As you could see from the below image, the SCL signal at 400kHz is NOT a good square wave.
1) Why & how to solve it, please?
2) Also, why SCL is between 0.4V to V_DD=3.25V? Shouldn't it be 0V to V_DD=3.25V?
As you could see from the below image, the SCL signal at 400kHz is NOT a good square wave.
1) Why & how to solve it, please?
2) Also, why SCL is between 0.4V to V_DD=3.25V? Shouldn't it be 0V to V_DD=3.25V?
1. Your pullup resistance value is too high. See: electronics.stackexchange.com/.../473799
2. Where do you get these figures from? It's probably allowing for the fact that actual electronic circuits are not perfect.
Also:
1. Your probe typically adds a 12pF capacitive load when attached, requiring stronger pull-ups.
2. Where on your circuit is your probe's ground reference attached? It seems like it has a lower voltage potential than the TWI circuit's ground reference.