DM8148 I2C rise/fall time, does this assume 10%/90% V swing?

Brad Caldwell

Genius 12595 points

In DM8148 datasheet revised Sep 2012

Table 8-44 Timing requirements for I2C Input Timings

#9, #10, #11 & #12 : Rise and fall times

Is this assuming a10-90% voltage swing for transition time?

over 12 years ago

0 Brad Griffis over 12 years ago

TI__Guru*** 125430 points

It's relative to Vih,min and Vil,max. Those are the numbers dictated by the I2C specification itself, and that's also how they're referenced in the standard.

This is also noted in Section 8.1.1 of the data manual, i.e. we state that all rise/fall parameters are related to Vih,min and Vil,max. There are a few cases that are different such as MMC which is why for that specification we explicitly state that we're referring to the 10%-90% transition time.

0 Brad Caldwell over 12 years ago in reply to Brad Griffis

TI__Genius 12595 points

Thanks Brad, that makes sense. To complete this forum post for others who may come across it, here are the values for the DM8148 so in this case it's really 30% to 70% for rise time

Processors

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DM8148 I2C rise/fall time, does this assume 10%/90% V swing?