 salem
Member
Messages : 102
Inscrit(e) le: 09/01/2008
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 Posté le 07/02/2013 08:09
 1360224596.DSN (104 Ko) | | | multible ds18b20 avec 876A |
bonjour a ts
je realise une carte de controle de temperature d'une chambre froid.
pour cette realisation j'utulise un pic 876A avec 3 ds18B20 comme capteur de temp
alors mon probleme et que je reussi a identifier les 3 ds et de lire les 3 temp
et ca fonctionne parfate avec une quartez de 4mhz
alors si je change de 4mhz a 20mhz je peut plus avoire des temp
tous ce que je peut lire des 0. -((rellement pas de lecture de s)
alors je pense que la probleme et dans le driver de one_wire.c
si il ya qeulq'un que le tester avec une quartez de 20mhz.
ou bien un nouveau driver de one_wire merci bcp
ceci one_wire.c
// One Wire bus functions - from Dallas publication AN162
// "Interfacing DS18x20/DS1822 1-wire Temperature Sensor in a Microcontroller
// Environment". Delays calculated from values given for 8051.
// Changed variable name ROM[] to RomBytes[] because ROM is a reserved word
// in version 4 of the CCS compiler.
// Global variables
int8 RomBytes[8];
int8 lastDiscrep = 0;
short doneFlag = 0;
int8 FoundROM[9][8]; // Table of found ROM codes, 8 bytes for each
int8 numROMs;
int8 dowcrc; // crc is accumulated in this variable
// crc lookup table
int8 const dscrc_table[] = {
0,94,188,226,97,63,221,131,194,156,126,32,163,253,31,65,
157,195,33,127,252,162,64,30,95,1,227,189,62,96,130,220,
35,125,159,193,66,28,254,160,225,191,93,3,128,222,60,98,
190,224,2,92,223,129,99,61,124,34,192,158,29,67,161,255,
70,24,250,164,39,121,155,197,132,218,56,102,229,187,89,7,
219,133,103,57,186,228,6,88,25,71,165,251,120,38,196,154,
101,59,217,135,4,90,184,230,167,249,27,69,198,152,122,36,
248,166,68,26,153,199,37,123,58,100,134,216,91,5,231,185,
140,210,48,110,237,179,81,15,78,16,242,172,47,113,147,205,
17,79,173,243,112,46,204,146,211,141,111,49,178,236,14,80,
175,241,19,77,206,144,114,44,109,51,209,143,12,82,176,238,
50,108,142,208,83,13,239,177,240,174,76,18,145,207,45,115,
202,148,118,40,171,245,23,73,8,86,180,234,105,55,213,139,
87,9,235,181,54,104,138,212,149,203,41,119,244,170,72,22,
233,183,85,11,136,214,52,106,43,117,151,201,74,20,246,168,
116,42,200,150,21,75,169,247,182,232,10,84,215,137,107,53
};
// Returns 0 for one wire device presence, 1 for none
int8 ow_reset(void)
{
int8 presence;
output_low(DQ);
delay_us(488); // Min. 480uS
output_float(DQ);
delay_us(72); // Takes 15 to 60uS for devices to respond
presence = input(DQ);
delay_us(424); // Wait for end of timeslot
return(presence);
}
//******************************************************************************
// Read bit on one wire bus
int8 read_bit(void)
{
output_low(DQ);
delay_us(1); // Added, 1uS min. Code relied on 8051 being slow.
output_float(DQ);
delay_us(12); // Read within 15uS from start of time slot
return(input(DQ));
}
//******************************************************************************
void write_bit(int8 bitval)
{
output_low(DQ);
if(bitval == 1) {
delay_us(1); // 1uS min. Code relied on 8051 being slow.
output_float(DQ);
}
delay_us(105); // Wait for end of timeslot
output_float(DQ);
}
//******************************************************************************
int8 read_byte(void)
{
int8 i;
int8 val = 0;
for(i=0;i<8;i++)
{
if(read_bit()) val |= (0x01 << i);
delay_us(120); // To finish time slot
}
return val;
}
//******************************************************************************
void write_byte(int8 val)
{
int8 i;
int8 temp;
for (i=0;i<8;i++)
{
temp = val >> i;
temp &= 0x01;
write_bit(temp);
}
delay_us(105);
}
//******************************************************************************
// One wire crc
int8 ow_crc(int8 x)
{
dowcrc = dscrc_table[dowcrc^x];
return dowcrc;
}
//******************************************************************************
// Searches for the next device on the one wire bus. If there are no more
// devices on the bus then false is returned.
int8 Next(void)
{
int8 m = 1; // ROM Bit index
int8 n = 0; // ROM Byte index
int8 k = 1; // Bit mask
int8 x = 0;
int8 discrepMarker = 0;
int8 g; // Output bit
int8 nxt; // Return value
short flag;
nxt = FALSE; // Reset next flag to false
dowcrc = 0; // Reset the dowcrc
flag = ow_reset();
if (flag||doneFlag) // If no parts return false
{
lastDiscrep = 0; // Reset the search
return FALSE;
}
write_byte(0xF0); // Send SearchROM command
do
{
x = 0;
if (read_bit() == 1) x = 2;
delay_us(120);
if (read_bit() == 1) x |= 1; // And it's complement
if (x == 3) // There are no devices on the one wire bus
break;
else
{
if (x > 0) // All devices coupled have 0 or 1
g = x >> 1; // Bit write value for search
// If this discrepancy is before the last discrepancy on a previous
// Next then pick the same as last time.
