STM32基于模拟I2C通信的8位和16位读取方法及多字节读取技巧

GPIO模拟I2C驱动的通用代码，I2C的寄存器地址有8位和16位的，主要解决了同一个MCU同时处理8位和16位寄存器地址芯片时候的驱动问题。

typedef enum {
    IIC_8BIT_BASE_ADDR,
    IIC_16BIT_BASE_ADDR
}iic_bits_e;
typedef struct {
    uint8_t DevAddr;
    uint16_t RegAddr;
    uint8_t data_len;
    uint8_t * data_buf;
    uint8_t bit_flag;
    uint16_t delay;
}iic_param_t;

以上是结构体，作为参数，其中DevAddr是芯片地址，RegAddr是寄存器地址，data_len是写入或者读取的数据长度，data_buf是写入或者读出的数据缓冲区，bit_flag是寄存器位数IIC_8BIT_BASE_ADDR是8位，IIC_16BIT_BASE_ADDR是16位。delay是根据需求读写数据时候的延时。根据芯片需求填写，用不到就填0

下面是用法：

写8bit寄存器

void bq27426_write_data(uint16_t reg, uint8_t * buf, uint8_t len)
{
    iic_param_t bq27426 = {
        BQ27426_DEV_ADDR,
        0,
        0,
        NULL,
        IIC_8BIT_BASE_ADDR,
        30
    };
    bq27426.RegAddr = reg;
    bq27426.data_buf = buf;
    bq27426.data_len = len;
    simulate_i2c_writeblock(&bq27426);

}

写16bit寄存器

void cypd3176_write_data(uint16_t reg, uint8_t * buf, uint8_t len)
{
    iic_param_t cypd3176 = {
        CYPD3176_DEV_ADDR,
        0,
        0,
        NULL,
        IIC_16BIT_BASE_ADDR,
        0
    };
    cypd3176.RegAddr = reg;
    cypd3176.data_buf = buf;
    cypd3176.data_len = len;
    simulate_i2c_writeblock(&cypd3176);
}

读8bit寄存器

void bq27426_read_data(uint16_t reg, uint8_t * buf, uint8_t len)
{
    iic_param_t bq27426 = {
        BQ27426_DEV_ADDR,
        0,
        0,
        NULL,
        IIC_8BIT_BASE_ADDR,
        30
    };
    bq27426.RegAddr = reg;
    bq27426.data_buf = buf;
    bq27426.data_len = len;
    simulate_i2c_readblock(&bq27426);

}

读16bit寄存器

void cypd3176_read_data(uint16_t reg, uint8_t * buf, uint8_t len)
{
    iic_param_t cypd3176 = {
        CYPD3176_DEV_ADDR,
        0,
        0,
        NULL,
        IIC_16BIT_BASE_ADDR,
        0
    };
    cypd3176.RegAddr = reg;
    cypd3176.data_buf = buf;
    cypd3176.data_len = len;
    simulate_i2c_readblock(&cypd3176);
}

下面是源码

#include "stdio.h"
#include "simulate.h"

#define PORT_I2C_SCL GPIOB
#define PIN_I2C_SCL GPIO_Pin_6

#define PORT_I2C_SDA GPIOB
#define PIN_I2C_SDA GPIO_Pin_7

#define simulate_IIC_SCL PBout(6) 
#define simulate_IIC_SDA PBout(7) 
#define simulate_READ_SDA PBin(7) 

static void i2c_Delay(void);
static void i2c_PinModeOutput(void);
static void i2c_PinModeInput(void);
static void i2c_SCL(uint8_t stat);
static void i2c_SDA(uint8_t stat);
static uint8_t i2c_ReadSDA(void);
static void i2c_Stop(void);

iic_param_t simulate = {
	simulate_ADDR,
	0,
	0,
	NULL,
	IIC_16BIT_BASE_ADDR,
	0
};


static void i2c_Delay(void)
{
	unsigned char t = 3;
	while (t--)
		;
}

static void i2c_PinModeOutput(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); // ʹ��A�˿�ʱ��
	GPIO_InitStructure.GPIO_Pin = PIN_I2C_SDA;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;  // �������
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; // �ٶ�50MHz
	GPIO_Init(PORT_I2C_SDA, &GPIO_InitStructure);	  // ��ʼ��PA0,1
}

static void i2c_PinModeInput(void)
{

	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); // ʹ��A�˿�ʱ��
	GPIO_InitStructure.GPIO_Pin = PIN_I2C_SDA;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;	  // �������
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; // �ٶ�50MHz
	GPIO_Init(PORT_I2C_SDA, &GPIO_InitStructure);	  // ��ʼ��PA0,1
}

static void i2c_SCL(uint8_t stat)
{
	if (stat)
	{
		simulate_IIC_SCL = 1;
	}
	else
	{
		simulate_IIC_SCL = 0;
	}
}

static void i2c_SDA(uint8_t stat)
{
	if (stat)
	{
		simulate_IIC_SDA = 1;
	}
	else
	{
		simulate_IIC_SDA = 0;
	}
}


