2025-10-06 11:45 AM
Hello ST,
FYI - It appears CubeMX was not updated since DP-FPU capability was added to the STM32N6 data sheets.
Regards,
Dave
2025-10-07 12:32 AM - edited 2025-10-07 2:28 AM
Hello @Bassett.David
DP-FPU enables hardware double-precision floating-point calculations. In STM32CubeIDE, it’s activated by selecting FPv5-D16 as the floating-point unit and setting the ABI to Hardware implementation (-mfloat-abi=hard) in the project’s MCU settings.
Additionally, the startup code in system_stm32n6xx_fsbl.c configures the processor’s control registers to grant full access to the FPU by setting CP10 and CP11, ensuring that both secure and non-secure states can use the hardware FPU. Together, these settings guarantee that your application can efficiently execute both single and double-precision floating-point calculations using the microcontroller’s built-in FPU.
/* FPU settings ------------------------------------------------------------*/
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
SCB->CPACR |= ((3UL << 20U)|(3UL << 22U)); /* set CP10 and CP11 Full Access */
SCB_NS->CPACR |= ((3UL << 20U)|(3UL << 22U)); /* set CP10 and CP11 Full Access */
#endif /* __FPU_PRESENT && __FPU_USED */
Also
THX
Ghofrane
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2025-10-14 6:00 AM
Hello Ghofrane,
I must apologize for not being more clear in my report. What I was noting is that the "MCU Selector" inside CubeMX does not show the STM32N6 when the filter "Core" "FPU" "Double-precision FPU" is checked. This corresponds to early datasheets for the STM32N6, but I was subsequently informed thet the STM32N6 DOES indeed have DP-FPU (happily!). I have confirmed this with the latest datasheet. I believe the selection filter in CubeMX should be updated accordingly.
I'm sorry to have created work for you in your nice response (above).
Regards,
Dave
2025-10-14 6:22 AM
Hello @Bassett.David
Thanks for bringing this issue to our attention.
An internal ticket 219691 has been raised to our dev team for resolution .
I will keep you posted with updates.
THX
Ghofrane
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