pull-up resistors of AM335x ICE V2.1Board

Kanae

Hi.
Regarding a schmatic of AM335x ICE V2.1Board,
there are pull-up resistors; R61 and R196 for I2C0_SDA
and I2C0_SCL in Page-4.
Are they really necessary?
If so, I would like to know the reason.

5165.tmdxice3359_sch_3h0013_v2_1a.pdf

Regards,
Kanae

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

The I2C specification requires pull-up resistors on both lines. If you are thinking about using AM335X internal pullups, their value is too high for I2C to operate properly.

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

Guru 10245 points

Thank you for quick reply.
I would like to make sure about pull-up resistors for I2C.
There are R70 and R71 pull-up resistors; 4.7k ohm in page-2.
Do R61 and R196 pull-up resistors; 2.2k ohm need for the ICE board?

Regards,
Kanae

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

TI__Guru**** 393215 points

One pair of pullups should be enough. I don't know whether both sets are populated on actual boards, or just one.

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

Guru 10245 points

Thank you for your reply.
I understand that one pair of pullups is enough.

Regards,
Kanae

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pull-up resistors of AM335x ICE V2.1Board