A40i使用笔记：文件IO驱动方式（慢）（无法应用于大部分ic）

一、前言

初学linux，从hellow word开始，但是我这现在连初学都算不上，还没到学习hellow word驱动那一步，目前就是利用文件io驱动最最最最简单基础的led或者最最最简单的不要求时序和速度的ic

注：本文未使用到驱动，只用到文件io输入输出，和交叉编译

二、环境

Ubuntu16

vaware 12

全志a40i（linux3.10）

window10

a40i交叉编译器

三、正文

1.输出

方式一：指定引脚PG8或其他输出

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
    while(1)
    {
        system("echo 1 > /sys/class/gpio_sw/PG8/data");
        usleep(10000);
        system("echo 0 > /sys/class/gpio_sw/PG8/data");
        usleep(10000);
    }
    return 0;
}

优点：无需初始化io输入输出状态，直接可以使用

方式二：将引脚转换为对应端口号驱动GPIO的计算公式为(32 * (bank) + (gpio))

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
char *GPIO_PATH = "/sys/class/gpio/gpio271/value";
int main(int argc, char *argv[])
{
    int fd;
    char *path;
    path = GPIO_PATH;
    system("echo 271 > /sys/class/gpio/export");//led6
    system("echo out > /sys/class/gpio/gpio271/direction");
    fd = open(path, O_WRONLY);
    if(fd<0)
    {
        printf("Failed to Open gpio %s\n", path);
        exit(1);
    }
    while(1)
    {
        write(fd, "1", 1);
        usleep(200000);
        write(fd, "0", 1);
        usleep(200000);
    }
    close(fd);
    return 0;
}

2.输入

方式一：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <poll.h>
#include <unistd.h>
#include <time.h> 
#include <sys/time.h>
char *GPIO_PATH = "/sys/class/gpio/gpio41/value";//PB9
long long times=0;
void sysUsecTime();
int main(int argc, char *argv[])
{
    system("echo 41 > /sys/class/gpio/export");//PB9
    system("echo in > /sys/class/gpio/gpio41/direction");//PB9
    //system("echo rising > /sys/class/gpio/gpio41/edge");//PB9
    //usleep(100000);//延时100ms
    int gpio_value = 1;
    char value_str[3];
    int fd;
    sysUsecTime();
    while(gpio_value)
    {
	fd = open(GPIO_PATH, O_RDONLY);
	if (fd < 0) {
	    perror("Failed to open gpio value for reading!");
	    return -1;
	}
	if (read(fd, value_str, 3) < 0) {
	    perror("Failed to read value!");
	    return -1;
	}
	gpio_value=atoi(value_str);
	close(fd);
	times++;
        //usleep(1000);
	if(times>1000000)//超时1秒退出
	    break;
    }
    printf("times:%d,value:%d\r\n",times,gpio_value);
    sysUsecTime();
    return 0;

}

方式二：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <poll.h>
#include <unistd.h>
#include <time.h> 
#include <sys/time.h> 
char *GPIO_PATH = "/sys/class/gpio/gpio41/value";//PB9
long long times=0;
void sysUsecTime();
int main(int argc, char *argv[])
{
    system("echo 41 > /sys/class/gpio/export");//PB9
    system("echo in > /sys/class/gpio/gpio41/direction");//PB9
    //system("echo rising > /sys/class/gpio/gpio41/edge");//PB9
    //usleep(100000);//延时100ms
    int gpio_value = 1;
    FILE *fp;
    sysUsecTime();
    while(gpio_value)
    {
	fp = fopen(GPIO_PATH,"rb+");
	fscanf(fp, "%d", &gpio_value);
	fclose(fp);
	times++;
        //usleep(1000);
	if(times>1000000)
	    break;
    }
    printf("times:%d,value:%d\r\n",times,gpio_value);
    sysUsecTime();
    return 0;

