1、SGM58031芯片详解

（1）SGM58031是一款低功耗，16位精度，delta-sigma (ΔΣ)模数转换器(ADC)。它从3V到5.5V供电。

（2）SGM58031包含一个片上参考和振荡器。它有一个I2C兼容接口，可以选择四个I2C从地址。

（3）SGM58031有两种工作模式：单次发射模式和连续转换模式。
在单次触发模式下，ADC执行一次转换并给出完整的固定数据，无需丢弃任何数据。一旦ADC完成转换，它就会进入低功率关闭模式。
在连续模式中，ADC在先前的转换完成后自动开始新的转换。给出了每一个转换结果。数据速率等于配置的数据速率。

（4）SGM58031的引脚说明

（5）参考电压

2、SGM58031工程代码编写

iic.c

#include "iic.h"

#define I2C1_SLAVE_ADDRESS7 0x90

void i2c_config(void)
{
	/* enable GPIOB clock */
    rcu_periph_clock_enable(RCU_GPIOB);
	
    /* enable I2C1 clock */
    rcu_periph_clock_enable(RCU_I2C1);
	rcu_periph_clock_enable(RCU_AF);
	
	/* connect PB10 to I2C1_SCL */
    /* connect PB11 to I2C1_SDA */
    gpio_init(GPIOB, GPIO_MODE_AF_OD, GPIO_OSPEED_50MHZ,  GPIO_PIN_10 | GPIO_PIN_11);
	
    i2c_clock_config(I2C1, 100000, I2C_DTCY_2);
    i2c_mode_addr_config(I2C1, I2C_I2CMODE_ENABLE, I2C_ADDFORMAT_7BITS, I2C1_SLAVE_ADDRESS7);
    i2c_enable(I2C1);
    i2c_ack_config(I2C1, I2C_ACK_ENABLE);
}

/* I2C写函数 */
void i2c_write(uint8_t reg_addr, uint16_t send_data)
{
		
	uint8_t high_val=0x00;
	uint8_t low_val=0x00;
	
	low_val = send_data&0x00ff;				
	high_val = (send_data>>8)&0x00ff;

    //写开始时序
	/* 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 */

    //写从机地址时序
	i2c_master_addressing(I2C1, I2C1_SLAVE_ADDRESS7, I2C_TRANSMITTER);
	/* wait until ADDSEND bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
	/* clear ADDSEND bit */
	i2c_flag_clear(I2C1, I2C_FLAG_ADDSEND);
	/* wait until the transmit data buffer is empty */
	while(!i2c_flag_get(I2C1, I2C_FLAG_TBE));

    //写寄存器地址时序
	i2c_data_transmit(I2C1, reg_addr);
	/* wait until the TBE bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
	
    //写 写入数据 时序
	/* data transmission */
	i2c_data_transmit(I2C1, high_val);//先发送高8位数据
	/* wait until the TBE bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
	i2c_data_transmit(I2C1, low_val);//再发送低8位数据
	/* wait until the TBE bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
	
    //写停止时序	
	/* send a stop condition to I2C bus */
	i2c_stop_on_bus(I2C1);
	/* wait until stop condition generate */ 
	while(I2C_CTL0(I2C1)&0x0200);
}


/* I2C读函数 */
uint16_t i2c_read_byte(uint8_t reg_addr)
{
	uint8_t high_val=0x00;
	uint8_t low_val=0x00;
	uint16_t recv_val = 0x0000;

    //写开始时序
	/* 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));    

    //写 从机地址+写 时序
	/* send slave address to I2C bus */
	i2c_master_addressing(I2C1, I2C1_SLAVE_ADDRESS7, I2C_TRANSMITTER);
	/* wait until ADDSEND bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_ADDSEND));
	/* clear ADDSEND bit */
	i2c_flag_clear(I2C1, I2C_FLAG_ADDSEND);
	/* wait until the transmit data buffer is empty */
	while(!i2c_flag_get(I2C1, I2C_FLAG_TBE));
	
    //写 读寄存器地址 时序
	i2c_data_transmit(I2C1, reg_addr);
	/* wait until the BTC bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));
	
    //写停止时序
	i2c_stop_on_bus(I2C1);
	while(I2C_CTL0(I2C1)&0x0200);
	
    //写开始时序	
	i2c_start_on_bus(I2C1);
	/* wait until SBSEND bit is set */
	while(!i2c_flag_get(I2C1, I2C_FLAG_SBSEND));

    //写 从机地址+读 时序
	/* send slave address to I2C bus */
	i2c_master_addressing(I2C1, I2C1_SLAVE_ADDRESS7, 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);
	/* wait until the RBNE bit is set	and clear it*/
	while(!i2c_flag_get(I2C1, I2C_FLAG_RBNE));
	
    //接收数据 时序
	high_val = i2c_data_receive(I2C1);
	while(!i2c_flag_get(I2C1, I2C_FLAG_RBNE));
	i2c_ack_config(I2C1, I2C_ACK_DISABLE);
    i2c_ackpos_config(I2C1,I2C_ACKPOS_NEXT);
	
	low_val = i2c_data_receive(I2C1);
	/* wait until the BTC bit is set */
	//while(!i2c_flag_get(I2C1, I2C_FLAG_BTC));代码卡死，屏蔽后不卡死，可以成功读取数据		

    //写停止时序
	/* send a stop condition to I2C bus */
	i2c_stop_on_bus(I2C1);
	/* wait until stop condition generate */ 
	while(I2C_CTL0(I2C1)&0x0200);

	recv_val = (high_val<<8)|low_val;
	
	i2c_ack_config(I2C1, I2C_ACK_ENABLE);

	return recv_val;
}

iic.h

#ifndef __IIC_H
#define __IIC_H

#include "gd32f30x.h"
#include "string.h"

void i2c_config(void);
void i2c_write(uint8_t reg_addr, uint16_t send_data);
uint16_t i2c_read_byte(uint8_t reg_addr);

#endif

main.c

    // 使能 RDY输出功能
	i2c_write(0x03,0x8000); // Write 0x8000 to Hi_Thresh
	i2c_write(0x02,0x0000); // Write  0x0000  to Lo_Thresh
	
	// 配置ADC输入， 启动连续转换模式
	i2c_write(0x01,0xC4e0);//Write config, OS=1, AIN0 to GND, G=2(+/-2.048V input range),
									 //continuous mode conversion, DR=800, others default 
									 //COMP_QUE = 00

	
    Vbat = i2c_read_byte(0x00);//读取电压值

    //转换  Vbat/65535*参考电压（比如4.096V)