Composite example. STMicroelectronics STSW-STM32121

Composite example UM0424

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This demo runs on the following STMicroelectronics evaluation boards, and can be easily tailored to any other hardware:

● STM3210B-EVAL

STM3210E-EVAL

STM32L152-EVAL

STM32373C-EVAL

STM32303C-EVAL

STM32L152D-EVAL

To select the STMicroelectronics evaluation board used to run the demo, uncomment the corresponding line in the platform_config.h

file.

A composite device is defined in the USB specification as follows:

"A device that has multiple interfaces controlled independently of each other is referred to as a composite device."

For more details on composite devices, please refer to “usb_20.pdf 5.2.3”, which is available on the usb.org website.

When using such devices, multiple functions are combined into a single device. In this example, the independent interfaces are Mass Storage (MSC) and HID.

The host can see all these available functions simultaneously, and assigns a separate

device driver to each Interface of the composite device as shown in Figure 23 .

Figure 23.

USB composite device with two interface functions

HOST PC

Composite Device

Function 0 HID: Interface Number 0 Device Driver 0

Function 1 MSC: Interface Number 1 Device Driver 1

MSv31509V1

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