STM32-笔记38-I2C-oled实验

一、什么是I2C？

        I2C总线，全称Inter-Integrated Circuit（互连集成电路），是一种由Philips（现NXP半导体）公司在1980年代初开发的同步 串行 半双工通信总线。

二、有了串口通信为什么要使用I2C？

串口通信对比I2C有一些缺点

        1. 串口通信通常需要至少三条线（TX、RX和GND），而 I2C 总线仅需要两条信号线（SDA和SCL）；
        2. 串口通信仅支持一对一通信，而 I2C 总线支持多机通信，允许单个主机与多个从机设备进行通信；
        3. 串口通信通常无应答机制，而 I2C 必须有应答机制；
        4. 串口通讯一般是异步通信，而 I2C 使用同步传输方式，数据在时钟信号（SCL）的控制下传输。

三、I2C的工作原理以及特点

四、IIC总线时序

4.1 起始信号

代码书写方式如下：

//开始信号
void oled_i2c_start(void)
{
    OLED_SCL_SET();
    OLED_SDA_SET();
    OLED_SDA_RESET();
    OLED_SCL_RESET();
}

4.2 停止信号

//停止信号
void oled_i2c_stop(void)
{
    OLED_SCL_SET();
    OLED_SDA_RESET();
    OLED_SDA_SET();
}

4.3 应答信号

//应答信号
void oled_i2c_ack(void)
{
    OLED_SCL_SET();
    OLED_SCL_RESET();
}

4.4 读写时序

一般都是发送，很少接收，这里只展现发送数据

//写一个字节信号
void oled_i2c_write_byte(uint8_t data)
{
    uint8_t i,tmp;
    tmp = data;
    for(i=0;i<8;i++)
    {
        if((tmp & 0x80) == 0x80)//取出最高位，判断最高位是不是1
            OLED_SDA_SET();//如果最高位是1，则sda给一个高电平
        else
            OLED_SDA_RESET();//如果最高位是0，则sda给一个低电平
        tmp = tmp << 1;
        OLED_SCL_SET();
        OLED_SCL_RESET();
    }
}

//写一个字节信号
void oled_i2c_write_byte(uint8_t data)
{
    uint8_t i,tmp;
    tmp = data;
    for(i=0;i<8;i++)
    {
        if((tmp & 0x80) == 0x80)//取出最高位，判断最高位是不是1
            OLED_SDA_SET();//如果最高位是1，则sda给一个高电平
        else
            OLED_SDA_RESET();//如果最高位是0，则sda给一个低电平
        tmp = tmp << 1;
        OLED_SCL_SET();
        OLED_SCL_RESET();
    }
}

4.5 一次完整的I2C时序

五、OLED实验目的

驱动 OLED 屏幕，显示点、线、字符、字符串、汉字、图片等内容。

六、项目实现-OLED通讯协议

复制项目文件19-串口打印功能

重命名为47-OLED实验

打开项目文件

加载文件

代码书写顺序：

oled.c

#include "oled.h"//初始化oled的gpio
void oled_gpio_init(void)
{GPIO_InitTypeDef gpio_initstruct;OLED_I2C_SCL_CLK();OLED_I2C_SDA_CLK();gpio_initstruct.Mode = GPIO_MODE_OUTPUT_PP;gpio_initstruct.Pin = OLED_I2C_SCL_PIN;gpio_initstruct.Pull = GPIO_PULLUP;gpio_initstruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(OLED_I2C_SCL_PORT,&gpio_initstruct);gpio_initstruct.Pin = OLED_I2C_SDA_PIN;HAL_GPIO_Init(OLED_I2C_SDA_PORT,&gpio_initstruct);
}/*IIC协议的分装*/
//开始信号
void oled_i2c_start(void)
{OLED_SCL_SET();OLED_SDA_SET();OLED_SDA_RESET();OLED_SCL_RESET();
}
//停止信号
void oled_i2c_stop(void)
{OLED_SCL_SET();OLED_SDA_RESET();OLED_SDA_SET();
}
//应答信号
void oled_i2c_ack(void)
{OLED_SCL_SET();OLED_SCL_RESET();
}
//写一个字节信号
void oled_i2c_write_byte(uint8_t data)
{uint8_t i,tmp;tmp = data;for(i=0;i<8;i++){if((tmp & 0x80) == 0x80)//取出最高位，判断最高位是不是1OLED_SDA_SET();//如果最高位是1，则sda给一个高电平elseOLED_SDA_RESET();//如果最高位是0，则sda给一个低电平tmp = tmp << 1;OLED_SCL_SET();OLED_SCL_RESET();}
}
//发送一个命令信号
void oled_write_cmd(uint8_t cmd)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x00);oled_i2c_ack();oled_i2c_write_byte(cmd);oled_i2c_ack();oled_i2c_stop();
}
//发送一个数据信号
void oled_write_data(uint8_t data)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x40);oled_i2c_ack();oled_i2c_write_byte(data);oled_i2c_ack();oled_i2c_stop();
}//初始化OLED函数
void oled_init(void)
{oled_gpio_init();
}

