CM4 core clock limited to 64 MHz while CM7 runs at full configured frequency?

[Prathiksha]

I am working on the NUCLEO-H755ZI-Q, which contains a dual-core STM32H755 (Cortex-M7 + Cortex-M4).

I configure the system clocks in CubeMX as follows:

• SPI1/2/3 Clock MUX: 400 MHz
• System Clock: Configured for high-speed operation
• CM7 core frequency: Correctly matches the configured value (e.g., 200 MHz / 400 MHz depending on settings)

However, when I debug or read the CM4 core clock, I always see:

• CM4 clock = 64 MHz
• It does NOT increase even when I configure higher values in CubeMX. 

Regards,

Prathiksha

[Prathiksha]

Hello and thank you for sharing the details. I will share the folder structure!

project\PUMP_LOOP_EJECTOR_CPP\CM4\Core\Src or Inc

project\PUMP_LOOP_EJECTOR_CPP\CM7\Core\Src or Inc

[mƎALLEm]

Hello,

You've previously shared that project but my question was: 

So please clarify how you measured the clock frequencies in the firmware attached.

[TDK]

Keep in mind what you are claiming is impossible. The CM7 and CM4 clocks are not independent. It is not possible for the CM7 to be at 200/400 MHz while the CM4 is only at 64 MHz. So there has to be an error in how you're measuring, or how you're interpreting something.