imx7 ADC Predevider

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imx7 ADC Predevider

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erikfriedel
Contributor III

Hi

This question may seems trivial, but I just can't find an answer.

In the i.MX7 Dual Applications Processor Reference Manual, "IMX7DRM.pdf" at page 4941 you can see 14.1.4: Clocks and timing.

The Global clock the ADC is receiving is 24MHz. The Manual says, that the adc analogue clock can vary from 300kHz to 6MHz and that the 24MHz clock can be devided by 4, 8, 16, 32, 64 and 128.

My problem is, that 24MHz : 128 = 187.5kHz.      How does this work, and why did the manual say 300kHz?

Could someone please explain it to me?

Best regards

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Yuri
NXP Employee
NXP Employee

 

Hello,

 

  According to hardware specs of the i.MX7, shown in i.MX7 Datasheet(s)

in table, named “Recommended operating conditions for 12-bit ADC”

parameter Main Clock Frequency FCLK should be in range 300 KHz - 6 MHz.

 

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Have a great day,

Yuri

 

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erikfriedel
Contributor III

Thank you

My question is, why you are able to select the 128 divider. This would result in a analogue core clock of 187500Hz, wouldn't it?

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Yuri
NXP Employee
NXP Employee

Hello,

  the 128 divider is a feature, supported by generic IP, embedded in i.MX.

Regards,

Yuri.

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