Analog IIC output does not reach the power supply voltage

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Analog IIC output does not reach the power supply voltage [Copy link]

I used a microcontroller to simulate IIC. I originally used AT24C12 to store data. SDA and SCL both used 10K pull-ups. The port was configured as open-drain output. There was no problem. Later, for some reasons, I had to replace AT24C12 with FM24CL16 (ferroelectric memory). The circuit was not changed and the pins were compatible. However, I found that the SDA pin was less than 3.3V and less than 0V. When pulled high, SDA was 1.1V and when pulled low, it was about 0.3V. What is going on? I tried to replace the pull-up resistor with 2.2K, but the problem still persisted. I checked the data and found that the SDA of FM24CL16 is also an open-drain output.

zenghao616

Is the CLK waveform normal?