SLAA202B February   2005  – December 2018 MSP430F149 , MSP430F149 , MSP430F2252-Q1 , MSP430F2252-Q1 , MSP430F2272-Q1 , MSP430F2272-Q1 , MSP430F2274 , MSP430F2274 , MSP430FG4619 , MSP430FG4619

 

  1.   Implementing IrDA With MSP430™ MCUs
    1.     Trademarks
    2. 1 Introduction
    3. 2 Hardware Description
      1. 2.1 Hardware Overview
      2. 2.2 Circuit Description
    4. 3 Software Description
      1. 3.1 Implementing IrPHY Layer Using Timer_A
        1. 3.1.1 Transmission
        2. 3.1.2 Reception
      2. 3.2 Implementing IrPHY Layer using USCI_A0
      3. 3.3 Implementing IrLAP
        1. 3.3.1 Discovery Services
        2. 3.3.2 Connect Services
        3. 3.3.3 Data Services
        4. 3.3.4 Disconnect Services
      4. 3.4 Implementing IrLMP
        1. 3.4.1 Discovery Services
        2. 3.4.2 Link Connect and Connect Services
        3. 3.4.3 Data Services
        4. 3.4.4 Disconnect Services
      5. 3.5 IAS Implementation
      6. 3.6 TTP Implementation
      7. 3.7 IrCOMM Implementation
      8. 3.8 Application Layer
    5. 4 PC Demonstration Application
    6. 5 IrDA Protocol Basics
      1. 5.1 Physical (IrPHY) Layer
      2. 5.2 Link Access Protocol (IrLAP) Layer
      3. 5.3 Link Management Protocol (IrLMP) Layer
      4. 5.4 Information Access Services (IAS)
      5. 5.5 Tiny Transfer Protocol (TTP)
      6. 5.6 IrCOMM
    7. 6 IrDA Communication Diagram
    8. 7 Frame Exchange Log
    9. 8 References
  2.   Revision History

5 IrDA Protocol Basics

Communication protocols are commonly divided into layers. These layers have their own responsibilities and dependencies to the layers above and below them, thus creating the concept of a protocol stack. Figure 15 shows the IrDA stack. This stack is built from the bottom up, with each layer dependant on the layers below. The first three layers shown are mandatory while those on top of IrLMP, except IAS, are optional protocols required only for specific applications. The required layers are:

  • IrPHY: Specifies optical characteristics following ISO standards, data encoding/decoding, and framing for various speeds.
  • IrLAP: Establishes the basic reliable connection, frame formatting, and parameter negotiation procedures.
  • IrLMP: Multiplexes services and applications on the IrLAP connection level.
  • IAS: Provides a database of services on a device.

Some of the optional layers are:

  • TTP: Manages per-channel flow control.
  • OBEX: Object exchange protocol, used to easily transfer files or other data objects.
  • IrCOMM: Serial and parallel port emulation enabling devices that use these services to use IrDA interchangeably without problems.
irda-stack.gifFigure 15. IrDA Stack