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High-Resolution HRCAP from within the CLA on F28069?

Cyril Lance
Intellectual 270 points

Hi,

I am using the High-Resolution mode of the HRCAP module on an F28069.  I have it working on the main MCU using the HCCAP library but I need to be able to get to these registers somehow from the CLA (in a similar way that I can control the HRPWM from the CLA).

There is no documentation on how to setup the HRCAP for high-resolution at the register level, or how the registers are being accessed.  If you look at the registers, they do not show any MEP resolution (i.e. the xxxxRISE0, xxxxFALL1, etc.).

Does anyone have any information on this?  Is there source-code for the library that would show how this information is being accessed?

Thanks,

Cyril

  • 0
    TI__Expert 6130 points

    Cyril,

    I'm sorry for the delay on this.

    Unfortunately the HRCAP is not accessible by the CLA, it can only be controlled by the C28 core.

    Best regards,

    Jason

  • 0 in reply to Jason Whiles
    Intellectual 270 points

    Hey Jason,

    Thanks for the reply.  It would be good to understand why this is the case. 

    The most important features of the Picollo family for us are the high-resolution micro-stepping and the CLA.  This is what places premium value on this MCU.  Not having access to the HR information at the register level for this very important control-loop resource, seems a big oversight and something to make sure is not propagated in future products.

    ESSENTIAL QUESTION:  is the CLA actually blocked from accessing the registers that retrieve this high-resolution timing information?  Or can one look at the disassembly for the HRCap_GetPeriod(), for example, and port this over to the CLA.

    ANOTHER IMPORTANT QUESTION:  it is unclear from the Technical Reference Manual whether one needs to run the HRCAP_Cal() routine regularly only on one module or whether one needs to run this regularly on each HRCAP module being used.

    Can you help with these questions?

    Thanks,  Cyril

  • 0 in reply to Cyril Lance
    TI__Mastermind 43730 points

    Cyril,

    Unfortunately the CLA is not connected to HRCAP on f28069, this is clear from the figure 1.1 in the TRM, there is no physical connection

  • 0 in reply to Cyril Lance
    TI__Expert 6130 points

    Cyril,

    The HRCAP registers are actually not memory mapped at all to the CLA on the F28069, so it just isn't possible.

    I am not personally familiar with the HRCAP, I'll have to ask around.  If you are able to access it from the C28 CPU perhaps you could pass that to the CLA.

    I'll ask about the HRCAP_CAL() question as well.

    Best regards,

    Jason

  • 0 in reply to Manish Bhardwaj
    Intellectual 270 points

    Manish,

    Thanks for the clarification!  Too bad - it would be very useful.

    Looking at Figure 9-1 of SPRUH18D from Feb.2013 - I see what you mean now.  I had assumed that the eCAP registers included the HRCAP registers as well in the same way that the ePWM and HRPWM share the same "block".

    Do some of the new Picollos / C2000 have the HRCAP connected to the CLA?

    Cyril

  • 0 in reply to Jason Whiles
    Intellectual 270 points

    Jason,

    Thanks for that update.  Now I understand the physical limitation.  I am currently passing the result from the C28 processor over to the CLA via the RAM so that is a work-around.

    I appreciate you're looking into this for us!

    Cyril

  • 0 in reply to Cyril Lance
    TI__Guru** 119680 points

    CLA has HRPWM access on other devices like the lower performance F28035 and higher performance Delfino F28337D. You will see other variants of the F28337D architecture this year that will be a good path for you coming from an F2806x.

  • 0 in reply to ChrisClearman
    Expert 1570 points

    Hi Chris,

    Will we be seeing the FAST running on a Delfino or some variant of higher speed mcu than the 28069 ?

    It would be interesting to see this with the Delfino that has 16bit ADC for large operating range...

  • 0 in reply to Mojo
    TI__Guru** 119680 points

    Yes, that would be quite interesting wouldn't it?

    Over the short term we will continue to focus FAST on the Piccolo class of device.