MDK-ARM Keil, MDK-ARM Datasheet - Page 111

• Manufacturer Part Number: MDK-ARM
• Description: KIT REALVIEW MCU DEVELOPMENT
• Manufacturer: Keil
• Type: Compiler and IDEr

Specifications of MDK-ARM

• For Use With/related Products: ARM MCUs
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Getting Started: Building Applications with RL-ARM
Chapter 5. RL-USB Introduction
Today the Universal Serial Bus (USB) is the standard way to connect external
peripherals to a Personal Computer (PC). Consequently, if you are designing an
embedded system that has to interact with a PC, your customers will expect it to
use a USB port. Although USB is not a simple protocol, the process of designing
a USB peripheral has become a lot easier over the last few years. In this chapter,
we will outline the key concepts of the USB protocol. Afterwards we will
consider using the RL-USB driver to design a number of USB-based peripherals.
The USB driver in RL-ARM can be used standalone or with RTX.
The USB Protocol – Key Concepts
The USB protocol was first introduced in 1996. It is supported by the Windows
operating system from Windows 2000 onwards. USB is a high-speed serial
interface designed to be “plug and play” making it easier to add peripherals. It
aims to allow end users to build sophisticated computing systems without having
to worry about the underlying technology. This ease of use comes at the expense
of a great deal of design complexity. To design USB peripherals, you need to
understand the microcontroller firmware, the USB protocol, the USB Device
Classes and the USB host operating system. This is much easier now that the
USB protocol has reached a mature stage of adoption.
USB Physical Network
The USB network supports three
communication speeds. Low
speed runs at 1.5 Mbit/s and is
primarily used for simple devices
like keyboards and mice. Full
speed runs at 12 Mbit/s and is
suitable for most other
peripherals. Finally, High speed
runs at 480 Mbit/s and is aimed
at video devices that require high
bandwidth.
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