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# AT90USBxxx USB device HID generic demonstration

## License

Use of this program is subject to Atmel's End User License Agreement.

Please read file LICENSE.TXT for copyright notice.

## Description

This embedded application code illustrates how to implement a USB application with the AT90USBxxx controller using the generic HID class implementation.

A pc side applications allow to communicate with the embedded firmware (see USB HID Generic PC demos).

This sample application can be configured for both STK525 or AT90USBKey hardware, see TARGET_BOARD define value in config.h file.

## Architecture

As illustrated in the figure bellow, the application entry point is located is the main.c file. The main function first performs the initialization of a scheduler module and then runs it in an infinite loop. The scheduler is a simple infinite loop calling all its tasks defined in the conf_scheduler.h file. No real time schedule is performed, when a task ends, the scheduler calls the next task defined in the configuration file (conf_scheduler.h).

The sample usb application is based on two different tasks:

- The usb_task (usb_task.c associated source file), is the task performing the USB low level enumeration process in device mode. Once this task has detected that the usb connection is fully operationnal, it updates different status flags that can be check within the high level application tasks.
- The hid task performs the high level device application operation. Once the device is fully enumerated (DEVICE SETUP_SET_CONFIGURATION request received), the task checks for received data on its OUT endpoint and transmit data on its IN endpoint.