i2c1采用DMA方式的读写函数

1、关于i2c1的DMA的映射如图

2、关于代码的宏定义配置
Application目录的Makefile中 ENABLE_I2C_TEST = yes才会编译I2C1的相关代码。
同时修改i2c.h文件，定义I2C1_MODE为I2C1_MODE_DMA，这样i2c1的配置为dma模式。

#define I2C1_MODE                   I2C1_MODE_DMA

3、I2C相关配置，外部调用函数，供main.c初始化i2c1时使用。
代码如下：

void i2c1_dma_init(void)
{/* enable GPIOB clock */rcu_periph_clock_enable(RCU_GPIOB);rcu_periph_clock_enable(RCU_DMA0);/* enable I2C1 clock */rcu_periph_clock_enable(RCU_I2C1);/* connect PB10 to I2C1_SCL *//* connect PB11 to I2C2_SDA */gpio_init(GPIOB, GPIO_MODE_AF_OD, GPIO_OSPEED_50MHZ, GPIO_PIN_10 | GPIO_PIN_11);//配置PB10,PB11为复用功能/* configure I2C clock */i2c_clock_config(I2C1, I2C1_SPEED, I2C_DTCY_2);/* configure I2C address */i2c_mode_addr_config(I2C1, I2C_I2CMODE_ENABLE, I2C_ADDFORMAT_7BITS, 0xff);/* enable I2C1 */i2c_enable(I2C1);/* enable acknowledge */i2c_ack_config(I2C1, I2C_ACK_ENABLE);
}

4、DMA发送函数，可发送多字节寄存器+数据格式。

static void i2c1_dma_tx_config(uint8_t *p_data,uint8_t len)
{dma_parameter_struct dma_init_struct;/* initialize DMA channel3 */dma_deinit(DMA0, DMA_CH3);dma_init_struct.direction = DMA_MEMORY_TO_PERIPHERAL;dma_init_struct.memory_addr = (uint32_t)p_data;dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE;dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT;dma_init_struct.number = len;dma_init_struct.periph_addr = (uint32_t)&I2C_DATA(I2C1);dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_8BIT;dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;dma_init(DMA0, DMA_CH3, &dma_init_struct);
}static void i2c1_dma_tx_data(uint8_t slave_addr,uint8_t *p_data,uint8_t len)
{/* wait until I2C bus is idle */while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));/* send a start condition to I2C bus */i2c_start_on_bus(I2C1);/* wait until SBSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));/* send slave address to I2C bus */i2c_master_addressing(I2C1, slave_addr, I2C_TRANSMITTER);/* wait until ADDSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));/* clear the ADDSEND bit */i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);/* wait until the transmit data buffer is empty */while( SET != i2c_flag_get(I2C1, I2C_FLAG_TBE));i2c1_dma_tx_config(p_data,len);/* enable I2C1 DMA */i2c_dma_config(I2C1, I2C_DMA_ON);/* enable DMA0 channel3 */dma_channel_enable(DMA0, DMA_CH3);/* DMA0 channel3 full transfer finish flag */while(!dma_flag_get(DMA0, DMA_CH3, DMA_FLAG_FTF));/* send a stop condition to I2C bus */i2c_stop_on_bus(I2C1);/* wait until the stop condition is finished */while(I2C_CTL0(I2C1)&0x0200);  
}
/*** 封装一个函数按寄存器写的函数，寄存器地址可以有多位。* 数据可以有多个* dma方式
*/
void i2c1_dma_send_data(uint8_t slave_addr,uint8_t *reg_addr,uint16_t addr_len,uint8_t *p_data,uint8_t data_len)
{uint8_t data[I2C_TX_RX_DATA_LEN_MAX] = {0};uint8_t *p;if ((addr_len + data_len) > I2C_TX_RX_DATA_LEN_MAX){perror("data to long and return\r\n");return ;}p = data;memcpy(p,reg_addr,addr_len);p += addr_len;memcpy(p,p_data,data_len);i2c1_dma_tx_data(slave_addr,data,(addr_len+data_len));}	

