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If you took the time to debug your code then you would know if it is causing an issue or not. What have you done to debug the code?
Temperature
- Thread starter FroceMaster
- Start date
Let us have a go at this tomorrow
Have u read back a couple of mess. Have got it to work. Just need to calculate
5000 mv divede by 1024 and 50 mv pr degree that should be possible to calc..
Or ???
Chip have 1024 steps. And 0-5 v ??
Or am i totally wrong ?
That is fine! the ADC conversion result can take values from 0 to 1023. So it has 1024 steps. Each step is Vref/1024. In your case Vref is 5 volt. So each step is 5/1024. To be a nitpick the range is 0 to 5-(5/1024) volt. But well it is common to ignore the last term
I think the OP has done every thing correct here, as far as I see it
By the way, you must include what the endless for loop shall like this
Rich (BB code):
for(;;)
{
some code
}Have a little calculate problem
if my input is 700 mv( measure by fluke).
and i calculate (5000/1024) * degree // IS THE degree in BIN ?
Thats should be the input in mv ?? right ?
but somehow it only calculate to arround 620 mv. ?
why ?
if my input is 700 mv( measure by fluke).
Rich (BB code):
while(GO_DONE) continue;
degree = ADRESL; // Get the 8 bit LSB result
degree += (ADRESH << 8); // Get the 2 bit MSB resultThats should be the input in mv ?? right ?
but somehow it only calculate to arround 620 mv. ?
why ?
You are talking about 80 mv difference. That is next to nothing. Who says your meter is right?
Unless you have an extremely stable voltage reference you are not going to get an exact match.
You could simply correct for the difference in software if the differences are consistent.
Unless you have an extremely stable voltage reference you are not going to get an exact match.
You could simply correct for the difference in software if the differences are consistent.
You can use an external voltage reference. It is a chip that will give a steady voltage at whatever you select.Any way to get around that ?
or do i have to live with it.
only 8 degree wrong
Check your math again. Is 50mv really that much of a difference in temperature?
All of this is why I suggested something like the DS1820 in the first place. A little hard to get the one wire protocol to work but once you are past that, it is easy.
Here is something I made last night. It should work. Please note this line
It is nothing magical about it. It is just Vref*100/1024. And in this case VDD=Vref. So just measure VDD and put this value times 100. It should give you better temperature accuracy.
Rich (BB code):
///*// Config Register: CONFIG
//#define CONFIG 0x2007
//// Oscillator Selection bits
//// RC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN
//#define FOSC_EXTRCCLK 0xFFFF
//// RCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, RC on RA5/OSC1/CLKIN
//#define FOSC_EXTRCIO 0xFFFE
//// INTOSC oscillator: CLKOUT function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN
//#define FOSC_INTRCCLK 0xFFFD
//// INTOSCIO oscillator: I/O function on RA4/OSC2/CLKOUT pin, I/O function on RA5/OSC1/CLKIN
//#define FOSC_INTRCIO 0xFFFC
//// EC: I/O function on RA4/OSC2/CLKOUT pin, CLKIN on RA5/OSC1/CLKIN
//#define FOSC_EC 0xFFFB
//// HS oscillator: High-speed crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
//#define FOSC_HS 0xFFFA
//// XT oscillator: Crystal/resonator on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
//#define FOSC_XT 0xFFF9
//// LP oscillator: Low-power crystal on RA4/OSC2/CLKOUT and RA5/OSC1/CLKIN
//#define FOSC_LP 0xFFF8
//// Watchdog Timer Enable bit
//// WDT enabled
//#define WDTE_ON 0xFFFF
//// WDT disabled and can be enabled by SWDTEN bit of the WDTCON register
//#define WDTE_OFF 0xFFF7
//// Power-up Timer Enable bit
//// PWRT disabled
//#define PWRTE_OFF 0xFFFF
//// PWRT enabled
//#define PWRTE_ON 0xFFEF
//// MCLR Pin Function Select bit
//// MCLR pin function is MCLR
//#define MCLRE_ON 0xFFFF
//// MCLR pin function is digital input, MCLR internally tied to VDD
//#define MCLRE_OFF 0xFFDF
//// Code Protection bit
//// Program memory code protection is disabled
//#define CP_OFF 0xFFFF
//// Program memory code protection is enabled
//#define CP_ON 0xFFBF
//// Data Code Protection bit
//// Data memory code protection is disabled
//#define CPD_OFF 0xFFFF
//// Data memory code protection is enabled
//#define CPD_ON 0xFF7F
//// Brown-out Reset Selection bits
//// BOR enabled
//#define BOREN_ON 0xFFFF
//// BOR enabled during operation and disabled in Sleep
//#define BOREN_NSLEEP 0xFEFF
//// BOR controlled by SBOREN bit of the PCON register
//#define BOREN_SBODEN 0xFDFF
//// BOR disabled
//#define BOREN_OFF 0xFCFF
//// Internal External Switchover bit
//// Internal External Switchover mode is enabled
//#define IESO_ON 0xFFFF
//// Internal External Switchover mode is disabled
//#define IESO_OFF 0xFBFF
//// Fail-Safe Clock Monitor Enabled bit
//// Fail-Safe Clock Monitor is enabled
//#define FCMEN_ON 0xFFFF
//// Fail-Safe Clock Monitor is disabled
//#define FCMEN_OFF 0xF7FF*/
#include <htc.h>
#include <stdio.h>
#include <stdlib.h>
#include "lcd.h"
__CONFIG (FCMEN_ON & IESO_OFF & BOREN_OFF & CPD_OFF & CP_OFF & MCLRE_OFF & PWRTE_ON & WDTE_OFF & FOSC_INTRCIO);
#define LED RC0
#define _XTAL_FREQ 4000000
//global defs
volatile bit timer_tick;
volatile bit blink;
union {
unsigned int res;
char bytes[2];
}ADC;
char ADC_num[6];
float temprature;
static void interrupt isr(void) // Here is interrupt function - the name is
// unimportant.
