Hi,
I used the On/Off board schematic for a custom boad with STM32, all part and value according to the schematic, as of now i only use the push buttons, the lines GP1 and GP2 are leaved unconnected. I can switch ON with the push button, and switch OFF with a long press, however when switched ON the circuit shuts down itself after about 15 second.
VCC is an USB port, slightly under 5.0V (4.8V), the load is the STM32F3 MCU. I monitored the line between the 300K and the 10uF capactor, it falls at 0V once the circuit switches ON, after about 12 second it start to increase, then the circuit switches OFF, an this line stays at 4.8V (VCC).
Does anyone have an idea of what is wrong?
Correction since it seems i cannot edit anymore, i checked again, the measure i gave is for another line (line from 1uF to SI4562) the measure for line from 10uF to 300K s actually:
0V when circuit is OFF
4.05V when push button activates
then constantly dropping at a fast rate, the circuit shuts OFF when it reach about 1.0V
If you leave GP2 disconnected, then the circuit will power off automatically. It must be pulled to 3.3v. The alternative is to remove t6 if you don't want the automatic poweroff.
Thank you for the clarification, i will tie GP2 to it GPIO (solder jumper) and set it high at startup. Nice 😀