else
{
if (m < lastDiscrep)
g = ((RomBytes[n] & k) > 0);
// If equal to last pick 1
else
g = (m == lastDiscrep); // If not then pick 0
// If 0 was picked then record position with mask k
if (g == 0) discrepMarker = m;
}
// Isolate bit in ROM[n] with mask k
if (g == 1) RomBytes[n] |= k;
else RomBytes[n] &= ~k;
write_bit(g); // ROM search write
m++; // Increment bit counter m
k = k << 1; // and shift the bit mask k
// If the mask is 0 then go to new ROM
if (k == 0)
{ // Byte n and reset mask
ow_crc(RomBytes[n]); // Accumulate the crc
n++;
k++;
}
}
} while (n < 8); // Loop through until through all ROM bytes 0-7
if (m < (65||dowcrc)) // If search was unsuccessful then
lastDiscrep = 0; // reset the last Discrepancy to zero
else // Search was successful, so set lastDiscrep, lastOne, nxt
{
lastDiscrep = discrepMarker;
doneFlag = (lastDiscrep == 0);
nxt = TRUE; // Indicates search not yet complete, more parts remain
}
return nxt;
}
//******************************************************************************
// Resets current state of a ROM search and calls Next to find the first device
// on the one wire bus.
int8 First(void)
{
lastDiscrep = 0;
doneFlag = FALSE;
return Next(); // Call Next and return it's return value;
}
//******************************************************************************
void FindDevices(void)
{
int8 m;
if(!ow_reset())
{
if(First()) // Begins when at least one part found
{
numROMs = 0;
do
{
numROMs++;
for (m=0;m<8;m++)
{
FoundROM[numROMs][m] = RomBytes[m];
}
printf("Device No.%u address ",numROMs);
printf("%X%X%X%X%X%X%X%X\n\r",
FoundROM[numROMs][7],FoundROM[numROMs][6],FoundROM[numROMs][5],
FoundROM[numROMs][4],FoundROM[numROMs][3],FoundROM[numROMs][2],
FoundROM[numROMs][1],FoundROM[numROMs][0]);
} while (Next() && (numROMs<10)); // Continues until no additional
// devices found.
}
}
putc('\n'); putc('\r');
}
//******************************************************************************
// Sends Match ROM command to bus then device address
int8 Send_MatchRom(void)
{
int8 i;
if (ow_reset()) return FALSE; // 0 if device present
write_byte(0x55); // Match ROM
for (i=0;i<8;i++)
{
write_byte(FoundRom[numROMs]); // Send ROM code
}
return TRUE;
}
et ceci mon pg
#include <16F876A.h>
#device adc=8
#FUSES NOWDT, HS, NOPUT, NOPROTECT, NODEBUG, NOBROWNOUT, NOLVP, NOCPD, WRT_50%
#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#define DQ PIN_A0 // One Wire Bus pin assignment
#include "1_wire.c"
#include "LCD420.c"
//#include "ds1307.c"
#include "kbd.c"
char key;
int8 i,temp1,temp2,temp3;
int8 day,mth,year,dow,hr,min,sec;
signed int16 temperature;
int8 scratch[9];
void get_temp()
{
if (!ow_reset()) // If a device is present
{
write_byte(0xCC); // Skip Rom command
write_byte(0x44); // Temperature convert command
output_float(DQ);
delay_ms(750); // Max. conv. time is 750mS for 12 bit
ow_reset();
//numroms=0;
if (Send_MatchRom())
{
write_byte(0xBE); // Read scratch pad command
dowcrc = 0;
for (i=0;i<=7;i++) // Get the data bytes
{
scratch = read_byte();
ow_crc(scratch);
}
scratch[8] = read_byte(); // Get crc byte
ow_reset();
if (scratch[8] == dowcrc)
{
temperature = (signed int16) make16(scratch[1],scratch[0]);
if (temperature >= 0) temperature = (temperature + 8)/16;
else
temperature = (temperature - 8)/16;
printf("%4Ld /n/r ",temperature);
}
}
}
}
void aff_date()
{
lcd_gotoxy(1,4);printf( lcd_putc, "%d/%d/%d", day,mth,year);
lcd_gotoxy(11,4);printf( lcd_putc, "%d:%d:%d", hr,min,sec);
}
void aff_temp()
{
lcd_gotoxy(9,1);printf( lcd_putc, "%d", temp1);
lcd_gotoxy(9,2);printf( lcd_putc, "%d", temp2);
lcd_gotoxy(9,3);printf( lcd_putc, "%d", temp3);
}
void main()
{
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_spi(SPI_SS_DISABLED);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
lcd_init();
//ds1307_init();
kbd_init();
// TODO: USER CODE!!
//printf( lcd_putc, "Starting....");
output_float(DQ); // Set as input. 4k7 pullup on bus.
FindDevices();
while(1)
{
numroms=0;
get_temp();temp1=temperature;
numroms=1;
//ds1307_get_time(hr,min,sec) ;
aff_date();
get_temp();temp2=temperature;
numroms=2;
//ds1307_get_time(hr,min,sec) ;
//aff_date();
get_temp();temp3=temperature;
lcd_putc(" \f");
//lcd_gotoxy(12,1);printf( lcd_putc, "%d", key);
lcd_gotoxy(1,1);printf( lcd_putc, "Temp1 : ");
lcd_gotoxy(1,2);printf( lcd_putc, "Temp2 : ");
lcd_gotoxy(1,3);printf( lcd_putc, "Temp3 : ");
aff_temp();
//ds1307_get_date(day,mth,year,dow);
//ds1307_get_time(hr,min,sec) ;
//aff_date();
}
}
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salem
