精英版寄存器硬件IIC

无敌是多么寂寞1 · 发表于 2020-3-27 21:20:50

本帖最后由无敌是多么寂寞1 于 2020-3-27 21:28 编辑

F103的硬件IIC读写AT24C02，已经可以实现读取了，但是会时不时出现小bug，也想请大家指教
void I2C_Init(u8 ADDR)
{
      RCC->APB2ENR |=1<<3;//开启PORTB时钟
      RCC->APB1ENR |=1<<21;//开启I2C1时钟
      RCC->APB1RSTR |= 1<<21; //复位I2C1
      RCC->APB1RSTR &= ~(1<<21); //复位结束I2C1
      I2C1->CR1 |= 1<<15; //复位寄存器
      I2C1->CR1 &= ~(1<<15); //复位结束

      GPIOB->CRL &=0X00FFFFFF;//初始化PB6、PB7
      GPIOB->CRL |=0XFF000000;//复用开漏50MHZ

      I2C1->CR2|=36<<0;//I2C时钟频率8M

      I2C1->CCR |= 180<<0; //标准模式时钟控制分频系数=PCLK1/2/f，f为想得到的频率  100KHz
      I2C1->TRISE |= 37; //最大允许SCL上升时间为1000ns，故TRISE[5:0]中必须写入(1us/(1/36)us = 36+1)
      I2C1->CCR &= ~(1<<15);//I2C主模式 0：标准模式的I2C 1：快速模式的I2C

      I2C1->OAR1 |= 1<<14; //必须始终由软件保持为1
      I2C1->OAR1 |=ADDR<<1;//设置地址

      I2C1->CR1 |=1<<0;//启用I2C
}

void I2C1_GPIO_Set(u8 mode)
{
      if(mode)
      {
            GPIOB->CRL &=0X00FFFFFF;//初始化PB6、PB7
            GPIOB->CRL |=0X33000000;//复用开漏50MHZ
            GPIOB->ODR &=~(3<<6);//强制拉低总线
            delay_us(1);
            GPIOB->ODR |=3<<6;//强制拉高总线
            delay_us(4);
      }
      else
      {
            GPIOB->CRL &=0X00FFFFFF;//初始化PB6、PB7
            GPIOB->CRL |=0XFF000000;//复用开漏50MHZ
      }
}

void I2C_WriteDate(u8 Data_Addr,u8 data)
{
      int clear;
      clear=clear;
      I2C1_GPIO_Set(I2C_GPIOPP);
      while(I2C1->SR2&(1<<1));//等待SR2.Busy=0(总线空闲)
      I2C1->CR1 |= 1<<8; //I2C1产生起始条件

      I2C1_GPIO_Set(I2C_GPIOAF);

      while(!(I2C1->SR1&=1<<0));//等待SR1.SB=1开始位已经发送
      I2C1->SR1 &= ~(1<<10);//SR1.AF清零
      I2C1->DR = AT24C02_Addr_Write;//写入AT24C02的地址Addr，写指令，SR1.SB清零

      while(!(I2C1->SR1&=1<<1));//等待SR1.ADDR=1，从设备应答
      clear=I2C1->SR1;
      clear=I2C1->SR2;//SR1.ADDR清零
      I2C1->DR = Data_Addr;//写入字节地址

      while(!(I2C1->SR1&(1<<2)));//等待SR1.BTF=1，字节地址发送完毕
      clear=I2C1->SR1;//SR1.BTF清零
      I2C1->DR = data;//发送要写入的数据

      while(!(I2C1->SR1&(1<<2)));//数据发送完成

      I2C1->CR1 |= 1<<9; //I2C1产生停止条件
}

u8 I2C_Read_Data(u8 Data_Addr)
{
      int clear;
      clear=clear;
      while(I2C1->SR2&(1<<1)); //等待SR2.Busy=0(总线空闲)
      I2C1->CR1 |= 1<<8; //I2C1产生起始条件

      while(!(I2C1->SR1&(1<<0)));//等待SR1.SB=1开始位已经发送
      I2C1->SR1 &= ~(1<<10);//SR1.AF清零
      I2C1->DR = AT24C02_Addr_Write;//写入AT24C02的地址Addr，写指令，SR1.SB清零

      while(!(I2C1->SR1&(1<<1)));//等待SR1.ADDR=1，从设备应答
      clear=I2C1->SR1;
      clear=I2C1->SR2;//SR1.ADDR清零
      I2C1->DR = Data_Addr;//读取字节地址

      I2C1->CR1 |= 1<<8; //I2C1产生起始条件

      while(!(I2C1->SR1&(1<<0)));//等待SR1.SB=1开始位已经发送
      I2C1->SR1 &= ~(1<<10);//SR1.AF清零
      I2C1->DR = AT24C02_Addr_Read;//写入AT24C02的地址Addr，读指令，SR1.SB清零

      while(!(I2C1->SR1&(1<<1)));//等待SR1.ADDR=1，从设备应答
      clear=I2C1->SR1;
      clear=I2C1->SR2;//SR1.ADDR清零

      while(!(I2C1->SR1&(1<<6)));//等待SR1.RxNE=1，接收到数据
      I2C1->CR1 |= 1<<9; //I2C1产生停止条件
      return I2C1->DR;
}