python调用C程序代码

DHT11的驱动使用C语言编写然后用python调用C的程序显示温湿度

pycall.py文件如下:

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import RPi.GPIO as GPIO
import time
import DHT11

pin=18

while True:
hum,tem=DHT11.read_data(pin)
print('hum:%f, tem:%f' %(hum,tem))
time.sleep(2)

c语言代码如下:

#include <stdio.h>
#include <wiringPi.h>
#include <time.h>

//2019.1.18  时序还没调试完成
//编译使用
//运行需要使用  g++ -Wall -o LEDtest LEDtest.cpp  -lwiringPi

//数据定义 sudo ./a.out
unsigned int U8T_data_H,U8T_data_L,U8RH_data_H,U8RH_data_L,U8checkdata;
unsigned int U8T_data_H_temp,U8T_data_L_temp,U8RH_data_H_temp,U8RH_data_L_temp,U8checkdata_temp;

typedef  unsigned char BOOL;
#ifndef TRUE
#define TRUE 1
#endif
 
#ifndef FALSE
#define FALSE 0
#endif

#define DHT11_PIN 14
typedef  unsigned short int u8;
typedef unsigned char uint8_t;
typedef  unsigned int u16;


void mdelay(u16 ms);

 
void udelay(u16 us);


static void DHT11_DataPin_Configure_Output(void)
{
    pinMode(DHT11_PIN,OUTPUT);
}

static void DHT11_DataPin_Configure_Input(void)
{
    pinMode(DHT11_PIN,INPUT);
}

BOOL DHT11_get_databit(void)
{
    int val;
    val=digitalRead (DHT11_PIN);
    if(val == LOW){
        return FALSE;
    }else{
        return TRUE;
    }
}
 
void DHT11_set_databit(BOOL level)
{
    if(level == TRUE){
        digitalWrite (DHT11_PIN, HIGH);
    }else{
        digitalWrite (DHT11_PIN, LOW);
    }
}

static uint8_t DHT11_read_byte(void)
{
    uint8_t i;
    uint8_t data = 0;
    long k=0;
    for(i = 0; i < 8; i++)
    {
        data <<= 1;
        while((!DHT11_get_databit()));
        delayMicroseconds(35);
        if(DHT11_get_databit()){
            data |= 0x1;
            while(DHT11_get_databit())
            {
                k++;
                if(k>200000)
                {
                    //printf("a \r\n"); 
                    return 0;
                }
            }
        }else{
        
        } 
    }
    return data;
}

static uint8_t DHT11_start_sampling(void)
{
    DHT11_DataPin_Configure_Output();
    //主机拉低18ms? ?
    DHT11_set_databit(FALSE);
    delay(20);
    DHT11_set_databit(TRUE);
    //总线由上拉电阻拉高 主机延时20us
    //udelay(10);
    //udelay(10);
    DHT11_DataPin_Configure_Input();
    delayMicroseconds(50);
    //主机设为输入 判断从机响应信号 
    DHT11_set_databit(TRUE);
     
    DHT11_DataPin_Configure_Input();
     
    //判断从机是否有低电平响应信号 如不响应则跳出，响应则向下运行?? ? ?
    if(!DHT11_get_databit())//T !?? ? ?
    {
        long  k=0;
        //判断从机是否发出 80us 的低电平响应信号是否结束?? ? 
        while((!DHT11_get_databit()))
        {
            k++;
            if(k>100000) {printf("b \r\n");return 0;}
        }
        // printf("DHT11 answers.\r\n");
        //判断从机是否发出 80us 的高电平，如发出则进入数据接收状态
        k=0;
        while((DHT11_get_databit()))
        {
            k++;
            if(k>100000){printf("c \r\n");;return 0;}
        }
            return 1;
    }
     
    return 0;
}
 
typedef  struct 
{
    unsigned int hh;
    unsigned int hl;
    unsigned int th;
    unsigned int tl;
}d_t;
 
d_t DHT11_get_data(void)
{
    u8 temp;
    d_t res;
    if(DHT11_start_sampling())
    {
        //printf("DHT11 is ready to transmit data\r\n");
        //数据接收状态
        U8RH_data_H_temp = DHT11_read_byte();
        
        U8RH_data_L_temp = DHT11_read_byte();
        res.hh=
        U8T_data_H_temp = DHT11_read_byte();
        res.th=
        U8T_data_L_temp = DHT11_read_byte();
        U8checkdata_temp = DHT11_read_byte();
         
        /* Data transmission finishes, pull the bus high */
        DHT11_DataPin_Configure_Output();
        DHT11_set_databit(TRUE);
        //数据校验 
     
        temp=(U8T_data_H_temp+U8T_data_L_temp+U8RH_data_H_temp+U8RH_data_L_temp);
        if(temp==U8checkdata_temp)
        {
            U8RH_data_H=U8RH_data_H_temp;
            res.hh=U8RH_data_H;
            U8RH_data_L=U8RH_data_L_temp;
            res.hl=U8RH_data_L;
            U8T_data_H=U8T_data_H_temp;
            res.th=U8T_data_H;
            U8T_data_L=U8T_data_L_temp;
            res.tl=U8T_data_L;
            U8checkdata=U8checkdata_temp;
             
            //printf("DHT11 tempature %d.%d humidity %d.%d \r\n",U8T_data_H,U8T_data_L,U8RH_data_H,U8T_data_L);
        }
        else
        {
            //printf("checksum failure \r\n");
            res.hh=0;res.hl=0;res.th=0;res.tl=0;
        } 
    }
    else
    {
        printf("DHT11 didn't answer. Sampling failed. \r\n");
    }
    return res;
}

void mdelay(u16 ms)
{
    if(ms != 0){
        delay(ms);
    }
}
 
void udelay(u16 us)
{
    while(us--);
}
/*
int main(void)
{
    int res=wiringPiSetupGpio();
    while(1)
    {
        DHT11_get_data();
        mdelay(1200);
    }
}
*/
//
//使用python来调用c写的函数
//
//

#include "Python.h"
static DHT_read_data(PyObject* self,PyObject* args)
{
    int pin=0;
    if(PyArg_ParseTuple(args,"i",&pin)==0)
        return NULL;    //失败
    d_t res=DHT11_get_data();
    
    float hum=res.hh+res.hl*1.0/100;
    float tem=res.th+res.tl*1.0/100;
    
    return Py_BuildValue("dd",hum,tem);
}

static PyMethodDef DHT11_methods[]=
{
    //注册
    {"read_data",DHT_read_data,METH_VARARGS}
};

void initDHT11()
{
    //模块初始化函数
    printf("dht11\n");
    wiringPiSetupGpio();
    Py_InitModule("DHT11",DHT11_methods);
}

//python setup.py build
//sudo python setup.py install

setup.py文件内容如下:

#!/usr/bin/env python
# -*- coding:utf-8 -*-

from distutils.core import setup,Extension

DHT11_Extension=Extension('DHT11',sources=['main.c'],libraries=['wiringPi'])

setup(name='DHT11',ext_modules=[DHT11_Extension])

然后编译C文件需要先编写setup.py 内容如上

python setup.py build 用于编译文件会出现一些警告信息可以忽略不理会

再使用这个 sudo python setup.py install 把这个模块安装到python

然后再使用sudo python pycall.py 如下图显示:

python调用C程序代码

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