ibutten_c.txt

一个标准的ibutten读写程序,请初学者留意,可以帮助你学习ONE_WIRE编程

//===========================================================================
// iButton DS1991 Functions
//***************************************************************************

＃i nclude "ibutton.h"
＃i nclude "typedef.h"
＃i nclude "resource.h"

#define bDataBus pinIButtonData

typedef struct _iButton
{
 UCHAR *PassWord;
 UCHAR Identify[8];
 UCHAR RomFuncCmd; //33h,55h,F0h,CCh-Skip ROM
}IBUTTON;

//--------------------------------------------------------------------------

IBUTTON iButton;
extern void DelayCycle(unsigned char nCycle);

//===========================================================================
UCHAR _iButtonReset(void)   //return 0 if exist device
{
    UCHAR i;
    EA=0;

    //发复位低脉冲tRSTL>80us
    bDataBus=0;
    DelayCycle(200); //about 439us

    //释放总线,等待上拉电阻将总线恢复高电平tPDH=5us~60us
    bDataBus=1;
    DelayCycle(12);  //跳过上拉电阻上拉总线时间, about 29us

    //等待对方返回低脉冲, tPDL=60us~240us
    i=0;
    while(bDataBus==1)
    {
        i++;
        if(i>27) {EA=1; return 0x0E;}
    }

    //等待对方恢复高电平
    DelayCycle(75);
    i=0;
    while(bDataBus==0)
    {
  if(i>54) break;
  i++;
    }
    DelayCycle(180);

    EA=1;
    return 0;
}
//===========================================================================
void _iButtonWriteBit(bit bBit)   //读或写周期60us~120us
{
 EA=0;

 //总线值低电平tLow1=1us~15us
 bDataBus=0;
 DelayCycle(0);

 //写周期TH=60us-tLow1, 对方在检测到总线=0开始15us后，将总线采样写入
 bDataBus=bBit;
 DelayCycle(14);
 bDataBus=1;

 EA=1;
 DelayCycle(15);
}
//===========================================================================
bit _iButtonReadBit(void)    //读周期60us~120us
{
 bit bRet;
 EA=0;

 //总线值低电平tSu<1us
 bDataBus=0;
 DelayCycle(0);

 //等待总线数据到达tLOW=1us~15us
 bDataBus=1;
 DelayCycle(2);

    //采样周期,对方在检测到总线=0开始15us后，将数据放在总线上,持续时间0~45us
    //然后释放总线,总时间共60us-TL.
 bRet=bDataBus;
 DelayCycle(14);

 EA=1;
 DelayCycle(15);
 return bRet;
}
//===========================================================================
void _iButtonWriteByte(UCHAR TxByte)
{
    UCHAR i=8;
    while(i>0)
    {
  _iButtonWriteBit(TxByte&0x01);
  TxByte>>=1;
  i--;
    }
}
//===========================================================================
UCHAR _iButtonReadByte(void)
{
    UCHAR RxByte;
    bit  bRx;
    UCHAR i=8;
    while(i>0)
    {
  RxByte>>=1;
  bRx=_iButtonReadBit();
  if(bRx) RxByte|=0x80;
  else    RxByte&=0x7F;
  i--;
    }
    return RxByte;
}
//===========================================================================
//pRxBuffer: 如果pRxBuffer==NULL, 将不对其所指向的地址写入系统码 
//Return:    返回系统码(FamillyCode(1byte)+SerialCode(6Byte)+CRC(1byte
//---------------------------------------------------------------------------
UCHAR _iButtonSendRomFuncCmd(UCHAR *pRxBuffer)
{
 UCHAR nBytes=0;

 _iButtonWriteByte(iButton.RomFuncCmd);
 if(iButton.RomFuncCmd==0xCC) return 0; //0xCC命令不不返回系统码

