< It's related to non-operation at high temperature >
When the surface temperature of the ADXL350 is 40°C or higher, the register is not read/write when the power is turned on/off.
In this state, it is maintained even when the JTAG debug is connected to reset the S/W, and does not return normally unless the power is turned on/off after cooling down.
What's unusual is that after removing L7 and L8 from the circuit, the switch is attached, and when the ADXL350 is powered on after the main power is turned on, it operates normally.
In addition, when the register is not read and the power of the ADXL350 is turned off and on, it will operate normally.
Even if the SW delays before ADXL350 control, if the MCU and ADXL350 power are tied up, there is still the same phenomenon when there is heat.
Devices that do not show stopping will operate normally even if they are heated at 70 °C or more.
Best & Regards,