Problem | BLE APP UART and Buttonless DFU with Bonding

[SK]

Hello Everyone,

I am working with nRF52832 chip on our custom board. I am using SDK 14.2 and SD v5.0.0  for development on a windows platform with Segger ES.

I am looking to include FOTA in our design but i am having troubles during runtime. 

Problem: 

What i have is two services, buttonless DFU and BLE NUS. I have taken the steps mentioned to have a proper integration.

1. Changed the UUID count to 2 

2. added buttoness dfu service and UUID added for advertising packet

3. Increased the RAM size (using RAM_START=0x20002978, RAM_SIZE=0xEB48)

4. Bond support set to 1

Made changes to bootloader:

1. Requires bonds set to 1 

Integration is completed and compiles successfully. I can see that bootloader also points to the correct address to start the application. 

For testing, i am using nRF Connect App since on our application, DFU service support is not implemented yet. 

What i am seeing after connection to the central are these  Issues - 

1. Sometimes, BLE NUS send sends error 8 -> INVALID STATE error

2. If (1) doesn't happen, then while trying to load the applicaion package for DFU, i see REMOTE DFU ERROR: OPERATION FAILED.

If i remove the buttonless DFU pieces, application runs fine. 

Could you please let me know what can be the cause for issues observed above? If you would like to know more, please let me know.

UPDATE:

When i try to do DFU, here's what i see at the debug terminal:

<info> app: Received indication state 1
<info> app: Writing peer data to the bootloader
<info> app: ---------------system attribute table: 8--------------
<error> app: Request to enter bootloader mode failed asynchroneously

UPDATE 2:

Looked into the forum for the error above, found the solution to it. Link below for reference. 

https://devzone.nordicsemi.com/f/nordic-q-a/42828/request-to-enter-bootloader-mode-failed-asynchronously

 

1. BLE NUS send sends error 8 -> INVALID STATE error on connection to nRF connect app. I am still not sure why, will keep looking. Please let me know on my leads.

Thanks a lot in advance! 

SK 

[Vidar Berg]

Hi,

Thanks for the update. 

1. BLE NUS send sends error 8 -> INVALID STATE error on connection to nRF connect app. I am still not sure why, will keep looking. Please let me know on my leads.

 The send function will return invalid state if you are trying to send data before the client (nRF connect app) has had time to enable notifications on for the characteristic. Could this be the problem?

[SK]

Hi Vidar Berg

Thank you for your reply. I will check and update here. Is there any way to know if Central has enabled notifications for the particular characteristic? Like an event on the peer side of the confirmation?  

[Vidar Berg]

Yes, you should receive BLE_NUS_EVT_COMM_STARTED in your nus_data_handler() callback as soon as notifications have been enabled by the client. 

[SK]

I checked for the same event (BLE_NUS_EVT_COMM_STARTED) but with nRF connect app, this event is not coming in the nus_data_handler(). :( 

Any idea why would that be? 

[Vidar Berg]

Notifications are not enabled automatically, you need to click the "Play" (Arrows if you use app on Android/iOS) button next to the tx characteristic to enable it. Did you do that?