Devboard UART influence on PCA10040

[amartino]

I'm trying to get the nRF52 on the PCA10040 dev board communicating through UART without the use of the programmer built into the dev board. So I'm connecting the UART pins directly to the headers of the devboard.

Given that I'm currently experiencing issues on getting the connectivity through the pins from the headers, can someone please confirm that the Segger chip has no way of interfering with the connections with the exposed header pins? If the board is powered by the micro USB port, does the Segger automatically take over the UART port?

[AmbystomaLabs]

On the DK the Segger is permanently connected to the UART associated gpio on the nRF. You can't just hook up to the header and expect it to work since the UART on the Segger chip is still connected.

You will need to cut SB22, SB23, SB24 and SB25 if you want to use an external UART.

Here is a blog entry where someone else was doing the same thing: devzone.nordicsemi.com/.../

[Matt]

It "may" still work even if the above SB2* are not cut. I recall hooking up the BMD350 evk, which is very similar to PCA10040, to the Telit GSM module through the uart pins and power the whole setup through the USB. The uart connection worked fine (luckily!!!) in my set up and I could send AT commands to the Telit module to set up GPRS connection through the GSM network.

But I agree with the answer that you better make some adjustments with regards to the above SB2* :)