IMX6Q EIM Maximal Frequency

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IMX6Q EIM Maximal Frequency

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alexeytsirlin
Contributor I

Hi,

What is the maximal EIM BCLK frequency in synchronous mode? According to the IMX6Q reference manual, the maximal frequency is 133MHz, but according to the IMX6Q datasheet, the maximal frequency is 104MHz.

What is the correct frequency?

Thanks,

Alexey.

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gusarambula
NXP TechSupport
NXP TechSupport

Hello Alexey Tsirlin,

The maximum allowed axi_clk frequency is 133 MHz.

I think the 104Mhz limitation may come from older versions of the EIM as that of the i.MX51 in which a note did indicated: “The maximum allowed axi_clk frequency is 133 MHz, whereas the maximum allowed BCLK frequency is 104 MHz. As a result if BCD = 0, axi_clk must be ≤104 MHz. If BCD = 1, then 133 MHz is allowed for axi_clk, resulting in a BCLK of 66.5 MHz. When the clock branch to WEIM is decreased to 104 MHz, other busses are impacted which are clocked from this source.” However, the i.MX6 BCD is fixed unlike in the i.MX51.

Regards,

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gusarambula
NXP TechSupport
NXP TechSupport

Hello Alexey Tsirlin,

Perhaps the following thread may serve as reference. I will investigate why this discrepancy and let you know when I find anything.

EIM Clock Frequency in I.MX6

Regards,

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gusarambula
NXP TechSupport
NXP TechSupport

Hello Alexey Tsirlin,

The maximum allowed axi_clk frequency is 133 MHz.

I think the 104Mhz limitation may come from older versions of the EIM as that of the i.MX51 in which a note did indicated: “The maximum allowed axi_clk frequency is 133 MHz, whereas the maximum allowed BCLK frequency is 104 MHz. As a result if BCD = 0, axi_clk must be ≤104 MHz. If BCD = 1, then 133 MHz is allowed for axi_clk, resulting in a BCLK of 66.5 MHz. When the clock branch to WEIM is decreased to 104 MHz, other busses are impacted which are clocked from this source.” However, the i.MX6 BCD is fixed unlike in the i.MX51.

Regards,

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alexeytsirlin
Contributor I

Hi,

So, basically, the datasheet is wrong and user manual is correct, right?

Thanks,

Alexey.

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gusarambula
NXP TechSupport
NXP TechSupport

Hello Alexey Tsirlin,

Yes, that appears to be the case. And that would be why this limitation is only mentioned once on the datasheet with no further elaboration anywhere else.

Regards,

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