Re: Serial IR receiver problem

In article <465a3d0c.300353312@xxxxxxxxxxxxx>,
nobody@xxxxxxxxxxxx (Dave Houston) writes:
andrew@xxxxxxxxxxxxxxxxxxxx (Andrew Gabriel) wrote:

I suspect that the USB driver (or possibly the Skype application)
is preventing the serial port driver from emptying the 16550A FIFO
before it wraps, resulting in lost characters. At 115200, the serial
port driver must service a 16550A almost once every millisecond to
avoid character loss. What speed is your IR interface? Do you have
any flow control? Can you run it at a lower speed to see if that
helps? I'm not familiar with how Windows handles serial ports, but
on Unix systems, the serial port driver's interrupt handler is
normally one of the highest interrupt priority interrupt handlers,
and that's for a good reason, as 16550A type ports have more
taxing real-time demands than every other peripheral on a standard
PC system.

Look at the schematic.

With this hardware, WinLirc treats the DCD line as a digital input - it has
nothing to do with the RS232 data line nor the FIFO. It's messing with the
timer and/or disabling interrupts.

That makes it much worse -- there's no FIFO on the modem signals.
If the application monitors DCD by spinning, then it's not likely
to work with anything else running on the system.
What sort of bit rate is the IR signal?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
.

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