nRF52840 power on led(Led 5) blinking continuously

[pankti583]

Hello,

nRF52840 led 5 blinks continuously causing reset and not performing code properly. I tried different USB cables but it still blinks. What could be the reason, is it only causing reset? and what can be done to make it proper?

Thank you

Pankti

[Amanda Hsieh]

Hi Pankti,

Try to press the IF BOOT/RESET button while power cycling the kit. It should then show up as a Removable Storage Device named "BOOTLOADER". Then you can drag-and-drop the J-LINK interface MCU firmware found here (v170724) onto the storage device to reprogram the JLINK firmware.

Please let me know this can help or not. Thanks. 

-Amanda H.

[pankti583]

Hi Amanda, 

 I tried the above steps, the led was blinking still. Power Led 5 is still blinking but it doesn't reset the code. Is it normal for led 5 to blink? or it is indicating some issue?

Thank you 

Pankti

[Amanda Hsieh]

Hi Pankti, 

After reprogramming the JLINK firmware, resetting the board again, for instance powering off and on again, should get it back into the normal state (LED 5 lights up continuously).

-Amanda H.

[pankti583]

Hi Amanda,

I performed the above step after reprogramming, LED still blinks. It even got reset few times.

Thank you

Amanda

[Amanda Hsieh]

Hi Pankti, 

It might be a bad USB HUB, or/and the USB cable is power-only. You can try another cable or connect the cable directly to the computer, and not via a USB HUB. We have had cases the customer had 4 power-only USB cables, the 5th USB cable had data lines. 

-Amanda H.