This application provides an example of Azure RTOS USBX stack usage on NUCLEO-C071RB board, it shows how to develop USB Device Human Interface "HID" mouse based application.
The application is designed to emulate an USB HID mouse device, the code provides all required device descriptors framework and associated class descriptor report to build a compliant USB HID mouse device.
At the beginning ThreadX calls the entry function tx_application_define(), at this stage, all USBx resources are initialized, the HID class driver is registered and the application creates 2 threads with the same priorities :
To customize the HID application by sending the mouse position step by step every 10ms. For each 10ms, the application calls the GetPointerData() API to update the mouse position (x, y) and send the report buffer through the ux_device_class_hid_event_set() API.
When plugged to PC host, the NUCLEO-C071RB must be properly enumerated as an USB HID mouse device. During the enumeration phase, device provides host with the requested descriptors (Device, configuration, string). Those descriptors are used by host driver to identify the device capabilities. Once the NUCLEO-C071RB USB device successfully completed the enumeration phase, the device sends a HID report after a user button press. Each report sent should move the mouse cursor by one step on host side.
Host PC shows that USB device does not operate as designed (Mouse enumeration failed, the mouse pointer doesn’t move).
User is familiar with USB 2.0 “Universal Serial BUS” Specification and HID class Specification.
The remote wakeup feature is not yet implemented (used to bring the USB suspended bus back to the active condition).
place in RAM_region { last section FREE_MEM };
either define the RW_IRAM1 region in the ".sct" file
or modify the line below in "tx_initialize_low_level.S to match the memory region being used
LDR r1, =|Image$$RW_IRAM1$$ZI$$Limit|
._threadx_heap :
{
. = ALIGN(8);
__RAM_segment_used_end__ = .;
. = . + 64K;
. = ALIGN(8);
} >RAM_D1 AT> RAM_D1
The simplest way to provide memory for ThreadX is to define a new section, see ._threadx_heap above.
In the example above the ThreadX heap size is set to 64KBytes.
The ._threadx_heap must be located between the .bss and the ._user_heap_stack sections in the linker script.
Caution: Make sure that ThreadX does not need more than the provided heap memory (64KBytes in this example).
Read more in STM32CubeIDE User Guide, chapter: "Linker script".
RTOS, ThreadX, USBXDevice, USB_DRD, Full Speed, HID, Mouse
In order to make the program work, you must do the following :