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z3ngew
Joined: 20 Apr 2013
Posts: 50
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| Timer & loops |
 Posted: Tue Apr 23, 2013 10:48 am |
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Hello everyone,
I have a problem in my code, i am using the ccp module of the pic16f877a, to generate 300hz pulses for my digital servo, but when i use infinite loop to always monitor the value of the variable, (Proteus just go crazy) overflow
here is the code
| Code: |
#include <16f877a.h>
#use delay(clock = 4Mhz)
#FUSES NOWDT //No Watch Dog Timer
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#define LCD_ENABLE_PIN PIN_D0
#define LCD_RS PIN PIN_D1
#define LCD_RW PIN PIN_D2
#define LCD_DATA_PORT D
#define LCD_TYPE 2
#include <lcd4.c>
int32 val;
int i = 0;
void main()
{
lcd_init();
delay_ms(50);
setup_adc(adc_clock_internal);
setup_adc_ports(PIN_A0);
set_adc_channel(AN0);
delay_ms(10);
output_low(PIN_C2);
setup_ccp1(CCP_PWM);
setup_timer_2(T2_DIV_BY_16, 210, 1);
do
{
val = read_adc();
delay_ms(10);
lcd_gotoxy(1,0);
printf(lcd_putc, "%lu", val);
}while(true);
}
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Thanks in advance,
z3ngew |
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Mike Walne
Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK
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| Posted: Tue Apr 23, 2013 12:02 pm |
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Tell us what happens with REAL hardware.
Nobody here can answer Proteus questions!
Mike |
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z3ngew
Joined: 20 Apr 2013
Posts: 50
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| Posted: Tue Apr 23, 2013 2:01 pm |
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I'm sry for this rush question, the problem was in the code, but i took care of it, and here is the code [analog pot change the duty cycle of 300hz train generated using ccp module]
| Code: |
#include <16f877a.h>
#DEVICE adc = 10;
#use delay(clock = 4Mhz)
#FUSES NOWDT //No Watch Dog Timer
#FUSES HS //High speed Osc (> 4mhz)
#FUSES NOPROTECT //Code not protected from reading
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#define LCD_ENABLE_PIN PIN_D0
#define LCD_RS PIN PIN_D1
#define LCD_RW PIN PIN_D2
#define LCD_DATA_PORT D
#define LCD_TYPE 2
#include <lcd4.c>
int32 val;
int i = 0;
void main()
{
lcd_init();
delay_ms(50);
setup_adc(adc_clock_internal);
setup_adc_ports(ALL_ANALOG);
delay_ms(10);
output_low(PIN_C2);
setup_ccp1(CCP_PWM);
setup_timer_2(T2_DIV_BY_16, 210, 1);
do
{
set_adc_channel(0);
val = read_adc();
set_pwm1_duty(val/2);
delay_ms(10);
lcd_gotoxy(1,0);
printf(lcd_putc, "%lu", val);
}
while(true);
}
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Good Luck,
z3ngew |
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Mike Walne
Joined: 19 Feb 2004
Posts: 1785
Location: Boston Spa UK
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| Posted: Tue Apr 23, 2013 2:20 pm |
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Does this mean problem is solved?
If so, you can amend title.
Mike
Last edited by Mike Walne on Tue Apr 23, 2013 2:23 pm; edited 1 time in total |
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z3ngew
Joined: 20 Apr 2013
Posts: 50
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| Posted: Tue Apr 23, 2013 2:21 pm |
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Yes, it work just fine in simulation, and in real life  |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19538
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| Posted: Wed Apr 24, 2013 1:04 am |
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There are several things I will comment that are faulty with the code as published though....
| Code: |
setup_adc(adc_clock_internal);
//Read the data sheet. Is this clock recommended at your CPU clock
//rate?. Accuracy will be spoiled by this.....
setup_adc_ports(ALL_ANALOG);
//Unless you are using all the pins as analog, don't select this
//Only select the pins you are going to use. Every pin that is selected to
//the analog multiplexer, increases the potential noise sources.
//Microchip have notes about this. Again degrades accuracy...
delay_ms(10);
output_low(PIN_C2);
setup_ccp1(CCP_PWM);
setup_timer_2(T2_DIV_BY_16, 210, 1);
do
{
set_adc_channel(0);
//Read the data sheet again. Is Tacq being satisfied here?.
//again accuracy will be killed....
//It'll work, since you are re-selecting the same channel
//Why?. select the channel once unless you need to change it
//but if you were changing channels, it wouldn't work...
val = read_adc();
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