【原创】用C控制GPIO的代码[可以直接看CPU占用率了]
本帖最后由 soloforce 于 2013-5-20 12:15 编辑现在不需要通过写IO文件来操作GPIO了，请参考这个帖子：http://forum.cubietech.com/forum.php?mod=viewthread&tid=464&page=1&extra=#pid2719
写了个C语言控制GPIO的代码，目前只支持数字IO（只有0和1）,分享一下。API模仿Arduino的风格，比较简单易用。#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
/**
* Here we use the GPIO expansion near the SATA connector, from PD1 ~ PD7
* */
#define MIN_PIN 1
#define MAX_PIN 7
/**
* Binary value that GPIO pins could accept
* */
typedef enum{
LOW=0,
HIGH=1
}value_t;
/**
* GPIO pins get/set direction
* */
typedef enum{
IN=0,
OUT=1
}direction_t;
FILE* value_fp;
/**
* @brief Initialize the GPIO ports' value file pointers
*
* */
void gpio_init()
{
int i;
for(i=MIN_PIN;i<=MAX_PIN;i++)
value_fp=NULL;
}
/**
* @brief Uninitialize the GPIO ports, unexport those exported and close files.
*
* */
int gpio_uninit()
{
int i;
FILE *unexport_fp=fopen("/sys/class/gpio/unexport","w");
if(!unexport_fp) return -1;
for(i=MIN_PIN;i<=MAX_PIN;i++){
if(value_fp){
fclose(value_fp);
fprintf(unexport_fp,"%d",i);
fflush(unexport_fp);
}
}
fclose(unexport_fp);
return 0;
}
/**
* @brief Set the GPIO pins to specified direction
*
* @param pin: GPIO pin to set direction
* @param dir: IN or OUT
*
* */
int pinMode(int pin, direction_t dir)
{
char direction_file;
char value_file;
FILE *export_fp=fopen("/sys/class/gpio/export","w");
if(!export_fp) return -1;
fprintf(export_fp,"%d",pin);
sleep(1);
fclose(export_fp);
sprintf(direction_file,"/sys/class/gpio/gpio%d_pd%d/direction", pin, pin);
FILE *direction_fp=fopen(direction_file,"w");
if(!direction_fp) return -2;
if(dir==OUT){
fprintf(direction_fp,"out");
}else fprintf(direction_fp,"in");
fclose(direction_fp);
sprintf(value_file,"/sys/class/gpio/gpio%d_pd%d/value", pin, pin);
value_fp=fopen(value_file,"w");
if(!value_fp) return -3;
return 0;
}
/**
* @brief Set the GPIO pins to specified binary value
*
* @param pin: GPIO pin to set value
* @param value: LOW or HIGH
*
* */
int digitalWrite(int pin, value_t value)
{
if(!value_fp)return -1;
if(pin<MIN_PIN) pin=MIN_PIN;
if(pin>MAX_PIN) pin=MAX_PIN;
fprintf(value_fp,"%d", value);
fflush(value_fp);
return 0;
}
/**
* @brief A demo to alternately set two GPIO pin's power level (LOW or HIGH),
* to flash a LED connected between the two pins.
* */
int main()
{
gpio_init();
pinMode(1,OUT);
pinMode(2,OUT);
int i;
for(i=0;i<10;i++){
digitalWrite(1,HIGH);
digitalWrite(2,LOW);
sleep(1);
digitalWrite(1,LOW);
digitalWrite(2,HIGH);
sleep(1);
}
gpio_uninit();
}
本帖最后由 soloforce 于 2013-5-9 21:35 编辑
再发一个用GPIO控制LED显示当前CPU繁忙情况的小程序。
在GPIO的LD1~LD6接了3只LED，以二进制码形式显示CPU使用率。#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <signal.h>
/**
* Here we use the GPIO expansion near the SATA connector, from PD1 ~ PD7
* */
#define MIN_PIN 1
#define MAX_PIN 7
/**
* Binary value that GPIO pins could accept
* */
typedef enum{
LOW=0,
HIGH=1
}value_t;
/**
* GPIO pins get/set direction
* */
typedef enum{
IN=0,
OUT=1
}direction_t;
typedef struct{
long int user,nice,sys,idle,iowait,irq,softirq;
}jiffies_t;
/**
* GPIO pin values' file pointers
* */
FILE* value_fp={NULL};
/**
* Signal actions structures
* */
struct sigaction int_act,term_act, old_act;
/**
* @brief Signal INT handler
* */
void sigint_handler(int sig_num)
{
printf("Uninitialzing GPIO...\n");
/* uninitialize the GPIO */
gpio_uninit();
/* change back to the original handler */
sigaction(SIGINT, &old_act,NULL);
/* emit the SIGINT again */
kill(0,SIGINT);
}
/**
* @brief Signal TERM handler
* */
void sigterm_handler(int sig_num)
{
printf("Uninitialzing GPIO...\n");
/* uninitialize the GPIO */
gpio_uninit();
/* change back to the original handler */
sigaction(SIGTERM, &old_act,NULL);
/* emit the SIGTERM again */
kill(0,SIGTERM);
}
/**
* @brief Initialize signals
* * */
void catch_signal_init()
{
memset(&int_act,0,sizeof(int_act));
memset(&term_act,0,sizeof(int_act));
memset(&old_act,0,sizeof(old_act));
int_act.sa_handler=&sigint_handler;
term_act.sa_handler=&sigterm_handler;
sigaction(SIGINT, &int_act, &old_act);
sigaction(SIGTERM, &term_act, &old_act);
}
/**
* @brief Initialize the GPIO ports' value file pointers
*
* */
void gpio_init()
{
int i;
for(i=MIN_PIN;i<=MAX_PIN;i++)
value_fp=NULL;
pinMode(1,OUT);
pinMode(2,OUT);
pinMode(3,OUT);
pinMode(4,OUT);
pinMode(5,OUT);
pinMode(6,OUT);
}
/**
* @brief Uninitialize the GPIO ports, unexport those exported and close files.
