Implementing Irda With The Msp430

 The development of Wireless Communications has occurred rapidly throughout the past
decade. One of the standards used is the Infrared Data Association (IrDA) specification.
The protocol introduced by this entity consists of three basic layers: IrPHY, IrLAP, and
IrLMP, which supply a base for many other applications. This application report
implements the IrDA Lite protocol (IrPHY, IrLAP, and IrLMP) on the MSP430 as well as
Tiny Transfer Protocol (TTP) and IrCOMM 3-wire services as a passive, secondary-only
device. IrPHY implementations are provided using a Timer_A-based approach as well as
using the USCI_A hardware module.   

Schematic using MSP430F149....................................................
Schematic using MSP430FG4619...............................................
Schematic using MSP430F2274..................................................
IR Byte..........................................................................................
Transmission With Timer_A........................................................
Detailed Byte Reception..............................................................
Unnumbered and XID Command Frame Formats......................
Discovery Response XID Format................................................
SNRM Frame Format ...................................................................
Information Frame Format ..........................................................
Disconnect Command Frame Format ........................................
Device Information Field Format ................................................
IrLMP Data Transfer Frame Format ............................................
IAP Frame Format........................................................................
IrDA Stack ....................................................................................
IrPHY Frame.................................................................................
IrLAP Frame Format ....................................................................
IrLAP Service Primitives .............................................................
IrLMP Frame Format ....................................................................
TTP Frame Formats.....................................................................
IrDA Communication Diagram....................................................
 It is helpful if the reader of this application report has some prior knowledge of the Infrared Data
Association (IrDA) specifications. Some general information on the stack is provided in Appendix
A but this is by no means interchangeable with the specifications provided by the IrDA Full
documentation and specifications for IrDA CAN be found at: http://www.irda.org.
This implementation follows the standards defined by IrDA Lite. The application uses IrPHY,
IrLAP, IrLMP, TTP, and IrCOMM 3-wire services to implement an IrDA serial port connection as
a passive, secondary-only device. When a primary IrDA peer transmits the string “t” to the
MSP430, it detects the string, reads the ADC internal Temperature Sensor and responds with
the temperature reading. Within this application report, three different projects are included:
•  IrDA demonstration application running on an MSP430F149 device, using Timer_A to
implement IrPHY encoding/decoding and the ADC12 to obtain the temperature reading
•  IrDA demonstration application running on an MSP430FG4619 device, using USCI_A0 to
implement IrPHY encoding/decoding and the ADC12 to obtain the temperature reading
•  IrDA demonstration application running on an MSP430F2274 device, using USCI_A0 to
implement IrPHY encoding/decoding and the ADC10 to obtain the temperature reading
To provide a more complete solution, a demonstration application for Windows
®
-based PCs is 
included as well. This application is written in the C programming language and shows how to
establish an IrDA connection between a PC and the MSP430 IrDA stack by using standard
Windows API calls only. 
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Schematic using MSP430F149
Schematic using MSP430F149

Schematic using MSP430FG4619
Schematic using MSP430FG4619


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