My Tab5 Extended GPIO and Power management library.

easytarget

Hi all;

This is something I've been working on; a easy way of taking control of the Tab5's power management circuitry from vanilla MicroPython; without needing a special board build.

https://codeberg.org/easytarget/tab5-egpio-micropython

The README there has the full install and usage notes; plus a list of the (30!) methods it provides. This is deigned to be very simple in use; it is self-contained and lets you:

Control power on/off for the WiFi chip, Speaker Amplifier, USB-A port and Expansion port 5V power.
Switch WiFi between internal and external antennas
Enable and disable battery charging, set the quick charge status, read the charge indicator pin.
Read the battery voltage and current in/out.
Detect if headphones are plugged in.
Set LCD backlight brightness
Trigger a poweroff event.
Send reset signals to the LCD, TouchPanel and Camera modules.

Use it to create a power control object and set the device up as you need:

from tab5_egpio import TAB5_EGPIO

tab5pwr = TAB5_EGPIO()
tab5pwr.wlan_pwr_on()
tab5pwr.charge_enable()

# later (let the charge controller settle first)
voltage, current = tab5pwr.battery_status()
print('Battery: {:.2f}V @ {:.3f}A'.format(voltage, current))

There are some demo's in the repo that show how to use this in more detail. And I have a page where I am documenting general hardware related Tab5 micropython information at: https://codeberg.org/easytarget/m5-tab5-micropython

[note: I'm cross-posting this here from the micropython official discussions, since it is specific to the Tab5]

felmue

Hello @easytarget

for me your current implementation to turn off M5Tab5 actually only does a reset.

The power off pulse needs to pulse to turn off M5Tab5. See here.

I modified poweroff_now function in your library like below:

def poweroff_now(self):
        """Instant full power off. Be sure you want to use this!"""
#        self._e2.set_output(_PWROFF_PULSE_PIN, HIGH)
        for x in range(10):
            self._e2.set_output(_PWROFF_PULSE_PIN, LOW)
            sleep(0.05)
            self._e2.set_output(_PWROFF_PULSE_PIN, HIGH)
            sleep(0.05)

and now my M5Tab5 turns off.

Thanks
Felix

easytarget

@felmue
Thank you! you are quite right! I hadn't really looked at what was happening properly :-(

The pin needs to be toggled high then low with a ~50ms delay for a full power off, just toggling it high does a full reset (after 1 second). I really wish there was a state diagram (or similar) available for the code in the PMS150G power control MCU.

I've extended my code to do the required pulse similar to your modification, and added a reset_device() method too. Plus relevant notes in the README etc, and done a new release.

[testing shows that the poweroff happens immediately after the first pulse, I'm not sure why they attempt to pulse several times but I guess they are just making sure.. ;-)]