DFU: How to split and send the firmware image?

[Andy]

Hello,

I'm developing firmware for a BLE central that performs a DFU on another NRF target. Right now I'm at the point where I need to start sending the firmware image part by part using the DFU packet characteristic.

My idea is that the BLE central will receive the firmware image via UART from a 3rd party and then it will transmit it to the target via BLE.

What is the file that I need to send and how should I split it? My guess is that I need to send the bin file, but how do I split it? Any advice on this?

Thank you in advance :)

[Andy]

Hi Bjorn, thanks for coming back to this! I checked the function you suggested, and I get it, but the thing that I'm missing is how this part works: mFirmwareStream.read(buffer); I want to know how to decompose the bin/hex file into several "buffers" so that I can then send them to the DFU packet characteristic

[Andy]

I found this project: git.panaceas.org/.../ Apparently it implements the DFU service in C, but it's poorly documented. If I figure how to decompose the bin file, I'll let you know :)

[Andy]

By the way, I don't know a thing about Java and I can't find mFirmwareStream anywhere :/

[bjorn-spockeli]

Im not a Java guy either, but according to our Android developer it is as simple as reading 20 bytes at the time from the bin file( I am assuming that this will be stored in flash on the nRF51), sending them and then read the next 20 bytes untill you reach the end. Doing this with hex files is another matter as you need to understand the Intelhex format.

[Andy]

I figured it out by looking at this file and this file. Thanks for your support!