}

快捷输入输出设置方式：

例子1：以AD7606驱动代码为例（目前此方式未成功驱动成功，怀疑此方法不适合驱动AD7606，需要使用驱动的方式）（只是IO输入输出做为参考）

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <poll.h>
#include <unistd.h>
#include <time.h> 
#include <sys/time.h>

#define SUNXI_PA_BASE	0
#define SUNXI_PB_BASE	32
#define SUNXI_PC_BASE	64
#define SUNXI_PD_BASE	96
#define SUNXI_PE_BASE	128
#define SUNXI_PF_BASE	160
#define SUNXI_PG_BASE	192
#define SUNXI_PH_BASE	224
#define SUNXI_PI_BASE	256
#define SUNXI_PJ_BASE	288
#define SUNXI_PK_BASE	320
#define SUNXI_PL_BASE	352
#define SUNXI_PM_BASE	384
#define SUNXI_PN_BASE	416
#define SUNXI_PO_BASE	448
#define AXP_PIN_BASE	1024
/* sunxi gpio name space */
#define GPIOA(n)	(SUNXI_PA_BASE + (n))
#define GPIOB(n)	(SUNXI_PB_BASE + (n))
#define GPIOC(n)	(SUNXI_PC_BASE + (n))
#define GPIOD(n)	(SUNXI_PD_BASE + (n))
#define GPIOE(n)	(SUNXI_PE_BASE + (n))
#define GPIOF(n)	(SUNXI_PF_BASE + (n))
#define GPIOG(n)	(SUNXI_PG_BASE + (n))
#define GPIOH(n)	(SUNXI_PH_BASE + (n))
#define GPIOI(n)	(SUNXI_PI_BASE + (n))
#define GPIOJ(n)	(SUNXI_PJ_BASE + (n))
#define GPIOK(n)	(SUNXI_PK_BASE + (n))
#define GPIOL(n)	(SUNXI_PL_BASE + (n))
#define GPIOM(n)	(SUNXI_PM_BASE + (n))
#define GPION(n)	(SUNXI_PN_BASE + (n))
#define GPIOO(n)	(SUNXI_PO_BASE + (n))
#define GPIO_AXP(n)	(AXP_PIN_BASE  + (n))

#define data15 get_gpio_value(GPIOB(3))
#define data14 get_gpio_value(GPIOB(5))
#define data13 get_gpio_value(GPIOI(15))
#define data12 get_gpio_value(GPIOG(5))
#define data11 get_gpio_value(GPIOG(4))
#define data10 get_gpio_value(GPIOG(3))
#define data09 get_gpio_value(GPIOG(2))
#define data08 get_gpio_value(GPIOG(0))
#define data07 get_gpio_value(GPIOG(1))
#define data06 get_gpio_value(GPIOI(3))
#define data05 get_gpio_value(GPIOI(2))
#define data04 get_gpio_value(GPIOI(1))
#define data03 get_gpio_value(GPIOI(0))
#define data02 get_gpio_value(GPIOB(12))
#define data01 get_gpio_value(GPIOB(10))
#define data00 get_gpio_value(GPIOB(8))

#define AD7606_BUSY get_gpio_value(GPIOI(11))
#define AD7606_FASTDATA get_gpio_value(GPIOH(0))//no used

#define AD7606_OS0_H()     set_gpio_value(GPIOF(5),"1")
#define AD7606_OS0_L()     set_gpio_value(GPIOF(5),"0")
#define AD7606_OS1_H()     set_gpio_value(GPIOF(4),"1")
#define AD7606_OS1_L()     set_gpio_value(GPIOF(4),"0")
#define AD7606_OS2_H()     set_gpio_value(GPIOF(3),"1")
#define AD7606_OS2_L()     set_gpio_value(GPIOF(3),"0")

#define AD7606_CS_RD_H()   set_gpio_value(GPIOF(0),"1")
#define AD7606_CS_RD_L()   set_gpio_value(GPIOF(0),"0")

