DFU for external BLE Sensor

[davidpatton]

Hi,

  I have a current project that is based on the nRf52840.  This project acts both as a peripheral and a central.  I have a need to update the firmware on a remote BLE sensor using DFU, i.e., I need to do exactly what the nRfConnect application does when it updates a peripheral firmware via DFU.  My thought was to use the nRf52840 dongle and develop this code on my PC and then port it to my embedded system.  I also thought the best starting point would be the source code for the nRfConnect application which I would port it but I see from user comments that nordic did not release the source code for this.  Is it possible to get this source code or is there another example that demonstrates what I need to accomplish?

Thanks!

[davidpatton]

Hi,

 Does nordic have a CBOR library that is suitable for use with my nRF SKD5 implementation?

Thanks..

[Vidar Berg]

Hi,

It looks like it should be straight forward to integrate tinycbor library we use in our nRF Connect SDK. The SDK is including the following files from the library: https://github.com/zephyrproject-rtos/tinycbor/blob/zephyr/zephyr/CMakeLists.txt which do not seem to have any external dependencies. 

[davidpatton]

Hi,

  Thanks to your help I have made significant progress towards uploading a new image via SMP but I need one more piece of information that I am hoping you could help me with.  What I need is an example of one Upload block for the DFU over SMP.  Note that I don't need the BLE overhead, just the DFU SMP data portion of the Upload Block.  What I am looking for is just the raw bytes that are sent for the Upload block.  Here is my attempt at creating and sending two Upload Blocks and the responses that I am getting back.

// Data sent for block 0 of the upload

A4 62 70 31 01 64 64 61 74 61 58 C0 3D B8 F3 96 00 00 00 00 00 02 00 00 FC A5 07 00 00 00 00 00 01 1B 02 00 C4 12 53 61 00 00 00 00 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 63 6C 65 6E 18 C0 63 6F 66 66 00 00

I checked the CBOR through cbor.me it is valid CBOR data and I get the following...

{"p1": 1, "data": h'3DB8F3960000000000020000FCA5070000000000011B0200C412536100000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF', "len": 192, "off": 0}

When I send this I get the following response

BF 62 72 63 00 63 6F 66 66 18 C0 FF

cbor.me tells me this is the CBOR:  {"rc": 0, "off": 192}

This seems like a valid response but when I try sending the 2nd block I get something back that is not valid.

// Data sent for block 1 of the upload

A4 62 70 31 01 64 64 61 74 61 58 C0 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF 63 6C 65 6E 18 C0 63 6F 66 66 18 C0

I checked the CBOR through cbor.me it is valid CBOR data and I get the following...
cbor.me: {"p1": 1, "data": h'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF', "len": 192, "off": 192}

// Block #1 response - this is INVALID according to cbor.me
BF 62 72 63 01 FF 6F 66 66 18 C0 FF

Thanks,

Dave 

[Vidar Berg]

Hi,

I am not familiar with the low level details of the mcumgr protocol or the cbor encoding, to be honest. But you can do DFU using the same image with nRF connect on Android or iOS, then inspect the log to see the cbor requests and responses that are being sent.

Here is the log I got from nRF connect on iOS for reference:

Let me know if this is not the data you are looking for.

Vidar

[davidpatton]

Hi,

  The image you sent contains the log output from the DFU, this is one level above where the actual bytes are sent.  Although that contains most of the data for an Upload block it is missing some stuff, I am looking for a log at the byte level.  Something that shows the actual bytes being sent over the BLE, if I get this I will know how to extract the data I need:

BLE Header (I don't really need this)
SMP Header (this is 8 bytes)
CBOR Data (this is variable length)

If possible a file containing the raw bytes would be AWESOME.  Thanks so much for your help, once I get this piece of information I am sure I will be able to complete this project.

Thanks,

Dave