GPIO模拟I2C 不通求拍砖

beary 提问时间：2015-9-22 13:57 /

#####################################################
i2c.h
#####################################################
#ifndef _I2C_H_
#define _I2C_H_
#include "stdbool.h"
#include "stm32f4xx_hal.h"

#define u8 uint8_t
#define u16 uint16_t

#define add_w 0x90
#define add_r 0x91
#define SDA_H GPIOB->BSRR=GPIO_PIN_8
#define SDA_L GPIOB->BSRR=(uint32_t)GPIO_PIN_8 << 16

#define SCL_H GPIOB->BSRR=GPIO_PIN_9
#define SCL_L GPIOB->BSRR=(uint32_t)GPIO_PIN_9 << 16

#define SDA_READ GPIOB->IDR& GPIO_PIN_8
#define SCL_READ GPIOB->IDR& GPIO_PIN_9

void writebyte(u8 sendbyte,u16 write_add,u8 device_add);
bool readbyte(u8* pBuffer,u8 length,u16 read_add,u8 device_add);

#######################################
i2c.c
######################################
#include "i2c.h"
void i2c_delay()
{
u8 i = 100;
while(i--);
}

bool i2c_start(void)
{
SDA_H;
SCL_H;
i2c_delay();

if(!SDA_READ)//test the sda != 0
return false;

SDA_L;
i2c_delay();

if(SDA_READ)//test the sda == 0
return false;

SCL_L;
i2c_delay();
return true;
}

void i2c_stop(void)
{
//scl == 0, and sda == 0
SCL_L;
i2c_delay();
SDA_L;
i2c_delay();
//scl = 1 , then sda = 1
SCL_H;
i2c_delay();
SDA_H;
i2c_delay();
}

void i2c_ack(void)
{
SDA_H;
i2c_delay();
SCL_H;
i2c_delay();
SCL_L;
i2c_delay();
SDA_L;
i2c_delay();
SCL_H;
i2c_delay();

}

bool i2c_waitack(void)
{
SCL_L;
i2c_delay();
SDA_H;
i2c_delay();
SCL_H;
i2c_delay();
if(SDA_READ)
{
SCL_L;
return false;
}
SCL_L;
return true;
}

void i2c_sendbyte(u8 send)
{
u8 i = 8;
while(i--)
{
SCL_L;
i2c_delay();
if(send&0x80)
SDA_H;
else
SDA_L;
send <<= 1;
i2c_delay();
SCL_H;
i2c_delay();
}
SCL_L;
}

u8 receivebyte(void)
{
u8 i = 8;
u8 receive = 0;
SDA_H;
while(i--)
{
receive<<=1;
SCL_L;
i2c_delay();
SCL_H;
i2c_delay();
if(SDA_READ)
{
receive |= 0x01;
}
}
SCL_L;
return receive;
}

void writebyte(u8 sendbyte,u16 write_add,u8 device_add)
{
device_add = device_add | 0x00;
i2c_start();
i2c_sendbyte(device_add);
i2c_delay();
i2c_sendbyte(write_add);
i2c_delay();
i2c_sendbyte(sendbyte);
i2c_delay();
i2c_stop();
}

bool readbyte(u8* pBuffer,u8 length,u16 read_add,u8 device_add)
{
device_add = device_add | 0x01;
if(!i2c_start())
return false;
i2c_sendbyte(device_add);
i2c_delay();
i2c_sendbyte(read_add-1);
i2c_delay();
i2c_sendbyte(*pBuffer);
i2c_delay();
i2c_ack();
i2c_delay();
i2c_stop();
return true;
}