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

[Mike]

it's a segger j-link education version. I have measured the voltage and it is 2.9V at the moment with the current battery, would that be a problem? (also I noticed that most of the button cell batteries I have are 3V, so how do I achieve 3.3V or more?)

but if the problem is with the battery, why does it work the first time if I plug in the JTAG first before the putting in the battery?

update: I have just tried to power it from the 3V3 of an arduino, exactly the same behaviour, it is only detected once if I plug in JTAG before powering it