一、提高代码复用性

        顶层与底层硬件区分开

        gpio.c

#include "gpio.h"

//传递参数为初始化的GIPIO的组，引脚号，状态

void init_gpio(GPIO_Type *base, int  pin, struct GPIO_Type_t *gpio)
{
    if(gpio->direction == gpio_output)
    {
        base->GDIR |= (1 << pin);
        if(gpio->defalut_value)
        {
            base->DR |= (1 << pin);
        }
        else
        {
            base->DR &= ~(1 << pin);
        }
    }
    else
    {
        base->GDIR &= ~(1 << pin);
    }
}

void write_gpio(GPIO_Type *base, int pin, int value)
{
    if(value)
    {
        base->DR |= (1 << pin);
    }
    else
    {
        base->DR &= ~(1 << pin);
    }
}

int read_gpio(GPIO_Type *base, int pin)
{
    return (base->DR & (1 << pin)) != 0;//返回1高电平，0低电平
}

        gpio.h

#ifndef _GPIO_H_
#define _GPIO_H_

#include "MCIMX6Y2.h"

enum GPIO_Diection
{
    gpio_output,
    gpio_input
};

struct GPIO_Type_t
{
    enum GPIO_Diection direction;
    int defalut_value;
};

extern void init_gpio(GPIO_Type *base, int  pin, struct GPIO_Type_t *gpio);
extern void write_gpio(GPIO_Type *base, int pin, int value);
extern int read_gpio(GPIO_Type *base, int pin);

#endif

根据上面的函数，那么我们的代码：led.c,beep.c就可以修改

led.c

#include "MCIMX6Y2.h"
#include "fsl_iomuxc.h"
#include "led.h"
#include "gpio.h"

void enable_clocks(void)
{
    CCM->CCGR0 = 0xffffffff;
    CCM->CCGR1 = 0xffffffff;
    CCM->CCGR2 = 0xffffffff;
    CCM->CCGR3 = 0xffffffff;
    CCM->CCGR4 = 0xffffffff;
    CCM->CCGR5 = 0xffffffff;
    CCM->CCGR6 = 0xffffffff;
}

void init_led(void)
{
    IOMUXC_SetPinMux(IOMUXC_GPIO1_IO03_GPIO1_IO03, 0);
    IOMUXC_SetPinConfig(IOMUXC_GPIO1_IO03_GPIO1_IO03, 0x10b0);
    //GPIO1 -> GDIR |= (1 << 3);
    struct GPIO_Type_t t = 
    {
        .direction = gpio_output,
        .defalut_value = 1,
    };
    init_gpio(GPIO1, 3, &t);
}

void led_on(void)
{
    //GPIO1 -> DR &= ~(1 << 3);
    write_gpio(GPIO1, 3, 0);
}

void led_off(void)
{
    //GPIO1 -> DR |= (1 << 3);
    write_gpio(GPIO1, 3, 1);
}

void led_nor(void)
{
    //GPIO1 -> DR ^= (1 << 3);
    write_gpio(GPIO1, 3, !read_gpio(GPIO1, 3)) ;
}

void delay(unsigned int n)
{
    while(n--);
}

beep.c

#include "beep.h"
#include "fsl_iomuxc.h"
#include "MCIMX6Y2.h"
#include "gpio.h"

void init_beep(void)//1500
{
    IOMUXC_SetPinMux(IOMUXC_SNVS_SNVS_TAMPER1_GPIO5_IO01, 0);
    IOMUXC_SetPinConfig(IOMUXC_SNVS_SNVS_TAMPER1_GPIO5_IO01, 0x10b0);
    //GPIO5 -> GDIR |= (1 << 1);
    struct GPIO_Type_t t = 
    {
        .direction = gpio_output,
        .defalut_value = 1,
    };
    init_gpio(GPIO5, 1, &t);
}

void beep_on(void)
{
    //GPIO5 -> DR &= ~(1 << 1);
    write_gpio(GPIO5, 1, 0);
}

void beep_off(void)
{
    //GPIO5 -> DR |= (1 << 1);
    write_gpio(GPIO5, 1, 1);
}

void beep_nor(void)
{
    //GPIO5 -> DR ^= (1 << 1);
    write_gpio(GPIO5, 1, !read_gpio(GPIO5, 1)) ;
}

