嵌入式中GPIO驱动,利用位带操作、库函数、驱动程序实现点亮8个LED灯
时间: 2023-07-15 13:15:16 浏览: 65
在嵌入式中,GPIO通常用于控制外设,如LED灯、按钮等。以下是三种不同的方法来实现点亮8个LED灯。
1. 位带操作
位带操作是一种直接访问单独位的方法,可以用于GPIO的控制。以下是使用位带操作点亮8个LED灯的示例代码:
```c
#define LED1_BIT 0x20000000 // PBIAS bit 29
#define LED2_BIT 0x10000000 // PBIAS bit 28
#define LED3_BIT 0x08000000 // PBIAS bit 27
#define LED4_BIT 0x04000000 // PBIAS bit 26
#define LED5_BIT 0x02000000 // PBIAS bit 25
#define LED6_BIT 0x01000000 // PBIAS bit 24
#define LED7_BIT 0x00800000 // PBIAS bit 23
#define LED8_BIT 0x00400000 // PBIAS bit 22
#define LED_PORT_BASE 0x01C20800 // GPIOC base address
#define LED_DDR_BASE 0x01C20C00 // GPIOC_DDR base address
#define LED_PORT_BIT_BAND_BASE 0x23300000 // GPIOC bit-band base address
#define LED_DDR_BIT_BAND_BASE 0x23300020 // GPIOC_DDR bit-band base address
// Pointers to GPIOC and GPIOC_DDR registers
volatile unsigned int* led_port = (volatile unsigned int*)LED_PORT_BASE;
volatile unsigned int* led_ddr = (volatile unsigned int*)LED_DDR_BASE;
// Pointers to bit-band regions for GPIOC and GPIOC_DDR registers
volatile unsigned int* led_port_bit_band = (volatile unsigned int*)LED_PORT_BIT_BAND_BASE;
volatile unsigned int* led_ddr_bit_band = (volatile unsigned int*)LED_DDR_BIT_BAND_BASE;
void led_init(void)
{
// Set GPIOC_DDR bits for LED1-LED8 as output
*led_ddr_bit_band |= LED1_BIT | LED2_BIT | LED3_BIT | LED4_BIT | LED5_BIT | LED6_BIT | LED7_BIT | LED8_BIT;
}
void led_on(unsigned char led)
{
// Set corresponding bit in GPIOC bit-band region to turn on LED
switch (led) {
case 1:
*led_port_bit_band |= LED1_BIT;
break;
case 2:
*led_port_bit_band |= LED2_BIT;
break;
case 3:
*led_port_bit_band |= LED3_BIT;
break;
case 4:
*led_port_bit_band |= LED4_BIT;
break;
case 5:
*led_port_bit_band |= LED5_BIT;
break;
case 6:
*led_port_bit_band |= LED6_BIT;
break;
case 7:
*led_port_bit_band |= LED7_BIT;
break;
case 8:
*led_port_bit_band |= LED8_BIT;
break;
default:
break;
}
}
void led_off(unsigned char led)
{
// Clear corresponding bit in GPIOC bit-band region to turn off LED
switch (led) {
case 1:
*led_port_bit_band &= ~LED1_BIT;
break;
case 2:
*led_port_bit_band &= ~LED2_BIT;
break;
case 3:
*led_port_bit_band &= ~LED3_BIT;
break;
case 4:
*led_port_bit_band &= ~LED4_BIT;
break;
case 5:
*led_port_bit_band &= ~LED5_BIT;
break;
case 6:
*led_port_bit_band &= ~LED6_BIT;
break;
case 7:
*led_port_bit_band &= ~LED7_BIT;
break;
case 8:
*led_port_bit_band &= ~LED8_BIT;
break;
default:
break;
}
}
```
2. 库函数
许多嵌入式开发板提供了库函数来简化GPIO的控制。以下是使用库函数点亮8个LED灯的示例代码:
```c
#include "stm32f10x.h" // STM32F10x library
void led_init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
// Enable clock for GPIOC
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
// Configure GPIOC_PIN0-PIN7 as output
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
void led_on(unsigned char led)
{
switch (led) {
case 1:
GPIO_SetBits(GPIOC, GPIO_Pin_0);
break;
case 2:
GPIO_SetBits(GPIOC, GPIO_Pin_1);
break;
case 3:
GPIO_SetBits(GPIOC, GPIO_Pin_2);
break;
case 4:
GPIO_SetBits(GPIOC, GPIO_Pin_3);
break;
case 5:
GPIO_SetBits(GPIOC, GPIO_Pin_4);
break;
case 6:
GPIO_SetBits(GPIOC, GPIO_Pin_5);
break;
case 7:
