52840 USB DFU

RE: 52840 USB DFU

Edvin — Fri, 27 Mar 2020 10:44:37 GMT

The init packet is created using nrfutil. You should use nrfutil to create these packets. nrfutil is open source.

The content isn't really well documented, but here are some approaches. The init packet is the .dat file in the zip file that you generate using nrfutil. You can generate init packets with different settings, and see what changes. E.g. set the application_version to different values, and see the differences in the .dat file.

Here is a brief overview of the fields in the init packet:

https://github.com/NordicSemiconductor/Android-nRF-Connect/blob/master/init%20packet%20handling/How%20to%20generate%20the%20INIT%20file%20for%20DFU.pdf

Also, take a look in the nrfutil repo on github.

Basically, you don't need to know what's inside the init packet, which is why this information isn't floating around. You need to know that you generate it with nrfutil, and that you transfer the init packet first, and then the application image. If you need more info on what the init packet contains, please refer to the nrfutil repo documentation and implementation.

Best regards,

Edvin

RE: 52840 USB DFU

Meng. — Fri, 27 Mar 2020 09:28:03 GMT

Hi Edvin，

As I said at the beginning.

I read the DFU Protocol documentation and the Serial documentation, but I didn't find anything about the init packet.

The above only said the init packet, but did not say what the specific content is.

RE: 52840 USB DFU

Edvin — Fri, 27 Mar 2020 07:56:39 GMT

Then, as Turbo J said, the protocl is described here.

What happens here is the transfer of the init packet. When this is done, and the CRC is calculated and it is executed, then the next step is to do the same with the firmware image, according to the message charts.

So the line with the red circle is 08: Write, and the rest is payload for the init or application image (in this case init, if it is near the start), except the "C0", which is part of the SLIP library.

I recommend that you read the DFU Protocol documentation and the Serial documentation, both the "Initialization", "Transfer of init packet" and "Tranfer of firmware image" sections.

RE: 52840 USB DFU

Meng. — Fri, 27 Mar 2020 01:37:48 GMT

Hi Edvin，

I am talking about the data drawn by the red circle as shown in the figure, and the red circle in the lower right corner is the full version of the first packet of data.

RE: 52840 USB DFU

Edvin — Thu, 26 Mar 2020 14:10:31 GMT

Hello,

As Turbo J said, the DFU protocol is described on nrfutil (see the link in his first reply).

Are you refering to the 21 22 23 ... packets? I am not sure, but it looks like generic "USB - set up connection" packets.

RE: 52840 USB DFU

Meng. — Thu, 26 Mar 2020 09:26:59 GMT

Thanks Turbo J.

What does this initial packet with metadata for update consist of?

We want to know how to organize this data.

RE: 52840 USB DFU

Turbo J — Thu, 26 Mar 2020 09:04:50 GMT

0x08 = NRF_DFU_OBJECT_WRITE

That (and the following 7 Bytes transaction) is the init packet with the metadata for the update.

RE: 52840 USB DFU

Meng. — Thu, 26 Mar 2020 08:23:44 GMT

Hi Turbo J，thanks for your response.

I found my problem, 0xC0 is the end of the packet.

The transfer is compliant with the SLIP library.

But what does the instruction I highlighted mean?

RE: 52840 USB DFU

Turbo J — Thu, 26 Mar 2020 08:06:28 GMT

[quote userid="89053" url="~/f/nordic-q-a/59519/52840-usb-dfu"]Not in the official documentation.[/quote]

That is not true: DFU serial protocol description, second sentence:

"The transport layer uses the SLIP library for encoding and decoding packets."