二、按键原理

        1.底板原理图

        

                key0按下低电平，不按高电平

        2.功能复用

        3.电气属性

                加一个22k的上拉电阻，值为0xF0B0

        4.输入输出方向

        5.数据寄存器

三、步骤

                1）初始化时钟

                2）设置引脚功能复用（GPIO）

                3）引脚电气属性（功率、电阻）

                4）设置外设引脚的输入输出方向

                5）设置数据寄存器拉低/拉高电平
 

四、代码

        结构与之前一样

        1.bsp

                1)key.c

                

#include "key.h"
#include "fsl_iomuxc.h"
#include "gpio.h"
#include "core_ca7.h"

void init_key(void)
{
    IOMUXC_SetPinMux(IOMUXC_UART1_CTS_B_GPIO1_IO18, 0);
    IOMUXC_SetPinConfig(IOMUXC_UART1_CTS_B_GPIO1_IO18, 0xF080);
    struct GPIO_Type_t t =
    {
        .direction = gpio_input
    };
    init_gpio(GPIO1, 18, &t);
}


int key_pressed(void)
{
    if(read_gpio(GPIO1, 18) == 0)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}

                2)key.h

#ifndef _KEY_H_
#define _KEY_H_

#include "fsl_iomuxc.h"
#include "gpio.h"

extern void init_key(void);
extern int key_pressed(void);

#endif

                3)led.c---beep.c

        2.project

                1)main.c

                

#include "led.h"
#include "beep.h"
#include "MCIMX6Y2.h"
#include "key.h"
#include "core_ca7.h"


void enable_clocks(void)
{
    CCM->CCGR0 = 0xFFFFFFFF;
    CCM->CCGR1 = 0xFFFFFFFF;
    CCM->CCGR2 = 0xFFFFFFFF;
    CCM->CCGR3 = 0xFFFFFFFF;        
    CCM->CCGR4 = 0xFFFFFFFF;
    CCM->CCGR5 = 0xFFFFFFFF;
    CCM->CCGR6 = 0xFFFFFFFF;  
}

void delay(unsigned int n)
{
    while(n--);
}

int main(void)
{
    enable_clocks();
    init_led();
    init_beep();
    init_key();
    while(1)
    {
        if(key_pressed())
        {
            led_on();
            beep_on();
        }
    }
    return 0;
}

                2)start.S

.global _start


_start:
	ldr pc, =_reset_handler
	ldr pc, =_undefine_handler
	ldr pc, =_svc_handler
	ldr pc, =_prefetch_abort_handler
	ldr pc, =_data_abort_handler
	ldr pc, =_reserved_handler
	ldr pc, =_irq_handler
	ldr pc, =_fiq_handler

_undefine_handler:
	ldr pc, =_undefine_handler

_svc_handler:
	ldr pc, =_svc_handler

_prefetch_abort_handler:
	ldr pc, =_prefetch_abort_handler

_data_abort_handler:
	ldr pc, =_data_abort_handler

_reserved_handler:
	ldr pc, =_reserved_handler

_irq_handler:
	ldr pc, =_irq_handler

_fiq_handler:
	ldr pc, =_fiq_handler


_reset_handler:
    mrs r0, cpsr
    bic r0, r0, #0x1F
    orr r0, r0, #0x12   //irq
    msr cpsr, r0

    ldr sp, =0x80600000

    mrs r0, cpsr
    bic r0, r0, #0x1F
    orr r0, r0, #0x1F   //system
    msr cpsr, r0   

    ldr sp, =0x80400000
    bl _bss_clear
    b main

_bss_clear:
    ldr r0, =__bss_start
    ldr r2, =__bss_end
loop:
    mov r1, #0
    str r1, [r0]
    add r0, r0, #4
    cmp r0, r2
    blt loop
    bx lr

finished:
    b finished