Device Name and NVDS

Hi TR_Dialog,

Thanks a lot for your reply. Before everything, all my code are based on your sample128 project.

1.I undefine CFG_NVDS and set device name in app_adv_func. When I try to discovery the device under Light Blue app for iOS, the device name is shown as the value I set in app_adv_func. But after I connect to the device, device name change to the value in NVDS. The device name in iOS paired device list is also the same as NVDS device name value.
I solved this problem by setting device name in NVDS before BLE stack is inited, but I am really curious about why the device name store in NVDS still shows in some place even I undefine CFG_NVDS.

2. I use Generated resolvable private random address and Security mode 1 Level 3 in my application. I paired two device to the same iPhone and each of these device has a unique IRK and device name. I could see two paired device in iOS paired device list. But after I paired the second device, the first device will shown as the second device's name. I change the device address in NVDS, everything is right.

From all the things I observed, I really want to know:
1 Why BLE still use information in NVDS even after I undefine CFG_NVDS.
2. What's the difference of setting advertising data in app_adv_func and NVDS data section.
3. Is that true that the Generated resolvable private random address is based on the device address value in NVDS?

Please feel free to contact me if any additional information is needed.

非常感谢，等待您的回复。

Hi TR_Dialog,

The reason why I undefined CFG_NVDS is I want to set the BLE parameter(device name, IRK...) through I2C bus by another processor.

So, to start with, I make the program wait at main_func for an I2C set device name package. After that, I store the device name in a buffer and use the buffer date to set device name and IRK in app_adv_func and app_configuration_func. Since I get the device name from my buffer, not from NVDS, so I disable CFG_NVDS.

In this way, the device name shows buffer value before I connect DA to my iPhone. But after I connected DA to my iPhone, the device name change to the value in NVDS. I am confused by why my device shows as two different names and what's the difference of setting device name in app_adv_func and setting device name in NVDS.

I solve this problem by setting the device name in NVDS according to my buffer data before BLE stack init. But I am still wondering why the device name stored in NVDS is still being used even I undefined CFG_NVDS and when exactly the information in NVDS is used.

Latter on, I found if I paired two of my devices to the same iPhone, iOS with regard the first device as the second one(latter paired device). I am sure each of them has a unique IRK. Latter, I change the device address value in NVDS according my I2C package before BLE stack is init and solve the problem. I think the reason here is even I use a private resolvable random address and undefined CFG_NVDS, the BLE stack still generate the resolvable random address base on the information in NVDS.

Again, I solve the two problems by changing the value in NVDS in the case that I think I totally disable NVDS. So, questions I want to ask is:

1. Why the date in NVDS is still being used even I undefined CFG_NVDS.

2. When device name stored in NVDS is used and when device set in app_adv_func is used? Why if the device name in NVDS is different from the on I set in app_adv_func, I could get two different names of the same device before and after the connection is built.

3. Is the generated resolvable private random address related to the device address store in NVDS? To expand this question, when the data store in NVDS is used?

Am I make things clear?

Thanks a lot.

Hi TR_Dialog,

If you use Light Blue app, you will see the device name change after I connect to the device. After connected, you could also find the Device name shown at the TOP is different from the advertisement package. Please make the device name in app_adv_func differ from value in NVDS. undefine NVDS and see whether you will get the same result as me.

My app_adv_func:

void app_adv_func(struct gapm_start_advertise_cmd *cmd)
{

// Start advertising. Fill GAPM_START_ADVERTISE_CMD message

// Device Name Length
uint8_t device_name_length;
int8_t device_name_avail_space;
uint8_t device_name_temp_buf[64];
uint8_t manufacture_date[10];

cmd->op.code = GAPM_ADV_UNDIRECT;
cmd->op.addr_src = GAPM_GEN_RSLV_ADDR;/*GAPM_GEN_STATIC_RND_ADDR;*///GAPM_PUBLIC_ADDR;
cmd-> op.renew_dur = 15000;
cmd->intv_min = APP_ADV_INT_MIN;
cmd->intv_max = APP_ADV_INT_MAX;
cmd->channel_map = APP_ADV_CHMAP;

cmd->info.host.mode = GAP_GEN_DISCOVERABLE;

