Path: utzoo!mnetor!uunet!mcvax!ukc!stl!stc!root44!pjh
From: pjh@root.co.uk (Paul Haffenden)
Newsgroups: comp.os.minix
Subject: Re: How do you turn on the AT's LEDs?
Message-ID: <537@root44.co.uk>
Date: 2 Feb 88 11:12:17 GMT
References: <1832@botter.cs.vu.nl>
Reply-To: pjh@root44.UUCP (Paul Haffenden)
Organization: UniSoft Ltd, London, England
Lines: 68

I have had a big struggle with getting the leds lights on my AT based
machine. Here is the code I use. I'm running V.3 on a 386 so it may
not be exactly what you want. My biggest problem is knowing when to
send the command to the keyboard. I check the input buffer full bit
but the keyboard will lock up if I don't have the delays in.

Here it is:

Keystate is a global int that indicates the state of the control keys
like shift and control. The bottom three bits are used to specify
the led status, so by just anding them I can load it directly into
the keyboard.

#define KB	0x60
#define	KBSTATUS	0x64
#define	LEDWRITE	0xed
#define INPUTFULL	2

/* the led defines */

#define		CAPSLOCK	0x04
#define		NUMSET		0x02
#define		SCROLLSET	0x01


/*
 * set up the keyboard leds.
 */

loadled()
{
	int led;
	int x1,x2,x3;
	int s;
	int n1,n2,n3;

	s = spl7();
	
	led = keystate & 0x7;
	x1 = 0xffff;
	do
	{
		tenmicrosec();
	}
	while(((n1=inb(KBSTATUS)) & INPUTFULL) && --x1);
	tenmicrosec();	tenmicrosec();	tenmicrosec();
	outb(KB,LEDWRITE);
	x2 = 0xffff;
	do
	{
		tenmicrosec();
	}
	while(((n2=inb(KBSTATUS)) & INPUTFULL) && --x2);
	tenmicrosec();	tenmicrosec();	tenmicrosec();
	outb(KB,led);
	tenmicrosec();
	x3 = 0xffff;
	while(((n3=inb(KBSTATUS)) & INPUTFULL) && --x3)
		;
/*printf("n1 x1 0x%x 0x%x n2 x2 0x%x 0x%x n3 x3 0x%x 0x%x\n",n1,x1,n2,x2,n3,x3);*/
	splx(s);

}	

If someone knows the correct way to do it without the finger in the air
delays please post it.

Paul.