static uint8_t i2c_ReadSDA(void)
{
	if (simulate_READ_SDA)
	{
		return 1;
	}
	else
	{
		return 0;
	}
}

void i2c_Start(void)
{
	i2c_PinModeOutput();

	i2c_SDA(1);
	i2c_Delay();
	i2c_SCL(1);
	i2c_Delay();

	i2c_SDA(0);
	i2c_Delay();

	i2c_SCL(0);
	i2c_Delay();
}

void i2c_Stop(void)
{
	i2c_PinModeOutput();

	i2c_SCL(0);
	i2c_SDA(0);
	i2c_Delay();

	i2c_SCL(1);
	i2c_Delay();
	i2c_SDA(1);
	i2c_Delay();
}

void i2c_WriteByte(uint8_t _ucByte)
{
	uint8_t i;

	i2c_PinModeOutput();

	i2c_SCL(0);
	i2c_Delay();

	for (i = 0; i < 8; i++)
	{
		if (_ucByte & 0x80)
		{
			i2c_SDA(1);
		}
		else
		{
			i2c_SDA(0);
		}

		_ucByte = _ucByte << 1;

		i2c_SCL(1);
		i2c_Delay();
		i2c_SCL(0);
		i2c_Delay();
	}

	i2c_SDA(1);
}

uint8_t i2c_ReadByte(void)
{
	uint8_t i;
	uint8_t recv = 0;

	i2c_PinModeOutput();

	i2c_SDA(1);
	i2c_Delay();

	i2c_PinModeInput();

	for (i = 0; i < 8; i++)
	{
		recv = recv << 1;

		i2c_SCL(1);
		i2c_Delay();

		if (i2c_ReadSDA())
		{
			recv |= 0x01;
		}
		else
		{
			recv |= 0x00;
		}

		i2c_SCL(0);
		i2c_Delay();
	}

	return recv;
}

void i2c_Ack(void)
{
	i2c_PinModeOutput();

	i2c_SCL(0);
	i2c_SDA(0);
	i2c_Delay();

	i2c_SCL(1);
	i2c_Delay();

	i2c_SCL(0);
}

void i2c_NAck(void)
{
	i2c_PinModeOutput();

	i2c_SCL(0);
	i2c_SDA(1);
	i2c_Delay();

	i2c_SCL(1);
	i2c_Delay();

	i2c_SCL(0);
}

uint8_t i2c_CheckAck(void)
{
	uint8_t time = 0;

	i2c_PinModeOutput();

	i2c_SDA(1);
	i2c_Delay();
	i2c_SCL(1);
	i2c_Delay();

	i2c_PinModeInput();

	while (i2c_ReadSDA())
	{
		time++;
		if (time >= 100)
		{
			return 1;
		}
	}

	i2c_SCL(0);

	return 0;
}

#define I2C_WR 0x00
#define I2C_RD 0x01
#define ACK 0
#define NOACK 1

void simulate_i2c_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); 
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;  
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);			  
	GPIO_SetBits(GPIOB, GPIO_Pin_6 | GPIO_Pin_7);
}

uint8_t iic_chip_select(iic_param_t *param, uint8_t rw_flag)
{
	uint16_t i = 0;
	if (param->data_len > 40)
	{
		return 0xf1;
	}
	if (param->data_buf == NULL)
	{
		return 0xF2;
	}
	for (i = 0; i < 3; i++)
	{
		i2c_Start();
		i2c_WriteByte((param->DevAddr << 1) | rw_flag); 
		if (i2c_CheckAck() == ACK)
		{
			break;
		}
	}
	if (i >= 3)
	{
		i2c_Stop();
		return 0xf1;
	}
	return 0;
}

uint8_t simulate_i2c_writeblock(iic_param_t *param)
{
	uint16_t i;
	if (0 != iic_chip_select(param, I2C_WR))
	{
		return 0xF1;
	}

	if (IIC_16BIT_BASE_ADDR == param->bit_flag)
	{
		i2c_WriteByte((param->RegAddr & 0xFF00) >> 8);
		if (i2c_CheckAck() == NOACK)
		{
			i2c_Stop();
			return 0xf7;
		}
	}
	i2c_WriteByte(param->RegAddr & 0x00FF);
	if (i2c_CheckAck() == NOACK)
	{
		i2c_Stop();
		return 0xf3;
	}

	for (i = 0; i < param->data_len; i++)
	{
		i2c_WriteByte(param->data_buf[i]);
		if (i2c_CheckAck() == NOACK)
		{
			i2c_Stop();
			return 0xf4;
		}
	}

	i2c_Stop();
	for (i = 0; i < 100; i++)
	{
		i2c_Delay();
	}
	return 0;
}

uint8_t simulate_i2c_readblock(iic_param_t *param)
{

	uint16_t i;
	int16_t j;

