INFRARED INTERFACE
The infrared interface provides
wireless communications port using infrared as
transmission medium. Several IR
implementations have been provided for the
second UART in this chip (logical device 5),
IrDA, Consumer Remote Control, and Amplitude
Shift Keyed IR. The IR transmission can use
the standard UART2 TXD2 and RXD2 pins or
optional IRTX and IRRX pins. These can be
selected through the configuration registers.
a
two-way
The Amplitude Shift Keyed IR allows
asynchronous serial communication at baud
rates up to 19.2K Baud. Each word is sent
serially beginning with a zero value start bit. A
zero is signaled by sending a 500KHz waveform
for the duration of the serial bit time. A one is
signaled by sending no transmission during the
bit time. Please refer to the AC timing for the
parameters of the ASK-IR waveform.
a
If the Half Duplex option is chosen, there is a
time-out when the direction of the transmission
is changed. This time-out starts at the last bit
transferred during a transmission and blocks the
receiver input until the timeout expires. If the
transmit buffer is loaded with more data before
the time-out expires, the timer is restarted after
the new byte is transmitted. If data is loaded
into the transmit buffer while a character is
being received, the transmission will not start
until the time-out expires after the last receive
bit has been received. If the start bit of another
character is received during this time-out, the
timer is restarted after the new character is
received. The IR half duplex time-out is
programmable via CRF2 in Logical Device 5.
This register allows the time-out to be
IrDA 1.0 allows serial communication at baud
rates up to 115.2 kbps. Each word is sent
serially beginning with a zero value start bit. A
zero is signaled by sending a single IR pulse at
the beginning of the serial bit time. A one is
signaled by sending no IR pulse during the bit
time. Please refer to the AC timing for the
parameters of these pulses and the IrDA
waveform.
The consumer remote control interface can
decode NEC PPM remote control frames in
hardware as well provide a general-purpose
synchronous
ASK
encoder/decoder
with
programmable carrier frequency and bit rates to
emulate many other popular remote control
encoding formats; including 38 kHz PPM, PWM
and RC-5. Consult the SMSC CIrCC data
sheet for more details.
programmed to any value between
10msec in 100usec increments.
0 and
80
SMSC [ SMSC CORPORATION ]
