Posted by bloggsfred00 on 01/06/07 23:19

Got it all going using MSComm32.OCX as a COM object using PHP COM
handling. All very simple when you know how....

Jerry Stuckle wrote:
> >>I need to read incoming bytes on a COM port but I do not want to have
> >>the script hang if there is nothing to read.
> >>
> >>Is there any way to have PHP interrogate a COM port buffer to see if
> >>there is any content before reading it?
> >>
> >>Any other method to achieve the result would also be welcome.
> >>
> >>Cheers,
> >>
> >>Fred.
> >
> >
>
> (Top posting fixed)
> hackajar@gmail.com wrote:
> > Windows "COM" ports (like com1, com2, etc) do not have a buffer. They
> > are a serial interface that connects directly to the CPU (or CPU bridge
> > I suppose with newer motherboards). You will have to be running in a
> > loop waiting for data on the COM port to get data off it.
> >
> > Think:
> >
> > while(0) {
> > $getData = comportcheckfuntion('com1'); //You would have to write
> > this function or get one off internet
> > if($getData) //do your stuff here
> > else sleep(1); //sleep for a second and then let loop check com port
> > again.
> > }
> >
> > Cheers,
> > Hackajar
> > bloggsfred00@hotmail.com wrote:
> >
>
>
> Incorrect.
>
> First of all, the serial port hardware itself has a 16 byte (or larger)
> buffer built in.
>
> Secondly, the COM port, like all devices in Windows, goes through a
> driver. Your program doesn't talk to the chip itself; it talks to the
> driver (through Windows). This driver has two buffers - a transmit and
> a receive buffer. And IIRC, both are 4K. But I haven't written any COM
> port software since WINNT, so this may have been increased in later
> versions.
>
> But it has not been decreased.
>
> P.S. Please don't top post.
>
>
> --
> ==================
> Remove the "x" from my email address
> Jerry Stuckle
> JDS Computer Training Corp.
> jstucklex@attglobal.net
> ==================

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