STM32 IIC 通信 库函数实现

reading stucture

device address

read command

write address to board

device address

read data from board

start

0xb0

ack

0x01

ack

address high

ack

address low

ack

start

0xb1

ack

data high

ack

data low

nack

stop

example to read   address 0x1234 and result 0x789A

start

0xb0

ack

0x01

ack

0x12

ack

0x34

ack

start

0xb1

ack

0x78

ack

0x9a

nack

stop

writing   stucture

device address

write command

write address to board

read data from board

start

0xb0

ack

0x81

ack

address high

ack

address low

ack

data high

ack

data low

ack

stop

example to write   address 0x5678 with data 0xcdef

start

0xb0

ack

0x81

ack

0x56

ack

0x78

ack

0xcd

ack

0xef

ack

stop

0x9a

Read Register

void Read_Reg(u8 *DataBuff,u8 ByteQuantity,uint16_t RegAddress,u8 SlaveAddress)
{
     //这句去掉也正常
     while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)); // Added by Najoua 27/08/2008

    /* Send START condition */     
     I2C_GenerateSTART(I2C1, ENABLE);
     while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
     /* 发送器件地址(写)*/
     I2C_Send7bitAddress(I2C1, SlaveAddress, I2C_Direction_Transmitter);
     while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)); /* EV7 */

     //这句去掉也正常
     /* Clear EV6 by setting again the PE bit */
     I2C_Cmd(I2C1, ENABLE);

    I2C_SendData(I2C1,01);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1,RegAddress>>8);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1,RegAddress);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTART(I2C1, ENABLE);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
     /* 发送器件地址(写)*/
    I2C_Send7bitAddress(I2C1, SlaveAddress, I2C_Direction_Receiver);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)); /* EV7 */

    while (ByteQuantity)
    {
        if(ByteQuantity==1)
        {
             I2C_AcknowledgeConfig(I2C1, DISABLE);    //最后一位后要关闭应答的
            I2C_GenerateSTOP(I2C1, ENABLE);            //发送停止位
        }
        
        while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED)); /* EV7 */
        *DataBuff = I2C_ReceiveData(I2C1);
        DataBuff++;
        /* Decrement the read bytes counter */
        ByteQuantity--;
    }
    //再次允许应答模式
    I2C_AcknowledgeConfig(I2C1, ENABLE);
    //errorflag=0;
    //break;
    
}

void Write_Reg(uint16_t WriteValue,uint16_t RegAddress,u8 SlaveAddress)
{


  while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY)); // Added by Najoua 27/08/2008
    
  /* Send START condition */
  I2C_GenerateSTART(I2C1, ENABLE);
  
  /* Test on EV5 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT)); 
  
  /* Send EEPROM address for write */
  I2C_Send7bitAddress(I2C1, SlaveAddress, I2C_Direction_Transmitter);
  
  /* Test on EV6 and clear it */
  while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));  

      I2C_SendData(I2C1,0x81);
   while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1,RegAddress>>8);
   while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1,RegAddress);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    I2C_SendData(I2C1,WriteValue>>8);
   while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C1,WriteValue);
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

  /* Send STOP condition */
  I2C_GenerateSTOP(I2C1, ENABLE);
}

/**
  * @brief  Transmits the address byte to select the slave device.
  * @param  I2Cx: where x can be 1 or 2 to select the I2C peripheral.
  * @param  Address: specifies the slave address which will be transmitted
  * @param  I2C_Direction: specifies whether the I2C device will be a
  *   Transmitter or a Receiver. This parameter can be one of the following values
  *     @arg I2C_Direction_Transmitter: Transmitter mode
  *     @arg I2C_Direction_Receiver: Receiver mode
  * @retval None.
  */
void I2C_Send7bitAddress(I2C_TypeDef* I2Cx, uint8_t Address, uint8_t I2C_Direction)
{
  /* Check the parameters */
  assert_param(IS_I2C_ALL_PERIPH(I2Cx));
  assert_param(IS_I2C_DIRECTION(I2C_Direction));
  /* Test on the direction to set/reset the read/write bit */
  if (I2C_Direction != I2C_Direction_Transmitter)
  {
    /* Set the address bit0 for read */
    Address |= OAR1_ADD0_Set;
  }
  else
  {
    /* Reset the address bit0 for write */
    Address &= OAR1_ADD0_Reset;
  }
  /* Send the address */
  I2Cx->DR = Address;
}

#define  I2C_Direction_Transmitter      ((uint8_t)0x00)
#define  I2C_Direction_Receiver         ((uint8_t)0x01)

7位模式下，地址字节最低位若是0则说明主机要进入发送模式，若是1则是接收模式