STM32F407的硬件IIC最全配置及读取写入函数解释

如果是使用硬件IIC,这里使用的是STM32的固件库，硬件模块使用之前必须配置其参数，IIC的配置如下：

void IIC_Config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

IIC_InitTypeDef IIC_InitStructure;

RCC_ClocksTypeDef rcc_clocks;

/* GPIO Peripheral clock enable */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA|RCC_AHB1Periph_GPIOB|RCC_AHB1Periph_GPIOC, ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_IIC1|RCC_APB1Periph_IIC2|RCC_APB1Periph_IIC3, ENABLE);

/* Reset IICx IP */

RCC_APB1PeriphResetCmd(RCC_APB1Periph_IIC1|RCC_APB1Periph_IIC2|RCC_APB1Periph_IIC3, ENABLE);

/* Release reset signal of IICx IP */

RCC_APB1PeriphResetCmd(RCC_APB1Periph_IIC1|RCC_APB1Periph_IIC2|RCC_APB1Periph_IIC3, DISABLE);

/*IIC1 configuration*/

GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_IIC1); //注意，此处不能合并写成GPIO_PinSource6|GPIO_PinSource7

GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_IIC1);

//PB6: IIC1_SCL PB7: IIC1_SDA

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_NOPULL;

GPIO_Init(GPIOB, &GPIO_InitStructure);

/* IIC Struct Initialize */

IIC_DeInit(IIC1);

IIC_InitStructure.IIC_Mode = IIC_Mode_IIC;

IIC_InitStructure.IIC_DutyCycle = IIC_DutyCycle_2;

IIC_InitStructure.IIC_OwnAddress1 = 0x00;

IIC_InitStructure.IIC_Ack = IIC_Ack_Enable;

IIC_InitStructure.IIC_ClockSpeed = 100000;

IIC_InitStructure.IIC_AcknowledgedAddress = IIC_AcknowledgedAddress_7bit;

IIC_Init(IIC1, &IIC_InitStructure);

/* IIC Initialize */

IIC_Cmd(IIC1, ENABLE);

/*IIC2 configuration*/

GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_IIC2); //注意，此处不能合并写成GPIO_PinSource6|GPIO_PinSource7

GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_IIC2);

//PB10: IIC2_SCL PB11: IIC2_SDA

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10|GPIO_Pin_11;

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_NOPULL;

GPIO_Init(GPIOB, &GPIO_InitStructure);

/* IIC Struct Initialize */

IIC_DeInit(IIC2);

IIC_InitStructure.IIC_Mode = IIC_Mode_IIC;

IIC_InitStructure.IIC_DutyCycle = IIC_DutyCycle_2;

IIC_InitStructure.IIC_OwnAddress1 = 0x00;

IIC_InitStructure.IIC_Ack = IIC_Ack_Enable;

IIC_InitStructure.IIC_ClockSpeed = 100000;

IIC_InitStructure.IIC_AcknowledgedAddress = IIC_AcknowledgedAddress_7bit;

IIC_Init(IIC2, &IIC_InitStructure);

/* IIC Initialize */

IIC_Cmd(IIC2, ENABLE);

/*IIC3 configuration*/

GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_IIC3);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_IIC3);

//PA8: IIC3_SCL

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;

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_NOPULL;

GPIO_Init(GPIOA, &GPIO_InitStructure);

//PC9: IIC3_SDA

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* IIC Struct Initialize */

IIC_DeInit(IIC3);

IIC_InitStructure.IIC_Mode = IIC_Mode_IIC;

IIC_InitStructure.IIC_DutyCycle = IIC_DutyCycle_2;

IIC_InitStructure.IIC_OwnAddress1 = 0x00;

IIC_InitStructure.IIC_Ack = IIC_Ack_Enable;

IIC_InitStructure.IIC_ClockSpeed = 100000;

IIC_InitStructure.IIC_AcknowledgedAddress = IIC_AcknowledgedAddress_7bit;

IIC_Init(IIC3, &IIC_InitStructure);

/* IIC Initialize */

IIC_Cmd(IIC3, ENABLE);

/*超时设置*/

RCC_GetClocksFreq(&rcc_clocks);

ulTimeOut_Time = (rcc_clocks.SYSCLK_Frequency /10000);

