【飞凌OKA40i-C开发板试用体验】流水灯

本文来源电子发烧友社区，作者：刘建华， 帖子地址：https://bbs.elecfans.com/jishu_2305990_1_1.html


【目的】熟悉LED灯的驱动
从手册上查到驱动LED的说明：

应该是向文件/sys/class/gpio/export写入IO的编号，然后往sys/class/gpioXX/value里面写1或者0来控制LED的亮与灭。
1、在虚拟机work目录下面新建LED文件夹，下面新建led.c文件：

#include 
#include 
#include 
#include 
#include 

int main(int argc ,char *argv[])
{
    FILE *fp=NULL;
    int i=0;
    fp = fopen("/sys/class/gpio/export","w");
    fprintf(fp,"%d",271);
    fclose(fp);
    fp = fopen("/sys/class/gpio/export","w");
    fprintf(fp,"%d",250);
    fclose(fp);
    fp = fopen("/sys/class/gpio/gpio271/direction","w");
    fprintf(fp,"out");
    fclose(fp);
    fp = fopen("/sys/class/gpio/gpio250/direction","w");
    fprintf(fp,"out");
    fclose(fp);
    fp = fopen("/sys/class/gpio/gpio43/direction","w");
    fprintf(fp,"out");
    fclose(fp);
    for(i=0;i<100;i++)
    {
        fp = fopen("/sys/class/gpio/gpio250/value","w");
        fprintf(fp,"%d",1);
        sleep(1);
        fclose(fp);
        fp = fopen("/sys/class/gpio/gpio250/value","w");
        fprintf(fp,"%d",0);
        sleep(1);
        fclose(fp);
        fp = fopen("/sys/class/gpio/gpio271/value","w");
        fprintf(fp,"%d",1);
        sleep(1);
        fclose(fp);
        fp = fopen("/sys/class/gpio/gpio271/value","w");
        fprintf(fp,"%d",0);
        sleep(1);
        fclose(fp);

    }
    fp = fopen("/sys/class/gpio/gpio271/unexport","w");
    fprintf(fp, "%d",271);
    fclose(fp);
    return 0;

}
2、编写makefile

TARGET =LED
DEST_DIR ?=_install
#CC ?=arm-linux-gcc
CC =arm-linux-gnueabihf-gcc-5.3.1
build:
@(CC) -o(TARGET) led.c

hold:
[url=home.php?mod=space&uid=70594]@echo[/url] "LED hold[skip]"

install:
[url=home.php?mod=space&uid=2293869]@MKDIR[/url] -p $(DEST_DIR)
@cp(TARGET)(DEST_DIR)

uninstall:
@rm -fr(DEST_DIR)/(TARGET)

distclean: uninstall
@rm -fr $(TARGET)
@rm -fr _install

编译好后上传开发板，运行，LED5、LED6交替闪烁。