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MSP430FR2512: REGISTER_I2C Pins On MSP430FR2512IRHL

Part Number: MSP430FR2512
Other Parts Discussed in Thread: BOOSTXL-CAPKEYPAD

Hi There!

I am wanting to use the REGISTSER_I2C interface on the MSP430FR2512IRHL with Captivate Design Center. Previously I had been pulling lines low to signal button events, but I would like to experiment with the register interface. 

So three questions: 

1. Can I use for the I2C lines any of P2.4, P2.5, or 2.6? If so, how can I do this? 

2. If I cannot use those pins, which pins should I be using? 

3. Related to my previous approach, when experimenting, I found the following issue:

In my application, I noticed that setting P2.4 to GPIO and outputting 1 and 0 on the lines work as expected. On the scope I get a 0 and a ~3.3V signal. However, with P2.6, I get 3.3 and ~ 1.3. This makes me think perhaps that pin is muxed to something via the generated captivate software. I can't find anything in the BSP_configureMCU() routine that suggests this however. What could be going on here? I've tried this with the micro just connected to power with the pins broken out so I am certain other elements are not influencing the signal. 

Thanks!

  • Hi Jay09,

    To use the alternate I2C pins on P2.4 and P2.5, you need to configure them by setting the SYSCFG2 |= USCIBRMP

    There is example code for the BOOSTXL-CAPKEYPAD with the Captivate Design Center examples -> "BOOSTXL-CAPKEYPAD-prototyping".  The example code is for FR2522 but will work on FR2512.  Here is a snippet from that example code showing how it is configured

    Now, regarding the use of a third pin for INT, nothing special.  Grab any available GPIO and don't forget to modify the CAPT_CommConfig.h file in the captivate\comm directory of your project.  See line #120 where you can redefine which pin you want the I2C slave driver to use.

  • Hi Dennis,

    This is so excellent, thank you so much for all of this helpful information! Such a clear answer. So SYSCFG2 |= USCIBRMP is enough to map both pins then, yes? It looks like from the diagram above this setting will set:

    P2.5 -> SDA

    P2.6 -> SCL

    Correct?

    Thanks again for the quick and helpful reply! 

  • Hi Jay09,

    You go it.  I'll mark this posting RESOLVED for now.

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