M5StickC : how to switch 5V out off?

Kabron

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Obviously EXT_VDD is enabled via EXT_BOOST_EN pin of the AXP192, so it must be a way to control it.

felmue

you can use this function to control the output of 5 V out (and Groove port):

M5.Axp.SetPeripherialsPower(true or false);

Thanks
Felix

Kabron

This post is deleted!

Kabron

I tested it - does not work at all

Kabron

@felmue It only switched 5V to Vbatt
I see the only way to reconnect EXT_BOOST_EN of the BOOST converter to VESP_3V3.

felmue

Hello @Kabron

hmm, I've tested with an M5StickC (not Plus, not Plus2) powered by USB-C (or battery) and an LED attached to the Groove port.

I agree, EXT_BOOST_EN needs to be turned on, which is exactly what the function I pointed out does. It sets bit 2 of register 0x10 of the AXP. See here. And here - page 34.

Edit: I just remembered, I think there was a similar discussion a couple of years ago. EXTEN actually seems to exist in two places. Bit 2 in register 0x10 and bit 6 in register 0x12.

Maybe try to manipulate bit 6 in register 0x12 to see if that works for you?

Thanks
Felix

Kabron

@felmue I tested it:
void AXP192::SetPeripherialsPower(uint8_t state) {
if (!state){
Write1Byte(0x10, Read8bit(0x10) & 0XFB);
Write1Byte(0x12, Read8bit(0x12) & 0XBF);
}
else if (state) {
Write1Byte(0x10, Read8bit(0x10) | 0X04);
Write1Byte(0x12, Read8bit(0x12) | 0X40);
}

EXT_BOOST_EN controlled correctly, DC-Boost stops generating, but bypassed input Vbatt to 5V output.

What an idiot designed this part of schematic?

I could not identify DC-Boost IC(Sot-23-5 marked IB3KB)/

Kabron

So, according to schematic switching off 5V is fundamentally impossible. IPSOUT via L1 and D3 allways present at output.

felmue

Hello @Kabron

I start to think that maybe the DC/DC IC has been changed over time in the M5StickC. The DC/DC IC in mine is marked SCAJF and the externally connected components look suspiciously like the 5VOUT_BOOST in the M5StickCPlus schematic.

This would at least explain the different results regarding on/off capability.

Thanks
Felix

Kabron

Definitelly, M5SticC and M5SticC Plus have different schematics. DC-Boost in M5SticC Plus is sgm6603-5.

felmue

Hello @Kabron

I beg to differ. At least between my M5StickCPlus and M5StickC the DC/DC boost circuit and IC look suspiciously identical.

on the left: M5StickCPlus; on the right: M5StickC

Thanks
Felix

Kabron

@felmue I draw schematic above from my exemplar. Obviously it's too old.
IC is SOT-23-5 and its marking corresond with MP1541 datasheet.

The root of the evil is M5STACK's absolutely lackadaisical documentation for all the products.