MSP430, DS18B20 Temperature Sensor
i do Temperature Sensor Project
I have some difficulty in program, i don't understand protocol between msp430 and DS18b20..., you can share a code or some documentation on the protocol?
thanks you !
there are some problem with this Code i don't practice on Proteus
#include "msp430f2131.h"
#define DQIN _P2_IN->_BIT.b3
#define DQOUT _P2_OUT->_BIT.b3
#define E_LCD (_P2_OUT->_BIT.b2)
// #define RW_LCD (_P2_OUT->_BIT.b1)
#define RS_LCD (_P2_OUT->_BIT.b0)
#define P0 (P1OUT)
union reg {
struct bit {
unsigned char b0:1;
unsigned char b1:1;
unsigned char b2:1;
unsigned char b3:1;
unsigned char b4:1;
unsigned char b5:1;
unsigned char b6:1;
unsigned char b7:1;
}_BIT;
unsigned char _BYTE;
};
union reg* _P2_DIRECT = (union reg*)0x2A ;
union reg* _P2_IN = (union reg*)0x28 ;
union reg* _P2_OUT = (union reg*)0x29 ;
union reg* _P1_DIRECT = (union reg*)0x22 ;
union reg* _P1_OUT = (union reg*)0x21 ;
__intrinsic void __delay_cycles(unsigned long __cycles);
//////////////////////////////////////////////////////////////////////////////
// su dung thach anh noi chu ki thi hanh 1 lenh msp la 62.5ns
// Reset is 480us, so delay
// value is (480-24)/16 = 28.5 - we use 29. Presence checked
// another 70us later, so delay is (70-24)/16 = 2.875 - we use 3.
unsigned char ow_reset(void)
{
unsigned char presence;
_P2_DIRECT->_BIT.b3 =1;
DQOUT = 0; //pull DQ line low
__delay_cycles(7680); // leave it low for 480us
DQOUT = 1; // allow line to return high
__delay_cycles(1) ; // wait for presence
_P2_DIRECT->_BIT.b3 = 0; // khai bao IN de nhan tin hieu co thiet bi ngoai vi
presence = DQIN; // get presence signal
__delay_cycles(8); // wait for end of timeslot
return(presence); // presence signal returned
// 0=presence, 1 = no part
}
//////////////////////////////////////////////////////////////////////////////
// READ_BIT - reads a bit from the one-wire bus. The delay
// required for a read is 15us, so the DELAY routine won't work.
// We put our own delay function in this routine in the form of a
// for() loop.
//
unsigned char read_bit(void)
{
_P2_DIRECT->_BIT.b3 =1;
DQOUT = 0; // pull DQ low to start timeslot
DQOUT = 1; // then return high
__delay_cycles(240); // delay 15us from start of timeslot
return(DQOUT); // return value of DQ line
}
//////////////////////////////////////////////////////////////////////////////
// WRITE_BIT - writes a bit to the one-wire bus, passed in bitval.
//
void write_bit(char bitval)
{
_P2_DIRECT->_BIT.b3 =1;
DQOUT = 0; // pull DQ low to start timeslot
if(bitval==1) DQOUT =1; // return DQ high if write 1
__delay_cycles(256); // hold value for remainder of timeslot
DQOUT = 1;
}// Delay provides 16us per loop, plus 24us. Therefore delay(5) = 104us
//////////////////////////////////////////////////////////////////////////////
// READ_BYTE - reads a byte from the one-wire bus.
//
unsigned char read_byte(void)
{
unsigned char i;
unsigned char value = 0;
for (i=0;i<8;i++)
{
if(read_bit()) value|=0x01<<i; // reads byte in, one byte at a time and then
// shifts it left
__delay_cycles(256); // wait for rest of timeslot
}
return(value);
}
//////////////////////////////////////////////////////////////////////////////
// WRITE_BYTE - writes a byte to the one-wire bus.
