I designed my first nRF series PCB.
I checked DEC1 ~ 6 voltage is fine, but the xtal pin is stable.
What is the next step to check?
What are you looking for? Are you just verifying if your design is working as intended? If so you can just try to flash it with a simple example, e.g. radio test example, and see if it runs as expected.
By the way, even though it seems to run as it should: C39 shall be 100pF.
But flashing was not successful.
I tried blinky example from SDK. It works good on 52840 DK PCA10056 board.
But when I try nrfjprog --family nRF52 --program nrf52840_xxaa.hex on my board,
It returned ERROR : There is no debugger connected to the PC.
I'm using st-link v2 from ST. Do I need correct tool? (SEGGER?)
duck4985 said:It returned ERROR : There is no debugger connected to the PC.
This is indicating that the reason for not flashing is related to your debugger, not your PCB. St-link debuggers are not verified by us and not a target for compatibility, and another factor is does the ST-link have support for nordic ICs and SW? There are a couple discussions related to ST-link on Devzone already, just search for them and you might find some interesting.
You can use your nRF52840 DK though, just hook the SWD interface on your external target up to P19 or P20. See the user guide for more.
nRF52840 DK works good as JTAG with my board.
Glad to hear that it is working, ST-Link is not officially supported.