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TM4C129XNCZAD: SPI SUPPORT IN TM4C129XNCZAD

Part Number: TM4C129XNCZAD

Hi ,

I am planning to use TM4C129XNCZAD for one of our project .

I have to interface few sensors and DAC 's that supports SPI interface(16 bit) and are from TI and Maxim Intergrated  respectively.

The problem is that there is no direct support for SPI in the core .

There is a SSI interface that supports Freescale SPI in its Legacy Mode .

My queries are :

1) Does my sensors and DAC support the SSI interface in its Legacy Mode (SPI Mode) ?

 2)Is there any specific SPO and SPH configurations that needs to be maintained ?

3) Any hardware changes needed to support my slaves ?

Thanks,

Chandan

4 Replies

  • You may not be correct in, "Selling the MCU's (flexible) support of SPI" short!

    Chandan kumar
    There is a SSI interface that supports Freescale SPI in its Legacy Mode

    While that appears true - your review of the MCU Manual should reveal "several" other "SPI format and/or protocol options."

    Chandan kumar
    Does my sensors and DAC support the SSI interface in its Legacy Mode (SPI Mode) ?

    You've not identified ANY of your sensors - or DAC - have you?      How then can such a question be answered?      And - is not that discovery - (your) job?

    Chandan kumar
    Is there any specific SPO and SPH configurations that needs to be maintained ?

    Indeed - you must "match" the MCU's SPI format (as it is programmable - thus flexible) to that of the (more restricted) sensor/DAC.       It is (expected) that you'll "Run into trouble" when the individual sensors and DAC - employ DIFFERENT SPI formats - among themselves!       This will force you to, "Alter the set-up/config. of your MCU - to support that particular sensor/DAC!"       Usually - but not always - this is best managed by choosing sensors & DACs which employ the "same SPI format!"

    Chandan kumar
    Any hardware changes needed to support my slaves ?

    It is likely that you'll employ separate, MCU GPIO pins, to serve as "CS" for (each) sensor & DAC.      SPI works best when all such (remote/slave) devices are in close proximity to their "Master."

  • Hi,
    The SSI in legacy mode is the SPI mode (Freescale format). You will need to check your sensors/DAC datasheet what polarity and phase they use and configure the SSI the same. I don't think there is an hardware changes needed.

    regards,

    Charles

    Please click the Verify Answer button on this post if it answers your question.

  • In reply to Charles Tsai:

    Might it be that (any) statement of "legacy mode" puts the "cart in front of the horse?"      Should we not note that our poster asks, "Do my sensors support (legacy) SPI mode?"     (he either does not know - or has not checked - so (any) review of legacy is premature!)

    It is the sensors - not the MCU - which dictate which SPI format/protocol the MCU must follow!      (this results as almost always - sensors do NOT provide flexible formats)

    Further - as stated (1st post arriving in response) the odds that ALL Sensors will share the (same) format are NOT especially high!       (unless sensors & DAC were chosen to conform to a single SPI format - which was the advice offered ONLY w/in "1st response!")

  • In reply to cb1_mobile :

    Hi All ,

    Thanks for all your comments and suggestions .

    I have selected sensors and DAC's which has a 4 wired SPI Interface . Also i had worked on the same sensors with other TI processors.

    Since i am not that familiar with SSI protocol and its flexible support for SPI specifically "FreeScale SPI ", i just wanted to know how different it is from a normal SPI interface that are usually provided in other TI controllers and processors and wanted to know any specific parameters that needs to be taken care to make it work in SPI Mode .

    But from your comments it looks like it will not be much difficult for me to interface my slave devices on it without a need for changing the hardware .


    Thanks,
    Chandan