PPK setup with nRF52: Solder SB11 ?

[mchartier]

nRF52 DK, PCA10040 v1.2.1

PPK PCA63511 rev 1.1.0 2018

I am connecting the PPK to the NRF52 DK in the simple case where I want to measure power consumption of the 52832 on the DK itself (not external board). I have a couple questions:

1) If I power both boards with a single USB connected to the DK should I short SB11 or SB12 or neither?

2) Will the results be more accurate if I use a battery to power the DK?  I was told that current consumption may rise as the battery voltage drops but I do not know how significant this may be for estimating power consumption.

3) If the DK is powered by battery how do I power the PPK?  Would I set SW4 to external and connect USB to the PPK?  

Some background info: 

The instructions say you must short SB11 or SB12 depending on which power source you choose, battery or external.  In section 6.3 of the DK user guide it says:  

The reverse voltage protection diodes will add a voltage drop to the supply voltage of the circuit. To avoid this voltage drop, the diodes can be bypassed by shorting one or more solder bridges.

However I found this comment in a forum post which seems to contradict the DK user guide:

1. If the PPK is used with the nRF5x DK, prepare the nRF5x DK for power measurements by cutting the PCB track shorting solder bridge SB9 according to Preparing the development kit board. Do not short the solder bridge SB11/SB12.

Thanks

[haakonsh]

1. Neither.
2. You should power the DK + PPK from the DK USB port.
3. Cut SB9, this will remove the DK's nRF52832 from the DK power supply, allowing it to be powered by the PPK.