what different between Human Interface Device and Custom Human Interface Device

Ehsan Farahani Asil · ‎2018-04-17

Posted on April 17, 2018 at 18:50

Hi all

i want to build new Software hardware lock with STMF103C8T6 micro controller, it run on HID USB device. in fact i have one host application that can conversation with HID micro controller with encryption messages. at the moment i have one question about different between Human Interface Device and Custom Human Interface Device.they are different function commands name and type. please tell me about the different.

Best Regards

Ehsan Farahani Asil

#usb #stm32f103c8t6 #custom-usb-hid #usb-hid

Andrew Neil · ‎2018-04-17

Posted on April 17, 2018 at 22:36

'Custom' means that something is specially made to a specific requirement - as opposed to just plain standard.

A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.

Ben K · ‎2018-04-18

Posted on April 18, 2018 at 20:45

In the STM32Cube and STM32_USB_Device_Library context, the HID class device provides a fixed mouse application, where the HID report is predefined. The Custom HID option allows you to have an application-defined report descriptor, and to use both IN and OUT endpoints. Both are limited by their fixed max endpoint size and period.

Ehsan Farahani Asil · ‎2018-04-18

Posted on April 18, 2018 at 22:48

thanks very much for your reply. could you please describe about max endpoint and period limitation condition?

Ben K · ‎2018-04-20

Posted on April 20, 2018 at 13:24

The USB configuration descriptors are defined as constant byte arrays in each class's source file. If you observe the USBD_CustomHID_CfgDesc (or something similarly named), you can see in the endpoint descriptor what the max packet size and the endpoint period is set to.