用stm32f407的iic驱动4针OLED显示屏的代码

下面是用STM32F407的I2C驱动4针OLED显示屏的代码，假设使用的OLED屏幕为128x64的分辨率：

#include "stm32f4xx.h"
#include "delay.h"
#include "oled.h"

void I2C_GPIO_Config(void);
void I2C_Config(void);
void I2C_Start(void);
void I2C_Stop(void);
void I2C_SendByte(uint8_t byte);
uint8_t I2C_ReadByte(void);
void I2C_SendACK(void);
void I2C_SendNACK(void);
void OLED_WriteCmd(uint8_t cmd);
void OLED_WriteData(uint8_t data);
void OLED_Init(void);

int main(void)
{
    I2C_GPIO_Config();
    I2C_Config();
    OLED_Init();
    OLED_Fill(0);
    OLED_ShowStr(0, 0, "Hello World!", 1);
    while (1)
    {
    }
}

void I2C_GPIO_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);
}

void I2C_Config(void)
{
    I2C_InitTypeDef I2C_InitStructure;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);

    I2C_DeInit(I2C1);

    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStructure.I2C_OwnAddress1 = 0;
    I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStructure.I2C_ClockSpeed = 400000;
    I2C_Init(I2C1, &I2C_InitStructure);
    I2C_Cmd(I2C1, ENABLE);
}

void I2C_Start(void)
{
    I2C_GenerateSTART(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
}

void I2C_Stop(void)
{
    I2C_GenerateSTOP(I2C1, ENABLE);
    while (I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF));
}

void I2C_SendByte(uint8_t byte)
{
    I2C_SendData(I2C1, byte);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
}

uint8_t I2C_ReadByte(void)
{
    I2C_AcknowledgeConfig(I2C1, ENABLE);
    while (!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));
    uint8_t byte = I2C_ReceiveData(I2C1);
    return byte;
}

void I2C_SendACK(void)
{
    I2C_AcknowledgeConfig(I2C1, ENABLE);
    I2C_GenerateSTOP(I2C1, DISABLE);
}

void I2C_SendNACK(void)
{
    I2C_AcknowledgeConfig(I2C1, DISABLE);
    I2C_GenerateSTOP(I2C1, DISABLE);
}

void OLED_WriteCmd(uint8_t cmd)
{
    I2C_Start();
    I2C_SendByte(0x78);
    I2C_SendByte(0x00);
    I2C_SendByte(cmd);
    I2C_Stop();
}

void OLED_WriteData(uint8_t data)
{
    I2C_Start();
    I2C_SendByte(0x78);
    I2C_SendByte(0x40);
    I2C_SendByte(data);
    I2C_Stop();
}

void OLED_Init(void)
{
    OLED_WriteCmd(0xAE);
    OLED_WriteCmd(0x20);
    OLED_WriteCmd(0x10);
    OLED_WriteCmd(0xb0);
    OLED_WriteCmd(0xc8);
    OLED_WriteCmd(0x00);
    OLED_WriteCmd(0x10);
    OLED_WriteCmd(0x40);
    OLED_WriteCmd(0x81);
    OLED_WriteCmd(0xff);
    OLED_WriteCmd(0xa1);
    OLED_WriteCmd(0xa6);
    OLED_WriteCmd(0xa8);
    OLED_WriteCmd(0x3f);
    OLED_WriteCmd(0xd3);
    OLED_WriteCmd(0x00);
    OLED_WriteCmd(0xd5);
    OLED_WriteCmd(0xf0);
    OLED_WriteCmd(0xd9);
    OLED_WriteCmd(0x22);
    OLED_WriteCmd(0xda);
    OLED_WriteCmd(0x12);
    OLED_WriteCmd(0xdb);
    OLED_WriteCmd(0x20);
    OLED_WriteCmd(0x8d);
    OLED_WriteCmd(0x14);
    OLED_WriteCmd(0xaf);
}

void OLED_Fill(uint8_t dat)
{
    uint8_t i, j;
    for (i = 0; i < 8; i++)
    {
        OLED_WriteCmd(0xb0 + i);
        OLED_WriteCmd(0x00);
        OLED_WriteCmd(0x10);
        for (j = 0; j < 128; j++)
        {
            OLED_WriteData(dat);
        }
    }
}

void OLED_ShowStr(uint8_t x, uint8_t y, uint8_t *str, uint8_t size)
{
    uint8_t c = 0, i = 0, j = 0;
    while (str[j] != '\0')
    {
        c = str[j] - 32;
        if (x > 120)
        {
            x = 0;
            y++;
        }
        OLED_ShowChar(x, y, c, size);
        x += size / 2;
        j++;
    }
}

void OLED_ShowChar(uint8_t x, uint8_t y, uint8_t chr, uint8_t size)
{
    uint8_t c = 0, i = 0, j = 0;
    c = chr - 32;
    if (x > 120)
    {
        x = 0;
        y++;
    }
    OLED_SetPos(x, y);
    for (i = 0; i < size; i++)
    {
        for (j = 0; j < size / 2; j++)
        {
            OLED_WriteData(F6x8[c][i * size / 2 + j]);
        }
    }
}

void OLED_SetPos(uint8_t x, uint8_t y)
{
    OLED_WriteCmd(0xb0 + y);
    OLED_WriteCmd(((x & 0xf0) >> 4) | 0x10);
    OLED_WriteCmd(x & 0x0f);
}

需要注意的地方：

1. OLED屏幕的I2C地址为0x78，因此在发送数据时需要将地址左移一位后再发送
2. OLED屏幕在初始化时需要发送一系列的命令才能正常工作，具体命令可以参考OLED的数据手册
3. OLED屏幕的显示需要将数据进行分页，每页8行128列，每个像素点使用一个字节表示
4. OLED屏幕的显示需要使用ASCII码表，因此需要对字符进行转换才能正确显示

以上代码应该可以满足你的要求，如果还有问题可以再和我交流。