{
if(TMR1IF)
{// Was this a timer overflow?
TMR1IF=0;//Clear interrupt flag, ready for next
TMR1H=0x80;
//If we set TMR1 to start at 0x8000 (32768), the TMR1 will overflow every 1 second
timer_tick=1;
GO_DONE=1;
}//we are done here
}
void setup(void)
{
TRISA0=0;
TRISC=0b01111000;//RC0-RC2 out,RC3-RC6 in,RC7 out
TRISB=0; //All port B output
GIE = 0; // Global interrupt disable just in case
ANSEL=0;
ANSELH=0;//turn off all analog functions
//timer1 settings
TMR1H=0x80;
TMR1L=0;
T1CON=0b00000110;//used during debug
//T1CON=0b00001110;
// See datasheet REGISTER 6-1: T1CON: TIMER 1 CONTROL REGISTER
// bit order T1GINV TMR1GE T1CKPS1 T1CKPS0 T1OSCEN !T1SYNC TMR1CS TMR1ON
//Timer1 Interrupt prepare
TMR1IE=1;// PIE1 register
PEIE=1; //INTCON register
PIR1=0; // Clear all bits PERIPHERAL INTERRUPT REQUEST REGISTER 1
//todo now in order to generate interrupt GEI=1 and TMR1ON=1
//setup LCD
lcd_init();
lcd_goto(0); // select first line
//set the globals
//week_day=0;
timer_tick=0;
blink=0;
//setup ADC
TRISA0 = 1;
ANSEL = 0b00000001; // Set PORT AN0 to analog input AN1 to AN7 digital I/O
ANSELH = 0;
ADCON0=0b10000000; // select right justify result. ADC port channel 0
ADCON1=0b01010000; // Select the FRC for 4 Mhz
ADON=1;
//other misc settings
timer_tick=0;//clear the tick
}
void main (void)
{
signed int l;
unsigned int rem;
setup();
// timer_tick=1;//just for debug
GIE=1;
TMR1ON=1;
lcd_puts("hello");
__delay_ms(1000);
lcd_goto(0x40);
lcd_puts("world :)");
__delay_ms(2000);
lcd_clear();
GIE=1;
TMR1ON=1;
while (1)
{
if (timer_tick)
{
lcd_clear();
while(GO_DONE);
ADC.bytes[0]=ADRESL;
ADC.bytes[1]=ADRESH;
utoa(ADC_num, ADC.res, 10);
lcd_puts("RAW ADC data ");
lcd_puts(ADC_num);
temprature=(float)ADC.res*478.1/1024;
temprature=temprature-50;
l = (signed int)temprature;
temprature -= (float)l;
rem = (unsigned int)(temprature* 1e1);
sprintf(&ADC_num, "%i.%u", l, rem);
lcd_goto(0x40);
lcd_puts("Temp ");
lcd_puts(ADC_num);
timer_tick=0;
blink=!blink;
LED=blink;
} // end if (timer_tick) Memo to my self put all this in sub function
}//end while endless loop
}//End mainWill try to implement it,
wondering why you put an interrupt go_done=1,
meaning it will calculate every second, ?
i have done it only every 3 seconds, no need to calculate while it doesnt show the temperature. or ?
need to check it out, when i got the time to it,
Just pick and mix as you want. I just wrote the program as an example for you that was tested. But it dos not harm to measure temperature say every second and then display an average value based on several measurements. However it nice to have and need to have. Focus on the simplest solution first. And then this work you can go for something more advanced.
I am a little concern that you will run out of program space using the compiler in lite mode(free). I will then suggest using the PIC16f1509. It should fit into your board. And is supported by PICKIT 2. You will be able to keep the core of your program. But some minor rewriting in the setup function will be required
Havent checked for space yet, but lets see.
as it is now, before the changes you suggested, there was lots of space.
maybee tomorrow i will work on it again.
Havent not enough space, if i use that. 99,9 % used,
and still need to implent some thing.
Nevermind the accarusy, i use a stabel powersupply, and then i can program my way out of it.
Have a couple of questions.
Can i set another temp-sensor to ex AN1(RA1 ) ?
and then i have both inside and outside temperature.
This calculations works, but how can i make it ex 20.5 degree and not just 20 and 21 ect.
Rich (BB code):
celcius=(((5000/1024)*degree)-500)/10;Your not going to find one. You need an external voltage reference.
Look at your code again. There are always places where you can optimize the code.
Not easily.Especially since you are already low on code memory. Again why I recommend the dallas sensors in the first place.
