¶ LED资源
下图显示，tinker board 2s有三个状态led灯，分别为
- LED0：Power (gpio0 RK_PA4)
- LED1：disk activity (gpio0 RK_PA3)
- LED2：Reserve (gpio0 RK_PB2)
Android系统需要通过adb登录进行操作，并且切换root权限。
使用usb type-c线连接tinker board 2s和电脑，启动adb命令窗口，输入如下命令：
$ adb shell setprop persist.sys.root_access 3
$ adb root
$ adb remount
$ adb shell
- 进入led设备目录
$ cd /sys/class/leds
$ ls
- 如果要操作 LED0，进入 pwr-led 目录
$ cd pwr-led
- 如果要操 LED1，进入 act-led 目录
$ cd act-led
- 如果要操作 LED2，进入 rsv-led 目录
$ cd rsv-led
- 用户通过 echo 命令向其 brightness 属性输入命令控制每一个 LED：
$ echo "1" > brightness #点亮
$ echo "0" > brightness #熄灭
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#define LED0 pwr-led/brightness
#define LED1 act-led/brightness
#define LED2 rsv-led/brightness
int main(int argc, char **argv)
{
char buf[50];
int gpiofd;
sprintf(buf, "/sys/class/leds/", LED0);
gpiofd = open(buf, O_WRONLY);
if(gpiofd < 0)
{
perror("Couldn't open IRQ file");
return -1;
}
write(gpiofd, 0, 1); //点亮LED
//write(gpiofd, 1, 1); //熄灭LED
close(gpiofd);
return 0;
}
public static void setLED(String date){
Process process = null;
String command1 = "echo 0 /sys/class/leds/act-led/brightness";
try {
process = Runtime.getRuntime().exec(command1);
process.waitFor();
} catch (IOException e) {
e.printStackTrace();
}finally{
if(process!=null){
process.destroy();
}
}
}