STM32F401xx双机I2C主从通信Proteus仿真及代码问题排查

开发者阿泽

2026-7-4

STM32F401xx I2C主从通信仿真故障排查指南

问题描述（翻译自英文提问）

在Proteus中使用两块STM32F401xx MCU搭建I2C主从通信系统：一块作为主设备（Master），另一块作为从设备（Slave）。主设备代码采用MicroC Pro For Arm编写，寄存器级I2C驱动代码如下：

#include <stdint.h>
#include <stdio.h>
uint8_t temp=0;
void begin(uint8_t addr);
void end(void);
void Write (uint8_t dat);
void main() {
       // Enable the I2C CLOCK and GPIO CLOCK
          RCC_APB1ENR |= (1<<21);  // enable I2C CLOCK
          RCC_AHB1ENR |= (1<<1);  // Enable GPIOB CLOCK

          // Configure the I2C PINs for ALternate Functions
          //PB8 and PB9 are connected to I2C1_SCL and I2C1_SDA
          GPIOB_MODER |= (2<<16) | (2<<18);

          GPIOB_OTYPER |= (1<<8) | (1<<9);
          GPIOB_OSPEEDR |= (3<<16) | (3<<18);
          GPIOB_PUPDR |= (1<<16) | (1<<18);
          GPIOB_AFRH |= (4<<0) | (4<<4);
          begin(0x08);
          Write(0x01);
          end();
}

void begin(uint8_t addr){
          //join I2C as a master mode
         //Generate a start condition
            I2C1_CR1 |= (1<<10);  // Enable the ACK
            I2C1_CR1 |= (1<<8);  // Generate START
            while (!(I2C1_SR1 & (1<<0)));  // Wait for SB bit to set to 1

           //Send the Slave Address to the DR Register
            I2C1_DR = addr;  //  send the address
            while (!(I2C1_SR1 & (1<<1)));  //
            temp = I2C1_SR1 | I2C1_SR2;  // read SR1 and SR2 to clear the ADDR bit

            // Reset the I2C
            I2C1_CR1 |= (1<<15); //I2C Peripheral under reset state -->page.493 manual
            I2C1_CR1 &= ~(1<<15); //I2C Peripheral not under reset  -->page.493 manual
            // Program the peripheral input clock in I2C_CR2 Register in order to generate correct timings
            I2C1_CR2 |= (42 <<0);  // PCLK1 FREQUENCY in MHz
            I2C1_CCR = 210<<0;  // Configure the clock control registers
            I2C1_TRISE = 43;  // Configure the rise time register
            I2C1_CR1 |= (1<<0);  // Enable I2C
}
 void end(void)  {

           I2C1_CR1 |= (1<<9);//stop generation
            // Wait until the STOP condition is complete
           while (I2C1_SR2 & (1<<0)); //Cleared by hardware after detecting a Stop condition on the bus
           // Clear the STOP bit
           I2C1_CR1 &= ~(1<<9);
  }

    void Write (uint8_t dat)
  {
          while (!(I2C1_SR1 & (1<<7)));  // wait for TXE bit to set
              I2C1_DR = dat   ;  // wait for BTF bit to set
          while (!(I2C1_SR1 & (1<<2))); //waiting while BTF=0 but when BTF=1; Data byte transfer succeeded

  }

从设备代码如下：

#include <stdint.h>
#include <stdio.h>
uint8_t temp=0;
uint8_t state =0x00;
void begin(uint8_t addr);
void end(void);
uint8_t Read ();
void main() {
          RCC_APB1ENR |= (1<<21);  // enable I2C CLOCK -
          RCC_AHB1ENR |= (1<<1);  // Enable GPIOB CLOCK
          RCC_AHB1ENR |= (1<<0);  // Enable GPIOA CLOCK
          GPIOA_MODER |=(1<<0); //set pin 0 as output
          // Configure the I2C PINs for ALternate Functions
          //PB8 and PB9 are connected to I2C1_SCL and I2C1_SDA
          GPIOB_MODER |= (2<<16) | (2<<18);

