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STM32F407的硬件I2C -

来源：网络用户发布，如有版权联系网管删除　2018-09-06　

[导读]我使用的是STM32的固件库。硬件模块使用之前必须配置其参数，I2C的配置如下：void IIC_Config(void){ GPIO_InitTypeDef GPIO_InitStructure; I2C_InitTypeDef I2C_InitStructure; RCC_ClocksTypeDef rcc_clocks;

我使用的是STM32的固件库。

本文引用地址: http://www.21ic.com/app/mcu/201808/782549.htm

硬件模块使用之前必须配置其参数，I2C的配置如下：

void IIC_Config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

I2C_InitTypeDef I2C_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_I2C1|RCC_APB1Periph_I2C2|RCC_APB1Periph_I2C3, ENABLE);

/* Reset I2Cx IP */

RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1|RCC_APB1Periph_I2C2|RCC_APB1Periph_I2C3, ENABLE);

/* Release reset signal of I2Cx IP */

RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1|RCC_APB1Periph_I2C2|RCC_APB1Periph_I2C3, DISABLE);

/*I2C1 configuration*/

GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_I2C1); //注意，此处不能合并写成GPIO_PinSource6|GPIO_PinSource7

GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_I2C1);

//PB6: I2C1_SCL PB7: I2C1_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);

/* I2C Struct Initialize */

I2C_DeInit(I2C1);

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = 0x00;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_ClockSpeed = 100000;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_Init(I2C1, &I2C_InitStructure);

/* I2C Initialize */

I2C_Cmd(I2C1, ENABLE);

/*I2C2 configuration*/

GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_I2C2); //注意，此处不能合并写成GPIO_PinSource6|GPIO_PinSource7

GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_I2C2);

//PB10: I2C2_SCL PB11: I2C2_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);

/* I2C Struct Initialize */

I2C_DeInit(I2C2);

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = 0x00;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_ClockSpeed = 100000;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_Init(I2C2, &I2C_InitStructure);

/* I2C Initialize */

I2C_Cmd(I2C2, ENABLE);

/*I2C3 configuration*/

GPIO_PinAFConfig(GPIOA, GPIO_PinSource8, GPIO_AF_I2C3);

GPIO_PinAFConfig(GPIOC, GPIO_PinSource9, GPIO_AF_I2C3);

//PA8: I2C3_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: I2C3_SDA

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;

GPIO_Init(GPIOC, &GPIO_InitStructure);

/* I2C Struct Initialize */

I2C_DeInit(I2C3);

I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;

I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;

I2C_InitStructure.I2C_OwnAddress1 = 0x00;

I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;

I2C_InitStructure.I2C_ClockSpeed = 100000;

I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

I2C_Init(I2C3, &I2C_InitStructure);

/* I2C Initialize */

I2C_Cmd(I2C3, ENABLE);

/*超时设置*/

RCC_GetClocksFreq(&rcc_clocks);

ulTimeOut_Time = (rcc_clocks.SYSCLK_Frequency /10000);

}

注意，I2C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I2C读一个字节与STM32F103类似，代码如下：

unsigned char I2C_Err=0;

uint8_t I2C_ReadOneByte(I2C_TypeDef *I2Cx,uint8_t I2C_Addr,uint8_t Reg_addr)

{

uint8_t readout;

u32 tmr;

tmr = ulTimeOut_Time;

while((--tmr)&&I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));

if(tmr==0) I2C_Err = 1;

I2C_GenerateSTART(I2Cx, ENABLE);

//发送I2C的START信号，接口自动从从设备编程主设备

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT)));

if(tmr==0) I2C_Err = 1;

I2C_Send7bitAddress(I2Cx,I2C_Addr,I2C_Direction_Transmitter);

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)));

if(tmr==0) I2C_Err = 1;

I2C_SendData(I2Cx, Reg_addr);

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx,I2C_EVENT_MASTER_BYTE_TRANSMITTED)));

if(tmr==0) I2C_Err = 1;

I2C_GenerateSTART(I2Cx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT)));

if(tmr==0) I2C_Err = 1;

I2C_Send7bitAddress(I2Cx, I2C_Addr, I2C_Direction_Receiver);

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED)));

if(tmr==0) I2C_Err = 1;

I2C_AcknowledgeConfig(I2Cx, DISABLE);

I2C_GenerateSTOP(I2Cx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!(I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_BYTE_RECEIVED)))); /* EV7 */

if(tmr==0) I2C_Err = 1;

readout = I2C_ReceiveData(I2Cx);

I2C_AcknowledgeConfig(I2Cx, ENABLE);

return readout;

}

I2C_ReadOneByte函数输入参数有3个，分别是：I2Cx，表示使用的I2C编号，I2C_addr，表示从设备的I2C地址，reg_addr，表示要读取的从设备寄存器地址。I2C_ReadOneByte的返回值就是I2C总线上读取到的数据。读I2C数据后需要检查I2C_Err是否为0，若为0，表示读取I2C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 I2C_Err=0;

void I2C_WriteOneByte(I2C_TypeDef *I2Cx,uint8_t I2C_Addr,uint8_t Reg_addr,uint8_t value)

{

u32 tmr;

tmr = ulTimeOut_Time;

while(I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));

while((--tmr)&&I2C_GetFlagStatus(I2Cx, I2C_FLAG_BUSY));

if(tmr==0) I2C_Err = 1;

I2C_GenerateSTART(I2Cx, ENABLE);

tmr = ulTimeOut_Time;

while((--tmr)&&(!I2C_CheckEvent(I2Cx, I2C_EVENT_MASTER_MODE_SELECT)));