NRF52 (Custom Board) Serial DFU Reset the device.

RE: NRF52 (Custom Board) Serial DFU Reset the device.

MartinBL — Fri, 01 Jun 2018 07:12:41 GMT

So it sounds like you need to debug the bootloader. It resets for a reason and by debugging it might be possible to figure out why. Debugging a bootloader is not as straight forwards as debugging an application, but here are the steps you need to follow: https://devzone.nordicsemi.com/f/nordic-q-a/4101/bootloader-debugging.

When an application works on a devkit, but not on custom hardware, the usual suspect is the low frequency clock. Are you using an external 32 kHz crystal on your custom HW? Can you verify that it is working properly? Can you upload your schematics and layout files (preferably in Gerber or Altium format)?

RE: NRF52 (Custom Board) Serial DFU Reset the device.

sonalkale — Thu, 31 May 2018 12:57:37 GMT

Hello,

Yes,it works on a development kit, but not on custom board.In my program it switch to bootloader mode when it receive specific character(in my case "@") from bluetooth device or from serial port.

When we receive "@" from bluetooth its reset the board...Actually its switch to bootloader mode but reset within a second.

RE: NRF52 (Custom Board) Serial DFU Reset the device.

MartinBL — Thu, 31 May 2018 11:50:50 GMT

Hi,

I'm not sure if I understand.

Your are doing DFU over UART, and it works on a development kit, but not on your custom board?

When the device resets it is likely that your code has hit an assert. Have you tried to debug and look for such asserts? Is it possible that the UART fails on your custom board?