exynos4412 的过程K2按键控制LED灯。第1次按,全亮;第2次按,流水灯;第3次按,全灭。循环往复。
时间: 2024-03-06 16:51:57 浏览: 88
按键控制LED灯的亮灭.C
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这是一个嵌入式系统的问题,需要通过编程来实现按键控制LED灯的功能。这里提供一个基本的思路:
1. 初始化GPIO口为输入和输出口
2. 定义一个变量来记录按键按下的次数
3. 在循环中读取GPIO口的状态,如果检测到按键按下,就增加按键计数器的值。注意 debounce 处理。
4. 根据按键计数器的值来控制LED灯的状态:
- 当按键计数器为1时,LED灯全亮
- 当按键计数器为2时,LED灯流水灯
- 当按键计数器为3时,LED灯全灭
- 当按键计数器大于3时,重置按键计数器为1
5. 每次改变LED灯的状态后,需要加入适当的延迟,以便让人眼可以看到灯的变化。
下面是一个简单的示例代码,仅供参考:
```c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#define GPIO_BASE 0x11000000
#define GPIO_SIZE 0x1000
#define LED_OFF 0
#define LED_ON 1
#define KEY_RELEASED 0
#define KEY_PRESSED 1
#define KEY_DEBOUNCE_TIME_MS 50
// Exynos4412 GPIO Register Map
typedef struct {
unsigned int con;
unsigned int dat;
unsigned int pud;
} gpio_reg_t;
// GPIO1_1 (K2) -> LED1
#define GPIO_K2 (1 << 1)
#define GPIO_LED1 (1 << 0)
// Set the GPIO direction to input or output
static void gpio_set_direction(int gpio, int is_output)
{
int fd;
void *gpio_map;
gpio_reg_t *gpio_reg;
fd = open("/dev/mem", O_RDWR|O_SYNC);
gpio_map = mmap(NULL, GPIO_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_BASE);
gpio_reg = (gpio_reg_t *)gpio_map;
if (is_output)
gpio_reg->con &= ~(0xf << 4*(gpio % 4)); // set as output
else
gpio_reg->con |= (0x4 << 4*(gpio % 4)); // set as input
munmap(gpio_map, GPIO_SIZE);
close(fd);
}
// Set the GPIO output value to high or low
static void gpio_set_value(int gpio, int value)
{
int fd;
void *gpio_map;
gpio_reg_t *gpio_reg;
fd = open("/dev/mem", O_RDWR|O_SYNC);
gpio_map = mmap(NULL, GPIO_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_BASE);
gpio_reg = (gpio_reg_t *)gpio_map;
if (value)
gpio_reg->dat |= (1 << gpio);
else
gpio_reg->dat &= ~(1 << gpio);
munmap(gpio_map, GPIO_SIZE);
close(fd);
}
// Get the GPIO input value
static int gpio_get_value(int gpio)
{
int fd;
void *gpio_map;
gpio_reg_t *gpio_reg;
int value;
fd = open("/dev/mem", O_RDWR|O_SYNC);
gpio_map = mmap(NULL, GPIO_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, GPIO_BASE);
gpio_reg = (gpio_reg_t *)gpio_map;
value = (gpio_reg->dat >> gpio) & 1;
munmap(gpio_map, GPIO_SIZE);
close(fd);
return value;
}
// Wait for a certain amount of time (in milliseconds)
static void delay_ms(int ms)
{
usleep(ms * 1000);
}
int main()
{
int key_state = KEY_RELEASED;
int key_counter = 0;
int led_state = LED_OFF;
gpio_set_direction(GPIO_K2, 0);
gpio_set_direction(GPIO_LED1, 1);
while (1) {
// Read the K2 state (with debounce)
if (gpio_get_value(GPIO_K2) == KEY_PRESSED) {
if (key_state == KEY_RELEASED) {
key_counter++;
key_state = KEY_PRESSED;
delay_ms(KEY_DEBOUNCE_TIME_MS);
}
}
else {
key_state = KEY_RELEASED;
}
// Change the LED state based on the key counter
if (key_counter == 1) {
led_state = LED_ON;
}
else if (key_counter == 2) {
led_state = LED_OFF;
gpio_set_value(GPIO_LED1, 1);
delay_ms(50);
gpio_set_value(GPIO_LED1, 0);
delay_ms(50);
gpio_set_value(GPIO_LED1, 1);
delay_ms(50);
gpio_set_value(GPIO_LED1, 0);
delay_ms(50);
gpio_set_value(GPIO_LED1, 1);
delay_ms(50);
gpio_set_value(GPIO_LED1, 0);
delay_ms(50);
}
else if (key_counter == 3) {
led_state = LED_OFF;
}
else {
key_counter = 1;
led_state = LED_ON;
}
// Set the LED state
gpio_set_value(GPIO_LED1, led_state);
delay_ms(50);
}
return 0;
}
```
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