00015-----集成了LED 外部中断按键、IIC读写24LC04及PWM控制蜂鸣器的应用程序

按不同的按键出不同的响声，其中有一个按键因为参数设置的为65535所以基本听不到蜂鸣器所产生的声音，因为高电平的占空比趋近于0了。应用程序如下，请参考：

 

 

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define pwm_start 0x01
#define pwm_stop  0x02
 int buttons_fd;
 int leds_fd;
 int eeprom_fd;
 int pwm_fd;
 char buttons[4] = {'0', '0', '0', '0',};
  int value[512];

int main(void)
{
  value[0]=0x12;
  value[1]=0x23;
  value[2]=0x34;
  value[3]=0x45;
  value[4]=0x56;
  value[5]=0x67;
 buttons_fd = open("/dev/keys_eint", O_RDWR);
 leds_fd=open("/dev/LED_CONTROL",O_RDWR);
 eeprom_fd=open("/dev/at24lc04",O_RDWR);
 pwm_fd=open("/dev/pwm_micro2440_drv",O_RDWR);
 if (buttons_fd < 0) {
  perror("open device buttons");
  exit(1);
 }
  if(leds_fd<0)
  {
    perror("open device leds");
   }
 while(1) {
  char current_buttons[4];
  int count_of_changed_key;
  int i;
  if (read(buttons_fd, current_buttons, sizeof current_buttons) != sizeof current_buttons) {
   perror("read buttons:");
   exit(1);
  }

  for (i = 0, count_of_changed_key = 0; i < sizeof buttons / sizeof buttons[0]; i++) {
   if (buttons[i] != current_buttons[i]) {
    buttons[i] = current_buttons[i];
    printf("%skey %d is %s", count_of_changed_key? ", ": "", i+1, buttons[i] == '0' ? "up" : "down");
    switch(i)
    {
         case 0:
                 ioctl(leds_fd,0);
                
                 write(eeprom_fd,value,1);
                 //sleep(1);
                 value[0]=0;
                 read(eeprom_fd,value,1);
                 printf("\n write reg[0]data:%x to at24lc04\n",value[0]);
                 ioctl(pwm_fd,pwm_start,1);
                 break;
         case 1:
                 ioctl(leds_fd,1);
                 //write(eeprom_fd,value+sizeof(value[0]),1);
                 write(eeprom_fd,value+1,1);
                 //sleep(1);
                 value[1]=0;
                 read(eeprom_fd,value+1,1);
                 printf("\n write reg[1]data:%x to at24lc04\n",value[1]);
                  ioctl(pwm_fd,pwm_start,2);
                 break;
         case 2:
                 ioctl(leds_fd,2);
                 write(eeprom_fd,value+2,10);
                 //sleep(1);
                  value[2]=0;
                 read(eeprom_fd,value+2,1);
                 printf("\n write reg[2]data:%x to at24lc04\n",value[2]);
                  ioctl(pwm_fd,pwm_start,1);
                 break;
         case 3:
                 ioctl(leds_fd,3);
                 write(eeprom_fd,value+3,1);
                 //sleep(1);
                  value[3]=0;
                 read(eeprom_fd,value+3,1);
                 printf("\n write reg[3]data:%x to at24lc04\n",value[3]);
                  ioctl(pwm_fd,pwm_start,65535);
               break;
         default:
                  break; 
    }
    count_of_changed_key++;
   }
  }
  if (count_of_changed_key) {
   printf("\n");
  }
  
  
 }
  close(eeprom_fd);
 close(buttons_fd);
 close(leds_fd);
 close(pwm_fd);
 return 0;
}
下一步搞ADC以及LCD控制器等