oled.h

#ifndef __OLED_H__
#define __OLED_H__#include "sys.h"
/*SCL引脚*/
#define OLED_I2C_SCL_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SCL_PORT    GPIOB
#define OLED_I2C_SCL_PIN     GPIO_PIN_6
/*SDA引脚*/
#define OLED_I2C_SDA_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SDA_PORT    GPIOB
#define OLED_I2C_SDA_PIN     GPIO_PIN_7
/*SCL引脚拉高拉低*/
#define OLED_SCL_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_SET)
#define OLED_SCL_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_RESET)
/*SDA引脚拉高拉低*/
#define OLED_SDA_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_SET)
#define OLED_SDA_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_RESET)#endif

七、项目实现-OLED实现点、线、字符

mian.c

#include "sys.h"
#include "delay.h"
#include "led.h"
#include "uart1.h"
#include "oled.h"extern const unsigned char shuai_data[];int main(void)
{HAL_Init();                         /* 初始化HAL库 */stm32_clock_init(RCC_PLL_MUL9); /* 设置时钟, 72Mhz */led_init();//初始化led灯uart1_init(115200);oled_init();printf("hello world!\r\n");oled_fill(0);//清屏函数//字母A-page0oled_set_cursor(0, 0);oled_write_data(0x00); oled_write_data(0x00);oled_write_data(0xC0);oled_write_data(0x38);oled_write_data(0xE0);oled_write_data(0x00);oled_write_data(0x00);oled_write_data(0x00);//page1oled_set_cursor(0, 1);oled_write_data(0x20);oled_write_data(0x3C);oled_write_data(0x23);oled_write_data(0x02);oled_write_data(0x02);oled_write_data(0x27);oled_write_data(0x38);oled_write_data(0x20);while(1){ }
}

