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LAUNCHXL-F28379D: Parallel Communication with Resolver

omer gundogmus
Intellectual 345 points
Part Number: LAUNCHXL-F28379D


Dear Sir/Madam,

 I would like to read position data from resolver chip with TI DSP parallel communication port. I have read some TI Forum discussion, and TI does not suggest to use parallel data reading for resolver position data applications. I want to verify why TI does not suggest parallel communication with resolver chip to read position data and you prefer to use SPI and QEP? In motor application, we have a lot of EMI and RF noises in the DSP environment, which method is more immunity to these noises. I would appreciate if you guide me more clearly and your advise for preference in more technical detail. 

Thank you for your great support. Your guidance will be essential for our design. 

Regards, 

Omer

     

  • 0
    TI__Mastermind 24095 points

    Hi,

    I'm not specifically aware of any issues with parallel port. Which document are you referring to?
    But you could certainly use SPI and QEP interfaces as well. If you use QEP, in case of noise, you can turn on GPIO filters on the incoming signals and it'll certainly improve the noise immunity. You could do the same for other interfaces as well, if they are operating at a reasonably lower speed.
    I would expect parallel port would be more sensitive to noise due to more signals and timing critical nature of signals and their clocks etc.
    So, it really depends on the frequency of the interface, how quickly you want to obtain the position, nature of noise, ability to filter noise etc. QEP could be a good option if you have a slower interface and use GPIO filters to suppress noise on the inputs.

  • 0 in reply to Subrahmanya
    Intellectual 345 points

    Hello Subrahmanya, 

    Thank you for your quick respond. I am sending link previous comment on the parallel communication below in the forum, do you have any experience and support for parallel communication for resolver position reading?

    https://e2e.ti.com/support/microcontrollers/c2000/f/171/t/688668?LAUNCHXL-F28379D-Parallel-Data-communication-interface

    The machine will operate upto 5000 rpm, I need to read position up to 50 KHz interrupt time interval, I need to process position 

    You mention parallel port would be more sensitive to noise due to more signals and timing critical nature of the signal and their clocks, how about SPI ? It has also clock and timing. SPI or parallel communication is more immunity to noise?  

    Thanks 

    Omer

  • 0 in reply to omer gundogmus
    TI__Mastermind 24095 points

    Hi,

    I do agree about the previous post regarding the lack of future support for uPP.
    Since you are reading at a lower speed (50KHz ISR rate), yes - you could use SPI  as well.

  • 0 in reply to Subrahmanya
    Intellectual 345 points

    Hello, 

    Hello,

    I would like to get comparison SPI and parallel communication in my previous email. You mention parallel port would be more sensitive to noise due to more signals and timing critical nature of the signal and their clocks, how about SPI ? It has also clock and timing. SPI or parallel communication is more immunity to noise? 

    External Memory Interface (EMIF) for parallel communication can be applicable for resolver applications or it is only data storage(memory) applications, and  is it more convenient than SPI or SPI is better option ? 

    I need your help to advise me to use parallel communication, it is worth or not for resolver application?  

    Regards,

    Omer

  • 0 in reply to omer gundogmus
    TI__Mastermind 24095 points

    Hi,

    SPI also has clock and timing - but as you are operating at a lower speed you could use some filtering on the input signals.
    There is no such comparative data between these interfaces available to my knowledge.
    Typically, the decision to use a particular interface is based on system requirements like performance, cost, available interfaces etc.

    omer gundogmus said:
    External Memory Interface (EMIF) for parallel communication can be applicable for resolver applications or it is only data storage(memory) applications, and  is it more convenient than SPI or SPI is better option ? 


    Which resolver chip are you using? YOu can refer to the data sheet of the resolver chip and check if it's compliant with EMIF.

    omer gundogmus said:
    I need your help to advise me to use parallel communication, it is worth or not for resolver application?  

    I think SPI seems appropriate as it's lower speed and given the noisy conditions you mentioned, you can add additional filtering. 

  • 0 in reply to Subrahmanya
    Intellectual 345 points

    Hello, 

    I am using Analog Devices "AD2S1210" chip, it has parallel communication features, 10-bit to 16-bit data ports. It does not specify EMIF complaint. Is there any specific complaint for EMIF which differs from standard parallel communication? Thanks for your help. 

    Regards, 

    Omer

  • 0 in reply to omer gundogmus
    TI__Mastermind 24095 points

    Hi,

    I checked with the EMIF expert - and the parallel interface provided by the resolver you mentioned above seems to be compliant to EMIF.