5、DMA接收函数封装，注意读取一个自己数据的时候，不能采用dma的方式，在函数中做了判断，一个字节的读取继续用poll方式。

uint8_t i2c1_buff_rx[128];static void i2c1_dma_rx_config(uint8_t *p_data,uint8_t len)
{dma_parameter_struct dma_init_struct;/* initialize DMA channel4 */dma_deinit(DMA0, DMA_CH4);dma_init_struct.direction = DMA_PERIPHERAL_TO_MEMORY;dma_init_struct.memory_addr = (uint32_t)p_data;dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE;dma_init_struct.memory_width = DMA_MEMORY_WIDTH_8BIT;dma_init_struct.number = len;dma_init_struct.periph_addr = (uint32_t)&I2C_DATA(I2C1);dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_8BIT;dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;dma_init(DMA0, DMA_CH4, &dma_init_struct);
}void i2c1_dma_receive_data(uint8_t slave_addr, uint8_t *reg_addr,uint16_t addr_len,  uint8_t* p_buffer, uint16_t number_of_byte)
{  /* wait until I2C bus is idle */while(i2c_flag_get(I2C1, I2C_FLAG_I2CBSY));/* send a start condition to I2C bus */i2c_start_on_bus(I2C1);/* wait until SBSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));/* send slave address to I2C bus */i2c_master_addressing(I2C1, slave_addr, I2C_TRANSMITTER);/* wait until ADDSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));/* clear the ADDSEND bit */i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);/* wait until the transmit data buffer is empty */while(SET != i2c_flag_get( I2C1 , I2C_FLAG_TBE));/* enable I2C1*/i2c_enable(I2C1);/* send the EEPROM's internal address to write to */while (addr_len){i2c_data_transmit(I2C1, *reg_addr++); addr_len--; /* wait until BTC bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));}/* send a start condition to I2C bus */i2c_start_on_bus(I2C1);/* wait until SBSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));/* send slave address to I2C bus */i2c_master_addressing(I2C1, slave_addr, I2C_RECEIVER);/* wait until ADDSEND bit is set */while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));/* clear the ADDSEND bit */i2c_flag_clear(I2C1,I2C_FLAG_ADDSEND);if(number_of_byte < 2) {/* disable acknowledge */i2c_ack_config(I2C1, I2C_ACK_DISABLE);/* clear ADDSEND register by reading I2C_STAT0 then I2C_STAT1 register (I2C_STAT0 has already been read) */i2c_flag_get(I2C1, I2C_FLAG_ADDSEND);/* send a stop condition to I2C bus*/i2c_stop_on_bus(I2C1);/* wait for the byte to be received */while(!i2c_flag_get(I2C1, I2C_FLAG_RBNE));/* read the byte received from the EEPROM */*p_buffer = i2c_data_receive(I2C1);/* decrement the read bytes counter */number_of_byte--;     } else{i2c1_dma_rx_config(p_buffer,number_of_byte);i2c_dma_last_transfer_config(I2C1, I2C_DMALST_ON);/* enable I2C1 DMA */i2c_dma_config(I2C1, I2C_DMA_ON);/* enable DMA0 channel5 */dma_channel_enable(DMA0, DMA_CH4);/* wait until BTC bit is set */while(!dma_flag_get(DMA0, DMA_CH4, DMA_FLAG_FTF));}/* wait until the stop condition is finished */while(I2C_CTL0(I2C1)&0x0200);i2c_stop_on_bus(I2C1);/* enable acknowledge */i2c_ack_config(I2C1,I2C_ACK_ENABLE);i2c_ackpos_config(I2C1,I2C_ACKPOS_CURRENT);}

5、main.c中调用，往eeprom中写入{0x02,0x07,0x05,0x45,0x56,0x89,0xF3，然后读出来，看看是否一致。

uint8_t addr = 0x00;
unsigned char data[7] = {0x02,0x07,0x05,0x45,0x56,0x89,0xF3};
i2c1_dma_init();
i2c1_dma_send_data(0xA0,&addr,1,data,7);delay_1ms(200);
unsigned char r_data[7];
i2c1_dma_receive_data(0xA0,&addr,1,r_data,7);
print_register_value(r_data,7);

读出来是一样的
6、代码路径：https://gitee.com/xiaoguo-tec_0/gd32-iap-code.git