oled.c

#include "oled.h"
#include "delay.h"//初始化oled的gpio
void oled_gpio_init(void)
{GPIO_InitTypeDef gpio_initstruct;OLED_I2C_SCL_CLK();OLED_I2C_SDA_CLK();gpio_initstruct.Mode = GPIO_MODE_OUTPUT_PP;gpio_initstruct.Pin = OLED_I2C_SCL_PIN;gpio_initstruct.Pull = GPIO_PULLUP;gpio_initstruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(OLED_I2C_SCL_PORT,&gpio_initstruct);gpio_initstruct.Pin = OLED_I2C_SDA_PIN;HAL_GPIO_Init(OLED_I2C_SDA_PORT,&gpio_initstruct);
}/*IIC协议的分装*/
//开始信号
void oled_i2c_start(void)
{OLED_SCL_SET();OLED_SDA_SET();OLED_SDA_RESET();OLED_SCL_RESET();
}
//结束信号
void oled_i2c_stop(void)
{OLED_SCL_SET();OLED_SDA_RESET();OLED_SDA_SET();}
//应答信号
void oled_i2c_ack(void)
{OLED_SCL_SET();OLED_SCL_RESET();
}
//写一个字节信号
void oled_i2c_write_byte(uint8_t data)
{uint8_t i,tmp;tmp = data;for(i=0;i<8;i++){if((tmp & 0x80) == 0x80)//取出最高位，判断最高位是不是1OLED_SDA_SET();//如果最高位是1，则sda给一个高电平elseOLED_SDA_RESET();//如果最高位是0，则sda给一个低电平tmp = tmp << 1;OLED_SCL_SET();OLED_SCL_RESET();}
}
//发送一个命令信号
void oled_write_cmd(uint8_t cmd)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x00);oled_i2c_ack();oled_i2c_write_byte(cmd);oled_i2c_ack();oled_i2c_stop();
}
//发送一个数据信号
void oled_write_data(uint8_t data)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x40);oled_i2c_ack();oled_i2c_write_byte(data);oled_i2c_ack();oled_i2c_stop();
}//初始化OLED函数
void oled_init(void)
{oled_gpio_init();delay_ms(100);oled_write_cmd(0xAE);    //设置显示开启/关闭，0xAE关闭，0xAF开启oled_write_cmd(0xD5);    //设置显示时钟分频比/振荡器频率oled_write_cmd(0x80);    //0x00~0xFFoled_write_cmd(0xA8);    //设置多路复用率oled_write_cmd(0x3F);    //0x0E~0x3Foled_write_cmd(0xD3);    //设置显示偏移oled_write_cmd(0x00);    //0x00~0x7Foled_write_cmd(0x40);    //设置显示开始行，0x40~0x7Foled_write_cmd(0xA1);    //设置左右方向，0xA1正常，0xA0左右反置oled_write_cmd(0xC8);    //设置上下方向，0xC8正常，0xC0上下反置oled_write_cmd(0xDA);    //设置COM引脚硬件配置oled_write_cmd(0x12);oled_write_cmd(0x81);    //设置对比度oled_write_cmd(0xCF);    //0x00~0xFFoled_write_cmd(0xD9);    //设置预充电周期oled_write_cmd(0xF1);oled_write_cmd(0xDB);    //设置VCOMH取消选择级别oled_write_cmd(0x30);oled_write_cmd(0xA4);    //设置整个显示打开/关闭oled_write_cmd(0xA6);    //设置正常/反色显示，0xA6正常，0xA7反色oled_write_cmd(0x8D);    //设置充电泵oled_write_cmd(0x14);oled_write_cmd(0xAF);    //开启显示
}
//分装的坐标函数
void oled_set_cursor(uint8_t x, uint8_t y)//x是列，y是page
{oled_write_cmd(0xB0 + y);oled_write_cmd((x & 0x0F) | 0x00); oled_write_cmd(((x & 0xF0) >> 4) | 0x10);
}
//清屏函数
void oled_fill(uint8_t data)
{uint8_t i, j;//外层循环循环pagefor(i = 0; i < 8; i++){oled_set_cursor(0, i);for(j = 0; j < 128; j++)oled_write_data(data);}
}

oled.h

#ifndef __OLED_H__
#define __OLED_H__#include "sys.h"
/*SCL引脚*/
#define OLED_I2C_SCL_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SCL_PORT    GPIOB
#define OLED_I2C_SCL_PIN     GPIO_PIN_6
/*SDA引脚*/
#define OLED_I2C_SDA_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SDA_PORT    GPIOB
#define OLED_I2C_SDA_PIN     GPIO_PIN_7
/*SCL引脚拉高拉低*/
#define OLED_SCL_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_SET)
#define OLED_SCL_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_RESET)
/*SDA引脚拉高拉低*/
#define OLED_SDA_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_SET)
#define OLED_SDA_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_RESET)void oled_init(void);
void oled_write_cmd(uint8_t cmd);
void oled_write_data(uint8_t data);
void oled_set_cursor(uint8_t x, uint8_t y);
void oled_fill(uint8_t data);
#endif

项目实现-显示任意字符汉字图片

mian.c

#include "sys.h"
#include "delay.h"
#include "led.h"
#include "uart1.h"
#include "oled.h"extern const unsigned char shuai_data[];int main(void)
{HAL_Init();                         /* 初始化HAL库 */stm32_clock_init(RCC_PLL_MUL9); /* 设置时钟, 72Mhz */led_init();//初始化led灯uart1_init(115200);oled_init();printf("hello world!\r\n");oled_fill(0);//清屏函数
//    //字母A page0
//    oled_set_cursor(0, 0);
//    oled_write_data(0x00); 
//    oled_write_data(0x00);
//    oled_write_data(0xC0);
//    oled_write_data(0x38);
//    oled_write_data(0xE0);
//    oled_write_data(0x00);
//    oled_write_data(0x00);
//    oled_write_data(0x00);
//    //page1
//    oled_set_cursor(0, 1);
//    oled_write_data(0x20);
//    oled_write_data(0x3C);
//    oled_write_data(0x23);
//    oled_write_data(0x02);
//    oled_write_data(0x02);
//    oled_write_data(0x27);
//    oled_write_data(0x38);
//    oled_write_data(0x20);oled_show_char(0, 0, 'L', 16);oled_show_char(8, 0, 'X', 16);oled_show_char(16, 0, '?', 16);oled_show_char(24, 0, '6', 16);//    oled_show_string(0, 2, "hello LX", 24);//    uint8_t i;
//    for(i = 0; i < 5; i++)
//        oled_show_chinese(i*24, 0, i, 24);//    oled_show_image(0, 0, 128, 8, (unsigned char *)shuai_data);while(1){ }
}

