autostart beaglebone when powered by GPIO

Hi there,

when a beagle bone green is powered by USB it starts automatically. This is not the case when it is powered by GPIO.

Is there a way to get this functionality?

How are you powering ? Which pins ?

P9 5,6,7,8 all to 5V
P9 1,2,34,43,44,45,46, P8 1,2

also using 3.3V generated by the BB for powering a CAN Transceiver.

P9 7&8 are outputs from the PMIC and it might not be happy with you connecting it to 5V. I would not connect anything to these pins.

P9 5&6 are physically the same as USB 5V so that should be enough to power the board.

minor nitpick: these pins are physically the same as the
dc barrel jack input (vdd_5v in the schematic), not usb_dc.

we’re powering a commercial embedded product via the p9 header, and the
one minor issue that we ran into during early tests was that the
pmic isn’t happy with a slow rising input. (one of our lousier
bench powersupplies frequently failed to tickle the bbb into starting.)

the datasheet for the pmic (tps65217c) has the details for maximum rise
time and so on.

Well if we are going to nitpick, you obviously did not pay too much attention to the first post, nor look at the BB Green schematic, because if you had you would have seen that VDD_5V is connected to the USB 5V and that the BB Green does not even have a DC barrel jack.

The fact remains that SYS_5V is an output from the PMIC and should not be connected to VDD_5V. Whether this is the cause of the board failing to boot or not, I could not say.

removing 5V from P9 7/8 did fix it.