I stumbled upon this: https://www.raspberrypi.org/forums/view ... 5#p1233749
i don't post much in this forum as i can easily be considered a Rpi beginner, though i am far more experienced with an Arduino.
in any case, i am planning on using a Rpi 3 as a GPS plotter using OpenPlotter (http://www.sailoog.com/openplotter). if i have gpio_poweroff, and gpio_shutdown understood correctly, i would like to use an Arduino to handle sending the safe shutdown signal to the gpio_shutdown pin, and once power to the Arduino is removed, i will use a set of supercaps to enable the arduino to be powered long enough to wait for the gpio_poweroff signal from the Rpi, and then remove power from the Rpi, and also sever the connection from the supercaps to the Arduino.
I will draw up a Eagle schematic once i am sure i have the understanding of the gpio_poweroff and gpio_shutdown signals correct.
so, the question: can i use both gpio_poweroff and gpio_shutdown, on separate pins, in the above described manner? in other words, does gpio_shutdown function as an input signal to trigger a safe shutdown? and does gpio_poweroff function as an output signal for when the safe shutdown is complete, and is ready for power to be removed?
I am still waiting for my HDMI screen for my Rpi to show up, so it is rather inconvenient to test my plan at the moment.
i thank you all in advance for any help.