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MSP430F5419A: About I2C SCLtHigh and tLow

Part Number: MSP430F5419A

Hi experts,

I have a qeustion about I2C SCL tHigh and tLow.

Formulas for calculating the minimum values of tHigh and tLow can be found in DS.

My customer's I2C has the following settings.

  • UCBRx:64
  • fBRCLK:25,000,000(25MHz)
  • I2C Master

For this setting, tHigh and tLow are:

tLow,MIN = tHIGH,MIN = (UCBRx/2)/fBRCLK
                                      = 64 / 2 / 25000000
                                      = 1.28 usec

The customer's I2C waveform is below.
Δt is 1.28usec. t1 is where SCL is 2.1V( Positive-going input threshold voltage).

Since the customer's waveform has a slow response, it is equivalent to the value of tHIGHMIN, and it is not possible to judge whether it can meet the required specifications of tHIGHMIN.

Please tell us about:
• Need a faster waveform response?
• Is there a problem with this waveform?

Best regards,
Sasaki

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