Project Analog - March 2008 - (Page 6)

An example of an IrDA standard embedded system is shown in Figure 1. In this system, the Primary device (PDA) searches for other IrDA standard devices. The Secondary device (Host Controller and mcP2150) will respond to queries from the Primary device. The host controller controls the MCP2150 by sending and receiving data through its UART interface port. The MCP2150, which is positioned between the host controller UART device and infrared optical transceiver, decodes and encodes the signal. The MCP2150 has two independent baud rates. One of the baud rates is for communication with the Primary device (PDA). The Primary device negotiates this baud rate with the MCP2150, as defined in the IrDA standard. The second baud rate is set with the two hardware pins, BAUD1 and BAUD0. This second baud rate is for communication with the host controller. The IrDA standard is a network protocol and follows a layered approach in its definition. A model of the IrDA protocol stack is shown in Figure 2. These protocols deal with a manageable set of responsibilities and also supply needed capabilities to the layers above and below. The MCP2150 is an IrDA standard Protocol Stack Controller, which provides support for the IrDA standard protocol “stack” plus bit encoding/decoding. One of the functions of the MCP2150 is to encode and decode the asynchronous serial data stream. The encode/decode translation format is shown in Figures 3 and 4. Figure 3 shows how the received IR data from the PDA is decoded to UART-formatted data. Figure 4 demonstrates how data is taken from the Host Controller, into the MCP2150, and encoded in preparation of transmission to the PDA. The IrDA bit format is the NAND of the UART signal. The bits are inverted and high pulses are shortened in order to reduce the optics power consumption. The MCP2150 decodes the IR data, which is then handled by the Contents Viewpoint Wireless Communication Using IrDA® Wireless Design Choices Advanced Communication Solutions for Lighting Analog news fig. 1 thE Primary dEvicE (Pda) sEnds data through thE infrarEd intErfacE to thE mcP2150. thE mcP21150 thEn dEcodEs this data into thE uart standard. aftEr translation, thE datE is sEnt to thE host controllE through thE uart intErfacE. thE host controllEr can also sEnd data to thE mcP2150 whErE thE data is EncodEd and madE rEady for transmission to thE Primary dEvicE. Microchip analog page Interface products overview Sample center microchipDIRECT Reference designs/ app notes Technical training fig. 2 this irda Protocol stacK has bEEn dEfinEd by thE irda iindustry-basEd grouP. within thE Protocol stacK data communications, dEtails, as wEll as thE data structurEs, arE dEfinEd. 6 · ProjeCt ANALog · mAr 08 http://www.microchip.com http://www.microchip.com/analog http://www.microchip.com/analog http://www.microchip.com/interface http://www.microchip.com/interface http://sample.microchip.com/Default.aspx?testCookies=true http://www.microchipdirect.com/catalogselection.aspx?returnURL=default.aspx http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1469&filter1=function&redirects=appnotes http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1423

Table of Contents Feed for the Digital Edition of Project Analog - March 2008

Project Analog - March 2008 Contents Viewpoint About Project Analog Sponsor Wireless Communication Using the IrDA® Standard Protocol Wireless Design Choices Advanced Communication Solutions for Lighting Putting 10-GbE PHY Options Into Perspective Ease Into the Flexible CANbus Network Technology and Drivers for Mobile WiMAX Analog News—Analog News from Multiple Sources Enter to Win an iPhone Contact Project Analog Sponsor Treelink Microchip Advanced Parts Selector (MAPS)

Project Analog - March 2008

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