INFRARED INTERFACE
The FDC37C669's infrared interface provides a two-
the duration of the serial bit time. A one is signaled by
sending no transmission the bit time. Please refer to
the AC timing for the parameters of the ASKIR
waveform.
way wireless communications port using infrared as a
transmission medium. Two infrared implementations
have been provided in the FDC37C669, IrDA and
Amplitude Shift Keyed IR.
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 time-
out 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
time-out is four character times. A character time is
defined as 10 bit times regardless of the actual word
length being used.
IrDA allows serial communication at baud rates up to
115K Baud. Each word is sent serially beginning with a
zero value start bit. A zero is signaled by sending a
single infrared pulse at the beginning of the serial bit time.
A one is signaled by sending no infrared pulse during the
bit time. Please refer to the AC timing for the parameters
of these pulses and the IrDA waveform.
The Amplitude Shift Keyed infrared allows 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
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