• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 81 subscribers
  • Views 525 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Data Logging and CC4 plus Motor Control Library Questions

Christopher Taylor
Intellectual 690 points

1.  Can data logging (as described in the motor control library for CC3) be done in CC4?

2.  There are no units for PWM period or duty in the source or documentation.  On the 28335 I have 150 MHz clock and intterupt running every 50 Khz for sampling.  Example shows 40 Mhz ISR frequencey and 20 Khz PWM rate.  I do not know how to interpret the outputs coming out or what the desired values in the example mean.

  • 0
    TI__Guru** 119680 points

    1. yes.

    2. the units are "counts" or clock ticks.  Which example are you looking at?

    If you download SPRC922 (Piccolo Dual Axis) and look here

    C:\TI_F28xxx_SysSW\MotorCtrl+PfcKit\PFC+1PM_Motors\~Docs

    The document explains the counts and timing.

    For you, I assume you want to run at 25 KHz PWM updates?

    25 KHz PWM = 40k ns

    150 MHz = 6.67 ns

    40k ns / 6.67 ns = 6000 "counts" for a PWM period

    For 3Ph this is usually set-up as a symmetrical up-down counter to PWM Period / 2 = 3000 counts

  • 0 in reply to ChrisClearman
    Intellectual 690 points

    The original problem that I was having was related to IQ math.  As someone that had never heard of IQ math before and given nothing but the chip and the example I was lost.  It wasn't until someone told me that the IQ math was twos complement that I was able to understand and move on.