dm6430-timers.c

rt 6430 采集卡 linux下驱动源代码

/*
	FILE NAME: dm6430-timers.c

	FILE DESCRIPTION: User timer sample program

		This program demonstrates how to program the 8254 programmable
		interval timers (PITs).  Counter 0 is programmed to run at 200
		Hz.  Counter 1 is used to count these pulses.  The result is
		converted into seconds and printed on the screen.

	PROJECT NAME: Linux DM6430 Driver, Library, and Example Programs

	PROJECT VERSION: (Defined in README.TXT)

	Copyright 2004 RTD Embedded Technologies, Inc.  All Rights Reserved.
*/


#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/poll.h>
#include <unistd.h>

#include <dm6430lib.h>


char *program_name_p;


static void
usage(void) {
    fprintf(
	stderr,
	"\n"
        "Usage: %s MINOR_NUMBER"
        "\n",
	program_name_p
    );
    exit(EXIT_FAILURE);
}


static void
verify_success(int status, const char *message_p) {
    if (status == -1) {
	perror(message_p);
	exit(EXIT_FAILURE);
    }
}


static int
isstdindata(int timeout) {
    struct pollfd	in = {0, POLLIN | POLLERR | POLLPRI, 0};
    int			num_fds;

    while (((num_fds = poll(&in, 1, timeout)) == -1) && (errno == EINTR))
	;

    return ((num_fds == 1) && (in.revents & (POLLIN | POLLPRI)));
}


int
main(int argument_count, char **arguments_p_p) {
    int			descriptor;
    int			status;
    unsigned int	minor_number;

    program_name_p = arguments_p_p[0];

    if (argument_count != 2) {
	fprintf(stderr, "Invalid number of options given.\n");
	usage();
    }

    if (sscanf(arguments_p_p[1], "%u", &minor_number) == 0) {
	fprintf(stderr, "Invalid device minor number.\n");
	usage();
    }

    descriptor = OpenBoard6430(minor_number);
    verify_success(descriptor, "OpenBoard6430() FAILED");

    status = InitBoard6430(descriptor);
    verify_success(status, "InitBoard6430() FAILED");

    status = SelectTimerCounter6430(descriptor, DM6430HR_USER_TC);
    verify_success(status, "SelectTimerCounter6430() FAILED");

    status = ClockMode6430(descriptor, DM6430HR_CLK0, DM6430HR_CLK_MODE2);
    verify_success(status, "ClockMode6430() FAILED");

    status = ClockMode6430(descriptor, DM6430HR_CLK1, DM6430HR_CLK_MODE0);
    verify_success(status, "ClockMode6430() FAILED");

    status = ClockDivisor6430(descriptor, DM6430HR_CLK0, 40000);
    verify_success(status, "ClockDivisor6430() FAILED");

    status = ClockDivisor6430(descriptor, DM6430HR_CLK1, 0xFFFF);
    verify_success(status, "ClockDivisor6430() FAILED");

    fprintf(
	stdout,
	"Counter 0 programmed to run at 200 Hz.\n"
	"Counter 1 is used to count these pulses.\n"
	"The result is converted into seconds.\n"
    );

    while (!isstdindata(200)) {
	u_int16_t	value;

	status = ReadTimerCounter6430(
	    descriptor,
	    DM6430HR_USER_TC,
	    DM6430HR_CLK1,
	    &value
	);
	verify_success(status, "ReadTimerCounter6430() failed");

	fprintf(stdout, "\t%6.1lf seconds\n", ((65535 - value) / 200.0));
    }

    status = DoneTimer6430(descriptor);
    verify_success(status, "DoneTimer6430() failed");

    exit(EXIT_SUCCESS);
}