USB HID Composite Device

[mahirmahota]

I am currently working on a project where I'm designing a keypad to send HID commands over USB. Now, I want the keys to register as if a keyboard was connected and a a rotary encoder to control mouse scroll wheel operations. To confirm, is this possible with a composite class such that it enumerates as a keyboard+mouse? Also, if anyone has experience with HID, is it possible to send power commands from the STM to the computer if a key is pressed?

[Saket_Om]

Hello @mahirmahota 

I reported your question internally.

Internal ticket number: 210439 (This is an internal tracking number and is not accessible or usable by customers).

[FBL]

Hello @mahirmahota 

If you are working on STM32F4 with classic library, you might find this example useful. Alternatively, if you are using USBX stack, you can start with this example.

[mahirmahota]

Hi,

Thank you, those samples help a lot! The USBX example is exactly what I was looking for and I might try to emulate that with FreeRTOS. Is a similar solution possible without threads using the classic library or does a composite HID device have to be multithreaded?

[FBL]

Hi @mahirmahota 

Indeed you can implement Dual HID using ST library. Check this article.

Some community articles may help as well :

• How to implement the USB device composite class (DFU + HID) article and its associated project
• How to implement USB device composite class in STM32H5 microcontrollers (HID + CDC) tutorial and project
• How to implement USB device composite class DUAL CDC article
• For STM32H7 boards, you can download this branch of firmware for composite examples