AT89STK-03 Atmel, AT89STK-03 Datasheet - Page 7

• Manufacturer Part Number: AT89STK-03
• Description: KIT STARTER FOR MCU AT8XC5122/23
• Manufacturer: Atmel

Specifications of AT89STK-03

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: AT89C5122
• Primary Attributes: *
• Secondary Attributes: *
• Processor To Be Evaluated: AT8xC512x
• Interface Type: RS-232, USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

7612B–SCR–01/07
Software Architecture
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
4-6
Application
Description
Configuration
Implementation
usb_task_init()
usb_task()
Figure 4-1. USB HID Keyboard Firmware Architecture Overview
The USB HID keyboard configuration is performed according to the “USB Device Class
Definition for Human Interface Device – Firmware Specification” version 1.1 (4/7/99).
The usb_task_init() function is called during the initialization phase. It enables the USB
controller, configures the PLL in order to generate the 48 MHz required by the USB con-
troller, and enables and configures the Endpoint 0. In addition, this function performs a
USB Detach/Attach in order to be re-enumerated by the Host. This could be necessary
after a Start Application is performed by the bootloader.
The usb_task manages the USB events: Suspend, Resume, USB Reset and Start of
frame.
When a SETUP token is detected on the Endpoint 0, the usb_task launches the enu-
meration process routine. Once the Control Transaction has been completed, the
enumeration process routine exits.
A Transmit Complete flag (TXCMPL) detection on the Endpoint 1 (IN endpoint for HID
keyboard) means that a HID report has been successfully transmitted to the Host. The
USB Task
SCIB Task
Scheduler
Tasks Init
Main
AT89STK03 Starter Kit Software User User Guide
USB KBD Task
- Timers Soft
- USB
- KBD