GPIO_SetBits(GPIOC, GPIO_Pin_6);
break;
case 8:
GPIO_SetBits(GPIOC, GPIO_Pin_7);
break;
default:
break;
}
}
void led_off(unsigned char led)
{
switch (led) {
case 1:
GPIO_ResetBits(GPIOC, GPIO_Pin_0);
break;
case 2:
GPIO_ResetBits(GPIOC, GPIO_Pin_1);
break;
case 3:
GPIO_ResetBits(GPIOC, GPIO_Pin_2);
break;
case 4:
GPIO_ResetBits(GPIOC, GPIO_Pin_3);
break;
case 5:
GPIO_ResetBits(GPIOC, GPIO_Pin_4);
break;
case 6:
GPIO_ResetBits(GPIOC, GPIO_Pin_5);
break;
case 7:
GPIO_ResetBits(GPIOC, GPIO_Pin_6);
break;
case 8:
GPIO_ResetBits(GPIOC, GPIO_Pin_7);
break;
default:
break;
}
}
```
3. 驱动程序
驱动程序是一种更底层的方法来控制GPIO,通常需要编写设备驱动程序。以下是使用驱动程序点亮8个LED灯的示例代码:
```c
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/gpio.h>
#define LED1_GPIO 24 // GPIO pin for LED1
#define LED2_GPIO 25 // GPIO pin for LED2
#define LED3_GPIO 26 // GPIO pin for LED3
#define LED4_GPIO 27 // GPIO pin for LED4
#define LED5_GPIO 28 // GPIO pin for LED5
#define LED6_GPIO 29 // GPIO pin for LED6
#define LED7_GPIO 30 // GPIO pin for LED7
#define LED8_GPIO 31 // GPIO pin for LED8
static int __init led_init(void)
{
int err;
// Request GPIO pins for LED1-LED8
err = gpio_request(LED1_GPIO, "LED1");
if (err)
return err;
err = gpio_request(LED2_GPIO, "LED2");
if (err)
return err;
err = gpio_request(LED3_GPIO, "LED3");
if (err)
return err;
err = gpio_request(LED4_GPIO, "LED4");
if (err)
return err;
err = gpio_request(LED5_GPIO, "LED5");
if (err)
return err;
err = gpio_request(LED6_GPIO, "LED6");
if (err)
return err;
err = gpio_request(LED7_GPIO, "LED7");
if (err)
return err;
err = gpio_request(LED8_GPIO, "LED8");
if (err)
return err;
// Set GPIO pins for LED1-LED8 as output
gpio_direction_output(LED1_GPIO, 0);
gpio_direction_output(LED2_GPIO, 0);
gpio_direction_output(LED3_GPIO, 0);
gpio_direction_output(LED4_GPIO, 0);
gpio_direction_output(LED5_GPIO, 0);
gpio_direction_output(LED6_GPIO, 0);
gpio_direction_output(LED7_GPIO, 0);
gpio_direction_output(LED8_GPIO, 0);
return 0;
}
static void __exit led_exit(void)
{
// Free GPIO pins for LED1-LED8
gpio_free(LED1_GPIO);
gpio_free(LED2_GPIO);
gpio_free(LED3_GPIO);
gpio_free(LED4_GPIO);
gpio_free(LED5_GPIO);
gpio_free(LED6_GPIO);
gpio_free(LED7_GPIO);
gpio_free(LED8_GPIO);
}
void led_on(unsigned char led)
{
switch (led) {
case 1:
gpio_set_value(LED1_GPIO, 1);
break;
case 2:
gpio_set_value(LED2_GPIO, 1);
break;
case 3:
gpio_set_value(LED3_GPIO, 1);
break;
case 4:
gpio_set_value(LED4_GPIO, 1);
break;
case 5:
gpio_set_value(LED5_GPIO, 1);
break;
case 6:
gpio_set_value(LED6_GPIO, 1);
break;
case 7:
gpio_set_value(LED7_GPIO, 1);
break;
case 8:
gpio_set_value(LED8_GPIO, 1);
break;
default:
break;
}
}
void led_off(unsigned char led)
{
switch (led) {
case 1:
gpio_set_value(LED1_GPIO, 0);
break;
case 2:
gpio_set_value(LED2_GPIO, 0);
break;
case 3:
gpio_set_value(LED3_GPIO, 0);
break;
case 4:
gpio_set_value(LED4_GPIO, 0);
break;
case 5:
gpio_set_value(LED5_GPIO, 0);
break;
case 6:
gpio_set_value(LED6_GPIO, 0);
break;
case 7:
gpio_set_value(LED7_GPIO, 0);
break;
case 8:
gpio_set_value(LED8_GPIO, 0);
break;
default:
break;
}
}
module_init(led_init);
module_exit(led_exit);
```
以上三种方法都可以用来点亮8个LED灯,选择哪种方法取决于开发人员的需求和设备的特性。