Is there a way to measure current and/or power consumption on the TK1?
I can see on the schematic that the VDD_SENSE_N lines feeding back to the PMIC can be optionally bridged to the VVDD_PROBE lines (unpopulated 0 Ohm resistor), but I’m not clear what the *PROBE lines actually do (they seem to be connected to the K1 chip, but I can’t find any documentation on them).
The brute-force solution would be of course to cut the power traces and install 1 Ohm series sense resistors, but I’d rather not have to cut up the board to measure power.
I have not looked at the particular traces you refer to, but I’d be very careful about this. There are cases where trace impedance is very important and in some cases actively measured and modified. What you are looking at could be part of drive strength and slew rate measurement/control. 0 ohm resistors may indeed be for optional configurations, but you first need to check the technical reference manual and look at everything connected (Tegra K1 TRM is available with some of the other documents for Jetson).
Tegra processors support remote power sense functionality for the VDD_CPU, VDD_CORE & VDD_GPU rails. VDD_CPU_SENSE, VDD_CORE_SENSE & VDD_GPU_SENSE balls are routed on the Tegra package/die to power rail locations near each load & provide the positive (SENSE+) functions to provide information back to the PMU/Regulator to allow the VDD_CORE/VDD_CPU supplies to adjust to any voltage variances.
VVDD_CPU_PROBE
This ball can be optionally routed out to a test point to help with troubleshooting CPU power noise issues. This ball connects to the VDD_CPU power area on the Tegra die. Keep VVDD_CPU_PROBE routing away from power supply components or noisy signals/power rails, either on the same layer or adjacent layers.
Jetson TK1 system total power could be measured on the 12V input line.
R5C11 resistor on the system power input line is 0.005 ohm, you can try to measure the power using this resistor or replace this resistor to other value sense resistor.
It’s hard to measure specific power rails power consumption(ex. VDD_CPU, VDD_GPU, VDD_CORE).