lpc1788 io port emulation iic

#ifndef __MYIIC_H_

#define __MYIIC_H_

#include "common.h"

#include "delay.h"

#include "debugserial.h"

//sda 027 scl 028

//IO direction setting

#define IIC1_SDA_IN()  P0dir(27) = 0

#define IIC1_SDA_OUT() P0dir(27) = 1

//IO operation function    

#define IIC1_READ_SDA P0in(27) //Input SDA

void my_iic_init(void); //Initialize IIC IO port     

void my_iic_start(void); //Send IIC start signal

void my_iic_stop(void); //Send IIC stop signal

void my_iic_sendByte(u8 txd); //IIC sends a byte

u8 my_iic_readByte(void); //IIC reads a byte

u8 my_iic_waitAck(void); //IIC waits for ACK signal

void my_iic_ack(void); //IIC sends ACK signal

void my_iic_nAck(void); //IIC does not send ACK signal

#endif

#include "myiic.h"

//This driver is for analog IIC operation

void my_iic_init(void) //Initialize IIC IO port 

{

    LPC_SC->PCONP |= (1<<15);

    LPC_IOCON->P0_27 = 0x00; //Select gpio function, disable hysteresis, non-reverse, normal push-pull

    LPC_IOCON->P0_27 |= (1<<8); //Dependent on pin configuration, modify according to actual pin

    LPC_IOCON->P0_28 = 0x00; //Select gpio function, disable hysteresis, non-reverse, normal push-pull

    LPC_IOCON->P0_28 |= (1<<8); //Dependent on pin configuration, modify according to actual pin

    P0dir(27) = 1; //scl output

    P0dir(28) = 1;//sda output

    P0high(27) = 1; //initialization is all high level

    P0high(28) = 1;

}

void my_iic_start(void) //Send IIC start signal

{

    IIC1_SDA_OUT(); //sda line output

    P0high(27)=1;       //SDA HIGH 

    P0high(28)=1;       //SCL HIGH

    DelayUs(5);

    P0low(27)=1;        //SDA LOW

    DelayUs(5);

    P0low(28)=1;        //SCL LOW

}

void my_iic_stop(void) //Send IIC stop signal

{

    IIC1_SDA_OUT(); //sda line output

    P0high(28)=1;       //SCL HIGH

    P0low(27)=1;        //SDA LOW

    DelayUs(5);

    P0high(27)=1; //Send I2C bus end signal SDA HIGH

    DelayUs(5);

}

void my_iic_sendByte(u8 txd) //IIC sends a byte

{

    u8 t;  

    IIC1_SDA_OUT();        

    for(t=0;t<8;t++)

    {             

        if(((txd&0x80)>>7))

            P0high(27) = 1;

        else

            P0low(27) = 1;

        txd<<=1;         

        P0high(28)=1;   //SCL HIGH

        DelayUs(5);

        P0low(28)=1;    //SCL LOW

        DelayUs(5);

    }  

}

u8 my_iic_readByte(void) //IIC reads a byte

{

    unsigned char i,receive=0;

    IIC1_SDA_IN(); //SDA is set as input

    for(i=0;i<8;i++ )

    {

        receive<<=1;

        P0high(28)=1;           //SCL HIGH  

        DelayUs(5);

        if(IIC1_READ_SDA)receive++;

        P0low(28)=1;            //SCL LOW

        DelayUs(5);     

    }                   

    return receive;

}

u8 my_iic_waitAck(void) //IIC waits for ACK signal

{

    u8 ucErrTime=0; 

    IIC1_SDA_OUT();

    P0high(27)=1;       //SDA HIGH 

    DelayUs(5);

    IIC1_SDA_IN(); //SDA is set as input      

    P0high(28)=1;               //SCL HIGH

    DelayUs(5); 

    while(IIC1_READ_SDA)

    {

        ucErrTime++;

        DelayUs(1);

        if(ucErrTime>250)

        {

            my_iic_stop();

            return 1;

        }

    }

    P0low(28)=1; //Clock output SCL LOW

    DelayUs(5);   

    return 0;

}

void my_iic_ack(void) //IIC sends ACK signal

{

    IIC1_SDA_OUT();

    P0low(27)=1;        //SDA LOW

    DelayUs(2);

    P0high(28)=1;       //SCL HIGH

    DelayUs(5);

    P0low(28)=1;        //SCL LOW

    DelayUs(5);

}

void my_iic_nAck(void) //IIC does not send ACK signal

{

    IIC1_SDA_OUT();

    P0high(27)=1;       //SDA HIGH

    DelayUs(2);

    P0high(28)=1;       //SCL HIGH

    DelayUs(5);

    P0low(28)=1;        //SCL LOW

    DelayUs(5);

}