【AT-START-F425测评】IO模拟IIC驱动OLED
本帖最后由 zhouminjie 于 2022-5-23 23:40 编辑1、关于IIC协议的分析介绍，可参考https://bbs.21ic.com/icview-2969754-1-1.html，此处不再赘述。
2、本次使用AT32F425 I/O模拟IIC来实现驱动0.96OLED液晶屏，接线方式如下：PF4连接OLED屏SDA引脚、PF5连接OLED屏SCL引脚。
3、软件设计在之前工程上增加hal_i2c.c、hal_i2c.h、hal_0.96oled.c、hal_0.96oled.h等.c.h文件，具体如下：
hal_i2c.c代码：
#include "hal_i2c.h"
#include "delay.h"
//设置SDA输入模式
void SDA_IN(void)
{
gpio_init_type gpio_init_struct;
//根据GPIO组初始化GPIO时钟
crm_periph_clock_enable(SDA_GPIO_CRM_CLK, TRUE); //使能GPIOF时钟
gpio_init_struct.gpio_pins = SDA_PIN;
gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
gpio_init_struct.gpio_pull = GPIO_PULL_UP;
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
gpio_init(SDA_GPIO, &gpio_init_struct);
}
//设置SDA为输出模式
void SDA_OUT(void)
{
gpio_init_type gpio_init_struct;
//根据GPIO组初始化GPIO时钟
crm_periph_clock_enable(SDA_GPIO_CRM_CLK, TRUE); //使能GPIOF时钟
gpio_init_struct.gpio_pins = SDA_PIN;
gpio_init_struct.gpio_mode = GPIO_MODE_OUTPUT;
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
gpio_init_struct.gpio_pull = GPIO_PULL_UP;
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
gpio_init(SDA_GPIO, &gpio_init_struct);
}
//设置SCL电平
void I2C_SCL(int n)
{
if(n == 1)
{
gpio_bits_write(SCL_GPIO, SCL_PIN, TRUE); //设置SCL为高电平
}
else
{
gpio_bits_write(SCL_GPIO, SCL_PIN, FALSE); //设置SCL为低电平
}
}
//设置SDA电平
void I2C_SDA(int n)
{
if(n == 1)
{
gpio_bits_write(SDA_GPIO, SDA_PIN, TRUE); //设置SDA为高电平
}
else
{
gpio_bits_write(SDA_GPIO, SDA_PIN, FALSE); //设置SDA为低电平
}
}
//读取SDA电平
unsigned char READ_SDA(void)
{
return gpio_input_data_bit_read(SDA_GPIO, SDA_PIN); //读取SDA电平
}
//I2C初始化
void I2C_Init(void)
{
gpio_init_type gpio_init_struct;
//根据GPIO组初始化GPIO时钟
crm_periph_clock_enable(SCL_GPIO_CRM_CLK, TRUE); //使能GPIOF时钟
crm_periph_clock_enable(SDA_GPIO_CRM_CLK, TRUE); //使能GPIOF时钟
//GPIO_SCL初始化设置
gpio_init_struct.gpio_pins = SCL_PIN;
gpio_init_struct.gpio_mode = GPIO_MODE_OUTPUT; //gpio output mode
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL; //output push-pull
gpio_init_struct.gpio_pull = GPIO_PULL_UP; //pull-up
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER; //stronger sourcing/sinking strength
gpio_init(SCL_GPIO, &gpio_init_struct);
//GPIO_SDA初始化设置
gpio_init_struct.gpio_pins = SDA_PIN;
gpio_init_struct.gpio_mode = GPIO_MODE_OUTPUT;
gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
gpio_init_struct.gpio_pull = GPIO_PULL_UP;
gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
gpio_init(SDA_GPIO, &gpio_init_struct);
//SCL、SDA的初始化均为高电平
I2C_SCL(1);
I2C_SDA(1);
