IR Half Duplex Turnaround Delay Time
If the Half Duplex option is chosen there is an IR Half Duplex Time-out that constrains IRCC direction mode changes.
This time-out starts as each bit is transferred and prevents direction mode changes until the time-out expires. The
timer is restarted whenever new data arrives in the current direction mode. For example, if data is loaded into the
transmit buffer while a character is being received, the transmission will not start until the last bit has been received
and the time-out expires. If the start bit of another character is received during this time-out, the timer is restarted
after the new character is received. The Half Duplex Time-out is programmable from 0 to 25.5ms in 100µs
increments (see section CR2D on page 112).
IrCC Block
TXD2
RXD2
TX1
RX1
RAW
TV
0
1
COM
IR
1
2
TX2
RX2
IRTX2
IRRX2
ASK
IrDA
FIR
OUT
MUX
1
0
TX3
RX3
AUX
COM
IR Mode
/IRR3
IR MODE
G.P. Data
FAST
Fast Bit
HPMODE
FIGURE 3 - INFRARED INTERFACE BLOCK DIAGRAM
SMSC DS – FDC37N3869
Page 69
Rev. 10/25/2000
SMSC [ SMSC CORPORATION ]
