STM32F103 Slave I2C配置
今年才接触STM32开发，由于项目需求需要，需要linux系统与STM32通过I2C进行通讯，网上合适资料有限，花了不少时间，所以记录在此。描述：Linux发送数据后，每隔10ms轮询stm32（应该做中断触发的，但由于硬件接口限制），只读一个字节判断是否有数据，如果有则读相应长度的内容。自定义缓冲区格式：首字节为长度信息，后面是内容信息，如uint8_t I2C_Buffer_Rx[128];//0:len 1...=>data（1）I2C Slave初始化
void IIC_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
I2C_InitTypeDef I2C_InitStructure;
RCC_APB2PeriphClockCmd (RCC_APB2Periph_GPIOB , ENABLE);
/* Configure I2C2 pins: SCL and SDA */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10|GPIO_Pin_11; //10:SCL 11:SDA
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;//Out_PP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
RCC_APB1PeriphClockCmd (RCC_APB1Periph_I2C2, ENABLE);
I2C_DeInit(I2C2);
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
I2C_InitStructure.I2C_OwnAddress1 = 0x10<<1;//temp addr
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_ClockSpeed = 400000;
I2C_Init(I2C2, &I2C_InitStructure);
I2C_ITConfig(I2C2, I2C_IT_EVT|I2C_IT_BUF, ENABLE);
I2C_Cmd(I2C2,ENABLE);
}void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = I2C2_EV_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 4;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}上述两条是基本操作，仔细看参数是没啥问题，最麻烦的是I2C状态，使用官方的问题很大，例如：
#define I2C_EVENT_SLAVE_TRANSMITTER_ADDRESS_MATCHED ((uint32_t)0x00060082) /* TRA, BUSY, TXE and ADDR flags */
而实还有0x20402的情况，类似情况太多了，经常冒出一个新状态，并且接收和停止可能合在一起。我开始使用case语句来判断状态的，待状态测试稳定后使用if来进行Bit位判断，目前比较稳定。见I2C中断处理。
（3）I2C中断处理
此地方核心是I2C状态处理，收发的数据格式类似串口操作，代码如下：
uint8_t I2C_Buffer_Rx[128];//0:len 1...=>data
static uint8_t I2C_Buffer_Tx[128];//0:len 1...=>data
void I2C2_EV_IRQHandler(void)
{
uint32_t I2CFlagStatus;
static uint8_t num = 0;
I2CFlagStatus = I2C_GetLastEvent(I2C2); // => (SR2<<16|SR1)
if ((I2CFlagStatus & 0x02) != 0){ //bit1:addr matched
if(I2CFlagStatus & 0x80) //bit7 Data register empty (transmitters)
{//read
num = 0;
I2C_SendData(I2C2, I2C_Buffer_Tx[num]);
}else{
num = 1;
I2C_Buffer_Tx[0] = 0;
I2C_Buffer_Rx[0] = 0;
}
}else if((I2CFlagStatus & 0x80) != 0){ // bit7 TxE -Data register empty (transmitters)
if((I2CFlagStatus & 0x04)==0){ //bit2 BTF (Byte transfer finished)
num++;
I2C_SendData(I2C2, I2C_Buffer_Tx[num]); //printf("I2C status:0x%x\r\n", I2CFlagStatus);
}
}else if((I2CFlagStatus & 0x40)&&(I2CFlagStatus & 0x10)){ //bit6(RxNE) + bit4(STOPF)
I2C_Buffer_Rx[num] = I2C_ReceiveData(I2C2); //g_debug_count1++;
num++;
I2C_Buffer_Rx[0] = num-1;
I2C2->CR1 |= 0x1000;//CR1_PEC_Set;
}else if((I2CFlagStatus & 0x40) != 0){ //bit6 RxNE -Data register not empty (receivers))
I2C_Buffer_Rx[num] = I2C_ReceiveData(I2C2);
num++;
}else if((I2CFlagStatus & 0x10) != 0){ //bit4 STOPF -Stop detection (slave mode)
I2C_Buffer_Rx[0] = num-1;
I2C2->CR1 |= 0x1000;//CR1_PEC_Set;
}else{
printf("I2C error status:0x%x\r\n", I2CFlagStatus);
}
I2C2->SR1=0;
I2C2->SR2=0;
}
（4）数据接收处理
我传输的数据长度是7到128字节之间。
void Recive_RXD_Deal(void)
{//I2C_Buffer_Rx 0:len 1->data
u8 i,len;
len = I2C_Buffer_Rx[0];
if(len)
{
/*printf("i2c recv len:%d:",len);
for(i=1; i<=len; i++)
printf(" %x ",I2C_Buffer_Rx[i]);
printf("end\r\n");*/
if(len < 7) return;
if( len != (I2C_Buffer_Rx[3]+1)) return;
if(I2C_Buffer_Rx[len-1] == (unsigned char )(Cheak_Sum(len-4, I2C_Buffer_Rx+3) &0xff))
{
UART2RXBuffer_Checked = &I2C_Buffer_Rx[1];
RXD_Deal_PROCESS();
}else{
printf("checksum error data[%d]=> ",len);
for(i=0; i<=len; i++) printf(" 0x%02x",I2C_Buffer_Rx[i]);
printf("end\n");
}
I2C_Buffer_Rx[0]=0;
}
}
（5）数据发送接口：
void Raspberry_Send_Datas(unsigned char *data,uint16_t length)
{
uint8 i;
// printf("send data len[%d]:",length);
for(i=0; i应该就上面这些了。