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smash
Guest
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| help pwm !!!!! control step pwm |
 Posted: Tue Dec 02, 2008 3:54 am |
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I'm having problems using the PWM of my PIC16F877. I want to change pwm using delay time such as from set_pwm1_duty(100) to set_pwm1_duty(200), and change it in single steps using delay_ms(50) +1 delay_ms(50) +1 from 100 +1 delay 50ms -->101 +1 delay 50ms --->102 +1 delay 50ms ---->....... to 200 and 200----->100 pwm
Help me
| Code: |
#include <16F877.h>
#device adc=8
#FUSES NOWDT //No Watch Dog Timer
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPUT //No Power Up Timer
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOCPD //No EE protection
#FUSES NOWRT //Program memory not write protected
#FUSES NODEBUG //No Debug mode for ICD
#use delay(clock=20000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
int c2,D2;
int16 value;
float c;
void main()
{
setup_timer_2(T2_DIV_BY_1,249,1); //20 khz
setup_ccp1(CCP_PWM);
setup_ccp2(CCP_PWM);
setup_adc_ports(ALL_ANALOG);
setup_adc(ADC_CLOCK_DIV_32);
while(true)
{
set_adc_channel(0);
delay_us(30);
value=read_adc(); //read adc
c = (float)(value * 5)/1023.0;
c2 = c*10; // max value 50
if(c2>=10)
{
output_high(PIN_B1);
output_low(PIN_B0);
D2=c2*2;// value = 100
set_pwm1_duty(D2);
}
else if(c2>=0)
{
output_high(PIN_B1);
output_low(PIN_B0);
D2=c2*4; // value = 200
set_pwm1_duty(D2);
}
}
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Tue Dec 02, 2008 4:20 am |
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If you want to continue monitoring the input while altering the PWM then something like this may do.
| Code: |
int speed = 100;
while(true)
{
set_adc_channel(0);
delay_us(30);
value=read_adc();//read adc
c = (float)(value * 5)/1023.0;
c2= c*10;// max value 50
if(c2>=10)
D2=c2*2;// value = 100
else if(c2>=0)
D2=c2*4;// value = 200
output_high(PIN_B1);
output_low(PIN_B0);
if (speed < D2)
speed++;
else if (speed > D2)
speed--;
set_pwm1_duty(speed);
delay_ms(50); // this will slow your response input response time down, there are other options if this is a problem!
}
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