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TMS320F28069M: TMS320F28069M：How to use 28069M to communicate with endat22

user4381058
Prodigy 30 points
Part Number: TMS320F28069M
Other Parts Discussed in Thread: DESIGNDRIVE, TMS320F28069, TIDM-1011

Hello,

I am trying to figure out if it is possible to use EnDat with F28069M MCU and could not find any information.

There is an example in the ControlSuite for F28379D under DesignDrive/Position Manager/ EnDat/Example Project; however, the code example does not contain information about EnDat configuration and library usage.

If I use TMS320F28069 and endat 22, how do I configure it?

Could you please guide me?

Regards,

Burak

  • 0
    TI__Guru* 89465 points

    Burak,

    We do not have anything readily available to help enable an absolute encoder interface on this device.  We have a reference example of a T-format encoder interface on the F2837x and F28004x devices (https://www.ti.com/tool/TIDM-1011). 

    The TIDM-1011 reference uses the C2000 Configurable Logic Block so it is not portable to the F28069.  This is also true of the EnDAT22 reference you found.   

    Best Regards

    Lori

  • 0
    Prodigy 30 points

    Hi,Lori,
    Does it mean that I cannot use PM_endat22_lib.lib to make TMS320F28069 and endat22 work, because TMS320F28069 does not have a logic configuration block CLB? If I do not use CLB and library files, I can directly read the endat data through SPI, is it possible?

    Regards,

    Burak

  • 0 in reply to user4381058
    TI__Guru* 89465 points

    user4381058 said:
    Does it mean that I cannot use PM_endat22_lib.lib to make TMS320F28069 and endat22 work, because TMS320F28069 does not have a logic configuration block CLB?

    Yes, this is correct.  

    user4381058 said:
    If I do not use CLB and library files, I can directly read the endat data through SPI, is it possible?

    TI hasn't done any evaluation of this scenario. It is likely possible with some limitations.  In the CLB-based solution, we use the CLB for controlling the clock and for delay compensation of the cable length.  If you are using a fixed/short cable length then that may not be a concern. 

    This thread has a discussion about implementing BiSS, which is a similar protocol, directly with SPI.   Specifically see the post by Giannis Roussos on how they implemented.

    Regards

    Lori

    edit: fixed broken link

  • 0 in reply to Lori Heustess
    Prodigy 30 points

    Can I use F28069M's SPI to read endat data directly? No longer use library functions for operations. In addition, I use the CLA module for configuration, is it feasible?

  • 0 in reply to user4381058
    TI__Guru* 89465 points

    user4381058 said:
    Can I use F28069M's SPI to read endat data directly? No longer use library functions for operations. In addition, I use the CLA module for configuration, is it feasible?

    Hello,

    TI hasn't done any evaluation of this scenario. It is likely possible with some limitations. 

    I suggest taking a look at this thread.  It is a discussion about implementing BiSS directly with SPI.  BiSS is a similar protocol with the same physical layer as EnDAT22.   Specifically see the post in the thread by Giannis Roussos on how they implemented BiSS with SPI.

    Regards

    Lori

    edit: fixed broken link

  • 0 in reply to Lori Heustess
    TI__Guru 57255 points

    Hi Burak,

    Note that EnDat's data line is bidirectional, where BiSS/SSI's data line is unidirectional.

    Because of this, with EnDat you will need to find some method to control the data line transceiver & change it between transmit or receive mode while communicating.  Bit-banging may be feasible, but it is likely only low-speed communication will be viable & a non-trivial amount of cycles would be needed from the C2000 processor to manage this.

    The CLB in the F28379x/F28004x takes care of the transceiver transmit enable and EnDat state machine.  I'd personally recommend using a different absolute encoder, if you need to use the F2806x device.  Or use a different C2000 device, if you need to interface to an EnDat encoder. 

    As Lori mentions, feel free to do your own investigation though.  Here I'm giving guidance on what I'd conclude based on prior high-level analysis & knowing what I know about the protocol.

    Good luck in your project!


    Thank you,
    Brett