}
//I2C Start
void I2C_Start(void)
{
SDA_OUT();
I2C_SDA(1);
I2C_SCL(1);
Delay_Us(4);
I2C_SDA(0); //START:when CLK is high,DATA change form high to low
Delay_Us(4);
I2C_SCL(0); //钳住I2C总线,准备发送或接收数据
}
//I2C Stop
void I2C_Stop(void)
{
SDA_OUT();
I2C_SCL(0);
I2C_SDA(0); //STOP:when CLK is high DATA change form low to high
Delay_Us(4);
I2C_SCL(1);
I2C_SDA(1); //发送I2C总线结束信号
Delay_Us(4);
}
//I2C_Wait_ack 返回HAL_OK表示wait成功,返回HAL_ERROR表示wait失败
unsigned char I2C_Wait_Ack(void) //IIC_Wait_ack,返回wait失败或是成功
{
unsigned char ucErrTime = 0;
SDA_IN();
I2C_SDA(1);
Delay_Us(1);
I2C_SCL(1);
Delay_Us(1);
while(READ_SDA())
{
ucErrTime++;
if(ucErrTime>250)
{
I2C_Stop();
return HAL_ERROR;
}
}
I2C_SCL(0);
return HAL_OK;
}
//产生ACK应答
void I2C_Ack(void)
{
I2C_SCL(0);
SDA_OUT();
I2C_SDA(0);
Delay_Us(2);
I2C_SCL(1);
Delay_Us(2);
I2C_SCL(0);
}
//产生NACK应答
void I2C_NAck(void)
{
I2C_SCL(0);
SDA_OUT();
I2C_SDA(1);
Delay_Us(2);
I2C_SCL(1);
Delay_Us(2);
I2C_SCL(0);
}
//I2C_Send_Byte,入口参数为要发送的字节
void I2C_Send_Byte(unsigned char txd)
{
unsigned char cnt = 0;
SDA_OUT();
I2C_SCL(0);
for(cnt = 0; cnt < 8; cnt++)
{
I2C_SDA((txd & 0x80) >> 7);
txd <<= 1;
Delay_Us(2);
I2C_SCL(1);
Delay_Us(2);
I2C_SCL(0);
Delay_Us(2);
}
}
//I2C_Read_Byte,入口参数为是否要发送ACK信号
unsigned char I2C_Read_Byte(unsigned char ack)
{
unsigned char cnt, rec = 0;
SDA_IN();
for(cnt = 0; cnt < 8; cnt++)
{
I2C_SCL(0);
Delay_Us(2);
I2C_SCL(1);
rec <<= 1;
if(READ_SDA())
{
rec++;
}
Delay_Us(1);
}
if(!ack)
{
I2C_NAck();
}
else
{
I2C_Ack();
}
return rec;
}
hal_0.96oled.c代码：
#include "hal_0.96oled.h"
#include "oledfont.h"
#include "delay.h"
//向设备写控制命令
static void OLED_Write_CMD(unsigned char cmd)
{
I2C_Start();
I2C_Send_Byte(0x78);
I2C_Wait_Ack();
I2C_Send_Byte(0x00);
I2C_Wait_Ack();
I2C_Send_Byte(cmd);
I2C_Wait_Ack();
I2C_Stop();
}
//向设备写数据
static void OLED_Write_Date(unsigned char date)
{
I2C_Start();
I2C_Send_Byte(0x78);
I2C_Wait_Ack();
I2C_Send_Byte(0x40);
I2C_Wait_Ack();
I2C_Send_Byte(date);
I2C_Wait_Ack();
I2C_Stop();
}
//坐标设置
static void OLED_Set_Pos(unsigned char x, unsigned char y)
{
OLED_Write_CMD(0xB0 + y);
OLED_Write_CMD(((x & 0xF0) >> 4) | 0x10);
OLED_Write_CMD(x & 0x0F);
}
//开启OLED显示
static void OLED_Display_On(void)
{
OLED_Write_CMD(0x8D); //SET DCDC命令
OLED_Write_CMD(0x14); //DCDC ON
OLED_Write_CMD(0xAF); //DISPLAY ON
}
//关闭OLED显示
static void OLED_Display_Off(void)
{
OLED_Write_CMD(0x8D); //SET DCDC命令
OLED_Write_CMD(0x10); //DCDC OFF
OLED_Write_CMD(0xAE); //DISPLAY OFF
}
//OLED清屏
void OLED_Clear(void)
{
unsigned char cnt, count;
