开发流程

1. 引脚初始化
2. 引脚功能定义
3. 实现读操作
4. 实现写操作

GD32F4软件I2C初始化

void SoftI2C_init() {// 时钟配置rcu_periph_clock_enable(SCL_RCU);// 设置输出模式gpio_mode_set(SCL_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, SCL_PIN);gpio_output_options_set(SCL_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, SCL_PIN);// 时钟配置rcu_periph_clock_enable(SDA_RCU);// 设置输出模式gpio_mode_set(SDA_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, SDA_PIN);gpio_output_options_set(SDA_PORT, GPIO_OTYPE_OD, GPIO_OSPEED_50MHZ, SDA_PIN);
}

• I2C引脚高低电平

GD32F4软件I2C引脚功能

#define SCL_RCU		RCU_GPIOB
#define SCL_PORT	GPIOB
#define SCL_PIN		GPIO_PIN_6
#define SCL_AF		GPIO_AF_4#define SDA_RCU		RCU_GPIOB
#define SDA_PORT	GPIOB
#define SDA_PIN		GPIO_PIN_7
#define SDA_AF		GPIO_AF_4/************** io ***************/
#define SCL(BIT) 		gpio_bit_write(SCL_PORT, SCL_PIN, BIT?SET:RESET)
#define SDA(BIT) 		gpio_bit_write(SDA_PORT, SDA_PIN, BIT?SET:RESET)
#define SDA_STATE() 	gpio_input_bit_get(SDA_PORT, SDA_PIN)#define SDA_IN()  	gpio_mode_set(SDA_PORT, GPIO_MODE_INPUT,  GPIO_PUPD_NONE, SDA_PIN)
#define SDA_OUT() 	gpio_mode_set(SDA_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, SDA_PIN)

• IO引脚定义
• 引脚输出模式高低电平输出：SCL高和低，SDA高和低
• SDA模式配置：SDA输出模式，SDA输入模式
• SDA输入模式状态读取。

写操作

uint8_t SoftI2C_write(uint8_t addr, uint8_t reg, uint8_t* data, uint32_t len) {start();send(addr << 1);			//发送设备写地址if(wait_ack()) return 1;	//等待响应send(reg);					//发送寄存器地址if(wait_ack()) return 2;	//等待响应do {send(*data++);if(wait_ack()) return 3;} while(--len);stop();return 0;
}

读操作

uint8_t SoftI2C_read(uint8_t addr, uint8_t reg, uint8_t* data, uint32_t len) {start();send(addr << 1);				//发送设备写地址if(wait_ack()) return 1;		//等待响应send(reg);						//发送寄存器地址if(wait_ack()) return 2;		//等待响应start();send((addr << 1) | 0x01);		//发送设备读地址if(wait_ack()) return 3;		//等待响应do {*data = recv();data++;if(len != 1) send_ack();	// 发送 ACK} while(--len);send_nack();					// 发送 NACKstop();return 0;
}