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AM263P4: RTI counter configuration

Ivan Ivanenko
Prodigy 115 points
Part Number: AM263P4
Other Parts Discussed in Thread: SYSCONFIG

Tool/software:

Hello.

I have several questions about RTI counter configuration

1. Is there any possibility to set compare value of the up counter to maximum 0xFFFFFFFF value with SysConfig? It allows input only of integers value to 'Desired Output Frequency (Hz)', and 1 Hz is actually minimal value available. Entering '0' seems give required behavior, but also leads to 'division to zero' warning.

2. What is 'NTU' signal? I found this in SDK API and register addendum, but no any description in reference manual.

3. What affect parameter 'clkSrc' in 'RTI_counterConfigure' function? I found this picture in reference manual, but no any descriptions in text about FRC clock select. Which values are valid?

  • 0
    TI__Expert 3395 points

    Hello,

    Apologies for the delay:

    1. I am looking into the SysConfig settings at the moment. Can you tell me which version you are using?

    2. NTU stands for Network Time Unit and refers to an external clocking source. I am trying to get some more information on this for your reference.

    3. I am having a little trouble understanding the question here. Are you asking which clocks are a vaalid source for the FRC?

    Thank you,

    Susan Moore

  • 0 in reply to Susan Moore
    Prodigy 115 points

    1. SysConfig integrated to CCS v 12.7.1

    2. Yes, but I could not find any description for it and see what settings should be used in different cases.

    3. Actually yes. What are valid values for "clkSrc" parameter.

  • 0 in reply to Ivan Ivanenko
    TI__Guru*** 134535 points

    Hi Ivan,

    Apologies for another delayed response here, this flagged to me by Susan but I wasn't able to get to looking into it sooner and I don't have firm answers on my end so I'll need to pull in another expert.

    To my knowledge the only way to change that setting to a value below 1 Hz would be to use a manual register write to override the SysConfig setting but I would need a SW expert to provide the detail on that.

    As for clkSrc I'm a bit unsure about this as well but what does seem clear so far is that it's not controlling the actual RTI source clock at a System level such as Sys Clk. The drivers set that based on the Input Clock Source without using the RTI_counterConfigure API.

    Best Regards,

    Ralph Jacobi

  • +1 in reply to Ralph Jacobi
    TI__Genius 11306 points

    Hi Ivan,

    1. Right now the only way is to write to the registers manually. I will sync up with the team internally on possible ways to fix and have a way to go below 1Hz.

    2. NTU is "Network Time unit'. For applications which are participating on a time-triggered communication bus, it is often beneficial to synchronize the application or operating system to the network time. The RTI provides a feature to increment Free Running Counter 0 (RTIFRC0) by a periodic clock provided by the communication module. You can find the MACROS and APIs for NTU0, NTU1, NTU2, NTU3 and option to use one of NTU as clock source of the free running counter. But right now, on the AM263x, NTU input to FRC0 is not supported.

    3. The clkSrc comes from you Sycfg for RTI. If the clkSrc is set to some NTU clocks, accordingly the registers will be written inside the RTI_counterConfigure API. If you are not using any NTU signal as your input, then the clock sources set from syscfg will be used.
     
    Regards,
    Shaunak