Dear Sir or Madam,
I am having problems getting communication with the PCA9534A.
I see the CLK and SDA lines are pulling the commands on the i2c bus low in the correct way. the same circuit work when implemented on a different board. The only difference between the two is the power supply structure.
The expander circuit is similar to the one in the datasheet (Fig. 10-1).
The only reason I can think of is the ramp-up speed of Vcc.
I am attaching it. Is this kind of Vcc ramp-up ok?
.