NRF52840 / NRF52832 DFU Bootloader for multiple transport layers.

Question

Hi There, 
 
 I am currently using a custom bootloader for my devices which was started from the secure bootloader example given in the SDK, I am using BLE as the transport layer, I was wondering if you guys have any examples that merge more than one transport layer in the bootloader, for instance BLE and USB for the NRF52840, or SPI and BLE for the NRF52832 in this case I am using a FTDI chip USB to SPI IC. 
 Any guidance or recommendations on this topic would be much appreciated. 
 
 Thanks, 
 Regards

Einar Thorsrud · Accepted Answer

Hi, 
 The nRF5 SDK supports multiple transports, but it is not demonstrated by any example. In practice, you need to add all files, includes and sdk_config.h configurations from both example projects (say BLE and USB). I suggest you start of with the BLE example and add the other transport into that, as the BLE example bootloader allready depends on the SoftDevice etc. You also need to reduce the bootloader start address and increase the size, to accommodate the larger bootloader. 
 Note that you need to do very little code changes, as the transports are automatically registered build time (using section variables). So as long as both transports are included in the build, both will be used. 
 You should also handle this issue , which could cause problems when using multiple transports. 
 Einar

NRF52840 / NRF52832 DFU Bootloader for multiple transport layers.

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