Tachyon based tracker - wake on external power

Tachyon
1

I want tachyon to boot whenever external power is applied to replicate the functionality I have already built into a vehicle tracker using a Pi4 and a UPS HAT. In this application I monitor the external power presence (via GPIO) and shutdown after a few minutes when the external power is off. The UPS HAT (geekworm X728 https://geekworm.com/products/x728 ) provides the "wake on power" functionality. Thus I can wake the Pi and begin tracking whenever the vehicle is operated, safely shutting down after the vehicle is powered off.

The tachyon SYSCON docs I can find seem to hint this is possible, using a GPIO "wake_pin" and the command sudo /usr/bin/particle-tachyon-syscon.sh set_config sys.wake_pin_enable:true but I can't find any docs that tell me which physical pin that might be...

gpioinfo |grep -i wake shows

line   3: "PCIE1_WAKE_N" "wake-gpio" input active-high [used]
line  89:          "-"  "wake-gpio"   input  active-high [used]
2

Hey zedstarr!

That would be a docs issue... Just updating them at the moment! The pin I believe is pin 40 I believe and it is high to wake but we'll loop back shortly with the info on how to set and how to trigger. You did indeed find the syscon docs however to enable this feature! Nice find! :slight_smile:

The PCIe wake pin is just for the PCIe interface so thankfully not involved here.

Thanks!

Nick.

3

Hey zedstarr,

Just following up, we need to update the microcontroller to make this work fully now we went to document it - will take us a few days and then we'll loop back! You can just 'apt update' then and it will pick it up, so nothing complex.

Thanks

Nick.