LED点灯

使能GPIO

CCM: Clock Controller Module (时钟控制模块)，使能GPIO所在的时钟
IOMUXC : IOMUX Controller，IO复用控制器，工作模式pin_mode
GPIO: General-purpose input/output，通用的输入输出口，工作方向dir，输入还是输出(<font style="color:rgb(0,0,0);">GPIO direction register (GPIO1_GDIR</font>)
data:IO，高低电平(<font style="color:rgb(0,0,0);">GPIO data register (GPIO1_DR</font>)

1.时钟

2.工作模式

pin_mode:是GPIO功能还是IIC或者SPI模式

ioMuxController

3.工作方向

4.工作方式

image.png

参考韦东山的代码：

static volatile unsigned int *CCM_CCGR1                              ;
static volatile unsigned int *IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3;
static volatile unsigned int *GPIO5_GDIR                             ;
static volatile unsigned int *GPIO5_DR   

CCM_CCGR1                               = (volatile unsigned int *)(0x20C406C);
IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3 = (volatile unsigned int *)(0x2290014);
GPIO5_GDIR                              = (volatile unsigned int *)(0x020AC000 + 0x4);
GPIO5_DR                                = (volatile unsigned int *)(0x020AC000);

# 使能GPIO5：默认使能了,不用操作也行
# a. 使能GPIO5
     * set CCM to enable GPIO5
     * CCM_CCGR1[CG15] 0x20C406C
     * bit[31:30] = 0b11
#
*CCM_CCGR1 |= (3<<30);

# 设置为GPIO功能
# b. 设置GPIO5_IO03用于GPIO
     * set IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3
     *      to configure GPIO5_IO03 as GPIO
     * IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3  0x2290014
     * bit[3:0] = 0b0101 alt5
#
val = *IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3;
    val &= ~(0xf);
    val |= (5);
*IOMUXC_SNVS_SW_MUX_CTL_PAD_SNVS_TAMPER3 = val;

# 设置为输出
# c. 设置GPIO5_IO03作为output引脚
     * set GPIO5_GDIR to configure GPIO5_IO03 as output
     * GPIO5_GDIR  0x020AC000 + 0x4
     * bit[3] = 0b1
#   
*GPIO5_GDIR |= (1<<3);
  
#让GPIO5输出为1/0
*GPIO5_DR |= (1<<3);  //高电平
*GPIO5_DR &= ~(1<<3); //低电平

.text
.global _start
_start:
  ;0xc0000000+0x100000:栈指针 (SP) 是指向栈的当前顶端的位置。
  当函数调用时，栈指针会向下（通常是减少地址）移动，并在函数返回时向上移动。
  ldr sp,=0xc0000000+0x100000
  bl main

韦东山的汇编代码:

.text
.global  _start
_start:     

    /* 使能GPIO模块 */

    /* 把GPIO5_3设置为GPIO功能 */
    LDR R0, =(0x02290000 + 0x14)
    LDR R1, [R0]
    ORR R1, R1, #0x5
    STR R1, [R0]
    
    /* 设置引脚为输出 */

    /* 把GPIO5_3设置为输出引脚 */
    LDR R0, =0x020AC004
    LDR R1, [R0]
    ORR R1, R1, #(1<<3)
    STR R1, [R0]

    /* DATA out register */
    LDR R2, =(0x020AC000)
    
Loop:
        
    /* 设置GPIO5_3输出1 */
    LDR R1, [R2]
    ORR R1, R1, #(1<<3)
    STR R1, [R2]

    LDR R0, =1000000
    BL Delay
     
    /* 设置引脚输出低电平 */
    LDR R1, [R2]
    BIC R1, R1, #(1<<3)
    STR R1, [R2]
    
    LDR R0, =1000000
    BL Delay

    b Loop

Delay:
    SUBS R0, R0, #1
    BNE Delay
    MOV PC, LR

自己写代码

image.png

手撕汇编

.text
.global  _start
_start:     

    /* 使能GPIO模块 */

    /* 把GPIO1_3设置为GPIO功能 */
    LDR R0, =0x020E0068
    LDR R1, [R0]
    ORR R1, R1, #0x5
    STR R1, [R0]  
    
    /* 设置引脚为输出 */

    /* 把GPIO1_3设置为输出引脚 */
    LDR R0, =0X0209C004
    LDR R1, [R0]
    ORR R1, R1, #(0b1<<3)
    STR R1, [R0]



    /* DATA out register */
    LDR R2, =(0X0209C000)
    
Loop:
        
    /* 设置GPIO1_3输出1 */
    LDR R1, [R2]
    ORR R1, R1, #(0b1<<3)
    STR R1, [R2]

    LDR R0, =1000000
    BL Delay
     
    /* 设置引脚输出低电平 */
    LDR R1, [R2]
    BIC R1, R1, #(0b1<<3)
    STR R1, [R2]
    
    LDR R0, =1000000
    BL Delay

    b Loop

Delay:
    SUBS R0, R0, #1
    BNE Delay
    MOV PC, LR

得到二进制的文件

led.bin:led.S
    arm-linux-gnueabihf-gcc led.S -c -o led.o
    arm-linux-gnueabihf-ld led.o -Ttext 0X80100000 -o led.elf
    arm-linux-gnueabihf-objcopy led.elf -O binary -S -g led.bin
    arm-linux-gnueabihf-objdump -D led.elf > led.dis

clean:
    rm -rf *.o led.bin led.elf led.dis

C开发

.text
.global _start
_start:
  ;0x80000000+0x100000:栈指针 (SP) 是指向栈的当前顶端的位置。
  当函数调用时，栈指针会向下（通常是减少地址）移动，并在函数返回时向上移动。
  ldr sp,=0x80000000+0x100000
  bl main


void delay(volatile int d)
{
    while(d--);
}

int main(void)
{
     volatile unsigned int *pReg;
     
    /* 使能GPIO5: 默认使能 */

    /* 把GPIO5_3设置为GPIO功能 */
    pReg = (volatile unsigned int *)(0x02290000 + 0x14);
    *pReg |= (0x5);

    /* 把GPIO5_3设置为输出引脚 */
    pReg = (volatile unsigned int *)(0x020AC004);
    *pReg |= (1<<3);

    pReg = (volatile unsigned int *)(0x020AC000);

    while (1)
    {
        /* 设置GPIO5_3输出1 */
        *pReg |= (1<<3);
        delay(1000000);

        /* 设置GPIO5_3输出0 */
        *pReg &= ~(1<<3);
        delay(1000000);     
    }

    return 0;
}

led.bin:led.S main.c
    arm-linux-gnueabihf-gcc led.S -c -o led.o
    arm-linux-gnueabihf-gcc main.c -c -o main.o
    arm-linux-gnueabihf-ld -T imx6ull.lds led.o main.o  -o led.elf
    arm-linux-gnueabihf-objcopy led.elf -O binary -S -g led.bin
    arm-linux-gnueabihf-objdump -D -m arm led.elf > led.dis
    mkimage -n ../asm/imximage.cfg.cfgtmp -T imximage -e 0x80100000 -d led.bin led.imx
    dd if=/dev/zero of=1k.bin bs=1024 count=1
    cat 1k.bin led.imx > led.img

clean:
    rm -rf *.o led.bin led.elf led.dis led.imx led.img *.o

LED点灯

使能GPIO

1.时钟

2.工作模式

3.工作方向

4.工作方式

自己写代码

手撕汇编

C开发

推荐阅读更多精彩内容