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pk178
Joined: 10 Mar 2010
Posts: 10
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| Help me with PWM |
 Posted: Wed Mar 10, 2010 7:56 am |
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Hi everybody !
I want to test PWM on CCP1 pin of PIC16F887A, this is my code :
| Code: | #include <16F887.h>
#device *=16,ADC = 8
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 4000000)
//==============================================================================
int duty = 25;
#int_ext
void interrupt_rb0(){
duty = read_ADC();
set_pwm1_duty(duty);
}
//==============================================================================
void main() {
set_tris_b(0x01);
setup_adc(ADC_CLOCK_DIV_32); // sample time = IC clock
setup_adc_ports(sAN0); // Set PIN_A0 as analog input 1
enable_interrupts ( int_ext ) ;
enable_interrupts ( global ) ;
setup_ccp1(CCP_PWM); // Configure CCP1 as a PWM
set_pwm1_duty(duty);
setup_timer_2(T2_DIV_BY_1, 255, 1);
while(1); // Prevent PIC from going to sleep (Important !)
}
//============================================================================== |
I want to use interrupt on RB0 pin to change duty cycle, duty cycle is read from ADC value at RA0, I simulated on proteus software. At first, the program run correctly, but when I press interrupt button to change duty cycle, the CCP1 pin always at 0 level, PWM is not working.
I don't know why, please help me ! Thanks ! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Mar 10, 2010 9:47 am |
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You need to set the ADC channel. Do this in main(), after the other
two lines that setup the ADC. |
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pk178
Joined: 10 Mar 2010
Posts: 10
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| Posted: Thu Mar 11, 2010 9:01 pm |
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I've already tested it in real circuit, It works well, no matter, the problem is simulator software !!!
Thanks for reply ! |
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