*
* */
int gpio_uninit()
{
int i;
FILE *unexport_fp=fopen("/sys/class/gpio/unexport","w");
if(!unexport_fp) return -1;
for(i=MIN_PIN;i<=MAX_PIN;i++){
if(value_fp){
fclose(value_fp);
fprintf(unexport_fp,"%d",i);
fflush(unexport_fp);
}
}
fclose(unexport_fp);
return 0;
}
/**
* @brief Set the GPIO pins to specified direction
*
* @param pin: GPIO pin to set direction
* @param dir: IN or OUT
*
* */
int pinMode(int pin, direction_t dir)
{
char direction_file;
char value_file;
FILE *export_fp=fopen("/sys/class/gpio/export","w");
if(!export_fp) return -1;
fprintf(export_fp,"%d",pin);
sleep(1);
fclose(export_fp);
sprintf(direction_file,"/sys/class/gpio/gpio%d_pd%d/direction", pin, pin);
FILE *direction_fp=fopen(direction_file,"w");
if(!direction_fp) return -2;
if(dir==OUT){
fprintf(direction_fp,"out");
}else fprintf(direction_fp,"in");
fclose(direction_fp);
sprintf(value_file,"/sys/class/gpio/gpio%d_pd%d/value", pin, pin);
value_fp=fopen(value_file,"w");
if(!value_fp) return -3;
return 0;
}
/**
* @brief Set the GPIO pins to specified binary value
*
* @param pin: GPIO pin to set value
* @param value: LOW or HIGH
*
* */
int digitalWrite(int pin, value_t value)
{
if(!value_fp)return -1;
if(pin<MIN_PIN) pin=MIN_PIN;
if(pin>MAX_PIN) pin=MAX_PIN;
fprintf(value_fp,"%d", value);
fflush(value_fp);
return 0;
}
/**
* @brief Get CPU jiffies from /proc/stat
*
* @param s(OUTPUT) Point of CPU jiffies structure
*
* */
int get_jiffies(jiffies_t *s)
{
char buf={0};
char cpu={0};
if(!s) return -1;
FILE* cpu_stat_fp = fopen("/proc/stat","r");
if(cpu_stat_fp == NULL){
return -1;
}
fgets(buf,sizeof(buf),cpu_stat_fp);
sscanf(buf,"%s%d%d%d%d%d%d%d",cpu, &(s->user),&(s->nice),&(s->sys),&(s->idle),&(s->iowait),&(s->irq),&(s->softirq));
fclose(cpu_stat_fp);
return 0;
}
/**
* @brief Get CPU usage
*
* @param usage(OUTPUT): CPU usage in a short time
*
* */
int get_cpu_usage(float * usage)
{
jiffies_t j1,j2;
float all1, all2;
int status;
if(!usage) return -1;
status=get_jiffies(&j1);
if(status) return -2;
usleep(100000);
status=get_jiffies(&j2);
if(status) return -2;
all1=j1.user+j1.nice+j1.sys+j1.idle+j1.iowait+j1.irq+j1.softirq;
all2=j2.user+j2.nice+j2.sys+j2.idle+j2.iowait+j2.irq+j2.softirq;
*usage=((all2-j2.idle)-(all1-j1.idle))/(all2-all1) ;
return 0;
}
/**
* @brief Show CPU usage to LEDs in binary-mode
*
* @param n(INPUT): CPU usage level, from 0~7
*
* */
void show_cpu_usage(int n)
{
if(n & 0x04){
digitalWrite(1,LOW);
digitalWrite(2,HIGH);
}else{
digitalWrite(1,HIGH);
digitalWrite(2,LOW);
}
if(n & 0x02){
digitalWrite(3,LOW);
digitalWrite(4,HIGH);
}else{
digitalWrite(3,HIGH);
digitalWrite(4,LOW);
}
if(n & 0x01){
digitalWrite(5,LOW);
digitalWrite(6,HIGH);
}else{
digitalWrite(5,HIGH);
digitalWrite(6,LOW);
}
}
/**
* @brief A daemon to show CPU usage through GPIO expansion
* to flash a LED connected between the two pins. Press Ctrl+C to Quit.
* */
int main()
{
float usage;
pid_t pid=fork();
/* Create a daemon process, and terminate the parent process. */
if(pid>0) exit(0);
if(pid<0) {
printf("Failed to create sub-process!\n");
exit(-1);
}
setsid();
catch_signal_init();
gpio_init();
while(1){
if(get_cpu_usage(&usage)){
printf("Failed to get CPU usage!\n");
break;
}
int n=(int)(usage*8);
if(n>7) n=7;
show_cpu_usage(n);
sleep(1);
}
}
赞！代码很工整 {:soso_e100:} 看到使用了两种不同函数命名规则 ：） unix风格和arduino风格。。。 有没有可能把树莓派的 WiringPi 直接移植过来？ 貌似他们的东西做得挺全的，有机会可以探讨一下 学习了，这个也是直接调用Python GPIO库？ 特别喜欢arduino风格，和以前我学的Action Script 2&3很像~ py的库好像内容不丰富啊 :)
版主有没有android的gpio的读写工具类或者源码
I2C读写的工具栏或源码呢？能否发一份呢？
谢谢！
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