#define AD7606_Reset_H()   set_gpio_value(GPIOF(1),"1")
#define AD7606_Reset_L()   set_gpio_value(GPIOF(1),"0")

#define AD7606_CONVT_H()   set_gpio_value(GPIOF(2),"1")
#define AD7606_CONVT_L()   set_gpio_value(GPIOF(2),"0")

#define LED_on()    set_gpio_value(GPIOB(11),"0")
#define LED_off()   set_gpio_value(GPIOB(11),"1")

需要以下代码做为支撑

long long times=0;
void sysUsecTime();
//创建gpio文件
void init_gpio_export(int n)
{
    FILE * fp =fopen("/sys/class/gpio/export","w");
    if (fp == NULL)
        perror("export open filed");
    else
        fprintf(fp,"%d",n);
    fclose(fp);
}
//设置gpio的模式 输入/输出 in/out
void set_gpio_direction(int n,const char *direction)
{
    char path[100] = {0};
    sprintf(path,"/sys/class/gpio/gpio%d/direction",n);
    FILE * fp =fopen(path,"w");
    if (fp == NULL)
        perror("direction open filed");
    else
        fprintf(fp,"%s",direction);
    fclose(fp);
}
//获取gpio(n)的数值 0/1
int get_gpio_value(int n)
{
    char path[64];
    char value_str[3];
    int fd;
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", n);
    fd = open(path, O_RDONLY);
    if (fd < 0) {
        perror("Failed to open gpio value for reading!");
        return -1;
    }
    if (read(fd, value_str, 3) < 0) {
        perror("Failed to read value!");
        return -1;
    }
    close(fd);
    return (atoi(value_str));
}
//输出gpio(n)的数值 0/1  (方式一)
void set_gpio_value(int n,const char *value)
{
    char path[50];
    //char value_str[3];
    int fd;
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", n);
    fd = open(path, O_WRONLY);
    //snprintf(value_str, sizeof(value_str), "%d", value);
    write(fd, value, 1);
    close(fd);
}
//输出gpio(n)的数值 0/1  (方式二)
int set_gpio_value1(int gpio, int value)
{
    FILE *p = NULL;
    char gpio_value_path[50];
    sprintf(gpio_value_path, "/sys/class/gpio/gpio%d/value", gpio);
    p = fopen(gpio_value_path, "w");
    fprintf(p, "%d", value);
    fclose(p);
    return 0;
}
//IO初始化函数
void IOinit(void)
{
/* ------------      AD7606_DB[0..15]       ----------- */
    init_gpio_export(GPIOB(8));//AD7606_DB0
    set_gpio_direction(GPIOB(8),"in");
    init_gpio_export(GPIOB(10));//AD7606_DB1
    set_gpio_direction(GPIOB(10),"in");
    init_gpio_export(GPIOB(12));//AD7606_DB2
    set_gpio_direction(GPIOB(12),"in");
    init_gpio_export(GPIOI(0));//AD7606_DB3
    set_gpio_direction(GPIOI(0),"in");
    init_gpio_export(GPIOI(1));//AD7606_DB4
    set_gpio_direction(GPIOI(1),"in");
    init_gpio_export(GPIOI(2));//AD7606_DB5
    set_gpio_direction(GPIOI(2),"in");
    init_gpio_export(GPIOI(3));//AD7606_DB6
    set_gpio_direction(GPIOI(3),"in");
    init_gpio_export(GPIOG(1));//AD7606_DB7
    set_gpio_direction(GPIOG(1),"in");
    init_gpio_export(GPIOG(0));//AD7606_DB8
    set_gpio_direction(GPIOG(0),"in");
    init_gpio_export(GPIOG(2));//AD7606_DB9
    set_gpio_direction(GPIOG(2),"in");
    init_gpio_export(GPIOG(3));//AD7606_DB10
    set_gpio_direction(GPIOG(3),"in");
    init_gpio_export(GPIOG(4));//AD7606_DB11
    set_gpio_direction(GPIOG(4),"in");
    init_gpio_export(GPIOG(5));//AD7606_DB12
    set_gpio_direction(GPIOG(5),"in");
    init_gpio_export(GPIOI(15));//AD7606_DB13
    set_gpio_direction(GPIOI(15),"in");
    init_gpio_export(GPIOB(5));//AD7606_DB14
    set_gpio_direction(GPIOB(5),"in");
    init_gpio_export(GPIOB(3));//AD7606_DB15
    set_gpio_direction(GPIOB(3),"in");
/* ------------      AD7606_AD_OS[0..2]       ----------- */
    init_gpio_export(GPIOF(5));//AD7606_OS0
    set_gpio_direction(GPIOF(5),"out");
    init_gpio_export(GPIOF(4));//AD7606_OS1
    set_gpio_direction(GPIOF(4),"out");
    init_gpio_export(GPIOF(3));//AD7606_OS2
    set_gpio_direction(GPIOF(3),"out");
/* ------------        RESET       ----------- */
    init_gpio_export(GPIOF(1));//AD7606_RESET
    set_gpio_direction(GPIOF(1),"out");
/* ------------        CONVST       ----------- */
    init_gpio_export(GPIOF(2));//AD7606_CONVST
    set_gpio_direction(GPIOF(2),"out");
/* ------------        BUSY       ----------- */
    init_gpio_export(GPIOI(11));//AD7606_BUSY
    set_gpio_direction(GPIOI(11),"in");
/* ------------        FSTDATA      ----------- */
    init_gpio_export(GPIOH(0));//AD7606_FASTDATA
    set_gpio_direction(GPIOH(0),"in");
/* ------------        CS/RD      ----------- */
    init_gpio_export(GPIOF(0));//AD7606_CS/RD
    set_gpio_direction(GPIOF(0),"out");


