When the board was initially powered on, all output voltages of the PCA9450 were normal. After downloading a program using SDPS mode on an M8P board without any program loaded, all power supplies to the PCA9450C except for LDO1 and LDO2 lost power.
Using an oscilloscope to observe the PCA9450C startup, it was found that all power supply voltages, except for LDO1 and LDO2, exhibited pulses with 100ms intervals. These pulses lasted for several cycles before the power supply returned to normal.
Below are the logs after downloading the program and the oscilloscope voltage readings.
Call me at 147.
@guoweisun , 感谢回复
Here we only look at the PCA9450 exception and test the VIN/BUCK1/POWER _ON_REQUEST waveforms