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IMX6ULL GPT input capture mode

Question asked by Sergei Poselenov on Apr 26, 2019
Latest reply on Apr 29, 2019 by igorpadykov


We need to measure input frequency of about 30 MHz. The idea is to use IMX6ULL GPT2, clocked internally with the 24MHz IPG clock, and configure the input frequency pin JTAG_MOD (ie to be measured) as External Clock in GPT2_CR, and JTAG_TDO as GPT2_CAPTURE2.


The Reference Manual has a statement:

To ensure proper operations of GPT, the external clock input frequency should be less than 1/4 of frequency of the peripheral clock (ipg_clk).

Now the question: if we use the divider "4" set in GPT2_PR, to divide the input 30MHz to the safe value of (30/(4+1)) 6MHz, will that satisfy the "1/4" restriction above?