          GPIOB_OTYPER |= (1<<8) | (1<<9);
          GPIOB_OSPEEDR |= (3<<16) | (3<<18);
          GPIOB_PUPDR |= (1<<16) | (1<<18);
          GPIOB_AFRH |= (4<<0) | (4<<4);
          begin(0x08);
          state =  Read();
          end();
        if (state == 0x01){
            GPIOA_ODR |=(1<<0);//set 1 for pin 0
         }
}
void begin(uint8_t addr){
            //join I2C bus as a slave mode
            I2C1_CR2 |= (42<<0);  // PCLK1 FREQUENCY in MHz
            I2C1_OAR1 = addr;//own address interface
            I2C1_CR1 |= (1<<0);  // Enable I2C
            I2C1_CR1 |= (1<<10);  // Enable the ACK ,indicate that a byte is received
}
 void end(void)  {
           I2C1_CR1 |= (1<<9);//stop generation
            // Wait until the STOP condition is complete
           while (I2C1_SR2 & (1<<0)); //Cleared by hardware after detecting a Stop condition on the bus

           // Clear the STOP bit
           I2C1_CR1 &= ~(1<<9);
  }
   uint8_t Read (){
            uint8_t receivedData = 0;
            I2C1_CR1 &= ~(1<<10);  // clear the ACK bit
            temp = I2C1_SR1 | I2C1_SR2;  // read SR1 and SR2 to clear the ADDR bit.... EV6 condition
            I2C1_CR1 |= (1<<9);  // Stop I2C
            while (!(I2C1_SR1 & (1<<6)));  // wait for RxNE to set
            receivedData = I2C1_DR; // Read the data from the DATA REGISTER
        return receivedData;
     }

参考STM32F401xx数据手册和参考手册编写了上述驱动，但仿真时LED始终未点亮，需排查代码问题并了解正确的Proteus仿真操作步骤。Proteus连接示意图说明：两块STM32F401xx的PB8（SCL）、PB9（SDA）分别相连，从设备PA0串联LED及限流电阻到GND，两块芯片均接3.3V电源与GND。

一、代码核心问题排查

1. 主设备代码错误

I2C初始化顺序完全颠倒：begin函数中先发送起始信号、从地址，再重置I2C并配置时钟参数，违反I2C初始化流程。正确顺序应为：重置I2C → 配置时钟参数 → 使能I2C → 发送起始信号 → 发送从地址。
从地址格式错误：I2C的8位设备地址由7位地址+1位读写位组成，主设备写操作需将7位地址左移1位（读写位设为0）。原代码直接传入0x08，应改为0x08 << 1（即0x10）。
重置操作时机错误：I2C重置应在配置时钟参数前执行，而非发送地址后。

修正后主设备begin函数：

void begin(uint8_t addr){
    // 重置I2C外设
    I2C1_CR1 |= (1<<15);
    I2C1_CR1 &= ~(1<<15);
    
    // 配置时钟参数
    I2C1_CR2 |= (42 << 0);  // PCLK1频率为42MHz
    I2C1_CCR = 210 << 0;    // 标准模式100kHz（CCR = PCLK1/(2*SCL频率) = 42000/(2*100)=210）
    I2C1_TRISE = 43;        // TRISE = PCLK1频率(MHz) + 1 = 42+1=43
    I2C1_CR1 |= (1<<10);    // 使能ACK
    I2C1_CR1 |= (1<<0);     // 使能I2C
    
    // 发送起始信号
    I2C1_CR1 |= (1<<8);
    while (!(I2C1_SR1 & (1<<0)));  // 等待SB位置位（起始信号发送完成）
    
