i2c.c

IARSOURCECODE是基于LPC2478嵌入式软件IAR EWARM V4.42的应用实例代码

/*****************************************************************************
 *   I2C.c:  Fast I/O module file for NXP LPC24xx Family Microprocessors
 *
 *   Copyright(C) 2006, NXP Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2006.07.13  ver 1.00    Prelimnary version, first Release
 *
******************************************************************************/
#include "LPC2468.h"				/* LPC24xx definitions */
#include "type.h"
#include "irq.h"
#include "timer.h"
#include "I2C.h"
#include "target.h"

#define Fi2c  400000                            // I2C总线速率
/*
I2C总线测试EEPROM器件函数:I2CInit,I2CWriteByte,I2CReadByte

*/
/*****************************************************************************
** Function name:		I2CInit
**
** Descriptions:		initialize I2C port
**
** parameters:			
** 						
** Returned value:		None
**
*****************************************************************************/
void I2CInit(void)
{
  PINSEL1 = 0x1400000;                            // SDA0,SCL0 引脚配置
  I20SCLH = (Fpclk/Fi2c + 1) / 2;                 // 速率设置
  I20SCLL = (Fpclk/Fi2c) / 2;
  I20CONCLR = (I2CONCLR_STAC|I2CONCLR_SIC|I2CONCLR_AAC);
  I20CONSET = I2CONSET_I2EN;                      // enable I2C as master
  //setup interrupt...
}
/*****************************************************************************
** Function name:		I2CWriteByte
**
** Descriptions:		向I2C总线写1个字节到AT24C02
**
** parameters:			data:数据
** 				address:写入地址
** Returned value:		None
**
*****************************************************************************/
BYTE I2CWriteByte(BYTE data,BYTE address)
{
   unsigned int i;
   I20CONCLR = (I2CONCLR_STAC|I2CONCLR_SIC|I2CONCLR_AAC);
   I20CONSET = I2CONSET_I2EN;                       //enable I2C as master
   I20CONSET = I2CONSET_STA;                        //send start condition

   while(I20STAT != 0x8);
   I20DAT = 0xA0;                                   //set SLA+W:1010000+0
   I20CONCLR = (I2CONCLR_SIC|I2CONCLR_STAC);        //clear SI bit to transmit SLA+W

   while(I20STAT != 0x18);
   I20DAT = address;                                //write address to eeprom
   I20CONCLR = I2CONCLR_SIC;                        //clear SI bit to transmit address

   while(I20STAT != 0x28);                          //stat must be 0x28
   I20DAT = data;                                   //write data to eeprom
   I20CONCLR = I2CONCLR_SIC;                        //clear SI bit to transmit data

   delayMs(0,1);                           //wait to send data to eeprom

   I20CONCLR = I2CONCLR_SIC;
   I20CONSET = I2CONSET_STO;                        //set STO bit to stop transmit

   delayMs(0,2);

   return 1;
}
/*****************************************************************************
** Function name:		I2CReadByte
**
** Descriptions:		从AT24C02中读取一个字节数据
**
** parameters:			address:读取地址
** 				
** Returned value:		None
**
*****************************************************************************/
BYTE I2CReadByte(BYTE address)
{
  char data;

  I20CONCLR = (I2CONCLR_STAC|I2CONCLR_SIC|I2CONCLR_AAC);
  I20CONSET = I2CONSET_I2EN;                          //enable I2C as master

  I20CONSET = I2CONSET_STA;                           //send a start condition
  I20CONSET = I2CONSET_STA;                           //test restart!!

  while(I20STAT != 0x8);//state word must be 0x8
  I20DAT = 0xA0;//set SLA+W
  I20CONCLR = 0x8|0x20;//clear SI bit to transmit SLA+W

  while(I20STAT != 0x18);//state word must be 0x18
  I20DAT = address;//eeprom read address
  I20CONCLR = I2CONCLR_SIC;//clear SI bit to transmit address

  while(I20STAT != 0x28);//state word must be 0x28
  I20CONSET = I2CONSET_STO;//stop dummy write
  I20CONCLR = I2CONCLR_SIC;//clear SI bit
  I20CONSET = I2CONSET_STA;//send another start condition

  while(I20STAT != 0x8);
  I20DAT = 0xA1;//send read order:1010000+1
  I20CONCLR = (I2CONCLR_SIC|I2CONCLR_STAC);//clear SI bit to transmit read order

  while(I20STAT != 0x40);//state word 0x40
  I20CONCLR = I2CONCLR_SIC;//clear SI bit,read eeprom
  while(I20STAT != 0x58);//received a data word,no ACK
  data = I20DAT;//read data


  I20CONCLR = (I2CONCLR_SIC|I2CONCLR_AAC);
  I20CONSET = I2CONSET_STO;//set STO bit to stop transmit
  return data;
}

/*********************************************************************************
**                            End Of File
*********************************************************************************/