 //如果RomFuncCmd!=0xCC,则接收系统码
 if(pRxBuffer)
 {
  while(nBytes<8)
  {
            *pRxBuffer=_iButtonReadByte();
            pRxBuffer++;
            nBytes++;
  }
 }
 return nBytes;
}
//===========================================================================
//iButtonAddr: SubKey0:    10h-3Fh; SubKey1: 50h-7Fh, Subkey2: 90h-BFh
//             ScratchPad: D0h-FFh
//OperateId:   0-Read, 1-Write, 2-Copy ScratchPad or Set Subkey Password
//---------------------------------------------------------------------------
void _iButtonWriteAddress(UCHAR iButtonAddr, UCHAR OperateId)
{
 UCHAR MemOpCmd;
 MemOpCmd=iButtonAddr&0xC0;
 if(MemOpCmd==0xC0)
 {
  if(OperateId==0) MemOpCmd=0x69; //读ScratchPad
  if(OperateId==1) MemOpCmd=0x96; //写ScratchPad
  if(OperateId==2) MemOpCmd=0x3C; //拷贝ScratchPad
 }
 else
 {
  if(OperateId==0) MemOpCmd=0x66; //读Subkey
  if(OperateId==1) MemOpCmd=0x99; //写Subkey
  if(OperateId==2) MemOpCmd=0x5A; //写Subkey密码
 }

 _iButtonWriteByte(MemOpCmd);
 _iButtonWriteByte(iButtonAddr);
 _iButtonWriteByte(~iButtonAddr);

    //如果是对Subkey操作的ROM命令,需要密码读取Identify标识码,并写入密码进行验证
    if((MemOpCmd==0x66)||(MemOpCmd==0x99)||(MemOpCmd==0x5A))
    {
  int i;
  for(i=0; i<8; i++)
  {
   iButton.Identify[i]=_iButtonReadByte(); //读出iButton的系列号
  }
  for(i=0; i<8; i++)
  {
   _iButtonWriteByte(iButton.PassWord[i]); //提供密码给iButton校验
  }
 }
}
//===========================================================================
void iButtonScratchpadWriteByte(UCHAR TargetAddr, UCHAR dbWriteByte) //TargetAddress=10h-3fh
{
    _iButtonReset();

    _iButtonSendRomFuncCmd(0); //0x00 needn't system code return
    _iButtonWriteAddress(0xC0|TargetAddr,1); //0xD0 in ScratchPad Section

    _iButtonWriteByte(dbWriteByte);
    _iButtonReset();
}
//===========================================================================
unsigned char iButtonScratchpadReadByte(UCHAR TargetAddr) //TargetAddress=10h-3fh
{
 UCHAR dbReadByte;
    _iButtonReset();

    _iButtonSendRomFuncCmd(0); //0x00 needn't system code return
    _iButtonWriteAddress(0xC0|TargetAddr,0); //0xD0 in ScratchPad Section

    dbReadByte=_iButtonReadByte();
    _iButtonReset();
    return dbReadByte;
}
//===========================================================================
/*void iButtonScratchpadWrite(UCHAR *pTxBuffer, UCHAR ByteCount) //整块写
{
    if(ByteCount==0) return;
    _iButtonReset();

    _iButtonSendRomFuncCmd(0); //0x00 needn't system code return
    _iButtonWriteAddress(0xD0,1); //0xD0 in ScratchPad Section

    while(ByteCount>0)
    {
        _iButtonWriteByte(*pTxBuffer);
        pTxBuffer++;
        ByteCount--;
    }

    _iButtonReset();
}
//===========================================================================
void iButtonScratchpadRead(UCHAR *pRxBuffer, UCHAR ByteCount) //整块读
{
    if(ByteCount==0) return;
    _iButtonReset();

    _iButtonSendRomFuncCmd(0); //0x00 needn't system code return
    _iButtonWriteAddress(0xD0,0); //0xD0 in ScratchPad Section

    while(ByteCount>0)
    {
        *pRxBuffer=_iButtonReadByte();
        pRxBuffer++;
        ByteCount--;
    }
    _iButtonReset();
}*/
//===========================================================================
void iButtonInit(UCHAR RomFuncCmd, UCHAR *pPassWord) //PassWord=33h,55h,F0h,CCh-Skip ROM
{
 iButton.RomFuncCmd=RomFuncCmd;
 iButton.PassWord=pPassWord;
}
//===========================================================================