/*-----------------------------------------------------------------------------------
* Set the Advertising Data and the Scan Response Data
*---------------------------------------------------------------------------------*/
cmd->info.host.adv_data_len = APP_ADV_DATA_MAX_SIZE;
cmd->info.host.scan_rsp_data_len = APP_SCAN_RESP_DATA_MAX_SIZE;
#ifdef HAS_WHITE_LIST
if (white_list_written)
cmd->info.host.adv_filt_policy = ADV_ALLOW_SCAN_WLST_CON_WLST;
else
cmd->info.host.adv_filt_policy = ADV_ALLOW_SCAN_ANY_CON_ANY;
#else
cmd->info.host.adv_filt_policy = ADV_ALLOW_SCAN_ANY_CON_ANY;
#endif

//cmd->info.host.adv_filt_policy = ADV_ALLOW_SCAN_ANY_CON_ANY;

// Advertising Data
#if (NVDS_SUPPORT)
if(nvds_get(NVDS_TAG_APP_BLE_ADV_DATA, &cmd->info.host.adv_data_len,
&cmd->info.host.adv_data[0]) != NVDS_OK)
#endif //(NVDS_SUPPORT)
{
//GPIO_SetActive(GPIO_PORT_1,GPIO_PIN_0);
cmd->info.host.adv_data_len = 10;

memcpy (&manufacture_date [0], " \ x09 \ xff ", 2);
memcpy(&manufacture_date[0] + 2, &bb_device_name[0] + 4, 8);
memcpy(&cmd->info.host.adv_data[0], &manufacture_date[0], cmd->info.host.adv_data_len);
}

// Scan Response Data
#if (NVDS_SUPPORT)
if(nvds_get(NVDS_TAG_APP_BLE_SCAN_RESP_DATA, &cmd->info.host.scan_rsp_data_len,
&cmd->info.host.scan_rsp_data[0]) != NVDS_OK)
#endif //(NVDS_SUPPORT)
{
cmd->info.host.scan_rsp_data_len = APP_SCNRSP_DATA_LENGTH;
memcpy(&cmd->info.host.scan_rsp_data[0], APP_SCNRSP_DATA, cmd->info.host.scan_rsp_data_len);
}

// Get remaining space in the Advertising Data - 2 bytes are used for name length/flag
device_name_avail_space = app_add_data_max_size - cmd-> info.host.adv_data_len - 2;

// Check if data can be added to the Advertising data
if (device_name_avail_space > 0)
{

// Get the Device Name to add in the Advertising Data (Default one or NVDS one)
/*#if (NVDS_SUPPORT)
device_name_length = NVDS_LEN_DEVICE_NAME;
if (nvds_get(NVDS_TAG_DEVICE_NAME, &device_name_length, &device_name_temp_buf[0]) != NVDS_OK)
#endif //(NVDS_SUPPORT)
{
// Get default Device Name (No name if not enough space)
device_name_length = strlen(APP_DEVICE_NAME);
memcpy(&device_name_temp_buf[0], APP_DEVICE_NAME, device_name_length);
}
*/
device_name_length = BB_DEVICENAME_SIZE;
memcpy(&device_name_temp_buf[0],bb_device_name,BB_DEVICENAME_SIZE);
//memcpy(device_name_temp_buf,"bfob01234567",12);
if(device_name_length > 0)
{
// Check available space
device_name_length = co_min(device_name_length, device_name_avail_space);

// Fill Length
cmd->info.host.adv_data[cmd->info.host.adv_data_len] = device_name_length + 1;
// Fill Device Name Flag
cmd->info.host.adv_data[cmd->info.host.adv_data_len + 1] = '\x09';
// Copy device name
memcpy (cmd - > info.host.adv_data [cmd - > info.host.adv_data_len + 2], device_name_temp_buf, device_name_length);

// Update Advertising Data Length
cmd->info.host.adv_data_len += (device_name_length + 2);
}
}

return;
}

Thanks!

HI TR_DIALOG,

I understand there is some special BLE policy in iOS, but it seems the device name shown in Light Blue after I connected the device will always keep the same as the one store in NVDS.

Also, I changed Sample128 project as AN-B-022 and I think the resolvable random address works fine for a single device: each time the device will show as a different address and iOS could reconnect to it after paired. But if I turn on two device at the same time and paired both of my device to the same iPhone. IPhone will regard both of them as the latter paired one.
Latter on, I changed the device in NVDS. After that, my iPhone could distinguish these two devices without any error.

Again, I guess even I undefine CFG_NVDS and set my own BLE setting in those app_xxx function, BLE still use information store in NVDS. So, I really want to check with your guys to see whether I configure something wrong and how exactly NVDS is utilized by BLE stack.

Thanks!