for(cnt = 0; cnt < 8; cnt++)
{
OLED_Write_CMD(0xB0 + cnt);
OLED_Write_CMD(0x00);
OLED_Write_CMD(0x10);
for(count = 0; count < 128; count++)
{
OLED_Write_Date(0x00);
}
}
}
//OLED清行
void OLED_Clear_Row(unsigned char n)
{
unsigned char count;
OLED_Write_CMD(0xB0 + n);
OLED_Write_CMD(0x00);
OLED_Write_CMD(0x10);
for(count = 0; count < 128; count++)
{
OLED_Write_Date(0x00);
}
}
//OLED填满屏幕
void OLED_Fill(void)
{
unsigned char cnt, count;
for(cnt = 0; cnt < 8; cnt++)
{
OLED_Write_CMD(0xB0 + cnt); //设置页地址（0~7）
OLED_Write_CMD(0x00); //设置显示位置—列低地址
OLED_Write_CMD(0x10); //设置显示位置—列高地址
for(count = 0; count < 128; count++)
{
OLED_Write_Date(0x01);
}
}
}
//指定位置显示一个字符
//x:0~127
//y:0~63
//chr:字符
//mode:0,反白显示;1,正常显示
//size:选择字体 16/12
void OLED_ShowChar(unsigned char x, unsigned char y, unsigned char chr, unsigned char size)
{
unsigned char offset = 0, cnt = 0;
offset = chr - ' '; //计算偏移量
if(x > 128 - 1)
{
x = 0;
y = y + 2;
}
if(size == 16)
{
OLED_Set_Pos(x, y);
for(cnt = 0; cnt < 8; cnt++)
{
OLED_Write_Date(F8x16);
}
OLED_Set_Pos(x, y + 1);
for(cnt = 0; cnt < 8; cnt++)
{
OLED_Write_Date(F8x16);
}
}
else
{
OLED_Set_Pos(x, y);
for(cnt = 0; cnt < 6; cnt++)
{
OLED_Write_Date(F6x8);
}
}
}
unsigned int oled_pow(unsigned char m, unsigned char n)
{
unsigned int result = 1;
while(n--)
{
result *= m;
}
return result;
}
//指定位置显示一个数字
//x,y:起点坐标
//num:数值(0~4294967295)
//len:数字的位数
//size:字体大小
//mode:模式 0,填充模式;1,叠加模式
void OLED_ShowNum(unsigned char x, unsigned char y, unsigned int num, unsigned char len, unsigned char size)
{
unsigned char cnt, temp;
unsigned char show = 0;
for(cnt = 0; cnt < len; cnt++)
{
temp = (num / oled_pow(10, len - cnt - 1)) % 10;
if(show == 0 && cnt < (len - 1))
{
if(temp == 0)
{
OLED_ShowChar(x + (size / 2) * cnt, y, ' ', size);
continue;
}
else
{
show = 1;
}
}
OLED_ShowChar(x + (size / 2) * cnt, y, temp + '0', size);
}
}
//指定位置显示字符串
void OLED_ShowString(unsigned char x, unsigned char y, unsigned char *chr, unsigned char size)
{
unsigned char cnt = 0;
while(chr != '\0')
{
OLED_ShowChar(x, y, chr, size);
x += 8;
if(x > 120)
{
x = 0;
y += 2;
}
cnt++;
}
}
//显示汉字
void OLED_ShowCHinese(unsigned char x, unsigned char y, unsigned char no)
{
unsigned char cnt, addr = 0;
OLED_Set_Pos(x, y);
for(cnt = 0; cnt < 16; cnt++)
{
OLED_Write_Date(Hzk);
addr++;
}
OLED_Set_Pos(x, y + 1);
for(cnt = 0; cnt < 16; cnt++)
{
OLED_Write_Date(Hzk);
addr++;
}
}
//OLED初始化
void OLED_Init(void)
{
I2C_Init();
Delay_Ms(200);
OLED_Write_CMD(0xAE); //display off
OLED_Write_CMD(0x00); //set low column address
