I am using TPS65217C available in Beaglebone Black (schematics https://raw.githubusercontent.com/CircuitCo/BeagleBone-Black/rev_b/BBB_SCH.pdf for testing a protoype. I have tested it with and without battery. The BeagleBone Black is running the latest debian image from elinux.org https://elinux.org/Beagleboard:BeagleBoneBlack_Debian#Flasher:_.28lxqt-4gb.29_.28All_BeagleBone_Variants_with_a_4GB_eMMC.29.
on issuing "systemctl poweroff" command from linux. I observe that the LDO4 voltage does not go down. Also observed that Vsys is dropping down to 3.94V from 5.5V ( I am using 4V battery)
I can clearly see PMIC PWR_EN bit go low. From I2C messages at boot up it is also noticed that the Status register is set to start the power down sequence when PWR_EN bit goes low.
My questions are
- Why does Vsys stay high ?
- What is preventing the PMIC from shutting down ?