飞凌2440开发板bootloader源码专题（一）

/*
to support wr/rd parameters to/from eeprom
*/
#include "def.h"
#include "2440addr.h"
#include "2440lib.h"

#define SLV_ADDR_24C02 0xa0
#define SLV_ADDR_CAMERA 0x42//0x5a

void mdelay(int ms);

static volatile int iic_ints;
static void __irq IicInt(void)
{
 ClearPending(BIT_IIC);
 iic_ints++;
}

static int iic_wr(U8 data, U8 cnt)
{
 int i, c;

 for(i=0; i<20; i++);
 
 if(cnt)
  rIICDS = data;
  
 rIICCON &= ~0x10;  //Resume IIC operation to send

 i = 3; //3ms
 //while(!(rIICCON&0x10)&&i--) mdelay(1);
 c = iic_ints;
 while(iic_ints==c&&i--) mdelay(1);
 //rIICCON &= ~0x10;
 
 if(!i)
  return -1;

 return (rIICSTAT&1)?-1:0;
}

static int iic_rd(U8 *pBuf)
{
 int i, c;
 
 for(i=0; i<20; i++);
 
 rIICCON &= ~0x10;  //Resumes IIC operation to receive
 i = 3; //3ms
 //while(!(rIICCON&0x10)&&i--) mdelay(1);
 c = iic_ints;
 while(iic_ints==c&i--) mdelay(1);
 
 if(i) {
  *pBuf = rIICDS;
  return 0;
 }
 
 return -1;
}

static int seek_iic_device(U8 slvAddr)
{
 int i;
 U8 d;
 
 i = 200;    //200ms
 while(i--) {
  rIICDS   = slvAddr;
  rIICSTAT = 0xb0; //read mode
  if(!iic_wr(0, 0)) {
   iic_rd(&d);
   break;
  }
  mdelay(1);
 }
 rIICSTAT = 0x90;
 rIICCON &= ~0x10;  //Resume IIC operation to send stop
 mdelay(1);

 return (i>=0)?0:-1;
}

//8 bits register address only
static int write_eeprom(U8 slvAddr, U8 addr, U8 data)
{
 int i;
 U8 ch[3];
 
 ch[1] = addr;
 ch[2] = data;
 
 rIICDS   = slvAddr;
 rIICSTAT = 0xf0;  //MasTx,Start
 for(i=0; i<3; i++)
  if(iic_wr(ch, i))
   break;
 rIICSTAT = 0xd0;  //Stop MasTx condition
 rIICCON &= ~0x10;  //Resume IIC operation to send stop
 mdelay(1);
 if(i<3)
  return -1;
  
 return seek_iic_device(slvAddr);
}