Did anybody seen similar?
I have no idea how to repair.

I already wrote about poor documentation(
https://community.m5stack.com/topic/2482/ecg-module-code)
Now, I tested acquisition speed of the device.
Maximum data rate(DisplayECG() - OFF, delay(5) - OFF) is 66Hz.
And it could not be increased without changing onboard STM32 FW.
This uC acts as BLACK BOX. No description, no source code.
DisplayECG() - ON, delay(5) - OFF - 45Hz
Any serious ECG measurements started with data rate at least 250Hz.

Initially, I planned to use it with IR pulse sensor for Blood Pressure estimation. Obviously, with 15 mS accuracy it is impossible.

Make your own conclusions

It is very shame that the product is not accompanied with any documentation.
Where is the detailed schematic?
Where is the description of the FW?
Where is the description of RawDisplay SW?
Where is description of the passthrough serial?
Where is protocol description?

ECG Module13.2 detailed schematic mandatory
Block-diagram absolutely non informative

I post it here
https://github.com/m5stack/M5Core2/issues/40

Now Battery Coulombs are calculated correctly.

@m5stack said in AXP192 coulomb counter issues:

it seems like a bug. I will contact our engineer to solve this problem.

Any progress?

According to datasheet IP5306 charging current is 1.8A.
Battery, used in M5 Core Bottom is 300mAh.
It means that charge current is 6(!) times greater than C/10.
Only special designed batteries could work with such charge rate!
For me it is nothing surprizing that batteryes in M5 Core lives nothing.
For me is surprizing that no flammable incidents were reported yet.
What your designers were thinked about?!

Got 2 M5stack Core2 yesterday.

Spent 2 hours trying to understand M5 logic with versions mess.
Burned Core2 via M5Burner(2.1.6) with UIFlow Beta4-core2.
Download UIFlow-Desktop-IDE and choosed Beta, because there is no Core2 in v1.4.5.
CheckUpdate gives Current Version 1.0.12 on both 1.4.5 and Beta.
What is 1.0.12 for?

After connecting to Core2, IDE reccomend update Firmware to 1.6.3,
WEB IDE reccomend update Firmware to 1.6.4.
What are 1.6.3 and 1.6.4 Firmwares and where are them located?

After switching off by double click on power button
M5stack Grey Spontaneously Turns ON after several minutes.
And it continues till battery discharge.
Does anybody observed such behaviour?

This example illustrates how to get information from multiple SPAD areas from VL53L1X TOF sensor. 16 Regions Of Interest(ROI) with size of 4 * 4 SPAD elements each are defined in SPAD sensor array. Thus, a 4 * 4 measurement matrix formed. Distances measured from each of 16 ROI, interpolated to 8 * 8 image and displayed as Thermal like image.
Code here:
https://yadi.sk/d/qpxO0fMItW4Qpw
Video here:
https://youtu.be/b18ghRCWawo