	if (0 != iic_chip_select(param, I2C_WR))
	{
		return 0xF1;
	}

	/* 发送地址 */

	if (IIC_16BIT_BASE_ADDR == param->bit_flag)
	{
		i2c_WriteByte((param->RegAddr & 0xFF00) >> 8);
		if (i2c_CheckAck() == NOACK)
		{
			i2c_Stop();
			return 0xf7;
		}
	}
	i2c_WriteByte(param->RegAddr & 0x00FF);
	if (i2c_CheckAck() == NOACK)
	{
		i2c_Stop();
		return 0xf8;
	}

	if (0 != iic_chip_select(param, I2C_RD))
	{
		return 0xF1;
	}

	for (i = 0; i < param->data_len - 1; i++)
	{
		for (j = 0; j < param->delay; j++)
		{
			i2c_Delay();
		}
		param->data_buf[i] = i2c_ReadByte();

		for (j = 0; j < param->delay; j++)
		{
			i2c_Delay();
		}
		i2c_Ack();
	}
	for (j = 0; j < param->delay; j++)
	{
		i2c_Delay();
	}
	param->data_buf[param->data_len - 1] = i2c_ReadByte();
	i2c_NAck();
	i2c_Stop();
	return 0;
}

#ifndef __IIC_DRIVER_H__
#define __IIC_DRIVER_H__

#include "sys.h"
#include "stdlib.h"	


#define simulate_ADDR  (0x5F)

typedef enum {
    IIC_8BIT_BASE_ADDR,
    IIC_16BIT_BASE_ADDR
}iic_bits_e;
typedef struct {
    uint8_t DevAddr;
    uint16_t RegAddr;
    uint8_t data_len;
    uint8_t * data_buf;
    uint8_t bit_flag;
    uint16_t delay;
}iic_param_t;


void simulate_i2c_init(void);
uint8_t simulate_i2c_readblock(iic_param_t * param);
uint8_t simulate_i2c_writeblock(iic_param_t * param);


#endif 

如果找不到PBout可用下面的头文件，其他平台可以自己实现设置管脚的输入和输出模式替换掉文中的PBout PBin的接口

/* Includes ------------------------------------------------------------------*/
#ifndef __SYS_H
#define __SYS_H	
#include "stm32f10x.h"


#define BITBAND(addr, bitnum) ((addr & 0xF0000000)+0x2000000+((addr &0xFFFFF)<<5)+(bitnum<<2)) 
#define MEM_ADDR(addr)  *((volatile unsigned long  *)(addr)) 
#define BIT_ADDR(addr, bitnum)   MEM_ADDR(BITBAND(addr, bitnum))


#define GPIOA_ODR_Addr    (GPIOA_BASE+12) //0x4001080C 
#define GPIOB_ODR_Addr    (GPIOB_BASE+12) //0x40010C0C 
#define GPIOC_ODR_Addr    (GPIOC_BASE+12) //0x4001100C 
#define GPIOD_ODR_Addr    (GPIOD_BASE+12) //0x4001140C 
#define GPIOE_ODR_Addr    (GPIOE_BASE+12) //0x4001180C 
#define GPIOF_ODR_Addr    (GPIOF_BASE+12) //0x40011A0C    
#define GPIOG_ODR_Addr    (GPIOG_BASE+12) //0x40011E0C    

#define GPIOA_IDR_Addr    (GPIOA_BASE+8) //0x40010808 
#define GPIOB_IDR_Addr    (GPIOB_BASE+8) //0x40010C08 
#define GPIOC_IDR_Addr    (GPIOC_BASE+8) //0x40011008 
#define GPIOD_IDR_Addr    (GPIOD_BASE+8) //0x40011408 
#define GPIOE_IDR_Addr    (GPIOE_BASE+8) //0x40011808 
#define GPIOF_IDR_Addr    (GPIOF_BASE+8) //0x40011A08 
#define GPIOG_IDR_Addr    (GPIOG_BASE+8) //0x40011E08 
 

#define PAout(n)   BIT_ADDR(GPIOA_ODR_Addr,n)
#define PAin(n)    BIT_ADDR(GPIOA_IDR_Addr,n)

#define PBout(n)   BIT_ADDR(GPIOB_ODR_Addr,n) 
#define PBin(n)    BIT_ADDR(GPIOB_IDR_Addr,n)

#define PCout(n)   BIT_ADDR(GPIOC_ODR_Addr,n)
#define PCin(n)    BIT_ADDR(GPIOC_IDR_Addr,n)

#define PDout(n)   BIT_ADDR(GPIOD_ODR_Addr,n) 
#define PDin(n)    BIT_ADDR(GPIOD_IDR_Addr,n) 

#define PEout(n)   BIT_ADDR(GPIOE_ODR_Addr,n) 
#define PEin(n)    BIT_ADDR(GPIOE_IDR_Addr,n)

#define PFout(n)   BIT_ADDR(GPIOF_ODR_Addr,n)
#define PFin(n)    BIT_ADDR(GPIOF_IDR_Addr,n) 

#define PGout(n)   BIT_ADDR(GPIOG_ODR_Addr,n)
#define PGin(n)    BIT_ADDR(GPIOG_IDR_Addr,n)  


#endif