Ble resets automatically

[PKSHER]

Hello.

This is becoming a very serious issue for me. When I program the nrf52840 dongle and when I switches on the power, it automatically goes into bootloader mode, means red LED starts blinking and I need to program the dongle again.

Regards,

[Amanda Hsieh]

Hi, 

If you add the DFU Trigger Library (USB) to your custom device firmware, it will trigger the DFU from nRF Connect for Desktop without using any buttons. Please refer to nRF52840 Dongle programming.

-Amanda H.

[PKSHER]

I am using dongle as it is, in my project. Not using any module.

What I am trying to say is that the dongle goes into bootloader mode whenever I switch on power supply, means I put the dongle in my project and when I switch on 3.3V to the dongle, it goes into bootloader mode without any button presses. 

[Amanda Hsieh]

Hi, 

What firmware does the dongle use? Do you program it with your custom firmware? If so, is the custom firmware build with the DFU Trigger Library?

What do you want the dongle to do in the project?

-Amanda H.

[PKSHER]

Hi, thanks for your reply.

I want the dongle to scan ble beacons and transmit their data to another device via UART, I am using APP_TIMER for sending at specific time. The project is battery powered. The dongle scans for one second every minute.

I am using external supply for dongle by cutting the jumper and soldering another jumper as mentioned in the userguide. Hence I give 3.3V to Vdd out pin.

I write and build my programs using segger embedded studio and program them using nRF connect programmer app. I am using SDK 15.3 and softdevice s140.

And I often need to switch the power on and off, and I noticed when I switch on the power, the dongle automatically goes into bootloader mode and the red led starts blinking. Then I need to program the dongle using nRF connect programmer app while the power is on. But when I swtich off the power and switch it on again, the dongle goes to bootloader mode. This is happening 80 % of the time. Maybe I am doing something wrong, kindly give some suggestions.

[Amanda Hsieh]

Hi, 

Which example is the project based on?

What user guide do you refer to? Could you kindly provide the link?

-Amanda H.