I’d like to do some power draw measurements, and I’m curious as to whether it’s possible remove power from some of the peripherals on the Dev Kit, such as the HDMI and USB connectors. I do, however, use the ethernet connector in order to SSH in.
Looking at the schematics it seems like there are a number of buck converters that step the 19V down to 1.8/3.3/5 V, and a boost to 12V for the fan. Aside from physically removing these components from the PCB, is there any way to isolate the TX2 such that it is the only significant component drawing current?
HDMI power provides output for the i2c query (the DDC/EDID wire…pin 18 is the power…https://upload.wikimedia.org/wikipedia/commons/thumb/4/48/HDMI_Connector_Pinout.svg/310px-HDMI_Connector_Pinout.svg.png). It’s only a tiny amount, and if you wait until after video has been set up there is no reason you couldn’t cut that wire yourself. You could literally get a short HDMI extension cable and cut that one wire…and insert a switch (cut the power line, not the DDC line…query line itself does not consume power).
USB has a sleep function, I’m not sure how to force it on…usually there is a kernel command line for “autosuspend=0” to disable it…you might research that and see if there is also a way to force autosuspend at all times.
PCIe won’t draw anything if nothing is connected.
WiFi might be high on the list of things you could disable with software.
There are a number of “minimal” expansion boards from other vendors, that have much fewer built-in peripherals. The J90-LE from Auvidea and the Astro (without additional motherboard) from Connect Tech come to mind.
The most accurate way of measuring only the Jetson module would be to build your own carrier board with your own Samtec module mezzanine connector to plug it into, and your own voltage converters and power sequencing.
VDD_MOD is for module, you can measure the current on it to get the power consumption of module.