Q&A: Is there an issue using odd DIV_SELECT values in mx6Q PLL Setting?

Document created by Yixing Kong Employee on Sep 2, 2013
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Q:Is there an issue using odd DIV_SELECT values?

When setting the CPU clock (maybe others also) in uboot, the code will only use even valuesfor the DIV_SELECT field.

There is nothing in the Reference Manual or Errata that indicates only even values can be used for this field.

 

There were 2 SR's that had conflicting answers and we are trying to determine what can be used.

 

The CPU freq setting trying to be achieved is 996MHz.

With a 24MHz source, you need 24MHz x 41.5 = 996MHz.

Since the DIV_SELECT is x2, a value of 83 would be needed.

 

A:

Below is the DIV_SELECT description of ARM PLL, since the Fin is 24MHz, so there is no odd issue of DVI_SELECT, as 24 / 2 = 12MHz. Such as for 996M, this value is 83, that is fine. "This field controls the pll loop divider. Valid range for divider value: 54-108. Fout = Fin * div_select/2.0."

 

This document was generated from the following discussion: mx6Q PLL Setting

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