Serial DFU is working only when connected via segger and not working when trying to flash firmware directly using USB to UART cable.

[Pranay]

Hi there,

I am working on having serial bootloader in nrf51422 to perform dfu over UART. DFU serial bootlaoder example in sdk11 claims to do the same.

After flashing the bootloader I tried to perform DFU using nrfGo App. It works fine when I am flashing firmware via segger com port, but then I tried to flash firmware over UART using same UART pins directly and this time it is failing to flash the firmware.

I also noticed that, when I am connecting both UART and segger com ports (Not with default uart pins), nrfGo was able to flash the firmware by selecting UART COM port. (Is presence of jlink segger port is necessary to flash firmware???)

I am using :-

DK                      - nrf51422

SDK                   - SDK11

Example code    - nRF5_SDK_11.0.0_89a8197\examples\dfu\bootloader\pca10028\dual_bank_serial_s130

tools& IDE         - nrfGo studio, keil4

[bjorn-spockeli]

Are you using a USB-FTDI cable/breakout when you're connecting to the non-default UART pins? Does this have FTDI cable have Flow control pins(RTS/CTS)?  Which pins are you connecting to which on the FTDI cable/breakout? 

[Pranay]

Hi @bjom-spockeli, I am using USB-TTL cable with no flow control pins(also disabled flow control in firmware as well as in nrfgo tool), only Tx and Rx pins connected to the MCU.