I have a question regarding supercap scheme. I have built RPi Zero to SIO for loading ATRs with Hias'es "atariserver" and figured I can power RPi through +5V pin from Atari SIO to cut down on a number of cables. I have a new 5V/2A PS for my Atari, and RPi Zero only needs about 100 mA. There's only one problem. RPi takes several seconds to boot, so I don't want to power it down when I power cycle Atari when reset doesn't work. To that end, I thought I'd use super capacitor. I bought one 1F supercap, some Schottky diodes and resistors. This is a scheme I came up with:
Does it make sense? I know it works, but I don't know if I need to bother with a resistor to limit inrush current. I don't know what supercap can tolerate. Perhaps just a diode + supercap would suffice.
With a 10 ohm R1 it takes about 20s to fully charge supercap, and then RPi can run for about 14 seconds after I turn off Atari. That's plenty of time to power cycle Atari.