MCP2140A-I/SS Microchip Technology, MCP2140A-I/SS Datasheet - Page 53

• Manufacturer Part Number: MCP2140A-I/SS
• Description: IC IRDA CONTROLLR DTE/DCE 20SSOP
• Manufacturer: Microchip Technology

Specifications of MCP2140A-I/SS

• Interface: UART
• Controller Type: IRDA Standard Protocol Stack Controller
• Voltage - Supply: 3 V ~ 5.5 V
• Current - Supply: 2.2mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Supply Voltage Range: 3V To 5.5V
• Power Dissipation Pd: 800mW
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Svhc: No SVHC (15-Dec-2010)
• Interface Type: UART
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MCP2140DM-TMPSNS - BOARD DEMO FOR MCP2140
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

C.1.2
The IrLAP protocol provides:
• Management of communication processes on the
• A device-to-device connection for the reliable,
• Device discover procedures
• Hidden node handling. 115.2 kbaud
Figure C-3
IrDA protocols. The bottom layer is the Physical layer,
IrPHY. This is the part that converts the serial data to
and from pulses of IR light. IR transceivers can’t
transmit and receive at the same time. The receiver
has to wait for the transmitter to finish sending. This is
sometimes referred to as a “Half-Duplex” connection.
The IR Link Access Protocol (IrLAP) provides the
structure for packets (or “frames”) of data to emulate
data that would normally be free to stream back and
forth.
FIGURE C-3:
© 2007 Microchip Technology Inc.
link between devices
ordered transfer of data
Note:
Host O.S. or Application
identifies the key parts and hierarchy of the
IrLAP
Not supported by MCP2140A.
IrLMP – IAS
IrCOMM
IrPHY
IrDA STANDARD PROTOCOL
LAYERS
IrLAP
IR pulses
transmitted
and
received
Protocols
resident in
MCP2140A
Figure C-4
The frame is preceded by some number of Beginning
of Frame characters (BOFs). The value of the BOF is
generally 0xC0, but 0xFF may be used if the last BOF
character is a 0xC0. The purpose of multiple BOFs is to
give the other station some warning that a frame is
coming.
The IrLAP frame begins with an address byte (“A”
field), then a control byte (“C” field). The control byte is
used to differentiate between different types of frames
and is also used to count frames. Frames can carry
status, data or commands. The IrLAP protocol has a
command syntax of it’s own. These commands are part
of the control byte. Lastly, IrLAP frames carry data.
This data is the information (or “I”) field. The integrity of
the frame is ensured with a 16-bit CRC, referred to as
the Frame Check Sequence (FCS). The 16-bit CRC
value is transmitted LSB first. The end of the frame is
marked with an EOF character, which is always a
0xC1. The frame structure described here is used for
all versions of IrDA protocols used for serial wire
replacement for speeds up to 115.2 kbaud.
FIGURE C-4:
In addition to defining the frame structure, IrLAP
provides the “housekeeping” functions of opening,
closing and maintaining connections. The critical
parameters that determine the performance of the link
are part of this function. These parameters control how
many BOFs are used, identify the speed of the link,
how fast either party may change from receiving to
transmitting, etc. IrLAP has the responsibility of
negotiating these parameters to the highest common
set so that both sides can communicate as quickly and
reliably as possible.
Note 1: The
2: Another IrDA standard that is entering
3: IrDA communication standards faster
X BOFs BOF A C
(1+N) of C0h payload
shows how the IrLAP frame is organized.
communication baud rate of 9600 baud.
into general usage is IR Object Exchange
(IrOBEX). This standard is not used for
serial connection emulation.
than 115.2 kbaud use a different CRC
method and physical layer.
IrLAP FRAME
MCP2140A
MCP2140A
I
bytes C1h
FCS
2
only
DS22050A-page 53
EOF
supports