dm6430-dma.c

rt 6430 采集卡 linux下驱动源代码

/*
	FILE NAME: dm6430-dma.c

	FILE DESCRIPTION: DMA (Direct Memory Access) sample program.

		This program uses DMA transfers to acquire data.

	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 DMA_BUF_SIZE5	0x2000			// The used size of the DMA buffer
#define DMA_CHAN5	DM6430HR_DMA1		// DMA channel
#define ADCHANNEL5	DM6430HR_AIN1		// A/D channel
#define GAIN5		DM6430HR_GAINx1		// Gain
#define SE_DIFF5	DM6430HR_SE_SE		// Single ended.
#define RATE5		100000			// Sampling rate
#define	AD_SLOPE5	(65536.0/20.0)		// Number Bits divided by AD Range


int
main(int argument_count, char **arguments_p_p) {
    double		Actual_PACER_RATE;
    int			descriptor;
    int			status;
    short		dmabuf[DMA_BUF_SIZE5 / 2];
    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");

    memset(dmabuf, 0, DMA_BUF_SIZE5);

    status = InstallDMA6430(descriptor, DMA_CHAN5);
    verify_success(status, "InstallDMA6430() FAILED");
      
    status = InitBoard6430(descriptor);
    verify_success(status, "InitBoard6430() FAILED");

    status = SetPacerClock6430(descriptor, RATE5, &Actual_PACER_RATE);
    verify_success(status, "SetPacerClock6430() FAILED");
 
    status = SetChannelGain6430(descriptor, ADCHANNEL5, GAIN5, SE_DIFF5);
    verify_success(status, "SetChannelGain6430() FAILED");

    status = SetStartTrigger6430(descriptor, DM6430HR_START_TRIG_SOFTWARE);
    verify_success(status, "SetStartTrigger6430() FAILED");

    status = SetStopTrigger6430(descriptor, DM6430HR_STOP_TRIG_SOFTWARE);
    verify_success(status, "SetStopTrigger6430() FAILED");
 
    status = SetConversionSelect6430(descriptor, DM6430HR_CONV_PACER_CLOCK);
    verify_success(status, "SetConversionSelect6430() FAILED");

    fprintf(
	stdout,
	"Channel %d sampled at %d Hz.\nThe DMA buffer size is %d bytes\n",
	ADCHANNEL5 + 1,
	RATE5,
	DMA_BUF_SIZE5
    );

    while (!isstdindata(200)) {
	int	done_flag;
	int	sample;
	size_t	transfer_size;

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

	status = StartDMA6430(descriptor, DMA_CHAN5, DMA_BUF_SIZE5);
	verify_success(status, "StartDMA6430() FAILED");

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

	status = IsADDMADone6430(descriptor, &done_flag);
	verify_success(status, "IsADDMADone6430() FAILED");
    
	do {
	    status = IsADDMADone6430(descriptor, &done_flag);
	    verify_success(status, "IsADDMADone6430() FAILED");
	} while (!done_flag);

	status = StopDMA6430(descriptor, DMA_CHAN5);
	verify_success(status, "StopDMA6430() FAILED");

	status = ClearADDMADone6430(descriptor);
	verify_success(status, "ClearADDMADone6430() FAILED");

	status = GetDmaData6430(
	    descriptor,
	    dmabuf,
	    DMA_CHAN5,
	    DMA_BUF_SIZE5,
	    0,
	    &transfer_size
	);
	verify_success(status, "GetDmaData6430() FAILED");
	
	// Display first couple of samples to see what is going on
	for (sample = 0 ; sample < 10; sample++)
	    fprintf(
	    stdout,
	    "Channel %d = %+5.2lf mV\n",
	    ADCHANNEL5 + 1,
	    ((double) dmabuf[sample]) / AD_SLOPE5
	);

	fprintf(stdout, "\n");
    }

    status = StopDMA6430(descriptor, DMA_CHAN5);
    verify_success(status, "StopDMA6430() FAILED");

    status = DeInstallDMA6430(descriptor, DMA_CHAN5);
    verify_success(status, "DeInstallDMA6430() FAILED");

    exit(EXIT_SUCCESS);
}