    // 发送带读写位的从地址（写操作，最低位为0）
    I2C1_DR = (addr << 1) | 0;
    while (!(I2C1_SR1 & (1<<1)));  // 等待ADDR位置位（地址匹配成功）
    temp = I2C1_SR1 | I2C1_SR2;    // 读取SR1和SR2清除ADDR标志
}

2. 从设备代码错误

从地址寄存器（OAR1）配置缺失关键位：STM32F4的I2C_OAR1寄存器第15位必须置1，否则从地址不生效；7位地址需左移1位存入OAR1的bit7-1位。原代码I2C1_OAR1 = addr应改为I2C1_OAR1 = (addr << 1) | (1 << 15)。
Read函数逻辑错误：从设备不应主动发送停止信号，停止信号由主设备发起；且需先等待地址匹配（ADDR置位）再读取数据，原代码直接清ACK、发停止，导致无法正确接收数据。
无地址匹配等待循环：从设备main函数中begin后直接调用Read，未等待主设备发起通信，需在Read中加入等待ADDR置位的循环。

修正后从设备begin和Read函数：

void begin(uint8_t addr){
    I2C1_CR2 |= (42 << 0);  // PCLK1频率为42MHz
    // 配置7位从地址，必须置位OAR1的bit15
    I2C1_OAR1 = (addr << 1) | (1 << 15);
    I2C1_CR1 |= (1<<10);    // 使能ACK
    I2C1_CR1 |= (1<<0);     // 使能I2C
}

uint8_t Read (){
    uint8_t receivedData = 0;
    // 等待地址匹配（ADDR位置位）
    while (!(I2C1_SR1 & (1<<1)));
    temp = I2C1_SR1 | I2C1_SR2;  // 读取SR1和SR2清除ADDR标志
    
    // 等待接收数据就绪（RxNE位置位）
    while (!(I2C1_SR1 & (1<<6)));
    receivedData = I2C1_DR;
    
    // 等待主设备发送停止信号（STOPF位置位）
    while (!(I2C1_SR1 & (1<<4)));
    temp = I2C1_SR1;  // 读取SR1清除STOPF标志
    return receivedData;
}

3. 通用代码问题

需确保RCC_APB1ENR、I2C1_CR1等寄存器已通过头文件或宏定义正确映射，避免编译错误。

二、Proteus正确仿真操作步骤

原理图搭建
- 放置两块STM32F401xx芯片，分别配置为主、从设备。
- I2C总线连接：主设备PB8（SCL）与从设备PB8相连，主设备PB9（SDA）与从设备PB9相连；总线需串联10kΩ上拉电阻到3.3V（I2C总线必须上拉，否则无法正常通信）。
- 从设备PA0串联220Ω限流电阻后连接LED，LED另一端接GND。
- 给两块芯片分别连接3.3V电源和GND。
代码编译与hex文件生成
- 使用MicroC Pro For Arm分别编译主、从设备代码，生成对应的hex文件。
- 编译时需选择正确的芯片型号（STM32F401xx），并配置时钟树，确保PCLK1为42MHz（与代码中I2C1_CR2的配置一致）。
Proteus仿真配置
- 分别给两块STM32芯片加载对应的hex文件：双击芯片 → 打开属性窗口 → 选择Program File为对应hex文件。
- 配置芯片系统时钟：设置为84MHz（STM32F401默认最大时钟，确保PCLK1为42MHz）。
- 启动仿真：点击运行按钮，观察LED状态。
调试技巧
- 使用Proteus的逻辑分析仪监测SCL、SDA信号，查看起始信号、地址帧、数据帧是否正常。
- 若通信无响应，优先检查总线是否上拉、芯片电源是否正常、寄存器配置是否正确。

内容的提问来源于stack exchange，提问作者Ahm2025

STM32F401xx双机I2C主从通信Proteus仿真及代码问题排查

问题描述（翻译自英文提问） #

一、代码核心问题排查 #

1. 主设备代码错误 #

2. 从设备代码错误 #

3. 通用代码问题 #