access IO Ports?

Kazmirzak · Post by **Kazmirzak** » Sat Mar 11, 2006 11:17 pm

How can I write a value in one of the computer's IO Ports?

In old dos basic languages it was simply done by "Out(port,value), where port was a value between 0 and 65000.

Under DOS I could achiever crazy things like with some random outs i could manage to get the computer making noises out of the soundcard without ANY driver! [and this was indeed a great thing under DOS]

Amiga5k · Post by **Amiga5k** » Sun Mar 12, 2006 2:54 am

Well, DOS allowed (and some times required) the programmer to do lots of things that modern OSes won't let you do directly, since more than one program could be trying to do the same thing. So... it's possible, but I'm certain you'd have to go through the OS's API (although you may be able to 'lock' access under some conditions). Have a look in the Win32.hlp file (look on Google) for information about port access.

Russell

Froggerprogger · Post by **Froggerprogger** » Sun Mar 12, 2006 10:53 am

You might have a look at the port.dll and the inpout32.dll.
Both let you access the serial and/or parallel port as well as e.g. the PC-speaker-port in an easy way.
But playing these digitalized sounds over the pc-speaker in the way it was done under DOS is not possible any longer due to the modern OS.
There could be a way by giving your program realtime-priority.

Amiga5k · Post by **Amiga5k** » Tue Mar 14, 2006 5:33 am

Actually, now that I think of it, there has to be a way to directly access the ports (or close to it), since my old Wacom tablet uses the serial port under XP with no problems. Sure, it was probably written in C (or perhaps asm because it is a driver), but it still works directly with the port.

Russell

Post by **Berikco** » Tue Mar 14, 2006 10:52 am

There is no way you can access IO ports directly under NT/W2K/XP/2003 without a device driver.

Post by **Dare2** » Tue Mar 14, 2006 11:13 am

Hi Berikco,

I have always wondered .. how is a driver accessed?

(The answer is probably so simple that I am going to wish I hadn't asked this).

Psychophanta · Post by **Psychophanta** » Tue Mar 14, 2006 12:30 pm

Here are some related threads:
http://www.purebasic.fr/english/viewtopic.php?t=18232
http://www.purebasic.fr/english/viewtopic.php?t=9316
http://www.purebasic.fr/english/viewtopic.php?t=2595

Dare2, drivers on WinNT, 2k, XP... patch and/or modify the NT kernel and/or the kernel shell.