Comments about the sample project

UM0463

28/30

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Comments about the sample project

The sample project is built on the ST72651 product. The project demonstrates how to use

the library in an application.

The polling model is selected to run the control endpoint state machine.

The project implements a USB HID (Human Interface Device) class to establish the

communication of the board with the PC. HID requests such as Get Report descriptor, Get

Report and Set Report, Get Idle and Set Idle, Get Feature and Set Feature are implemented

on EP0 and these requests have the same meaning as requests in HID specification [2.]

with the same name. All these requests are implemented in HIDLayer.c and .h file.

The application replies Get Descriptor (Report descriptor) request with the content in the

array Report_Descriptor[].

The implementation of Get Descriptor, Get Idle, Get Output and Get Feature requests

shows how to send data through a control endpoint upon the request and the

implementation of Set Idle, Set Output and Set Feature requests shows how to receive data

from the control endpoint.

The sample project also shows how to send and receive data on a noncontrol endpoint in

file "application.c". In this sample, the data transfer on the EP2_IN and EP2_OUT is

demonstrated. Please use the USB Demonstration GUI for the evaluation which is freely

available on the internet.

The application also supports Loop Back feature. One macro, LOOP_BACK in appli.h is

used to enable/disable this feature. If it is enabled, then sent data to the hardware will be

received back from the hardware in the application mode. If it is disabled, then sent data will

not be received back automatically by the GUI.

When USB Demonstration GUI is used and LOOP_BACK is not enabled, then pressing the

LED button on the GUI allows the LED to glow on the hardware board present on PD0,

otherwise pressing the LED button on the GUI status allows the button to glow on the GUI

itself. A similar functionality can be tested for the scroll bar on the GUI.

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References

1.

"Universal Serial Bus Specification", Revision 1.1, 23 September 1998

2.

"Device Class Definition for Human Interface Devices (HID)", version 1.0 Draft #4

3.

"Universal Serial Bus Device Class Specification for Device Firmware Upgrade"

(Version 1.1 Aug 5, 2004)

4.

"ST7265 Datasheet" (version 3.0 Sep 10, 2006)

5.

"ST7265 Mass Storage Evaluation Kit"