© 2000 Ubicom, Inc. All rights reserved. - 2 - www.ubicom.com AN16 SX IrDA Virtual Peripheral Implementation The link-access-protocol (LAP) layer controls the flow of
frames  and  provides  a  connection-based  bi-directional
reliable  data  transfer  service.  It  manages  the  discovery
process, the connection and negotiation process, and the
transfer of reliable data.
The   link-management-protocol   (LMP)   layer   serves   to
multiplex   the   LAP   connection   between   a   number   of
higher layers and/or applications using the reliable data
transfer service of the LAP layer.
The  information-access-server  (IAS)  provides  a  way  for
an IrDA device to get specific details about the high level
services another IrDA device offers.
The  IrComm  interface  provides  a  reliable  bi-directional
virtual  COM  or  LPT  interface  between  to  devices.  The
API interface can be considered to be that of a UART and
is intended to allow the use of software designed only to
work with a wired connection to be able to used a IrDA
virtual wired connection. 1. 2 SX IrDA SPECIFICATIONS The implementation is based on the IrDA Lite specifica-
tions  for  a  secondary  only  device  with  support  for  con-
nection speeds up to 115200bps and with the following
primary features:
•    Support for initiating XID discovery.
•    Support for sending unnumbered-information frames. 1.2.1   Physical Layer Multi-speed   IrDA   UART   Virtual   Peripheral   supporting
115200, 57600, 38400, 19200, and 9600bps 1.2.2   Framing Layer Byte-at-a-time  processing  of  data  including  16-bit  CRC
protection of data. 1.2.3   LAP Layer •    SX can discover other devices by initiating the discov-       ery process.
•    SX can be discovered by other devices by responding       a discovery request.
•    SX can accept a connection request and negotiate a       high speed for the connection.
•    SX can maintain a bi-directional flow of reliable data       within a connection.
•    SX can transmit unreliable data frames outside of a       connection.
•    SX can accept unreliable data frames outside of a con- nection. 1.2.4   LMP Layer Minimal  implementation  to  allow  multiplexing  between
the IAS and the IrCOMM service. 1.2.5   IAS Support  for  “GetValueByClass”  queries  to  provide  gen-
eral and IrCOMM specific device information. 1.2.6   IrCOMM Support  for  the  3-wire  raw  IrCOMM  protocol  providing
both serial (COM) and LPT (IrLPT) services.