newName;
    ad->data_len = strlen(newName);
    err = bt_le_ext_adv_set_data(adv, ad, ARRAY_SIZE(ad), NULL, 0);
    //err = bt_le_adv_update_data(ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd));
    if(err) {
      printk("Error updating advertised name: %d\n", err);
    } else {
printk("Changed encoded advertised name to: %s\n", newName);
    }
btAdvertisingReStart();
  }
  return err;
}

Note... This works in "normal" BLE, but not in "coded". (Is scannable data legal in "coded")?

RE: Dynamically changing Advertisement name when using PHY ENCODED

Einarh — Thu, 08 Sep 2022 09:29:41 GMT

Looking at bt_le_ext_adv_update_param():

When changing the option BT_LE_ADV_OPT_USE_NAME then bt_le_ext_adv_set_data needs to be called in order to update the advertising data and scan response data.

And then looking at BT_LE_ADV_OPT_USE_NAME:

Include the GAP device name automatically when advertising.
By default the GAP device name is put at the end of the scan
response data.
When advertising using BT_LE_ADV_OPT_EXT_ADV and not
BT_LE_ADV_OPT_SCANNABLE then it will be put at the end of the
advertising data. [...]

And from bt_le_ext_adv_set_data():

When both BT_LE_ADV_OPT_EXT_ADV and BT_LE_ADV_OPT_SCANNABLE are enabled then advertising data is ignored. When BT_LE_ADV_OPT_SCANNABLE is not enabled then scan response data is ignored.

How do you currently include your advertising name in your advertising data? Is it in your advertising data or your response data? If BT_LE_ADV_OPT_SCANNABLE is disabled it seems like the GAP device name set by bt_set_name() will be included in your advertising data, have you tried this?

-Einar

RE: Dynamically changing Advertisement name when using PHY ENCODED

CktDesigner — Wed, 07 Sep 2022 17:06:05 GMT

Hi Einarh,

Thanks...

The text in the bt_set_name() definition says to use bt_le_adv_update_data or bt_le_ext_adv_set_data once advertising has been started.

I tried using bt_le_adv_update_data, but it fails with error -EINVAL (-22). (This is the call I use to change the name when using "normal" BLE.) Tracing through the code, it looks like bt_le_adv_update_data expects the "struct bt_le_ext_adv" variable (adv) to be in the "bt_dev" structure. Following the "coded" example, I declared the "adv" variable separately. And there doesn't seem to be a call to assign the value to the "bt_dev" structure. So the call to "bt_le_adv_lookup_legacy()" inside bt_le_adv_update_data returns NULL, causing the error.

So I tried using bt_le_ext_adv_set_data.

"bt_le_ext_adv_set_data" is used to set the advertising name after the advertising set is created (using "bt_le_ext_adv_create"), It is then used again when trying to change the name. The function call returns without error, but the original name is still advertised.

What is the appropriate way to change the advertising name (when using PHY CODED)? Thoughts?

PS... I also tried stopping advertising prior to calling bt_le_ext_adv_set_data(), then restarting it. Still advertises with original name...

RE: Dynamically changing Advertisement name when using PHY ENCODED

Einarh — Wed, 07 Sep 2022 12:17:26 GMT

Hello

According to the description of bt_set_name(), it looks like it might be bt_le_ext_adv_set_data() you are looking for?

Or have you tried using bt_set_name()?

Best regards,

Einar