// **********ds1620.c

// Jonathan W. Valvano 1/15/02

// Interface between MC68HC812 and DS1620

 

// Copyright 2002 by Jonathan W. Valvano, valvano@uts.cc.utexas.edu 

//    You may use, edit, run or distribute this file 

//    as long as the above copyright notice remains 



// See Valvano, Embedded Microcomputer Systems, Chap 3

// bit	status	Configuration/Status Register meaning

// 7	DONE	1=Conversion done, 0=conversion in progress

// 6	THF	1=temperature above TH, 0=temperature below TH

// 5	TLF	1=temperature below TL, 0=temperature above TL

// 1	CPU	1=CPU control, 0=stand alone operation

// 0	1SHOT	1=one conversion and stop, 0=continuous conversions

// temperature 	digital value (binary)	digital value (hex)

// +125.0 C    011111010                 $0FA

//  +64.0 C    010000000                 $080

//   +1.0 C    000000010                 $002

//   +0.5 C    000000001                 $001

//      0 C    000000000                 $000

//   -0.5 C    111111111                 $1FF

//  -16.0 C    111100000                 $1E0

//  -55.0 C    110010010                 $192

// DS1620 MC68HC812A4

// 1 DQ    PS5

// 2 CLK   PS6

// 3 RST   PS7

// 4 GND   ground

// 5 TCOM  not connected

// 6 TLOW  not connected

// 7 THIGH not connected

// 8 Vcc   +5 V with bypass cap to ground

 

void DS1620_Init(void){ // PS7=RST=0

  DDRS = 0xE0;   // PS6=CLK=1

  PORTS = 0x60;  // PS5=DQ=1

}

void static out8(char code){ int n;

  for(n=0;n<8;n++){

     PORTS &= 0xBF;   // PS6=CLK=0

     if(code&0x01){

       PORTS |= 0x20; // PS5=DQ=1

     }

     else{

       PORTS &= 0xDF; // PS5=DQ=0

     }

     PORTS |= 0x40;   // PS6=CLK=1

     code = code>>1;

   }

 }

void DS1620_Start(void){

  PORTS |= 0x80;   // PS7=RST=1

  out8(0xEE);

  PORTS &= 0x7F;   // PS7=RST=0

}

void DS1620_Stop(void){

  PORTS |= 0x80;   // PS7=RST=1

  out8(0x22);

  PORTS &= 0x7F;  // PS7=RST=0

}





void DS1620_WriteConfig(char data){

  PORTS |= 0x80;   // PS7=RST=1

  out8(0x0C);

  out8(data);

  PORTS &= 0x7F;   // PS7=RST=0

}



void static out9(int code){ int n;

  for(n=0;n<9;n++){

    PORTS &= 0xBF;   // PS6=CLK=0

    if(code&0x01){

      PORTS |= 0x20; // PS5=DQ=1

    }

    else{

      PORTS &= 0xDF; // PS5=DQ=0

    }

    PORTS |= 0x40;   // PS6=CLK=1

    code = code>>1;

  }

}

void DS1620_WriteTH(int data){

  PORTS |= 0x80;   // PS7=RST=1

  out8(0x01);

  out9(data);

  PORTS &= 0x7F;   // PS7=RST=0

}

void DS1620_WriteTL(int data){

  PORTS |= 0x80;   // PS7=RST=1

  out8(0x02);

  out9(data);

  PORTS &= 0x7F;   // PS7=RST=0

}

unsigned char static in8(void){ int n;

unsigned int result=0;

  DDRS &= 0xDF; // PS5=DQ input

  for(n=0;n<8;n++){

    PORTS &= 0xBF;   // PS6=CLK=0

    result = result>>1;

    if(PORTS&0x20){

      result |= 0x80; // PS5=DQ=1

    }

    PORTS |= 0x40;    // PS6=CLK=1

  }

  DDRS |= 0x20; // PS5=DQ output

  return result;

}

unsigned char DS1620_ReadConfig(void){

unsigned char value;

  PORTS |= 0x80;   // PS7=RST=1

  out8(0xAC);

  value = in8();

  PORTS &= 0x7F;   // PS7=RST=0

  return value;

}



unsigned int static in9(void){ int n;

unsigned int result=0;

  DDRS &= 0xDF;         // PS5=DQ input

  for(n=0;n<9;n++){

    PORTS &= 0xBF;      // PS6=CLK=0

    result = result>>1;

    if(PORTS&0x20){

      result |= 0x0100; // PS5=DQ=1

    }

    PORTS |= 0x40;      // PS6=CLK=1

  }

  DDRS |= 0x20;         // PS5=DQ output

  if(result&0x0100){

    result |= 0xFE00;

  }

  return result;

}



unsigned int DS1620_ReadTH(void){

unsigned int value;

  PORTS |= 0x80;   // PS7=RST=1

  out8(0xA1);

  value = in9();

  PORTS &= 0x7F;   // PS7=RST=0

  return value;

}

unsigned int DS1620_ReadTL(void){

unsigned int value;

  PORTS |= 0x80;   // PS7=RST=1

  out8(0xA2);

  value = in9();

  PORTS &= 0x7F;   // PS7=RST=0

  return value;

}



unsigned int DS1620_ReadT(void){

unsigned int value;

  PORTS |= 0x80;   // PS7=RST=1

  out8(0xAA);

  value = in9();

  PORTS &= 0x7F;   // PS7=RST=0

  return value;

}