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IIC Clock use and Uart start/stop bit on Coldfire

Question asked by Adrien Segura on Jun 5, 2019
Latest reply on Jun 17, 2019 by Adrien Segura


I work on Codewarrior 10.4 with a PE multilink universal on a coldfire MCF51CN128.

My objective is to imitate an IIC and an UART frame, and on both, i have problems :


-On my IIC frame, i succeed to imitate the initial frame with the SDA (data), but, the SCL (clock) is not exactly the same :

my generated frame :

and the frame i want :


I apologize for the poor quality of my records. Green : SCL, Yellow : SDA.

The objective of the IIC is a transmission only : the Coldfire MCF51CN128 transmit this data to a TCA6424A without any return. as you can see, there is a problem between frames : the "end of trame" is not here on my generation, and more important, my end of transmission isn't good. It has to be like this :

and, on my generated frame,the stop condition is wrong.



-On my UART frame i succeed to generate a frame with exactly the good data that i need, but, what i try to imitate isn't a single frame, it's 2 frames who take turns. The problem is : My communication start is too long : it is 3 bits longs to high level before the communication starts, given that there is 2 frames , i have 3 bits instead of 1 on the middle of my communication. This UART communicates with a kinetis MKL03Z16.


Any ideas of what are my problems? Thanks for the help and for your attention ! Have a nice day !


Adrien Segura