    init_gpio_export(GPIOB(11));
    set_gpio_direction(GPIOB(11),"out");
}
//IO释放函数
void IOreleaset(void)
{

}
void IO_In_test(void)
{
printf("\r\n");
printf("channel0=%d\r\n",data00);
printf("channel1=%d\r\n",data01);
printf("channel2=%d\r\n",data02);
printf("channel3=%d\r\n",data03);
printf("channel4=%d\r\n",data04);
printf("channel5=%d\r\n",data05);
printf("channel6=%d\r\n",data06);
printf("channel7=%d\r\n",data07);
printf("channel8=%d\r\n",data08);
printf("channel9=%d\r\n",data09);
printf("channel10=%d\r\n",data10);
printf("channel11=%d\r\n",data11);
printf("channel12=%d\r\n",data12);
printf("channel13=%d\r\n",data13);
printf("channel14=%d\r\n",data14);
printf("channel15=%d\r\n",data15);
printf("busy=%d\r\n",AD7606_BUSY);
printf("fastdata=%d\r\n",AD7606_FASTDATA);
}
void IO_out_test(void)
{
    AD7606_OS0_L();
    AD7606_OS1_L();
    AD7606_OS2_L();
    AD7606_CS_RD_L();
    AD7606_Reset_L();
    AD7606_CONVT_L();
    LED_off();
}
//AD7606初始化函数
void AD7606init(void)
{
    AD7606_OS0_L();
    AD7606_OS1_L();
    AD7606_OS2_L();

    AD7606_CONVT_H();
    AD7606_CS_RD_H();

    AD7606_Reset_L();
   // AD7606_Reset_H();
    //AD7606_Reset_L();
}
int16_t ADC_buf[8];//读取ad缓存
int16_t ADC_1_2[8];//待存储的采集原始数据
float   ADC_buf_float[8];//调试查看的转换值，0x38为零漂，这里暂时设为这个，上位机在单独配置每个通道的零漂  和  计算实际数值
//读取数值函数
void AD7606_Read(void)
{
    //AD7606_Reset_H();
    //AD7606_Reset_L();

