dm6430-soft-trigger.c

rt 6430 采集卡 linux下驱动源代码

/*
	FILE NAME: dm6430-soft-trigger.c

	FILE DESCRIPTION: Software triggering sample program

		This program demonstrates how to initiate an analog to digital
		conversion using a software trigger.  Samples are taken from
		the A/D board using software triggering.  The acquired data
		is displayed 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)));
}


#define ADCHANNEL8	DM6430HR_AIN1	// A/D channel
#define ADSLOPE8	(65536.0/20.0)	// Number Bits divided by AD Range


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 = SetConversionSelect6430(descriptor, DM6430HR_CONV_SOFT_TRIGGER);
    verify_success(status, "SetConversionSelect6430() FAILED");

    status = SetChannelGain6430(
	descriptor,
	ADCHANNEL8,
	DM6430HR_GAINx1,
	DM6430HR_SE_SE
    );
    verify_success(status, "SetChannelGain6430() FAILED");

    status = ClearADFIFO6430(descriptor);
    verify_success(status, "ClearADFIFO6430() FAILED");

    fprintf(stdout, "Single A/D conversion at AIN %d\n", (ADCHANNEL8 + 1));
    fprintf(stdout, "Hit the ENTER key to perform one sample.\n");
    fprintf(stdout, "Hit CONTROL-C to exit the program.\n");

    while (isstdindata(-1)) {
	int	empty_flag;
	int16_t	data;

	status = ClearADFIFO6430(descriptor);
	verify_success(status, "ClearADFIFO6430() FAILED");

	status = StartConversion6430(descriptor);
	verify_success(status, "StartConversion6430() FAILED");

	do {
	    status = IsADFIFOEmpty6430(descriptor, &empty_flag);
	    verify_success(status, "IsADFIFOEmpty6430() FAILED");
	} while (empty_flag);

	status = ReadADData6430(descriptor, &data);
	verify_success(status, "ReadADData6430() FAILED");
	fprintf(stdout, "%2.2lf V", data / ADSLOPE8);
	while(isstdindata(1))
	    getc(stdin);
    }

    exit(EXIT_SUCCESS);
}