OLED_Write_CMD(0x10); //set high column address
OLED_Write_CMD(0x40); //set start line address
OLED_Write_CMD(0xB0); //set page address
OLED_Write_CMD(0x81); //contract control
OLED_Write_CMD(0xFF); //128
OLED_Write_CMD(0xA1); //set segment remap
OLED_Write_CMD(0xA6); //normal / reverse
OLED_Write_CMD(0xA8); //set multiplex ratio(1 to 64)
OLED_Write_CMD(0x3F); //1/32 duty
OLED_Write_CMD(0xC8); //Com scan direction
OLED_Write_CMD(0xD3); //set display offset
OLED_Write_CMD(0x00); //
OLED_Write_CMD(0xD5); //set osc division
OLED_Write_CMD(0x80); //
OLED_Write_CMD(0xD8); //set area color mode off
OLED_Write_CMD(0x05); //
OLED_Write_CMD(0xD9); //Set Pre-Charge Period
OLED_Write_CMD(0xF1); //
OLED_Write_CMD(0xDA); //set com pin configuartion
OLED_Write_CMD(0x12); //
OLED_Write_CMD(0xDB); //set Vcomh
OLED_Write_CMD(0x30); //
OLED_Write_CMD(0x8D); //set charge pump enable
OLED_Write_CMD(0x14); //
OLED_Write_CMD(0xAF); //turn on oled panel
}
模拟i2c时，delay.c代码：
#include "at32f425.h"
#include "hal_timer.h"
static unsigned char fac_us = 0; //us延时倍乘数
static unsigned short fac_ms = 0; //ms延时倍乘数
//初始化延迟函数
//SYSTICK的时钟固定为HCLK时钟的1/8
//SYSCLK:系统时钟
void Delay_Init(void)
{
crm_clocks_freq_get(&crm_clocks_freq_struct);
fac_us = crm_clocks_freq_struct.sclk_freq / (8000000U); //systick为HCLK/8,fac_us为systick的1/8/1000000,即每1us systick的VAL减的数目
fac_ms = (unsigned short)fac_us * (1000U); //每1ms需要的systick时钟数,即每1ms systick的VAL减的数目
}
//延时nus
//nus为要延时的us数
void Delay_Us(unsigned int nus)
{
unsigned int temp;
SysTick->LOAD = (unsigned int)(nus * fac_us); //时间加载
SysTick->VAL = 0x00; //清空计数器
SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk; //开始倒数
do
{
temp = SysTick->CTRL;
}
while((temp & 0x01) && !(temp & (1 << 16))); //等待时间到达
SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk; //关闭计数器
SysTick->VAL = 0x00; //清空计数器
}
//延时nms
//注意nms的范围
//SysTick->LOAD为24位寄存器,所以,最大延时为:
//nms<=0xffffff*8*1000/SYSCLK
//SYSCLK单位为Hz,nms单位为ms
//对96M条件下,nms<=1398
void Delay_Ms(unsigned short nms)
{
unsigned int temp;
SysTick->LOAD = (unsigned int)(nms * fac_ms); //时间加载(SysTick->LOAD为24bit)
SysTick->VAL = 0x00; //清空计数器
SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk; //开始倒数
do
{
temp = SysTick->CTRL;
}
while((temp & 0x01) && !(temp & (1 << 16))); //等待时间到达，看CTRL的第16位（COUNTFLAG）是否为1，看STRL的第0位（ENABLE）是否为1
SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk; //关闭计数器
SysTick->VAL = 0x00; //清空计数器
}
4、显示效果：
5、工程代码：
这开发板都是白色的么？看着挺清新 感谢楼主分享，借鉴了一下I2C 很多时候IIC都是用IO模拟的。
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