I use stm32h745 MCU cortex-m4. When I increase fdcan initialization, why is the execution time of the program twice as slow? But When I blocked line 608, the program execution time returned to normal.

Hi @jiazi.1​ ,

In order to be able to bring you some help, it is required to provide some more details.

So, could you please tell us:

1. what do you mean by "I increase fdcan initialization"?
2. do you have other peripherals than FDCAN running on your application?
3. When, in your program, is HAL_FDCAN_DeInit called?

-Amel

PS: STM32H745 is a Dual core Arm Cortex-M7+ Cortex-M4 MCU.

1�?To develop CAN communication function, it is necessary to initialize the FDCAN peripheral

2�?The peripheral devices used in M4 core are shown in Figure 1,At the same time, the peripheral devices used in M7 core are shown in Figure 2.

Figure 1

Figure 2

3�?As shown in Figure 3, the peripheral initialization function is called when the program initializes. As shown in Figure 4, the initialization function of the CAN communication is called in the initialization of the peripheral, and the function of the HAL_FDCAN_DeInit is called in this function, as shown in Figure 5.

Figure 3

Figure 4

Figure 5

PS: I know that stm32h745 is a dual core arm cortex-m7 + cortex-m4 microcontroller. We use cortex-m7 and cortex-m4 at the same time. After adding can communication function program into the normal running time program, it is found that the running speed of the program becomes slower in the debugging process. Then find out the cause and find out that after shielding 608 line, the program running time returns to normal.