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EK-TM4C1294XL: QEI maximum frequency

Leevi Korhonen
Prodigy 10 points
Part Number: EK-TM4C1294XL

Hi,

I was looking at the EK-TM4C1294XL for a motion control application where I have an incremental quadrature linear encoder on a track for a very accurate position measurement. The quadrature signal has a maximum frequency of 15Mhz or a minimum edge separation of 0.07us. Is this in the range of the QEI in the EK-TM4C1294XL to read it accurately without missing many pulses? The controller itself has a maximum clock of 120Mhz so can the QEI function up to this frequency or is this frequency divided by some number? If not, what is the highest frequency that it is quaranteed to work with? 

I tired to search google and PDF's but I couldn't find any real info with the search terms I could think of.

Thank you for your help.

-Leevi

  • 0
    Guru 13040 points
    Hi Leevi,

    Datasheet says on chapter 24:
    "The input frequency of the QEI inputs may be as high as 1/4 of the processor frequency (for example, 12.5 MHz for a 50-MHz system)"
    You are surely good to go if you are using TM4C @120MHz.

    As for reading the encoder values, take a look at the TivaWare Drilverlib User Guide, chapter 22. It should be straightforward to obtain the measurements you need.

    Bruno