Posted by Jerry Stuckle on 01/07/07 03:21

bloggsfred00@hotmail.com wrote:
> 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
>>==================
>
>

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

(Top posting fixed)

Yes, you can use the com activex object, and it does help. But it's not
necessary.

You can even open the COM port as a r/w file if you can accept the
default settings (perhaps set up at boot time). No activex object required.

P.S. Please don't top post. Thanks.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

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