AM335x - I2C Pull-ups

RNJ

Other Parts Discussed in Thread: TPS65910, TPS65910A

Hello,

I was reading the Texas Cheklist for Sitara's Processors. link http://processors.wiki.ti.com/index.php/AM335x_Schematic_Checklist and I found the information in the I2C part telling to use 4k7 Pull-ups in both signals of I2C (I2C_DATA and I2C_CLK).

When looking to the PMIC Guide (link http://www.ti.com/lit/ug/swcu093c/swcu093c.pdf ) page 6 shows a diagram of TPS65910 with AM335x using 1k2 pull-ups in these lines.

I'm a little confuse right now, which design should I follow? The value of the pull-up must be the same in all I2Cs from AM335x? Or this value is dependent of each slave I2C that am I using?

Thanks guys!!!

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Ricardo,

4.7kOhm pullups are used in all our reference designs for I2C0 lines between AM335X and TPS65910A. This is for a 3.3V interface.

0 RNJ over 12 years ago in reply to Biser Gatchev-XID

Prodigy 87 points

Hello Biser,

But why the TPS65910A guide do not consider this value? It's a Texas PN, I know that these guides come from different teams, but should have the same "spec" in both documents no?

0 Biser Gatchev-XID over 12 years ago in reply to RNJ

TI__Guru**** 393215 points

I cannot say why. If you are concerned both values should work with no problems. I have seen people use 1.2kOhm - makes no difference (except higher current draw).

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AM335x - I2C Pull-ups