parallel breakout board

Discussion in 'The Projects Forum' started by lancellot07, Jan 17, 2013.

  1. lancellot07

    Thread Starter New Member

    Jul 2, 2012
    i found this schematic somewhere in the internet and would like to ask if this is functional.. picture is attached..

    and if anybody could direct me to other sites that has a very simple schematics on parallel port breakout board..

    Last edited: Jan 17, 2013
  2. nerdegutta


    Dec 15, 2009

    Which software are you going to use?
  3. lancellot07

    Thread Starter New Member

    Jul 2, 2012
    emc or probably mach2
  4. KrisBlueNZ


    Oct 17, 2012
    Back 10 years ago, or more, a PC parallel port could be used for general purpose parallel interfacing to external hardware such as stepper motors. You still had to provide an external +5V power supply, because the port cannot supply much current (a few mA). Nowadays, the 25-pin parallel connector is unheard-of because printers are all USB-interfaced. In between then and now, many 25-pin parallel ports used hardware that would not provide steady output signals, presumably to save power. I believe (but have not confirmed) that these ports only asserted the eight data signals when an actual data strobe was in progress; at other times, they would tri-state the data outputs.

    Many parallel ports also supported multiple modes - SPP (standard), PS/2, EPP and ECP. Obviously to use one of these as a standard port, you need to set it to SPP compatibility. This is normally done through the BIOS Setup.

    Also, multi-tasking operating systems (Windows, at least) do not normally allow user software to access the parallel port registers directly; you can access them directly under MS-DOS, Windows 3.x and Windows 95/98, but anything newer requires a DLL to allow an application program to access the hardware directly. Google "direct i/o dll".

    So that circuit used to be appropriate; whether it will work for you depends on what operating system and hardware you have.
  5. lancellot07

    Thread Starter New Member

    Jul 2, 2012
    so this wil work for older version of wndows..thats alright.. im gonna use win98. i have an old pc and win98 installer.. thanks very much..
  6. atschirner

    New Member

    Jan 23, 2013