Makes sense - I'll do some research on this. Do you have a functional setup or something similar you've implemented to this kind of a thing? I'm assuming it would be like PWR_BTN->EMBEDDED_CTRLR->BOLT to signal power on - and then other states the Bolt would need to communicate back to the controller (sleep, pwr off, etc.) to then signal the PSU?
EC (MEC1705) is in the loop. Unfortunately only it knows the actual CPU state and the S5 signal is not exposed. May be checking the PWR_LED/Sleep_LED state is a good enough approximation. Naturally, a human being observing (as in the loop) can also be considered. To be honest, for the sake of turning off the fans, there are better strategies. Bottomline is this: UDOO Bolt, in my view, was not designed to mimic a PC thus certain capabilities ain't there. (I.e., it takes DC power input from a power brick, not from an ATX Power Supply. When Bolt is powered down, it only consumes very little power from the power brick thus no need to remove the power from it.) In another word, if the plan is to make it too much like a PC, then buying a PC probably is the easiest way out.
I really would like UDOO to provide an official guide for this - I've been asking them since May 2019 and I don't want to do any kind of DIY setup unless I'm assured it won't brick the system.
I've managed to use the +5V_RUN (pin 4 on CN-15 SATA power connector) to switch a relay on/off to control the ATX power ON (just grabbed spare bits I had). The 5V_RUN is only active when the CPU is active, so automatically already turns on/off for sleep/hibernate/ or ON/OFF, and you don't have to monitor the Bolt power switch. May be more elegant ways around it, but seems to work so far. Working through some monitor issues with returning from sleep, but hibernate seems OK. As for the why? With a new small quiet fan on the CPU, the small ATX power supply and a moderate graphics card not being pushed to hard are all super quiet. Built HTPCs before for the TV cabinet, and never managed to get a setup this fast and quiet.
Hi all. Is it possible to get some pictures of you guys' power 'hacks'? I'm trying to run off a single psu but am looking at the same issues. (I did try to start a seperate thread to keep things neater but it's still in moderation) Thanks!
