IRCC2.0 SMSC Corporation, IRCC2.0 Datasheet - Page 79

• Manufacturer Part Number: IRCC2.0
• Description: Infrared Communications Controller
• Manufacturer: SMSC Corporation

Receive
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.
Example: Receive a 256-byte IrDA Message
1.
IOCHRDY Time-out
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
(Figure
Set an appropriate FIFO Threshold for the
system type.
FIFO Int. Enable
EOM Interrupt
FIFO Interrupt
DMA Enable
String Move
48).
until
RxServReq
Rx Enable
FIGURE 47 - INTERRUPT DRIVEN PROGRAMMED I/O RECEIVE TIMING
the
IOR
If
message
IOCHRDY
reception
remains
is
79
2.
3.
inactive for more than 10Fs, a time-out error
occurs and subsequent IOCHRDY cycles are
prevented until the string move bit is specifically
reactivated.
time-out, it is recommended that string move
timing only be used for 1.152 Mbps transfers and
above.
Set the FIFO Interrupt Enable active and
enable the receiver.
Service the FIFO Interrupts as required
(Figure 47).
remaining in the FIFO following the last
service request (RxServReq) in Figure 47 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.
Because of the 10Fs IOCHRDY
Note: The amount of data