LPC47N227-MN View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
'LPC47N227-MN' PDF : 202 Pages View PDF
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 (See subsection CR2D in the Configuration section).
IrCC Block
RAW
TV
TX1
0
COM RX1
1
1
TX2
ASK
OUT
1
MUX
IR
RX2
20
IrDA
FIR
COM
TX3
AUX RX3
G.P. Data
IR MODE
TXD2
RXD2
IRTX2
IRRX2
IR Mode
/IRRX3
Fast Bit
FAST
HPMODE
FIGURE 2 – INFRARED INTERFACE BLOCK DIAGRAM
IR Transmit Pins
The TXD2 and IRTX2 pins default to output, low on VCC POR and hard reset. These pins are not
powered by VTR. These pins function as described below.
Following a VCC POR, the TXD2 and IRTX2 pins will be output and low. They will remain low until one
of the following conditions are met.
IRTX2 Pin (CR0A bits [7:6]=01):
• This pin will remain low following a VCC POR until serial port 2 is enabled by setting the UART2
power down bit (CR02, bit 7), at which time the pin will reflect the state of the IR transmit output of
the IRCC block (if IR is enabled through the IR Option Register for Serial Port 2).
87
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