Read and write MMA7455 program on STC89C52

main.c

#include 
#include "mytype.h"
#include "iic.h"
#include "mma7455.h"

uint8 X,Y,Z;
void main()
{
 uint8 i,temp;
 EA=1; //Open interrupt
 EX1=1; //Open external interrupt INIT1
 
  //Initialize IIC bus
 IIC_init();

 //Write data
  IIC_start();
 IIC_write_byte(MMA7455_ADDER_WRITE); //1. Address MMA7455 on IIC bus
 IIC_respons();
 IIC_write_byte(MMA7455_Mode_Control_Register); //2. Address mode setting register
 IIC_respons();
 IIC_write_byte(0x05); //3. Write mode register data
 IIC_respons();
 IIC_stop();

 //Write data
  IIC_start();
 IIC_write_byte(MMA7455_ADDER_WRITE); //1. Address MMA7455 on the IIC bus
 IIC_respons();
 IIC_write_byte(MMA7455_Mode_Control_Register); //2. Address the range detection setting register
 IIC_respons();
 IIC_write_byte(MMA7455_2G_Measurement_Mode); //3. Set the range to 2G, detection mode. Write the range detection setting register configuration data
 IIC_respons();
 IIC_stop();

  while(1)
 {
  //Read X-axis data
  IIC_start();
  IIC_write_byte(MMA7455_ADDER_WRITE); //1. IIC address addressing
  IIC_respons();
  IIC_write_byte(MMA7455_READ_X); //2. X-axis data register addressing
  IIC_respons();
  IIC_start(); //3.
  IIC_write_byte(MMA7455_ADDER_READ); //Change read and write direction
  IIC_respons();
  X=IIC_read_byte(); //4.Read data
  IIC_stop();
  //Read Y-axis data
  IIC_start();
  IIC_write_byte(MMA7455_ADDER_WRITE); //1. IIC address addressing
  IIC_respons();
  IIC_write_byte(MMA7455_READ_Y); //2. X-axis data register addressing
  IIC_respons();
  IIC_start(); //3.
  IIC_write_byte(MMA7455_ADDER_READ); //Change read and write direction
  IIC_respons();
  Y=IIC_read_byte(); //4.Read data
  IIC_stop();
  //Read X-axis data
  IIC_start();
  IIC_write_byte(MMA7455_ADDER_WRITE); //1. IIC address addressing
  IIC_respons();
  IIC_write_byte(MMA7455_READ_X); //2. X-axis data register addressing
  IIC_respons();
  IIC_start(); //3.
  IIC_write_byte(MMA7455_ADDER_READ); //Change read and write direction
  IIC_respons();
  Z=IIC_read_byte(); //4.Read data
  IIC_stop();
 }
}

iic.c

#include
#include
#include "iic.h"
#include "mytype.h"

#define  NOP()   _nop_()  
#define  _Nop()  _nop_()  

void IIC_start() 
{
 SDA=1;        
 _Nop();
 SCL=1;
 _Nop();       
 _Nop();
 _Nop();
 _Nop();
 _Nop();   
 SDA=0;        
 _Nop();       
 _Nop();
 _Nop();
 _Nop();
 _Nop();      
 SCL=0;      
 _Nop();
 _Nop();
}

void IIC_stop()  
{
SDA=0;     
_Nop();      
SCL=1;     
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
SDA=1;     
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
_Nop();
}

void IIC_init()  //
{
 SDA=1;
 SCL=1;
}

void IIC_write_byte(int8 adder)
{
 uint8 i,temp;
 temp=adder;
 for(i=0;i<8;i++)
 {
  temp=temp<<1;
  SDA=CY;
  SCL=1;              
  _Nop();
  _Nop();            
  _Nop();
  _Nop();
  _Nop();
  SCL=0;
 }
    _Nop();
    _Nop();
    SDA=1;               
    _Nop();
    _Nop();
    SCL=1;
    _Nop();
    _Nop();
    _Nop();
}

uint8 IIC_read_byte()
{
 uint8 i,j,k;
 SCL=0;
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
 SDA=1;
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
 for(i=0;i<8;i++)
 {
  SCL=1;
     _Nop();
     _Nop();
     _Nop();
  j=SDA;
  k=(k<<1)|j;
  SCL=0;
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();
     _Nop();

 }
    _Nop();
    _Nop();
    _Nop();
 return k;

}

uint8 IIC_respons()
{

    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    _Nop();
    if(SDA==1)
 {
  return 0;
 }
    SCL=0;
    _Nop();
    _Nop();
 return 1;
}

iic.h

#ifndef __IIC_H_
#define __IIC_H_

#include

sbit SDA = P2^1; //PIN 13 of MA7455 is data
sbit SCL = P2^0; //PIN 14 of MA7455 is clock

void IIC_delay();
void IIC_init();
void IIC_start();
void IIC_stop();

void IIC_write_byte(uint8);
uint8 IIC_read_byte();
uint8 IIC_respons();

mma7455.c

#include
#include
#include "iic.h"
#include"mma7455.h"

#define NOP() _nop_()  
#define _Nop() _nop_()  

void IIC_adder_write_byte(int8 adder,int8 rw)
{
 uint8 i,temp;
 temp=adder;
 temp=temp<<1; //Shift left one bit from device address,
 temp=temp|rw; //Read and write one bit later

 IIC_delay();
 for(i=0;i<8;i++)
 {
  temp=temp<<1;
  SDA=CY;
  SCL=1;              
  _Nop();
  _Nop();            
  _Nop();
  _Nop();
  _Nop();
  SCL=0;
 }
    _Nop();
    _Nop();
    SDA=1;               
    _Nop();
    _Nop();
    SCL=1;
    _Nop();
    _Nop();
    _Nop();
}

mma7455.h

#ifndef __MMA7455_H__
#define __MMA7455_H__

#define MMA7455_ADDER_WRITE 0x3A //0x1D shift left, add a write bit 0 at the end, get 0x3A
#define MMA7455_ADDER_READ 0x3B //0x1D shift left, add a read bit 1 at the end, get 0x3B
#define MMA7455_Mode_Control_Register 0x16
#define MMA7455_WHOAMI 0X0F
#define MMA7455_2G_Measurement_Mode 0x05
#define MMA7455_READ_X 0x06 //Read 8bits X-axis data address
#define MMA7455_READ_Y 0x07 //Read 8bits Y-axis data address
#define MMA7455_READ_Z 0x08 //Read 8bits Y-axis data address

void IIC_adder_write_byte(int8,int8);

mytype.h

#ifndef _MY_TYPE_H__
#define _MY_TPYE_H__

#define uint8 unsigned char 
#define uint16 unsigned short int
#define uint32 unsigned long int
#define uint64 unsigned long long int

#define int8 signed char
#define int16 signed short int
#define int32 signed long int
#define int64 signed long long int

#endif