Zdravím, potřeboval bych pomoci s úpravou mého kódu. Našel jsem rutinu na DS18B20 která funguje výborně, můj problém je, že to měří na 4 desetinná místa. Já bych ale potřeboval aby to měřilo jen na jedno desetnné místo. Mohl by mi někdo poradit jak na to? Moooc děkuji 
Code:
#include <avr/io.h>
#include <util/delay.h>
#include <stdint.h>
#include “lcd_h.h”
char buffer[12];
#define F_CPU 1000000UL
#define THERM_CMD_CONVERTTEMP 0x44
#define THERM_CMD_RSCRATCHPAD 0xbe
#define THERM_CMD_WSCRATCHPAD 0x4e
#define THERM_CMD_CPYSCRATCHPAD 0x48
#define THERM_CMD_RECEEPROM 0xb8
#define THERM_CMD_RPWRSUPPLY 0xb4
#define THERM_CMD_SEARCHROM 0xf0
#define THERM_CMD_READROM 0x33
#define THERM_CMD_MATCHROM 0x55
#define THERM_CMD_SKIPROM 0xcc
#define THERM_CMD_ALARMSEARCH 0xec
/* Thermometer Connections /
#define THERM_PORT PORTA
#define THERM_DDR DDRA
#define THERM_PIN PINA
#define THERM_DQ PA0
/ Utils */
#define THERM_INPUT_MODE() THERM_DDR&=~(1<<THERM_DQ)
#define THERM_OUTPUT_MODE() THERM_DDR|=(1<<THERM_DQ)
#define THERM_LOW() THERM_PORT&=~(1<<THERM_DQ)
#define THERM_HIGH() THERM_PORT|=(1<<THERM_DQ)
#define THERM_DECIMAL_STEPS_12BIT 625 //.0625
uint8_t therm_reset(){
uint8_t i;
//Pull line low and wait for 480uS
THERM_LOW();
THERM_OUTPUT_MODE();
_delay_us(480);
//Release line and wait for 60uS
THERM_INPUT_MODE();
_delay_us(60);
//Store line value and wait until the completion of 480uS period
i=(THERM_PIN & (1<<THERM_DQ));
_delay_us(420);
//Return the value read from the presence pulse (0=OK, 1=WRONG)
return i;
}
void therm_write_bit(uint8_t bit){
//Pull line low for 1uS
THERM_LOW();
THERM_OUTPUT_MODE();
_delay_us(1);
//If we want to write 1, release the line (if not will keep low)
if(bit) THERM_INPUT_MODE();
//Wait for 60uS and release the line
_delay_us(60);
THERM_INPUT_MODE();
}
uint8_t therm_read_bit(void){
uint8_t bit=0;
//Pull line low for 1uS
THERM_LOW();
THERM_OUTPUT_MODE();
_delay_us(1);
//Release line and wait for 14uS
THERM_INPUT_MODE();
_delay_us(14);
//Read line value
if(THERM_PIN&(1<<THERM_DQ)) bit=1;
//Wait for 45uS to end and return read value
_delay_us(45);
return bit;
}
uint8_t therm_read_byte(void){
uint8_t i=8, n=0;
while(i–){
//Shift one position right and store read value
n>>=1;
n|=(therm_read_bit()<<7);
}
return n;
}
void therm_write_byte(uint8_t byte){
uint8_t i=8;
while(i–){
//Write actual bit and shift one position right to make the next bit ready
therm_write_bit(byte&1);
byte>>=1;
}
}
int main( void )
{
lcd_init();
lcd_clrscr();
while(1){
lcd_gotoxy(0,0);
lcd_puts(“Teplota”);
therm_read_temperature(buffer2) ;
}
}
void therm_read_temperature(char *buffer){
// Buffer length must be at least 12bytes long! “+XXX.XXXX C”]
uint8_t temperature[2];
int8_t digit;
uint16_t decimal;
//Reset, skip ROM and start temperature conversion
therm_reset();
therm_write_byte(THERM_CMD_SKIPROM);
therm_write_byte(THERM_CMD_CONVERTTEMP);
//Wait until conversion is complete
while(!therm_read_bit());
//Reset, skip ROM and send command to read Scratchpad
therm_reset();
therm_write_byte(THERM_CMD_SKIPROM);
therm_write_byte(THERM_CMD_RSCRATCHPAD);
//Read Scratchpad (only 2 first bytes)
temperature[0]=therm_read_byte();
temperature[1]=therm_read_byte();
therm_reset();
//Store temperature integer digits and decimal digits
digit=temperature[0]>>4;
digit|=(temperature[1]&0x7)<<4;
//Store decimal digits
decimal=temperature[0]&0xf;
decimal*=THERM_DECIMAL_STEPS_12BIT;
//Format temperature into a string +XXX.XXXX C]
sprintf(buffer, "%+d.%04u C", digit, decimal);
lcd_clrscr();
lcd_gotoxy(0,1);
sprintf(buffer, “%+d.%04u”, digit, decimal);
lcd_puts(buffer);
lcd_putc(‘C’);
}
administrator: přejmenováno z "Teplomer s DS18B20 - pomoc s upravou kodu"
4 desetinné místa. zkoušel jsem tam toto
.