    AD7606_CS_RD_H();

    AD7606_CONVT_L();
    AD7606_CONVT_H();
    while(AD7606_BUSY);
    AD7606_CS_RD_L();
    for(int i=0;i<8;i++)
    {
	ADC_buf[i] = 0;
	AD7606_CS_RD_L();
	ADC_buf[i] = data15;
	ADC_buf[i] = ADC_buf[i]<<1 | data14;
	ADC_buf[i] = ADC_buf[i]<<1 | data13;
	ADC_buf[i] = ADC_buf[i]<<1 | data12;
	ADC_buf[i] = ADC_buf[i]<<1 | data11;
	ADC_buf[i] = ADC_buf[i]<<1 | data10;
	ADC_buf[i] = ADC_buf[i]<<1 | data09;
	ADC_buf[i] = ADC_buf[i]<<1 | data08;
	ADC_buf[i] = ADC_buf[i]<<1 | data07;
	ADC_buf[i] = ADC_buf[i]<<1 | data06;
	ADC_buf[i] = ADC_buf[i]<<1 | data05;
	ADC_buf[i] = ADC_buf[i]<<1 | data04;
	ADC_buf[i] = ADC_buf[i]<<1 | data03;
	ADC_buf[i] = ADC_buf[i]<<1 | data02;
	ADC_buf[i] = ADC_buf[i]<<1 | data01;
	ADC_buf[i] = ADC_buf[i]<<1 | data00;
	AD7606_CS_RD_H();
    }	
    AD7606_CS_RD_L();
    printf("\r\n");
    for(int i=0;i<8;i++)
    {
	//ADC_buf_float只是看，没使用到
	ADC_buf_float[i] = (float)(ADC_buf[i]) * 5 / 32768*4;
	ADC_1_2[i] = ADC_buf[i];
        printf("ad7606 get channel-%d value = %f, hex = %d\r\n",i+1,ADC_buf_float[i],ADC_1_2[i]);
    }

}
int main()
{
    sysUsecTime();
    IOinit();
    AD7606init();
    times=0;
    while(1)
    {
        usleep(1000000);
	
	//IO_out_test();
	AD7606_Read();
	//IO_In_test();

	//if(data00)LED_H();	
	//else LED_L();
		
    }

    return 0;

}
void sysUsecTime() 
{ 
    struct timeval    tv; 
    struct timezone tz; 
       
    struct tm         *p; 
       
    gettimeofday(&tv, &tz); 
    //printf("tv_sec:%ld\n",tv.tv_sec); 
    //printf("tv_usec:%ld\n",tv.tv_usec); 
    //printf("tz_minuteswest:%d\n",tz.tz_minuteswest); 
    //printf("tz_dsttime:%d\n",tz.tz_dsttime); 
       
    p = localtime(&tv.tv_sec); 
    printf("time_now:%d-%d-%d %d:%d:%d.%ld\n", 1900+p->tm_year, 1+p->tm_mon, p->tm_mday, p->tm_hour, p->tm_min, p->tm_sec, tv.tv_usec); 
} 

 例子2：以HX711驱动代码为例（同样未成功，使用逻辑分析仪发现sda输入只有一个脉冲，怀疑是此类文件io方式驱动未设置io为浮空上拉模式，故失败，需要采用驱动的形式在测试）（只是IO输入输出做为参考）

//参考链接：https://blog.csdn.net/u011983700/article/details/106923194/
/GPIO的计算公式为(32 * (bank) + (gpio))/
//direction:设置输出还是输入模式
//设置为输入：echo “in” > direction
//设置为输出：echo “out” > direction

//value:输出时，控制高低电平；输入时，获取高低电平 
//高电平：echo 1 > value
//低电平：echo 0 > value

//edge:控制中断触发模式，引脚被配置为中断后可以使用poll() 函数监听引脚 
//非中断引脚： echo “none” > edge
//上升沿触发：echo “rising” > edge
//下降沿触发：echo “falling” > edge
//边沿触发：echo “both” > edge

