Mystery that makes pairing impossible using DK 52(10040)

[Hiro]

Hello everybody. Please answer my question.

I repeated the Bluetooth pairing ON → OFF of my smartphone and DK 52 (PCA 10040 + HRM) and checked the connection, I encountered a mysterious phenomenon. HRM : heart_rate_demo.hex

1. It is a phenomenon that the pairing between the smartphone and the DK 52 becomes unsuccessful twice. If pairing fails even once, you can not pair it twice. · Is it momentarily displayed as "being connected with Nordic_HRM" and ignored · "Rejected" is displayed and fails. The cause of failing pairing remains unknown.

2. When this symptom occurs, connect the DK 52 and the PC via USB, copy the sample code to the J-LINK drive and write it again

3. Search available devices from Smartphone, find them immediately, When "Nordic_HRM" is selected, the dial gauge is immediately displayed on the right side of "Nordic_HRM" and the pairing succeeds.

It seems that Spartphone is not affecting, but some trouble has occurred on the DK 52 and it can not be recovered, and it can be recovered by rewriting the code.

Although it is sample code, it is interpreted as a fatal defect as Bluetooth Since there is a possibility, please check clear cause and solution. let me know.

Best Regards.

[Bjørn Kvaale]

Which SDK are you currently using?

[Hiro]

To the DK board just purchased (PCA 10040 V 1.2.1 / 2017.22) I use Sample Code on WEB. It is only possible to examine it on the WEB to see which SDK was coded. www.nordicsemi.com/.../nRF52-DK-heartrate-monitor-demo

I have not compiled on SDK yet. Can you get any information?

[Bjørn Kvaale]

Could you first download the SDK 14.1.0 from this location? Then, could you please download nrf go studio (either 32-bit or 64-bit). Lastly, could you unzip the sdk 14.1.0, open nrf go studio, attach your dk to the pc via usb, find the dk under Device Managers (should be called Segger and then a number), press the erase all button & finally press on the Program Application tab. There, you can browse for a hex file. I want you to find the hex file under examples/ble_peripheral/ble_app_hrs/hex/ble_app_hrs_pca10040_s132.hex & flash this hex file to your dk. Lastly, download the nrf toolbox app from iOS or Android, open the HRM example & try to connect to your dk.