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AR# 34385

ML605 - IIC pull-ups needed when using FMC card


If you are implementing I2C LPC interface on the ML605 Evaluation Kit with an FMC daughter card, then you need to check that the appropriate pull-up resistors are present, either on the ML605 or on the daughter card.


If you are using the ML605 together with an FMC daughter card, please note the following:

The I2C LPC interface requires pull-up resistors on transistors Q26 and Q27 for the SCL and SDA signal lines.
Please check your ML605 board to see if the IIC pull-up resistors are present, or not.

If not, then check the schematics of the FMC Mezzanine Card you are using to see if the resistors are included on these signal lines on the card. If so, no change is necessary to meet with specifications.

If there are no pull-ups on the SCL and SDA signal lines on both the ML605 base board and the FMC card, then please add a 2k ohm resistor across leads 1 and 2 of Q26, and another 2k ohm resistor across leads 1 and 2 of Q27.

See the following figure for details:

Article 34385
Article 34385
AR# 34385
Date Created 03/19/2010
Last Updated 03/19/2010
Status Active
Type General Article