June 22, 2008
June 22, 2008
June 25, 2008
13.545.1 - 13.545.9
Enhancing Laboratory Experience to Students by Introducing USB Connectivity into Lab Environment Using FTDI
With over 4 billion devices using Universal Serial Bus (USB) connectivity, USB has become a de-facto standard for connecting peripherals. For a large variety of electronic devices such as cameras, USB flash memory, PC, PDAs, set top boxes, mobile phones and consumer electronics, USB has provided a seamless hot swappable connectivity solution where USB devices can be added or removed while the computer is operating.
This ease of use comes with an elaborate USB specification, device firmware programming, HOST drivers, HOST APIs, standard and custom driver integration, Windows Hardware Quality Labs testing (WHQL) certification, USB compliance testing, and logo certification. For development of any USB based application, a developer must have advanced technical skills in above mentioned USB topics. These are complex topics and a few education/training classes are available. Arizona State University at the Polytechnic campus and Future Technology Devices International (FTDI) Ltd. are partnering to provide venues for both education and training classes for ASU students and FTDI customers respectively. The classes will aim to provide adequate understanding of emerging technologies.
1. Introduction Traditionally connecting peripherals to PC required cumbersome process of setting jumpers, interrupt requests (IRQs), installing additional hardware and software. USB provides a fast, bi- directional, low-cost and dynamically attachable serial interface. The plug-n-play feature of USB and the support for different communication classes and speeds has led to growing popularity of USB to the extent that today USB is truly a universal connection standard. The USB protocol is based on Token, Data and Handshake packets. Before applications can communicate with the device, the host needs to learn about the device and assign a device driver. Enumeration is defined as the initial exchange of information that accomplishes this. During the enumeration process, the device moves through Powered, Default, Address and Configured states as defined by the USB V2.0 specification. Two other USB device states are Attached and Suspend.
A USB device can have only one device descriptor but multiple configurations. Each configuration may in turn support multiple interfaces. An interface is a related set of endpoints that present a single feature or function of the device to the host. A device endpoint is a uniquely addressable portion of a USB device that is the source or sink of information in a communication flow between the host and device. Endpoint direction refers to the direction of data transfer on the USB. The configuration descriptor specifies values such as the amount of power this particular configuration uses, if the device is self or bus powered and the number of interfaces it has. When a device is enumerated, the host reads the device descriptors and can make a decision of which configuration to enable. With this basic introduction to USB, let’s discuss some sample laboratory applications in detail.
Singh, G., & Munukutla, L. (2008, June), Enhancing Laboratory Experience To Students By Introducing Usb Connectivity Into Lab Environment Using Ftdi Paper presented at 2008 Annual Conference & Exposition, Pittsburgh, Pennsylvania. https://peer.asee.org/3829
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