For the M8 Mini: Is it possible to generate an MCLK of 12.288MHz internally for use both in the an SAI module and externally for an audio codec, or do I need to generate this frequency externally?

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For the M8 Mini: Is it possible to generate an MCLK of 12.288MHz internally for use both in the an SAI module and externally for an audio codec, or do I need to generate this frequency externally?

787 Views
ykagan
Contributor I

12.288MHz is a common frequency used an the master clock for 48KHz audio streams. It can be generated from 24MHz by a full-blown PLL by placing 125 in the divisor and 64 in the multiplier. It is not clear to me whether this can be done in the M8 Mini.

1 Reply

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igorpadykov
NXP Employee
NXP Employee

Hi Yishai

seems this could be possible, as example one can look at wm8254 in EVK

 Design Tool (1)
    i.MX 8M Mini Evaluation Kit Design Files

i.MX 8M Mini Evaluation Kit | NXP 

linux/arch/arm64/boot/dts/freescale/fsl-imx8mm-evk.dts

&sai3 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_sai3>;
    assigned-clocks = <&clk IMX8MM_CLK_SAI3_SRC>,
            <&clk IMX8MM_CLK_SAI3_DIV>;
    assigned-clock-parents = <&clk IMX8MM_AUDIO_PLL1_OUT>;
    assigned-clock-rates = <0>, <24576000>;
    status = "okay";

clock driver :

clk-imx8mm.c\imx\clk\drivers - linux-imx - i.MX Linux kernel 

Description of linux audio subsystem can be found in Chapter 7 Audio

attached Linux Manual.

Best regards
igor
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