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[Bug 1001397] I2C driver for Kinetis microcontrollers


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http://bugs.ecos.sourceware.org/show_bug.cgi?id=1001397

--- Comment #59 from Mike Jones <mjones@linear.com> ---
After setting CPU clock to 100Khz:

Freq        Mode         Meas
100Khz      Std          98Khz
100Khz      Agr          111Khz
400Khz      Std          363Khz
400Khz      Agr          416Khz

>From an application point of view, this is a little problematic, in that:

- When you set the goal and value, you don't get feedback in the configuration
that tells you what the result will be. You have to get a scope and measure it.

- If you want to make it more accurate, you have to either guess the correct
CPU clock, or reverse engineer the algorithm to calculate the required clock
manually.

One solution might be to have the configuration calculate the proper CPU clock
so you can then manually change the clock to get a better result. 

I am ok with committing the solution as is because I can figure it out for 100
and 400 and will have the only answers I need. I think it is just a question of
how much you want to help the application programmer.

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