"Kiran Ananthpur Bacche \(kbacche\)" <kbacche@...> says:
> Will LIRC work if I use a USB-to-Serial Adapter (BAFO BF-810) and then
> attach the serial port IR receiver to the RS-232 end of the adapter ?
The serial receiver used for LIRC does its timing by looking at the "Carrier
Detect" line and using the CPU to determine its timing. The USB's serial port
also has this line, but must transmit information back to the processor for its
ON/OFF signal to be read. In doing so, it loses most (if not all) of the
critical (LIRC uses microseconds) timing information. Originally serial ports
used the "modem control" signals ("carrier detect" is but one) with a "coarse"
granularity. The timing of these lines was not that critical (one character
time at 1200 bps was "OK"). Others found out that the structure of the chips
used for interfacing with these signals generated an interrupt on every
transition of the signal. With this information, and a CPU that has a
microsecond counter (or equivalent) one can determine the "ON" time (referred
to as "pulse" in the LIRC documentation) and the "OFF" time (referred to as
"space") for the signal presented to the "Carrier Detect" line of the
interface. Other interfaces to the IR detector exist that do this timing
themselves (IRMAN?) and send this information on a serial line, but they are
Hope this helps.
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