[Gambas-user] Asking about a new Command

[Timothy Marshal-Nichols]

> -----Original Message-----
> From: gambas-user-admin at lists.sourceforge.net
> [mailto:gambas-user-admin at lists.sourceforge.net]On Behalf Of nando
> Sent: Wednesday, 24 May 2006 19:33
> To: gambas-user at lists.sourceforge.net
> Subject: Re: [Gambas-user] Asking about a new Command
> 
> 
> Thanks to everyone for your replies.
> 
> This project is over a year in the making at considerable cost
> and is quite involved.  It operates as a set of concurrent multiple
> programs and runs on hundreds of computers.  There is use of some
> specialized communication equipment.
> 
> The particular problem is I need to wait a small amount of time
> for a particular hardware condition to be ready.
> 
> In my case, with Serial Port characters streaming in, if I use
> the WAIT 0.5, inside the _Read, it will recurse more _Reads while
> the processing of the first is incomplete.
> This actually makes the stream processed out of order because
> the 'newer' _Read process the next char while the original _Read
> that invoked the WAIT is still unfinished.
> So, processing events is forbidden in this case.
> 
> A empty loop consumes CPU...other programs are running.
> WAIT allows processing of things out of order.
> Although the SHELL sleep works, it is too much overhead.
> 
> This problem exists in the VB world when using DoEvents.
> My solution in the VB world is to use a Boolean inside
> the critical SUBs that can recurse and simply exit when busy.
> That too, still uses too much CPU because there are always
> characters waiting and _Read will 'event' by the interpreter
> just to do a quick exit.
> 
> A Delay statement sounded like a you might have been interested in.
> Essentially it would be sleeping using the kernel.
> 
> Eventhough we use fast computers, managing and minimizing CPU usage
> is still an important item.
> 
> Of course, I may be ignorant and uninformed of other ways and
> overlooking something easy...to which you all have been helpful.
> 
> Thanks
> -Fernando
> 

Surly the normal way to use a serial port is something like the following:

PRIVATE buffer AS String

PUBLIC SUB SerialPort1_Read()
  DIM s AS String

  ' Read data from serial port
  LINE INPUT #SerialPort1, s

  ' Add data to buffer
  buffer = buffer & s

  ' Test if we have all the required data
  IF yourBufferCompleteText THEN

    ' Process buffer

    ' Clear buffer
    buffer = ""
  END IF
END

This way there is no need for a wait at all.

Thanks

8-{)} Timothy Marshal-Nichols
<mailto: timothy.marshal-nichols at ...247...>