oled.c

#include "oled.h"
#include "delay.h"
#include "font.h"//初始化oled的gpio
void oled_gpio_init(void)
{GPIO_InitTypeDef gpio_initstruct;OLED_I2C_SCL_CLK();OLED_I2C_SDA_CLK();gpio_initstruct.Mode = GPIO_MODE_OUTPUT_PP;gpio_initstruct.Pin = OLED_I2C_SCL_PIN;gpio_initstruct.Pull = GPIO_PULLUP;gpio_initstruct.Speed = GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(OLED_I2C_SCL_PORT,&gpio_initstruct);gpio_initstruct.Pin = OLED_I2C_SDA_PIN;HAL_GPIO_Init(OLED_I2C_SDA_PORT,&gpio_initstruct);
}/*IIC协议的分装*/
//开始信号
void oled_i2c_start(void)
{OLED_SCL_SET();OLED_SDA_SET();OLED_SDA_RESET();OLED_SCL_RESET();
}
//结束信号
void oled_i2c_stop(void)
{OLED_SCL_SET();OLED_SDA_RESET();OLED_SDA_SET();}
//应答信号
void oled_i2c_ack(void)
{OLED_SCL_SET();OLED_SCL_RESET();
}
//写一个字节信号
void oled_i2c_write_byte(uint8_t data)
{uint8_t i,tmp;tmp = data;for(i=0;i<8;i++){if((tmp & 0x80) == 0x80)//取出最高位，判断最高位是不是1OLED_SDA_SET();//如果最高位是1，则sda给一个高电平elseOLED_SDA_RESET();//如果最高位是0，则sda给一个低电平tmp = tmp << 1;OLED_SCL_SET();OLED_SCL_RESET();}
}
//发送一个命令信号
void oled_write_cmd(uint8_t cmd)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x00);oled_i2c_ack();oled_i2c_write_byte(cmd);oled_i2c_ack();oled_i2c_stop();
}
//发送一个数据信号
void oled_write_data(uint8_t data)
{oled_i2c_start();oled_i2c_write_byte(0x78);oled_i2c_ack();oled_i2c_write_byte(0x40);oled_i2c_ack();oled_i2c_write_byte(data);oled_i2c_ack();oled_i2c_stop();
}//初始化OLED函数
void oled_init(void)
{oled_gpio_init();delay_ms(100);oled_write_cmd(0xAE);    //设置显示开启/关闭，0xAE关闭，0xAF开启oled_write_cmd(0xD5);    //设置显示时钟分频比/振荡器频率oled_write_cmd(0x80);    //0x00~0xFFoled_write_cmd(0xA8);    //设置多路复用率oled_write_cmd(0x3F);    //0x0E~0x3Foled_write_cmd(0xD3);    //设置显示偏移oled_write_cmd(0x00);    //0x00~0x7Foled_write_cmd(0x40);    //设置显示开始行，0x40~0x7Foled_write_cmd(0xA1);    //设置左右方向，0xA1正常，0xA0左右反置oled_write_cmd(0xC8);    //设置上下方向，0xC8正常，0xC0上下反置oled_write_cmd(0xDA);    //设置COM引脚硬件配置oled_write_cmd(0x12);oled_write_cmd(0x81);    //设置对比度oled_write_cmd(0xCF);    //0x00~0xFFoled_write_cmd(0xD9);    //设置预充电周期oled_write_cmd(0xF1);oled_write_cmd(0xDB);    //设置VCOMH取消选择级别oled_write_cmd(0x30);oled_write_cmd(0xA4);    //设置整个显示打开/关闭oled_write_cmd(0xA6);    //设置正常/反色显示，0xA6正常，0xA7反色oled_write_cmd(0x8D);    //设置充电泵oled_write_cmd(0x14);oled_write_cmd(0xAF);    //开启显示
}
//分装的坐标函数
void oled_set_cursor(uint8_t x, uint8_t y)//x是列，y是page
{oled_write_cmd(0xB0 + y);oled_write_cmd((x & 0x0F) | 0x00); oled_write_cmd(((x & 0xF0) >> 4) | 0x10);
}
//清屏函数
void oled_fill(uint8_t data)
{uint8_t i, j;//外层循环循环pagefor(i = 0; i < 8; i++){oled_set_cursor(0, i);for(j = 0; j < 128; j++)oled_write_data(data);}
}
//指定显示字符 - 列坐标-page -哪个字符-字符大小
void oled_show_char(uint8_t x, uint8_t y, uint8_t num, uint8_t size)
{uint8_t i, j, page;num = num - ' ';page = size / 8;if(size % 8)//判断字符大小page++;for(j = 0; j < page; j++)//page循环{oled_set_cursor(x, y + j);for(i = size / 2 * j; i < size /2 * (j + 1); i++){if(size == 12)oled_write_data(ascii_6X12[num][i]);else if(size == 16)oled_write_data(ascii_8X16[num][i]);else if(size == 24)oled_write_data(ascii_12X24[num][i]);}}
}
//显示字符串
void oled_show_string(uint8_t x, uint8_t y, char *p, uint8_t size)
{while(*p != '\0'){oled_show_char(x, y, *p, size);x += size/2;//偏移字符p++;}
}
//显示汉字
void oled_show_chinese(uint8_t x, uint8_t y, uint8_t N, uint8_t size)
{uint16_t i, j;for(j = 0; j < size/8; j++){oled_set_cursor(x, y + j);for(i = size *j; i < size * (j + 1); i++){if(size == 16)oled_write_data(chinese_16x16[N][i]);else if(size == 24)oled_write_data(chinese_24x24[N][i]);}}
}
//显示图片
void oled_show_image(uint8_t x, uint8_t y, uint8_t width, uint8_t height, uint8_t *bmp)
{uint8_t i, j;for(j = 0; j < height; j++){oled_set_cursor(x, y + j);for(i = 0; i < width; i++)oled_write_data(bmp[width * j + i]);}
}

