changing the BLE device name, BLE service and GATT Characteristics dynamically

Hi,

It is possible to add BLE service and characteristics dynamically, but it is not possible to remove them. It is required to send a service change notification to let the gatt client know that the attribute table has been updated.
Regarding the device name, it is possible to change device name using sd_ble_gap_device_name_set().

Best regards,
Dejan

I would like to mention that I wanted to change the BLE service and characteristics dynamically so that nRF module connects with different GATT client in run time. In this case, may I know how service change notification would help? Please share any references if possible.

user112716 said:

What I tried:
In main(), I initialized only the UART module. Once UART is up, the nRF module receives data from an application chip (MCU).
In uart_event_handle function, I use a function call to process the received data and set the BLE device name accordingly, inside this function call I am initializing BLE stack, GAP parameters, GATT Init, Services Init followed by BLE advertisement.

This way, I was successfully able to set BLE device name and Services dynamically. However, after few minutes of communication with a GATT client, incorrect/incomplete data is being transmitted to that peer device.

Is it good to initialize BLE this way? If not, what should be done?

Also, I would like to know if this method which I followed is correct or not. 

Please help, Thanks.

Hi,

user111786 said:

Could you be more specific about your use case? Is there a specific reason why you need to do it dynamically?

I have added the use case in this nRF_usecase document, please check. Thank you.

Hi,

In addition to the name, could you provide more information about service and characteristics?
How do you want to change characteristics dynamically and when (in relation to the reset)?

Best regards,
Dejan

Hi,

I have added additional information on how I'm changing services and characteristics w.r.t reset in this updated_pseudocode text file. Kindly check.

Thank you!

Hi,

Your case has been looked into internally. I'll get back to you when I get new information.

Best regards,
Dejan

Okay, sure. Thank you for the support!

Okay, sure. Thank you for the support!

Hi,

Could you please replace your uart_event_handle() with the one provided below and try to reproduce your issue?




Best regards,
Dejan

Thank you so much!!  With this modified changes, communication is taking place for more than an hour now, without an issue. 

I would like to get clarifications on the following:

I attempted similar approach as what you have suggested, but the difference is that I copied the contents of data_array to the different buffer and passed that new buffer to ble_nus_data_send() function. 

For process_mcu_data(), I sent the data_array as it is. Why this change could not make an impact?

Hi,

The main issue seems to be in do-while loop.
You probably enter "if" part and pass the pointer to the process_mcu_data(), data_array gets somehow changed and in next while iteration you go to ble_nus_data_send() with changed data.

Best regards,
Dejan

Okay, thank you so much for the support!!