We’re still having this issue. I’m wondering if it could be a problem with the pmic communication… when we see this issue, the enable pin is 3.3, and the regulator is 3.3 but the mcu does not boot and the led doesen’t blink. About 2 weeks ago we added the following lines of code in our setup() routine:
//shamelessley coppied from Rftop on the forums, ensures that the pmic reboots every time the boron restarts and doesen't power down after a no sun scenario, also ups the charge rate limit current.
pmic.begin();
//detachInterrupt(LOW_BAT_UC); //this is necessary if we use boron firmware above v1.1, apparently they screwed up in later versions...
pmic.setInputVoltageLimit(5080); // for 6V Solar Panels
pmic.setChargeVoltage(4208); // Set Li-Po charge termination voltage to 4.21V, // this is a bit high.. ?
pmic.enableDPDM();
pmic.enableBuck(); // enableBuck required when using EN Pin Shutdown.
pmic.enableCharging();
pmic.setChargeCurrent(1,1,1,1,1,1); //no limit on charge current, solar voltage shouldn't drop below 5.08v(set above), so the system is in voltage control mode
we added this a few days before we started seeing this bug, so it would seem to correspond but I’m not sure how that is possible. I guess I don’t really know what some of this means. enableBuck and enabledpdm are especially baffling to me. I assume that enablebuck sets the register in the pmic to enabl the buck converter even while the mcu is off. I couldn’t find too much info on exactly what either of these does.
anyways what I don’t understand about this is that the pmic and the 3.3v regulator seem to be working fine when enabled. I guess what I’m wondering is what the 1st thing the boron does, even before it flashes leds? Is there an i2c conversation with the pmic that could hang and explain my behavior?