oled.h

#ifndef __OLED_H__
#define __OLED_H__#include "sys.h"
/*SCL引脚*/
#define OLED_I2C_SCL_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SCL_PORT    GPIOB
#define OLED_I2C_SCL_PIN     GPIO_PIN_6
/*SDA引脚*/
#define OLED_I2C_SDA_CLK()   __HAL_RCC_GPIOB_CLK_ENABLE()
#define OLED_I2C_SDA_PORT    GPIOB
#define OLED_I2C_SDA_PIN     GPIO_PIN_7
/*SCL引脚拉高拉低*/
#define OLED_SCL_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_SET)
#define OLED_SCL_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SCL_PIN,GPIO_PIN_RESET)
/*SDA引脚拉高拉低*/
#define OLED_SDA_SET()       HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_SET)
#define OLED_SDA_RESET()     HAL_GPIO_WritePin(OLED_I2C_SCL_PORT,OLED_I2C_SDA_PIN,GPIO_PIN_RESET)void oled_init(void);
void oled_write_cmd(uint8_t cmd);
void oled_write_data(uint8_t data);
void oled_set_cursor(uint8_t x, uint8_t y);
void oled_fill(uint8_t data);
void oled_show_char(uint8_t x, uint8_t y, uint8_t num, uint8_t size);
void oled_show_string(uint8_t x, uint8_t y, char *p, uint8_t size);
void oled_show_chinese(uint8_t x, uint8_t y, uint8_t N, uint8_t size);
void oled_show_image(uint8_t x, uint8_t y, uint8_t width, uint8_t height, uint8_t *bmp);
#endif

font.h

#ifndef __FONT_H__
#define __FONT_H__//16号汉字
const unsigned char chinese_16x16[][32] =
{    /*汉字的字模*/};//24号汉字
const unsigned char chinese_24x24[][72] =
{/*汉字的字模*/
};const unsigned char ascii_6X12[][12]={/*可见的ASCII字符集字模*/
};//16*16 ASCII字符集点阵
const unsigned char ascii_8X16[][16]=      
{/*可见的ASCII字符集字模*/
};//16*16 ASCII字符集点阵
const unsigned char ascii_12X24[][36]=
{/*可见的ASCII字符集字模*/ 
};
//汉字帅
const unsigned char shuai_data[] = {/*汉字帅的字模*/
};#endif