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young
Joined: 24 Jun 2004
Posts: 285
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| PIC16f684 does not accept variable for function |
 Posted: Thu Nov 10, 2005 3:48 pm |
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I have used pwm function for several chips, and it works very well so far, I can set duty as constant as well as variable, however, when it comes to pic16f684 chip, I just got the set_pwm1_duty() function work for constant, it is not working for variable,any ideas? attached is the testing code.
| Code: |
#if defined(__PCM__)
#include <16F684.h>
#fuses INTRC_IO, NOBROWNOUT,NOWDT,NOPROTECT,NOPUT,NOMCLR
//#device ADC=10
#use delay(clock =8000000)
void main()
{
int8 i;
SET_TRIS_a(0x07);
SET_TRIS_c(0x07);
setup_comparator(NC_NC_NC_NC);
setup_adc(ADC_OFF);
SETUP_ADC_PORTS(NO_ANALOGS);
setup_timer_2(T2_DIV_BY_1, 255, 1);
SETUP_CCP1(CCP_PWM);
disable_interrupts(GLOBAL);
while(1)
{
/*if(input(PIN_A0))
SET_PWM1_DUTY(88);
else if(input(PIN_A1))
SET_PWM1_DUTY(96);
else if(input(PIN_A2))
SET_PWM1_DUTY(112);
else if(input(PIN_C0))
SET_PWM1_DUTY(128);
else if(input(PIN_C1))
SET_PWM1_DUTY(144);
else if(input(PIN_C2))
SET_PWM1_DUTY(160);
else
SET_PWM1_DUTY(88);
*/ //the above code is work, the following is not
for (i=0;i<=254;i++)
{
SET_PWM1_DUTY(i);
output_high(PIN_C3);
delay_ms(1500);
output_low(PIN_C3);
delay_ms(1500);
}
}
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Nov 10, 2005 4:27 pm |
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| Quote: |
SET_PWM1_DUTY(88);
SET_PWM1_DUTY(96);
SET_PWM1_DUTY(112);
SET_PWM1_DUTY(128);
SET_PWM1_DUTY(144);
SET_PWM1_DUTY(160);
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All of these tests above have a cycle value of 88 or greater.
In this test below, you are starting with a duty cycle of 0 and you
increase it by 1, every 3 seconds. So to get up to 88, which you
declare to be working, it takes 88 x 3 = 264 seconds = 4 minutes
and 24 seconds. Do you really wait for almost 5 minutes, while
watching the output ? I wonder.
| Quote: |
for (i=0;i<=254;i++)
{
SET_PWM1_DUTY(i);
output_high(PIN_C3);
delay_ms(1500);
output_low(PIN_C3);
delay_ms(1500);
} |
I suggest you use a very simple test, like this:
| Code: |
i = 88;
SET_PWM1_DUTY(i); // Set duty cycle value = 88
while(1); // Wait here and let PWM run.
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young
Joined: 24 Jun 2004
Posts: 285
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| Posted: Fri Nov 11, 2005 8:17 am |
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Thank you PCM:
you are right, I tested it again it is working, before when I was testing it, I run the for loop too fast that the meter could not followed it. |
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