AT89STK-05 Atmel, AT89STK-05 Datasheet - Page 11

• Manufacturer Part Number: AT89STK-05
• Description: KIT STARTER FOR AT89C5131
• Manufacturer: Atmel

Specifications of AT89STK-05

• Main Purpose: *
• Embedded: *
• Utilized Ic / Part: AT89C5131
• Primary Attributes: *
• Secondary Attributes: *
• Processor To Be Evaluated: AT89C5131A
• Interface Type: RS-232, USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

4246B–USB–11/04
Software Architecture
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
4-10
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.
This function also initializes the LED controller of the AT89C5131A part.
The usb_task manages the USB events: Suspend, Resume, USB Reset and Start of
frame. When the USB bus is in Suspend state, the LED 3 is turned On. If a USB
Resume occurs, the firmware turns Off this LED.
Each time a Start of Frame occurs on the USB bus, a counter is increased. When this
counter reaches 255, this counter is reset and the LED 1 is toggled.
USB Task
USB LCD Task
Scheduler
Tasks Init
Main
AT89C5131A Starter Kit Software User Guide
USB KBD Task
- Timers Soft
- TWI Lib
- LCD
- USB
- KBD