}

注意，IIC一定要加上超时的设置，否则当IIC总线出错时，没有超时检测可能造成MCU卡死在这里。

STM32F407的硬件IIC读一个字节与STM32F103类似，代码如下：

unsigned char IIC_Err=0;

uint8_t IIC_ReadOneByte(IIC_TypeDef *IICx,uint8_t IIC_Addr,uint8_t Reg_addr)

{

uint8_t readout;

u32 tmr;

tmr = ulTimeOut_Time;

while((--tmr)&&IIC_GetFlagStatus(IICx, IIC_FLAG_BUSY));

if(tmr==0) IIC_Err = 1;

IIC_GenerateSTART(IICx, ENABLE);

//发送IIC的START信号，接口自动从从设备编程主设备

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx, IIC_EVENT_MASTER_MODE_SELECT)));

if(tmr==0) IIC_Err = 1;

IIC_Send7bitAddress(IICx,IIC_Addr,IIC_Direction_Transmitter);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx,IIC_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)));

if(tmr==0) IIC_Err = 1;

IIC_SendData(IICx, Reg_addr);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx,IIC_EVENT_MASTER_BYTE_TRANSMITTED)));

if(tmr==0) IIC_Err = 1;

IIC_GenerateSTART(IICx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx, IIC_EVENT_MASTER_MODE_SELECT)));

if(tmr==0) IIC_Err = 1;

IIC_Send7bitAddress(IICx, IIC_Addr, IIC_Direction_Receiver);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx,

IIC_EVENT_MASTER_RECEIVER_MODE_SELECTED)));

if(tmr==0) IIC_Err = 1;

IIC_AcknowledgeConfig(IICx, DISABLE);

IIC_GenerateSTOP(IICx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!(IIC_CheckEvent(IICx, IIC_EVENT_MASTER_BYTE_RECEIVED)))); /* EV7 */

if(tmr==0) IIC_Err = 1;

readout = IIC_ReceiveData(IICx);

IIC_AcknowledgeConfig(IICx, ENABLE);

return readout;

}

IIC_ReadOneByte函数输入参数有3个，分别是：IICx，表示使用的IIC编号，IIC_addr，表示从设备的IIC地址，reg_addr，表示要读取的从设备寄存器地址。IIC_ReadOneByte的返回值就是IIC总线上读取到的数据。读IIC数据后需要检查IIC_Err是否为0，若为0，表示读取IIC数据时出错（超时），读到的数据可能不正确。

向从设备写入一个字节的数据，代码如下：

unsigned char IIC_Err=0;

void IIC_WriteOneByte(IIC_TypeDef *IICx,uint8_t IIC_Addr,uint8_t

Reg_addr,uint8_t value)

{

u32 tmr;

tmr = ulTimeOut_Time;

while(IIC_GetFlagStatus(IICx, IIC_FLAG_BUSY));

while((--tmr)&&IIC_GetFlagStatus(IICx, IIC_FLAG_BUSY));

if(tmr==0) IIC_Err = 1;

IIC_GenerateSTART(IICx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx, IIC_EVENT_MASTER_MODE_SELECT)));

if(tmr==0) IIC_Err = 1;

IIC_Send7bitAddress(IICx, IIC_Addr, IIC_Direction_Transmitter);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx,

IIC_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)));

if(tmr==0) IIC_Err = 1;

IIC_SendData(IICx, Reg_addr);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx, IIC_EVENT_MASTER_BYTE_TRANSMITTED)));

if(tmr==0) IIC_Err = 1;

IIC_SendData(IICx, value);

tmr = ulTimeOut_Time;

while((--tmr)&&(!IIC_CheckEvent(IICx, IIC_EVENT_MASTER_BYTE_TRANSMITTED)));

if(tmr==0) IIC_Err = 1;

IIC_GenerateSTOP(IICx, ENABLE);

//IIC_AcknowledgeConfig(IICx, DISABLE);

}

写IIC函数比读仅多了一个输入参数，即要写入的数据。同理，在函数执行完成后，需要检查IIC_Err是否为0以判断IIC是否出错。

有了读1个字节和写入1个字节的函数，当需要一次性读或写多个数据时，可以在上述函数的基础上扩展多字节操作。