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Louati
Joined: 26 Mar 2012
Posts: 16
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| Réaliser un signal PWM 500hz |
 Posted: Wed May 30, 2012 2:48 am |
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Bonjour 
Je suis en train de réaliser un signal PWM de fréquence 500hz dont le rapport cyclique est variable à l'aide d'un potentiomètre.
Sur ISIS le programme fonctionne parfaitement mais en pratique il coince :/
Voici le code de mon programme :
#include <18f2550.h>
#device adc=10
#FUSES NOWDT
#FUSES WDT128
#FUSES PLL1
#FUSES CPUDIV1
#FUSES NOUSBDIV
#FUSES INTRC_IO
#FUSES NOFCMEN
#FUSES NOIESO
#FUSES BORV27
#FUSES NOVREGEN
#FUSES NOPBADEN
#FUSES NOLPT1OSC
#FUSES NOMCLR
#FUSES NOLVP
#FUSES NOXINST
#use delay(clock=8000000)
#byte porta = 0xF80
#byte portb = 0xF81
#byte portc = 0xF82
#byte portd = 0xF83
#byte trisa = 0xF92
#byte trisb = 0xF93
#byte trisc = 0xF94
#byte trisd = 0xF95
char a=0;
char i;
int16 valeur=0,j,p;
void main(void){
portc=0b00000000;
trisc=0b01111111;
setup_adc_ports(AN0);
setup_adc(ADC_CLOCK_INTERNAL|ADC_CLOCK_DIV_2);
set_adc_channel(0);
delay_ms(5000);
valeur=read_adc();
j=(int16)(2000.0*(valeur/1023));
p=2000-j;
while(1){
valeur=read_adc();
j=(int16)(2000.0*(valeur/1023));
p=2000-j;
for(i=1;i;i++){
output_high(pin_C7);
delay_us(j);
output_low(pin_C7);
delay_us(p);
}
}
}
Si quelqu'un de vous a un code plus fiable, prière de me le proposer et merci d'avance |
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Mike Walne
Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK
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| Posted: Wed May 30, 2012 4:28 am |
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Please use English on this forum.
Get rid if PROTEUS. It's full of bugs.
Use REAL hardware from the start.
Mike |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19541
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| Posted: Wed May 30, 2012 6:17 am |
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Agree about ISIS/PROTEUS.
Also _use the code buttons_
| Code: |
#include <18f2550.h>
#device adc=10
#FUSES NOWDT, INTRC_IO, NOFCMEN, NOIESO, BORV27, NOVREGEN, NOPBADEN, NOLPT1OSC, NOMCLR, NOLVP, NOXINST
#use delay(internal=8000000)
char a=0;
char i;
int16 valeur=0,j,p;
void main(void){
output_c(0);
setup_adc_ports(AN0);
setup_adc(ADC_CLOCK_DIV_2); //Only one clock can be used
set_adc_channel(0);
delay_ms(5000);
//j=(int16)(2000.0*(valeur/1023)); This won't work. (0 to 1023)/1023
//using int16 arithmetic=0
//j=(2000*(int32)valeur)/1023;
//p=2000-j;
//No point in doing it all first anyway, since it is done in the loop
while(1){
valeur=read_adc();
j=(2000*(int32)valeur)/1023;
//Use int32, since 1023*2000 is too large to fit in int16. Divide _after_
//multiplication.
p=2000-j;
for(i=1;i;i++) {
output_high(pin_C7);
delay_us(j);
output_low(pin_C7);
delay_us(p);
} //will loop 255 times. 0.51 seconds between updates
}
}
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Big mistake is in the arithmetic.
All the port stuff is unwanted.
Best Wishes |
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