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| Author |
Message |
mohammad3d
Joined: 28 Mar 2009
Posts: 17
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| Pure PWM sine wave generator |
 Posted: Tue Mar 26, 2013 12:14 am |
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Hi all,
I try to write a Sine wave generator and think it must be helpful for
others.
This routine tested and work fine.
I use sine PWM at 10khz to create 50Hz sine wave.
| Code: |
// Pure PWM sine wave generator
//
// D0 ->--/\/\/\--|-- Sine output(~ 3vpp)
// 33Kohm |
// --- 100 nf
// ---
// |
// GND
#include <30F6014A.h>
#fuses XT
#use delay(clock=10M)
int16 i;
int16 PWM=0;//pwm step counter
int16 sin_table1[181];//Store 0~180 degree sine lookup table
int16 sin_table2[181];//Store 181~360 degree sine lookup table
#define PI 3.14159265
#define Step_delay 50 //micro second
#INCLUDE <math.h>
void main()
{
//////////////// setup PWM ///////////////////////////
setup_timer3(TMR_INTERNAL | TMR_DIV_BY_1, 0x00fa);//PWM set to 250(0xfa)step at 10 Khz
setup_compare(1, COMPARE_PWM | COMPARE_TIMER3);//PIN 58 (PORT D0)
//////// fill sine lookup table //////////////////////
for (i = 0; i <=180; i++)
{
sin_table1[i]=125+floor(125*sin(i * PI /180));
sin_table2[i]=250-sin_table1[i];
}
//////// main loop ///////////////////////////////////
for(;;)
{
//////////// 0~180 degree loop ///////////////////////
PWM=0;
while(PWM<181)
{
set_pwm_duty(1,sin_table1[PWM]);
PWM++;
delay_us(Step_delay);
}
//////////// 181~359 degree loop /////////////////////
PWM=1;
while(PWM<180)
{
set_pwm_duty(1,sin_table2[PWM]);
PWM++;
delay_us(Step_delay);
}
}
} |
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mohammad3d
Joined: 28 Mar 2009
Posts: 17
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| improve algorithm ... |
| Posted: Thu Mar 28, 2013 1:10 am |
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Hi all,
I improve last software algorithm.
| Code: |
// Pure PWM sine wave generator
//
// D0 ->--/\/\/\--|-- Sine output(~ 3vpp)
// 33Kohm |
// --- 100 nf
// ---
// |
// GND
#include <30F6014A.h>
#fuses XT
#use delay(clock=10M)
int8 resync_step=0;
int16 i;
int16 Sine_wave_step=0;//pwm step counter
int16 sin_table[361];//Store 0~360 degree sine lookup table
#define PI 3.14159265
#define Step_delay 50 //micro second
#INCLUDE <math.h>
void main()
{
//////////////// setup PWM ///////////////////////////
setup_timer3(TMR_INTERNAL | TMR_DIV_BY_1, 0x00fa);//PWM set to 250(0xfa)step at 10 Khz
setup_compare(1, COMPARE_PWM | COMPARE_TIMER3);//PIN 58 (PORT D0)
//////// fill sine lookup table //////////////////////
for (i = 0; i <=180; i++)
{
sin_table[i]=125+floor(125*sin(i * PI /180));
sin_table[i+180]=250-sin_table[i];
}
//////// main loop ///////////////////////////////////
for(;;)
{
//////////// 0~360 degree loop ///////////////////////
Sine_wave_step=0;
while(Sine_wave_step<360)
{
set_pwm_duty(1,sin_table[ Sine_wave_step]);
Sine_wave_step++;
delay_us(Step_delay);
}
}
} |
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ihsanbu
Joined: 14 Oct 2006
Posts: 27
Location: islamabad,pakistan
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| Posted: Thu Apr 25, 2013 11:39 pm |
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ThanK for these codes , i need code to interface SIM900D GSM module with pic18f452 micro-controller.
regard
ihsanbu@gmail.com
_________________
ihsan ullah khan
Embedded Designer Since 2003 |
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ihsanbu
Joined: 14 Oct 2006
Posts: 27
Location: islamabad,pakistan
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| Posted: Thu Apr 25, 2013 11:41 pm |
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hi can i use this for pic18f452
_________________
ihsan ullah khan
Embedded Designer Since 2003 |
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mohammad3d
Joined: 28 Mar 2009
Posts: 17
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| Posted: Thu Apr 25, 2013 11:58 pm |
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Hi dear ihsan,
Yes, you can use this code for any kind of PIC18f series, but you must
configure your chip PWM module and step delay to get right frequency.
