nRF52840 DK Heart Rate Demo is not working

[Peter Murphy]

Hi Everyone,

I recently purchased the NRF52840 DK with a PCA10056 designation. I connected the DK to my Windows 7 laptop via the USB.  This resulted in the JLINK(D:) drive showing up in my Windows explorer. Next, I downloaded the Heart Rate Demo to the computer and copied it to the JLINK(D:) folder.  When I do this, LED1 goes off (prior to this it had been blinking) and I'm not able to connect to the nRF52840 DK from inside the nRF Toolbox app which I installed on my Android phone. When I press the "HRM" button inside the nRF Toolbox app and then press "Connect", the nRF52840 device does not show up.  I should mention that I am able to copy the blinky demo (available after downloading the SDK to my laptop) to JLINK(D:) and things work as expected (i.e., the LEDs blink as expected).

Before crafting this question I did a search for "Heart Rate Demo not working" and found a handful of related posts/question. The one that seemed the closest to what I'm experiencing is the following one: https://devzone.nordicsemi.com/f/nordic-q-a/20520/heart-rate-monitor-demo-does-not-work.  However, both the "nrfjprog" and "nRFgo Studio" links in the answer are stale.

Any suggestion would be appreciated.

Thank you.

Peter

[Susheel Nuguru]

I think this is a basic thing you might have already done, but all BLE applications needs the softdevice (BLE stack) to be flashed first. you need flash S140 version based on the SDK you are using. You can find the softdevice in your nRF5_SDK_xxx\components\softdevice\s140\hex. You need flash this softdevice first and then flash your heart rate application.