HSE clock configuration for nucleo STM32F429zi board at 80MHz

[Dushyantsingh]

&clk_lsi {

status = "okay";

};

&clk_hse {

hse-bypass;

clock-frequency = <DT_FREQ_M(8)>; /* STLink 8MHz clock */

status = "okay";

};

&pll {

div-m = <15>;

mul-n = <96>;

div-p = <2>;

div-q = <4>;

clocks = <&clk_hse>;

status = "okay";

};

&rcc {

clocks = <&pll>;

clock-frequency = <DT_FREQ_M(80)>; /* highest value to get a precise USB clock */

ahb-prescaler = <1>;

apb1-prescaler = <2>;

apb2-prescaler = <1>;

};

But the above configuration is not working can you please provide any idea on this.

[Issamos · Accepted solution]

Hello @Dushyantsingh 

You may take a look at the configuration of HSE bypass in this project.

Best regards.

II

[Peter BENSCH]

@Dushyantsingh it looks like you are using the NUCLEO-F429ZI with Zephyr, right?

However, your settings are not plausible, because with HSE=8MHz and &pll {div-m = <15>; ...} you only get 533.333kHz. The PLLM output frequency must be at least 950kHz. The current values in &pll{} also result in only 12.8MHz instead of 48MHz at output Q of the main PLL. So you should check your settings again with the RM0090 or CubeMX or CubeIDE.

Regards
/Peter