I don't know SIM900 module and don't know which kind of PWM you need,
but my code just simulate sine wave form just like 220v/50hz power line.
Regards,
Mohammad. |
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AsadZero2
Joined: 18 Dec 2013
Posts: 1
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| 18f4550 |
| Posted: Wed Dec 18, 2013 10:20 am |
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aoa Mohammed3d
I know I'm asking this after ages but i hope you or someone will be able to help me. I'm new to the uController thing and i need to generate a sine wave that'll vary in frequency upon certain conditions.
I used the code however there were some things i couldn't get to fix according to the pic18f4550.
| Code: |
#fuses XT
#use delay(clock=10M)
int8 resync_step=0;
int16 i;
int16 Sine_wave_step=0;//pwm step counter
int16 sin_table[361];//Store 0~360 degree sine lookup table
#define PI 3.14159265
#define Step_delay 50 //micro second
#INCLUDE <math.h>
void main()
{
//////////////// setup PWM ///////////////////////////
setup_timer3(TMR_INTERNAL | TMR_DIV_BY_1, 0x00fa);//PWM set to 250(0xfa)step at 10 Khz
setup_compare(1, COMPARE_PWM | COMPARE_TIMER3);//PIN 58 (PORT D0)
//////// fill sine lookup table //////////////////////
for (i = 0; i <=180; i++)
{
sin_table[i]=125+floor(125*sin(i * PI /180));
sin_table[i+180]=250-sin_table[i];
}
//////// main loop ///////////////////////////////////
for(;;)
{
//////////// 0~360 degree loop ///////////////////////
Sine_wave_step=0;
while(Sine_wave_step<360)
{
set_pwm_duty(1,sin_table[ Sine_wave_step]); // *** I'm getting paranthesis error in this line
Sine_wave_step++;
delay_us(Step_delay);
}
}
}
|
So i changed the CODE to:
| Code: |
#include <18F4550.h>
#fuses XT
#use delay(clock=10M)
int8 resync_step=0;
int16 i;
int16 Sine_wave_step=0;//pwm step counter
int16 sin_table[361];//Store 0~360 degree sine lookup table
#define PI 3.14159265
#define Step_delay 50 //micro second
#INCLUDE <math.h>
void main()
{
//////////////// setup PWM ///////////////////////////
setup_timer_3(t3_INTERNAL | t3_DIV_BY_1);//PWM set to 250(0xfa)step at 10 Khz
//setup_compare(1, COMPARE_PWM | COMPARE_TIMER3);//PIN 58 (PORT D0) // *** I HAD TO DISABLE THIS LINE TO MAKE IT WORK
//////// fill sine lookup table //////////////////////
for (i = 0; i <=180; i++)
{
sin_table[i]=125+floor(125*sin(i * PI /180));
sin_table[i+180]=250-sin_table[i];
}
//////// main loop ///////////////////////////////////
for(;;)
{
//////////// 0~360 degree loop ///////////////////////
Sine_wave_step=0;
while(Sine_wave_step<360)
{
set_pwm1_duty(sin_table[Sine_wave_step]);
Sine_wave_step++;
delay_us(Step_delay);
}
}
} |
I need to know which pin is it giving output on and how can i change the frequency of the output wave. |
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mohammad3d
Joined: 28 Mar 2009
Posts: 17
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| change sine wave frequency. |
| Posted: Mon Dec 23, 2013 5:04 am |
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Dear asad,
You can change "Step_delay" to take other period time.
If "step_delay = 50 ", your while loop execute about 0.02 second or 50 time
per second and you have an sine output with 50 Hz frequency.
Regards,
Mohammad Kouchekzadeh. |
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joanpebupe
Joined: 19 Feb 2015
Posts: 1
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| Pure PWM sine wave generator |
| Posted: Thu Feb 19, 2015 11:03 am |
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Good afternoon!
I was looking for that style of code to do a sine wave with the pwm. i'm using PIC18F4331 and i would really like to know how implement this code but using power pwm instead of CCP/PWM.
above all i would like to know how configure the sentence:
set_power_pwm0_duty(*******)
cause I think it works different on power PWM.
Thanks!
Juanpe |
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