1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
/*
Copyright (C) 2000-2002 Jos Roberto B. de A. Monteiro <jrm@sel.eesc.usp.br>
and Pedro Zorzenon Neto <pzn@vztech.com.br>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Do not forget to visit Free Software Foundation site: http://fsf.org
$Id: mcdelay.c,v 1.2 2003/06/30 17:20:25 pzn Exp $
*/
/*
From http://www.linuxdoc.org/HOWTO/mini/IO-Port-Programming.html
an outb to port 0x80 gives a delay of aprox 1microsec independent
of your machine type/clock.
See also documentation in asm/io.h
*/
#include "common.h"
#include "mcdelay.h"
#include <stdio.h>
#include <stdlib.h>
#ifdef __dos__
# include <dos.h>
#else
# include <unistd.h>
# include <sys/io.h>
# include <sys/types.h>
#endif
int old_port_value;
unsigned int m_f;
void microdelay_init(unsigned int multiply_factor) {
/* permition to write in port 0x80
nothing is suposed to use this port
however, we will write the same value we read... */
#ifdef __dos__
old_port_value=inportb(0x80);
#else
if (geteuid()!=0) {
fprintf(stderr,"ERROR: this programs needs root permisions to access parallel port. Please use root user to run or setuid bit.\n");
abort();
}
ioperm(0x80,1,1);
old_port_value=inb(0x80);
#endif
m_f = multiply_factor;
}
void microdelay(unsigned int microsec) {
unsigned long int i;
i = m_f * microsec;
while (i)
{
#ifdef __dos__
outportb(0x80, old_port_value);
#else
outb(old_port_value,0x80);
#endif
i--;
}
}
|
