#include <stdio.h>
#include
<unistd.h> /* for sleep() */
#include
<stdint.h> /* for uintptr_t */
#include
<hw/inout.h> /* for in*() and out*() functions
*/
#include <sys/neutrino.h> /* for ThreadCtl()
*/
#include <sys/mman.h> /* for mmap_device_io()
*/
/* The Neutrino IO port used here corresponds to a
single register, which is
* one byte long
*/
#define PORT_LENGTH 1
/* The
first parallel port usually starts at 0x378. Each parallel port
is
* three bytes wide. The first byte is the Data
register, the second byte is
* the Status register, the
third byte is the Control register. */
#define
DATA_ADDRESS 0x378
#define CTRL_ADDRESS
0x37a
/* bit 2 = printer initialisation (high to
initialise)
* bit 4 = hardware IRQ (high to enable)
*/
#define INIT_BIT 0x04
#define
LOW 0x00
#define HIGH
0xFF
#define MAX_COUNT
60
/*
______________________________________________________________________
*/
int
main(
)
{
int
privity_err;
uintptr_t
ctrl_handle;
uintptr_t
data_handle;
int count;
/* Give
this thread root permissions to access the hardware
*/
privity_err = ThreadCtl( _NTO_TCTL_IO, NULL
);
if ( privity_err == -1
)
{
fprintf( stderr, "can‘t get root
permissions\n" );
return
-1;
}
/* Get a handle to the
parallel port‘s Control register */
ctrl_handle =
mmap_device_io( PORT_LENGTH, CTRL_ADDRESS );
/* Get a
handle to the parallel port‘s Data register */
data_handle
= mmap_device_io( PORT_LENGTH, DATA_ADDRESS );
for (
count = 0; count < MAX_COUNT; count++
)
{
/* Output a byte of lows to the data
lines */
out8( data_handle,
LOW);
out8( ctrl_handle, (LOW & 0x0f )
);
printf( "Low\n" );
sleep( 1
);
/* Output a byte of highs to the data lines
*/
out8( data_handle, HIGH );
out8(
ctrl_handle, (HIGH & 0x0f ));
printf( "High\n"
);
sleep( 1
);
}
return
0;
}
QNX LPT Port Programming,布布扣,bubuko.com
原文：http://www.cnblogs.com/zhhkang/p/3745388.html