//IO配置
//输入IO
//;IIC_SDA1  PG0
//;IIC_SDA2  PG3
//;IIC_SDA3  PG5
//;IIC_SDA4  PI2
//;IIC_SDA5  PI0

//输出IO
//;IIC_SCK1  PG2
//;IIC_SCK2  PG4
//;IIC_SCK3  PI15
//;IIC_SCK4  PI3
//;IIC_SCK5  PI1



#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <poll.h>
#include <unistd.h>
#include <time.h> 
#include <sys/time.h>

#define SUNXI_PA_BASE	0
#define SUNXI_PB_BASE	32
#define SUNXI_PC_BASE	64
#define SUNXI_PD_BASE	96
#define SUNXI_PE_BASE	128
#define SUNXI_PF_BASE	160
#define SUNXI_PG_BASE	192
#define SUNXI_PH_BASE	224
#define SUNXI_PI_BASE	256
#define SUNXI_PJ_BASE	288
#define SUNXI_PK_BASE	320
#define SUNXI_PL_BASE	352
#define SUNXI_PM_BASE	384
#define SUNXI_PN_BASE	416
#define SUNXI_PO_BASE	448
#define AXP_PIN_BASE	1024
/* sunxi gpio name space */
#define GPIOA(n)	(SUNXI_PA_BASE + (n))
#define GPIOB(n)	(SUNXI_PB_BASE + (n))
#define GPIOC(n)	(SUNXI_PC_BASE + (n))
#define GPIOD(n)	(SUNXI_PD_BASE + (n))
#define GPIOE(n)	(SUNXI_PE_BASE + (n))
#define GPIOF(n)	(SUNXI_PF_BASE + (n))
#define GPIOG(n)	(SUNXI_PG_BASE + (n))
#define GPIOH(n)	(SUNXI_PH_BASE + (n))
#define GPIOI(n)	(SUNXI_PI_BASE + (n))
#define GPIOJ(n)	(SUNXI_PJ_BASE + (n))
#define GPIOK(n)	(SUNXI_PK_BASE + (n))
#define GPIOL(n)	(SUNXI_PL_BASE + (n))
#define GPIOM(n)	(SUNXI_PM_BASE + (n))
#define GPION(n)	(SUNXI_PN_BASE + (n))
#define GPIOO(n)	(SUNXI_PO_BASE + (n))
#define GPIO_AXP(n)	(AXP_PIN_BASE  + (n))



#define HX711_SDA1_IN() get_gpio_value(GPIOG(0))
#define HX711_SDA2_IN() get_gpio_value(GPIOG(3))
#define HX711_SDA3_IN() get_gpio_value(GPIOG(5))
#define HX711_SDA4_IN() get_gpio_value(GPIOI(2))
#define HX711_SDA5_IN() get_gpio_value(GPIOI(0))

#define HX711_SDA1_H()     set_gpio_value(GPIOG(0),"1")
#define HX711_SDA1_L()     set_gpio_value(GPIOG(0),"0")
#define HX711_SCL1_H()     set_gpio_value(GPIOG(2),"1")
#define HX711_SCL1_L()     set_gpio_value(GPIOG(2),"0")

#define HX711_SDA2_H()     set_gpio_value(GPIOG(3),"1")
#define HX711_SDA2_L()     set_gpio_value(GPIOG(3),"0")
#define HX711_SCL2_H()     set_gpio_value(GPIOG(4),"1")
#define HX711_SCL2_L()     set_gpio_value(GPIOG(4),"0")

#define HX711_SDA3_H()     set_gpio_value(GPIOG(5),"1")
#define HX711_SDA3_L()     set_gpio_value(GPIOG(5),"0")
#define HX711_SCL3_H()     set_gpio_value(GPIOI(15),"1")
#define HX711_SCL3_L()     set_gpio_value(GPIOI(15),"0")

