nrf51 smart beacon kit jtag programming

[Mike]

Hi,

I have just received my smart beacon kit (nRF51822 based), I have wired up my JLink programmer according to devzone.nordicsemi.com/.../

However I am having trouble detecting the beacon kit on nRFgo Studio. nRFgo studio keeps saying that no device detected.

Normally, after inserting the battery, the beacon's LED will start flashing. If I plug in the programmer afterwards, nRFgo studio doesn't detect the device.

After a few tries, I managed to find 1 particular condition that allows the nRFgo studio to detect the device, which is connecting the JTAG programmer first, and then put the battery in. Now the LED doesnt turn on at all. When I click the refresh button for the first time on nRFgo studio, the device is detected, with the correct IDs, SD version etc. Then the LED would start flashing. However, if I click the refresh button again, the device is no longer detected.

I suspect that once the device is booted and the application is running, it somehow cuts out the JTAG interface.

Could anyone share some light in this issue? Cheers.

Warm regards, Mike

[Stian Røed Hafskjold]

I've never experienced anything like that, so I'm not really sure what is going on. The reset pin is not really needed since the device is reset through the SWDIO pin. Actually on the nRF51 chip nRESET and SWDIO is the same pin, so in order to reset, the J-Link goes out of debug mode and then pulls the SWDIO pin low. Are you sure you bought a genuine Segger? It is a lot of copies out there.

You can try to download the latest drivers for your J-Link, www.segger.com/jlink-software.html, and then flash it with the newest firmware (Using J-Link Configurator).

You also mentioned that you had a pull up on the SWDIO, you can try to remove this as it is not really needed. There is an internal pull up on the chip.

Other than that, the only thing I can think of is HW issues. If it turns out it is the HW on the beacon, you can open up a case in the support portal and get a replacement.