STM32Cube USB Host Library CPU time utilization seems too high
My MCU is STM32H753 on custom PCB. It is running at 480 Mhz.
I use USB USB_OTG_FS it is clocked by RC48.
On “Middleware and Software packs” I have enabled “FATFS”, “FREERTOS” and “USB_HOST”
I generated project by using CubeMX 6.17 with “STM32Cube_FW_H7_V1.13.0”.
For more details see attached pictures with configurations.
I use FreeRTOS function uxTaskGetSystemState to get info about CPU time per task.
In my project I have FatFS test module that performs some read write tests.
When I check CPU usage I get this numbers for tasks:
- “fatfs_test” CPU: 43%
- “USBH_Queue” CPU: 46%
- left 11% are utilized by GUI.
I ran tests with USB DMA enabled and disabled - there is no difference.
So, the question is: Is it OK for “USBH_Queue” task to utilize that much CPU when read/write operations in progress???
For example I have similar test for SD-card, and I get this numbers for tasks:
- “fatfs_test” CPU: 51%
- “IDLE” CPU: 35%
- GUI and other tasks CPU: 14%
