My I2C slave is not pulling down the bus all the way for the ACK.
I have tried replacing 1.5k pullup with 10k pullup, but the ACK voltage remains the same (1.6V).
System Voltage: 2.5V
Slave: NXP NT3H211
I have confirmed that the NT3H2211 is recognizing its address, because when I send another address (0x56 instead of 0x55), I see no response. (See screenshot).
I have confirmed that the NT3H2211 has a good ground and power supply, stable during the I2C access.
I have also ruled out an I2C peripheral issue on the master by writing a bit-bang rutine with the same result.
In this situation, how to proceed?