IRCC SMSC Corporation, IRCC Datasheet - Page 73

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

Receive
Description
Receiving messages with Programmed I/O using
FIFO Interrupt requires reading a fixed number of
data bytes, usually related to the threshold,
whenever the FIFO Interrupt becomes active.
An appropriate FIFO Threshold value allows the
host to efficiently satisfy the FIFO service
requests
complete.
IOCHRDY Time-out
Description
In programmed I/O mode when AEN = low and
String Move = active, IOCHRDY can be used to
slightly extend the access cycle if the FIFO is
temporarily unable to fulfill the transfer request
FIFO Int. Enable
EOM Interrupt
FIFO Interrupt
DM A Enable
String M ove
until
RxServReq
Rx Enable
FIGURE 45 - INTERRUPT DRIVEN PROGRAMMED I/O RECEIVE TIMING
the
IOR
message
reception
is
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Example: Receive a 256-byte IrDA Message
1.
2.
3.
(Figure 46).
more than 10us, a time-out error occurs and
subsequent IOCHRDY cycles are prevented until
the string move bit is specifically reactivated.
Because of the 10us IOCHRDY time-out, it is
recommended that string move timing only be
used for 1.152Mbps transfers and above.
Set an appropriate FIFO Threshold for the
system type.
Set the FIFO Interrupt Enable active and
enable the receiver.
Service the FIFO Interrupts as required
(Figure 45).
remaining in the FIFO following the last
service request (RxServReq) in Figure 45 is
probably less than the typical read block
size. This will occur when an IrDA EOF has
been detected, the FIFO Receive Threshold
has not been reached and the FIFO Not
Empty flag is true.
If IOCHRDY remains inactive for
Note: the amount of data