Trying to make sense of SAMD I2C datasheets

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ezharkov
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Posted by ezharkov: Fri. Jul 3, 2020 - 06:46 PM
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They have two formulas (see SAMD10 datasheet, for example):
fSCL = 1 / tLOW + tHIGH + tRISE
fSCL = fGCLK / (2 * (5 + BAUD) + fGCLK * tRISE)
Am I the only one who thinks that the second formula make no sense? Specifically, the tRISE part of it. Unless they mean two completely different "fSCL" things in two cases.

 

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Atmel SMART ARM-based MCUs and MPUs, Atmel Cortex-M MCUs
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ezharkov
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Posted by ezharkov: Fri. Jul 3, 2020 - 07:19 PM
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No way to delete the OP? Oh, well. Never mind then. I think I got it now. I just didn't think that they would dynamically adjust fSCL based on the actual tRISE. But I guess they are really doing that. In that case the second formula does make sense.

 

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awneil
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Posted by awneil: Sat. Jul 4, 2020 - 08:43 AM
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ezharkov wrote:
I think I got it now

So please mark that as the solution - see Tip #5 in my signature, below:

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