IRCC SMSC Corporation, IRCC Datasheet - Page 21

• Manufacturer Part Number: IRCC
• Description: INFRARED COMMUNICATIONS CONTROLLER
• Manufacturer: SMSC Corporation

The IrCC can account for system-dependent
limitations such as long interrupt latencies and
transceiver stabilization times by increasing the
number of STA flags at the beginning of every
HDLC frame (Figure 14).
HDLC Back-to-Back Frame Transmission
HDLC back-to-back, or brick walled frames are
allowed with two or more flags, '7E'hex, in
between.
back-to-back, the gap between the last STO flag
of the first frame and the first STA field of the
second frame are separated by at least seven bit
times (abort sequence).
'01111110'
If two consecutive frames are not
binary
STA
Appends 0 - 4095 Flags to
'01111110'
BOF COUNT register
Beginning of Frame
FIGURE 14 - EXTENDED BEGINNING-OF-FRAME
binary
STA
8-bit Address
ADDR
Field
21
8-bit Control field plus up to 2K - 3 bytes
additional start flags that are to be appended to
the standard BOF characters.
NOTE: the BOF COUNT extensions only apply
to messages that start from an idle line state; i.e.,
BOF counting does not apply to brick walled
messages.
The IrDA FIR 1.152Mbps and .576Mbps physical
layer specification allows back-to-back message
packets with three flag characters which act as
the closing flag of the first frame and the opening
flags of the brick walled packet. Additional flags
can be added by programming the Brick Wall
Count register (Figure 15).
NOTE: The BOF COUNT extensions do not
apply to brick walled messages.
Information Field
DATA