#define HX711_SDA4_H()     set_gpio_value(GPIOI(2),"1")
#define HX711_SDA4_L()     set_gpio_value(GPIOI(2),"0")
#define HX711_SCL4_H()     set_gpio_value(GPIOI(3),"1")
#define HX711_SCL4_L()     set_gpio_value(GPIOI(3),"0")

#define HX711_SDA5_H()     set_gpio_value(GPIOI(0),"1")
#define HX711_SDA5_L()     set_gpio_value(GPIOI(0),"0")
#define HX711_SCL5_H()     set_gpio_value(GPIOI(1),"1")
#define HX711_SCL5_L()     set_gpio_value(GPIOI(1),"0")

long long times=0;
void sysUsecTime();
//创建gpio文件
void init_gpio_export(int n)
{
    FILE * fp =fopen("/sys/class/gpio/export","w");
    if (fp == NULL)
        perror("export open filed");
    else
        fprintf(fp,"%d",n);
    fclose(fp);
}
//设置gpio的模式 输入/输出 in/out
void set_gpio_direction(int n,const char *direction)
{
    char path[100] = {0};
    sprintf(path,"/sys/class/gpio/gpio%d/direction",n);
    FILE * fp =fopen(path,"w");
    if (fp == NULL)
        perror("direction open filed");
    else
        fprintf(fp,"%s",direction);
    fclose(fp);
}
//获取gpio(n)的数值 0/1
int get_gpio_value(int n)
{
    char path[64];
    char value_str[3];
    int fd;
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", n);
    fd = open(path, O_RDONLY);
    if (fd < 0) {
        perror("Failed to open gpio value for reading!");
        return -1;
    }
    if (read(fd, value_str, 3) < 0) {
        perror("Failed to read value!");
        return -1;
    }
    close(fd);
    return (atoi(value_str));
}
//输出gpio(n)的数值 0/1  (方式一)
void set_gpio_value(int n,const char *value)
{
    char path[50];
    //char value_str[3];
    int fd;
    snprintf(path, sizeof(path), "/sys/class/gpio/gpio%d/value", n);
    fd = open(path, O_WRONLY);
    //snprintf(value_str, sizeof(value_str), "%d", value);
    write(fd, value, 1);
    close(fd);
}
//输出gpio(n)的数值 0/1  (方式二)
int set_gpio_value1(int gpio, int value)
{
    FILE *p = NULL;
    char gpio_value_path[50];
    sprintf(gpio_value_path, "/sys/class/gpio/gpio%d/value", gpio);
    p = fopen(gpio_value_path, "w");
    fprintf(p, "%d", value);
    fclose(p);
    return 0;
}
//IO初始化函数
void IOinit(void)
{
    init_gpio_export(GPIOG(0));//HX711_SDA1
    set_gpio_direction(GPIOG(0),"in");
    init_gpio_export(GPIOG(3));//HX711_SDA2
    set_gpio_direction(GPIOG(3),"in");
    init_gpio_export(GPIOG(5));//HX711_SDA3
    set_gpio_direction(GPIOG(5),"in");
    init_gpio_export(GPIOI(2));//HX711_SDA4
    set_gpio_direction(GPIOI(2),"in");
    init_gpio_export(GPIOI(0));//HX711_SDA5
    set_gpio_direction(GPIOI(0),"in");
   
    init_gpio_export(GPIOG(2));//HX711_SCL1
    set_gpio_direction(GPIOG(2),"out");
    init_gpio_export(GPIOG(4));//HX711_SCL2
    set_gpio_direction(GPIOG(4),"out");
    init_gpio_export(GPIOI(15));//HX711_SCL3
    set_gpio_direction(GPIOI(15),"out");
    init_gpio_export(GPIOI(3));//HX711_SCL4
    set_gpio_direction(GPIOI(3),"out");
    init_gpio_export(GPIOI(1));//HX711_SCL5
    set_gpio_direction(GPIOI(1),"out");
}
//IO释放函数
void IOreleaset(void)
{

