Motorola MPC823e - Page 743

Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-289
COMMUNICATION
16
PROCESSOR MODULE
SCCs
16.9.20.2 MIDDLE-SPEED IRDA PROTOCOL. The middle-speed IrDA protocol consists
of a data link layer and a physical layer.
• The data link layer is derived from the preexisting synchronous HDLC protocol
standard. The frame format follows the standard HDLC format except that it requires
two start flags. The frame consists of two start flags, an address field, a control field, an
information field, a frame check sequence field and minimum of one ending flag. 0x7E
is used for the start flag as well for the end flag.
• The physical layer defines the electrical parameters of the signals between the
encoder/decoder module and the infrared transducer module. The signal waveform is
shown in Figure 16-96. For 0.576 and 1.152Mb/s, the minimum and maximum pulse
duration are the nominal
1
/
4
of the bit duration (plus or minus the protocol-defined
tolerance).
Figure 16-95. Middle Speed Packet Format
Figure 16-96. Middle-Speed IrDA Data Format
START FLAG
1 BYTE
START FLAG
1 BYTE
ADDRESS
1 BYTE
CONTROL
1 BYTE
INFORMATION
N BYTES
CRC
2 BYTES
END FLAG
1 BYTE
10100110
DATA BITS
1/4 BIT TIME
(A)
(B)