//
void write_byte(char val)
{
unsigned char i;
unsigned char temp;
for (i=0; i<8; i++) // writes byte, one bit at a time
{
temp = val>>i; // shifts val right 'i' spaces
temp &= 0x01; // copy that bit to temp
write_bit(temp); // write bit in temp into
}
__delay_cycles(256);
}
unsigned char Read_Temperature(void)
{
char get[10];
char temp_lsb,temp_msb;
int k;
ow_reset();
write_byte(0xCC); //Skip ROM
write_byte(0x44); // Start Conversion
__delay_cycles(256);
ow_reset();
write_byte(0xCC); // Skip ROM
write_byte(0xBE); // Read Scratch Pad
for (k=0;k<9;k++){get[k]=read_byte();}
temp_msb = get[1]; // Sign byte + lsbit
temp_lsb = get[0]; // Temp data plus lsb
if (temp_msb <= 0x80){temp_lsb = (temp_lsb/2);} // shift to get whole degree
temp_msb = temp_msb & 0x80; // mask all but the sign bit
if (temp_msb >= 0x80) {temp_lsb = (~temp_lsb)+1;} // twos complement
if (temp_msb >= 0x80) {temp_lsb = (temp_lsb/2);}// shift to get whole degree
if (temp_msb >= 0x80) {temp_lsb = ((-1)*temp_lsb);} // add sign bit
return(temp_lsb);
}
// giao tiep hien thi LCD
// giao tiep hien thi LCD
// giao tiep hien thi LCD
// giao tiep hien thi LCD
void delay_short()
{
unsigned int i;
for(i=0;i<300;i++);
}//--------------****------------------//
//------------Ham tre 2---------------//
void delay(unsigned int time) // Thoi gian time ms
{ int i,j;
for(i=0;i<time;i++)
{
for(j=0;j<500;j++)
{
}
}
}
//-----------------******----------------//
//--------------Ham kiem tra co ban (busy_flag)--------------??
void kt_ban()
{
unsigned int x;
for(x=0;x<1000;x++)
{
}
}//-----------*******--------------------//
//---------------Ham ghi lenh giao tiep voi LCD---------------//
void ghi_lenh(unsigned char lenh)
{
kt_ban();
delay(50);
P0 = lenh;
RS_LCD = 0; // Chon thanh ghi lenh
//RW_LCD = 0; // Chon che do ghi du lieu tu 8051 vao LCD
E_LCD = 1;
delay_short();
E_LCD = 0;
}//------------*******-----------------//
//-----------Ham ghi ky tu ra LCD------------//
void ghi_kytu(unsigned char kytu)
{
kt_ban();
delay(50);
P0 = kytu;
RS_LCD = 1; // Chon che do doc du lieu tu 8051
//RW_LCD = 0;
E_LCD =1;
delay_short();
E_LCD = 0;
}//------------*******-----------------//
//-----------Ham ghi nhanh ky tu ra LCD------------//
void ghi_nhanh ( unsigned char kytu)
{
delay_short();
P0 = kytu;
RS_LCD = 1;
//RW_LCD = 0;
E_LCD = 1;
delay_short();
E_LCD = 0;
}//--------------***********-------------//
//-----------Ham ghi chuoi ky tu ra LCD------------//
void ghi_chuoi(char *str)
{
while(*str)
{
delay(50);
ghi_kytu(*str);
str++;
}
}//-----------********------------//
//-----------Ham ghi nhanh chuoi ky tu ra LCD------------//
void ghi_nhanh_chuoi(char *str)
{
while(*str){
ghi_nhanh(*str);
str++;
}
}
//-----------************------------//
//-----------Ham ghi so nguyen ra LCD------------//
void ghi_so_nguyen(unsigned char so)
{
unsigned char a,b,c;
a=so/100; // Lay phan tram
b=(so-100*a)/10; // Lay phan chuc
c=(so-100*a-10*b); // Lay phan don vi
ghi_nhanh(a+48); // Doi ra hang tram, ma ascii
ghi_nhanh(b+48); // Doi ra hang chuc, ma ascii
ghi_nhanh(c+48); // Doi ra hang don vi, ma ascii
}
//-----------***********------------//
//-----------Ham khoi tao LCD------------//
void setting_LCD()
{
ghi_lenh(0x38);
ghi_lenh(0x01); // Xoa man hinh
ghi_lenh(0x0f); // Co dich hien thi
}
//-----------**********------------//
/*********************************/
/* CON DAY LA CHUONG TRINH CHINH */
/* ----------??????--------------*/
/*********************************/
void main( void )
{
WDTCTL = WDTPW + WDTHOLD;
_P2_DIRECT->_BIT.b0=1;
_P2_DIRECT->_BIT.b1 =1;
_P2_DIRECT->_BIT.b2 =1;
_P1_DIRECT->_BYTE=0xff;
int nhietdo;
while(1)
{
nhietdo= Read_Temperature();
setting_LCD();
ghi_lenh(0x0c);
ghi_so_nguyen(nhietdo);
delay(300);
}
}
