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i2c internal pull-up resistors

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First post!!!!

I want to enable internal pull-ups for i2c on pins P1_6 and P1_7. A search on existing discussion on this topic yielded this:



"I2C requires a pull up resistor on both SCL and SDA. You can enable the internal pull up in the msp430 on the I2C lines by doing:

pinMode(P1_6, INPUT_PULLUP);

pinMode(P1_7, INPUT_PULLUP);"


Is that right? I tried it and it does not work. I was wondering that i2c SDA is bidirectional so setting pinmode as INPUT might not be the right thing. Has anyone tested this and gotten it to work without external pull-up resistors. 


Thanks in advance,



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Thanks spirilis once again. I confirmed your frequency number of 100 Khz on the scope to be correct. Did you infer it from the energia libraries ? Also I put the external resistors and my problem is resolved. 

Two followup questions:

  1. The MSP430G2553 spec says that there are internal pullup/pull down resistors available on Port 1. Does any one know their value ?
  2. Can these resistors be enabled using CCS if not energia. 


Thanks in advance,

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