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TMS320F280049C: Help in CMPSS pin selection

Siddham Jain
Prodigy 30 points
Part Number: TMS320F280049C
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

I am making a custom board based on F280049CPZS chip, I have a doubt in pin use and placement of CMPSS.

suppose I have to use CMPSS-7 there are multiple option like high negative, high positive, low negative and low positive and total of 12 options, but I need 2 pins only for comparator operations. Help me in which pins I need to choose and how to configure it.

  • 0
    TI__Mastermind 19351 points

    Hi Siddhham,

    Each CMPSS has 2 individual comparators in them, one "high" comparator and one "low" comparator. And each of these comparators has a positive and a negative input. 

    For most use cases it is fine to just use the positive side of a comparator as the negative side is supplied by an internal DAC reference. This would apply for example if you are using the CMPSS for overcurrent, then you are only concerned the with the reading with respect to the analog ground.

    You only need to supply to negative side if you are using truly differential comparator for 2 input signals. 

    You can treat the high comparator and low comparator in each CMPSS as separate comparators for different applications but you can also leverage them to use as a windowed comparator, like if you wanted to send both under and over current

    Regards,

    Peter

  • 0 in reply to Peter Luong1
    Prodigy 30 points

    Thank you for the information, Peter.

    I am having one more question, I wanted to know whether we can program the internal DAC via CCS?

    Regards,

    Siddham

  • 0 in reply to Siddham Jain
    TI__Mastermind 19351 points

    Hi Siddhham,

    Yes you can program the internal CMP DAC value using either DriverLib or SysConfig within CCS. I recommend you take a look at the CMPSS section within C28x Academy for more information

    Regards,

    Peter