Debug why DFU start packet not starting DFU

[cswanson420]

Firstly, platform: Sparkfun 52832 breakout board, DFU using UART, flashing an application, using nrfutil.

The problem fundamentally is the nRF52832 is not sending an ack that it received the DFU start packet. The packet is formatted correctly as defined by infocenter.nordicsemi.com/.../bledfu_transport_serial.html

the nrfutil code indicates a timeout as a result of not receiving the ack for the start packet.

I have the capability to use the nRF52DK with J-Commander to look at various places in memory and the registers, I just don't know how to go about determining why the SoC is not replying.

I also am guessing that there is the possibility the CPU in the nRF52832 may not actually be running the bootloader code, although from the appearance of the flashing LED the hardware presents itself as being in the bootloader mode.

Questions:

1. Is there a means to derive whether the code executing is the bootloader code,
2. If the code is bootloader code, how could one determine why the start packet is not being acknowledged and subsequently moving the the next state in the DFU state machine.

[bjorn-spockeli]

No, nrfjprog uses the SWD interface, it wraps a jlink .dll, so its basically the same as J-Link Commander, but with some extra nrf5x only features. The SoftDevice should be flashed with 0x00000000 as the start address and the bootloader should be flashed to the nRF52 starting from 0x7A000. Its much easier to just use nrfjprog, which handles this for you, just provide it with the hexfile.