基于IMX6UL裸机程序开发-01_LED

本次练习实践开发板为飞凌IMX6UL开发板，教程资料参考韦东山老师的嵌入式教程。

看原理图确定引脚及操作方法

从上面的原理图和资源列表中，可以确认LED2对应GPIO引脚为GPIO5_09,。

点亮LED涉及的寄存器操作

步骤1： 使能GPIO1和GPIO5
具体参考IMX6UL手册IMX6ULRM.pdf第18章CCM system clock部分表格

对应寄存器为CCM_CCGR1中的CG13和CG15。每2个bit的CGR值设置为11，表示Clock使能。

/* 1. set CCM enable GPIO_09 and GPIO5_09
 * CCM_CCGR1[CG15] [CG13]  Address: 20C_4000h base + 6Ch offset = 20C_406Ch
 * bit[31:30] = 0b11
 * bit[27:26] = 0b11
 */

步骤2： 设置GPIO1_09和GPIO5_09为GPIO
从IMX6UL手册的第31章 IOMUXC Memory Map/Register Definition部分可以找到这两个引脚复用的配置寄存器信息。

/*	2. set GPIO1_09 and GPIO5_09 as GPIO
 *	set IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9 to configure GPIO5_09 as GPIO 
 *	set IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09 to configure GPIO1_09 as GPIO 
 *	IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9 Address: 20E_0000h base + 40h offset = 20E_0040h
 *	IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09 Address: 20E_0000h base + 80h offset = 20E_0080h
 *	bit[3:0] = 0b101 alt5
 *	bit[3:0] = 0b101 alt5
 */

步骤3：设置GPIO5_09和GPIO1_09为输出引脚，设置输出电平
GPIO5和GPIO1寄存器地址如下所示：


设置方向寄存器，第n位为GPIO组第n个GPIO的输入输出配置：

设置数据寄存器，当GPIO设置为输出时，第n位为GPIO组第n个GPIO的输出电平。注意在输出GPIO时，GPIOx_DR对应位存储的是要设置的电平值，并不是实际的电平值。

/*  3. set GPIO5_09 and GPIO1_09 as output pin
 * 	  set GPIO5_GDIR and GPIO1_GDIR to configure GPIO5_09 GPIO1_09 as output  
 *	  GPIO5_GDIR  0x20A_C000h + 0x4h = 0x20A_C004h
 *	  GPIO1_GDIR  0x209_C000h + 0x4h = 0x209_C004h
 *	  bit[9] = 0b1
 */

/*	4. set GPIO5_09 and GPIO1_09 output low level
 *	   set GPIO5_DR and GPIO1_DR to configure GPIO5_09 GPIO1_09 output 0
 *	   GPIO5_DR	0x20A_C000h + 0x0h = 0x20A_C000h
 *	   GPIO1_DR	0x209_C000h + 0x0h = 0x209_C000h
 *	   bit[9] = 0b0
 */

/*	5. set GPIO5_09 and GPIO1_09 output high level
 *	   set GPIO5_DR and GPIO1_DR to configure GPIO5_09 GPIO1_09 output 1
 *	   GPIO5_DR	0x20A_C000h + 0x0h = 0x20A_C000h
 *	   GPIO1_DR	0x209_C000h + 0x0h = 0x209_C000h
 *	   bit[9] = 0b1
 */

主要功能代码

#include "led.h"

void led_init(void)
{
    unsigned int val;
    CCM_CCGR1                           = (unsigned int*)(0x20C406C); 
    IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9  = (unsigned int*)(0x20E0040);
    IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09    = (unsigned int*)(0x20E0080);
    GPIO5_GDIR                          = (unsigned int*)(0x20AC004);
    GPIO1_GDIR                          = (unsigned int*)(0x209C004);
    GPIO5_DR                            = (unsigned int*)(0x20AC000);
    GPIO1_DR                            = (unsigned int*)(0x209C000);
    
    /* 1. set CCM enable GPIO_09 and GPIO5_09
     *    CCM_CCGR1[CG15] [CG13]  Address: 20C_4000h base + 6Ch offset = 20C_406Ch
     *    bit[31:30] = 0b11
     *    bit[27:26] = 0b11
     */
    val = *CCM_CCGR1;
    val |= (3<<30);
    val |= (3<<26);
    *CCM_CCGR1 = val;

    /* 2. set GPIO1_09 and GPIO5_09 as GPIO
     *	  set IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9 to configure GPIO5_09 as GPIO 
     *	  set IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09 to configure GPIO1_09 as GPIO 
     *	  IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9 Address: 20E_0000h base + 40h offset = 20E_0040h
     *	  IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09 Address: 20E_0000h base + 80h offset = 20E_0080h
     *	  bit[3:0] = 0b101 alt5
     *	  bit[3:0] = 0b101 alt5
     */
    val = *IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9;
    val &= ~(0xf);
    val |= 5;
    *IOMUXC_SW_MUX_CTL_PAD_SNVS_TAMPER9 = val;
    val = *IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09;
    val &= ~(0xf);
    val |= 5;
    *IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO09 = val;

    /* 3. set GPIO5_09 and GPIO1_09 as output pin
     * 	  set GPIO5_GDIR and GPIO1_GDIR to configure GPIO5_09 GPIO1_09 as output  
     *	  GPIO5_GDIR  0x20A_C000h + 0x4h = 0x20A_C004h
     *	  GPIO1_GDIR  0x209_C000h + 0x4h = 0x209_C004h
     *	  bit[9] = 0b1
     */
    val = *GPIO5_GDIR;
    val |= (1<<9);
    *GPIO5_GDIR = val;
    val = *GPIO1_GDIR;
    val |= (1<<9);
    *GPIO1_GDIR = val;
}

void led_ctl(int status)
{
    unsigned int val;
    if (status) {
       /*　4. set GPIO5_09 and GPIO1_09 output low level
        *	  set GPIO5_DR and GPIO1_DR to configure GPIO5_09 GPIO1_09 output 0
        *	  GPIO5_DR	0x20A_C000h + 0x0h = 0x20A_C000h
        *	  GPIO1_DR	0x209_C000h + 0x0h = 0x209_C000h
        *	  bit[9] = 0b0
        */
        #if 1
        val = *GPIO5_DR;
        val &= ~(1<<9);
        *GPIO5_DR = val;
        #endif
        val = *GPIO1_DR;
        val &= ~(1<<9);
        *GPIO1_DR = val;
    }else {
        /*	5. set GPIO5_09 and GPIO1_09 output high level
         *	   set GPIO5_DR and GPIO1_DR to configure GPIO5_09 GPIO1_09 output 1
         *	   GPIO5_DR	0x20A_C000h + 0x0h = 0x20A_C000h
         *	   GPIO1_DR	0x209_C000h + 0x0h = 0x209_C000h
         *	   bit[9] = 0b1
         */ 
        #if 1 
        val = *GPIO5_DR;
        val |= (1<<9);
        *GPIO5_DR = val;
        #endif
        
        val = *GPIO1_DR;
        val |= (1<<9);
        *GPIO1_DR = val;
    }   
}

以上功能程序和主程序实现两个LED灯的闪烁效果。

完整程序代码参考

01_led程序