}
void IO_In_test(void)
{
    printf("\r\n");
    printf("HX711_SDA1_IN=%d\r\n",HX711_SDA1_IN());
    printf("HX711_SDA2_IN=%d\r\n",HX711_SDA2_IN());
    printf("HX711_SDA3_IN=%d\r\n",HX711_SDA3_IN());
    printf("HX711_SDA4_IN=%d\r\n",HX711_SDA4_IN());
    printf("HX711_SDA5_IN=%d\r\n",HX711_SDA5_IN());

}
void IO_out_test(void)
{
    HX711_SDA1_H();
    HX711_SCL1_H();
    HX711_SDA2_H();
    HX711_SCL2_H();
    HX711_SDA3_H();
    HX711_SCL3_H();
    HX711_SDA4_H();
    HX711_SCL4_H();
    HX711_SDA5_H();
    HX711_SCL5_H();
}

unsigned long HX711_Read(void)  //读取711读到的数据
{ 
    unsigned long val; 
    unsigned char i; 

    HX711_SDA1_H(); 
    usleep(5); 
    HX711_SCL1_L(); 
    val = 0;
    while(HX711_SDA1_IN()); 
    usleep(1); 
    for(i=0;i<24;i++){ 
	HX711_SCL1_H(); 
	val=val<<1; 
	usleep(1);  
	HX711_SCL1_L(); 
	if(HX711_SDA1_IN()) 
	    val++; 
	usleep(1); 
    } 
    HX711_SCL1_H(); 
    val = val^0x800000; 
    usleep(5); 
    HX711_SCL1_L(); 
    usleep(1); 

    return val; 	
}
double hx711_buffer=0;//定义hx711_buffer来接受hx711read读取的信息
double weight_maopi=0;//毛皮重量
double weight_shiwu=0;//实物重量
double Get_Maopi(void)
 {
    hx711_buffer=HX711_Read();
    weight_maopi=hx711_buffer;
    return weight_maopi;
}
double Get_Weight(void)
{
    hx711_buffer=HX711_Read();
    weight_shiwu=hx711_buffer-weight_maopi;
    weight_shiwu=weight_shiwu/100;
    weight_shiwu=(unsigned int)((float)weight_shiwu/4.30+0.05);//每一个传感器需要矫正4.30这个除数。当发现测试出来的重量偏大时，增加该数值。如果测试出来的重量偏小时，减小改数值.该数值一般在4.0-5.0之间。因传感器线性斜率不同而定。
//		if(hx711_buffer>weight_maopi)
//				weight_shiwu=hx711_buffer-weight_maopi;
    return weight_shiwu;
}
int main()
{
    double maopi,shiwu;
    sysUsecTime();
    IOinit();
    maopi=Get_Maopi();
    printf("maopi = %.4fg\r\n",maopi);
    times=0;
    while(1)
    {
        usleep(1000000);
	shiwu=Get_Weight();
	printf("shiwu = %.4fg\r\n",shiwu);//输出实物重量并保留两位小数	
    }

    return 0;

}
void sysUsecTime() 
{ 
    struct timeval    tv; 
    struct timezone tz; 
       
    struct tm         *p; 
       
    gettimeofday(&tv, &tz); 
    //printf("tv_sec:%ld\n",tv.tv_sec); 
    //printf("tv_usec:%ld\n",tv.tv_usec); 
    //printf("tz_minuteswest:%d\n",tz.tz_minuteswest); 
    //printf("tz_dsttime:%d\n",tz.tz_dsttime); 
       
    p = localtime(&tv.tv_sec); 
    printf("time_now:%d-%d-%d %d:%d:%d.%ld\n", 1900+p->tm_year, 1+p->tm_mon, p->tm_mday, p->tm_hour, p->tm_min, p->tm_sec, tv.tv_usec); 
} 

四、结语