IRCC SMSC Corporation, IRCC Datasheet - Page 58

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

When active, the DATA DONE flag in Register
Block Zero, Line Control Register A alerts the
transmitter that the next FIFO underrun condition
signifies the end of the valid payload data and
that an EOF should begin (Figure 24). During
DMA operations TC automatically sets the DATA
DONE flag.
A message byte counter that is initialized with the
value in the data size register when the message
begins can also signal the end of the valid
payload data. If the message byte counter goes
EOM Interrupt
Active Frame
FIFO Empty
FIGURE 24 - IrDA FIR TX MESSAGE TIMING (SOFTWARE CRC)
EOM Interrupt
Data Done
Tx Enable
Data Done/TC
Active Frame
FIFO Empty
Tx Enable
EOM
FIGURE 25 - TX ABORT ON UNDERRUN TIMING
EOM
BOF
BOF
A
A
58
C
to zero before the FIFO is empty and the Brick
Wall bit is one, a FIFO underrun with an active
DATA DONE flag is simulated, a hardware CRC
is appended (if required), and the next message
is brick walled (not shown).
If the FIFO is empty, the DATA DONE flag is
always cleared following the EOM, regardless of
how the bit was set. If the DATA DONE flag is
inactive
transmitter aborts the message and set the Abort
and Underrun errors appropriately (Figure 25).
C
I
I
when
Underrun Error
Abort Error
Abort
FCS
an
underrun
EOF
occurs,
the