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How to set the PWM duty with the accelerometer value?

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pacman91

Joined: 17 Jun 2011
Posts: 28
Location: Malaysia

How to set the PWM duty with the accelerometer value?

Posted: Sat Jul 23, 2011 12:08 am

Code:

#include<18F4520.h>
#DEVICE ADC=8
#fuses HS,NOWDT,NOPROTECT,NOLVP, BROWNOUT, PUT
#use delay(clock=4000000)
//#Define timer PIN_C2
#include <flex_lcd.c>
#define data_width 3

int8 AccData[data_width];
long valuex,valuey,

void main(void)
{
int i;

output_high(LCD_POWER); // Turn on power to LCD
output_low(LCD_RW);
lcd_init();

setup_adc(ADC_CLOCK_INTERNAL);//enables the a/d module
//and sets the clock to internal adc clock
setup_adc_ports(AN0_TO_AN2); //set the adc pins to analog

output_low(PIN_C1); // Set CCP2 output low
output_low(PIN_C2); // Set CCP1 output low

setup_ccp1(CCP_PWM); // Configure CCP1 as a PWM
setup_ccp2(CCP_PWM); // Configure CCP2 as a PWM
enable_interrupts(int_timer2);
enable_interrupts(GLOBAL);
setup_timer_2(T2_DIV_BY_16, 250, 5); // 4 ms

while(1)
{
disable_interrupts(int_timer2);
disable_interrupts(GLOBAL);

for(i = 0; i < data_width; i++)
{

   set_adc_channel(i);
   delay_us(10);       //a small delay is required after setting the channel
   AccData[i] = read_adc(); //starts the conversion
   }

   lcd_gotoxy(1,1);
   printf(lcd_putc, "x = %u y = %u ", AccData[0], AccData[1]);
   lcd_gotoxy(1,2);
   printf(lcd_putc, "z = %u ", AccData[2]);
   delay_ms(10);

valuex = AccData[0];
valuey = AccData[1];

enable_interrupts(int_timer2);
enable_interrupts(GLOBAL);
}

#int_timer2 // setup_timer_2(T2_DIV_BY_16, 250, 5); // 4 ms * 5(postscale) =20ms

void ISR_Timer2()
{
disable_interrupts(int_timer2); // which disable is needed in this program? teach me.
//disable_interrupts(GLOBAL); //
set_pwm1_duty(valuex); // duty cycle on pin C2
set_pwm2_duty(valuey); // duty cycle on pin C1
enable_interrupts(int_timer2);
//enable_interrupts(GLOBAL);
}

Quote:

I just simply type this code to let you all know what i wanted to do, the program is not simulated, PWM period is 4ms, please teach me how to set to 20ms, the variable in program, valuex and valuey in the set_pwm_duty(), I just simply put, because i dun know how to set the value with the reading of the accelerometer with the short range from 126_to_142(x-axis) and also the Y-axis

Quote:

I though that the program can run as I imagine, after20ms, execute interrupt, set PWM duty cycle, 0.5ms_to_2.35ms( the time of SERVO MOTOR 0_to_180 degree), but the output of RC2 and RC1 result is 4ms, doesn't have any change with the postscale.

the value read from the MMA7269Q
AXIS = Angle of SERVO MOTOR ( 0 90 180)
X = 126 134 142 ( the range of the reading from accelerometer)
0 90 180 degree
Y = 69 81 96
Z = I don't want use it.
those value is the reading from accelerometer, I wanted to set the MIN, MEDIUM, and MAX value as the 0,90,180 degree of the SERVO MOTOR. I want to control 2 servo motor( model C36R) for the X-axis and Y-axis turning with the accelerometer.

Last edited by pacman91 on Sat Jul 23, 2011 3:22 am; edited 1 time in total

pacman91

Joined: 17 Jun 2011
Posts: 28
Location: Malaysia

Posted: Sat Jul 23, 2011 12:30 am

Code:

#include<18F4520.h>
#DEVICE ADC=8
#fuses HS,NOWDT,NOPROTECT,NOLVP, BROWNOUT, PUT
#use delay(clock=4000000)
#include <flex_lcd.c>
#define data_width 3

int8 AccData[data_width];
long timerx,timery,valuex,valuey;
void main(void)
{
int i;

output_high(LCD_POWER); // Turn on power to LCD
output_low(LCD_RW);
lcd_init();

setup_adc(ADC_CLOCK_INTERNAL);//enables the a/d module
//and sets the clock to internal adc clock
setup_adc_ports(AN0_TO_AN2); //set the adc pins to analog

enable_interrupts(int_timer2);
enable_interrupts(GLOBAL);
setup_timer_2(T2_DIV_BY_16, 250, 5);

while(1)
{
disable_interrupts(int_timer2);
disable_interrupts(GLOBAL);

output_low(PIN_B0);
output_low(PIN_B1);
   for(i = 0; i < data_width; i++)
   {

      set_adc_channel(i);
      delay_us(10);       //a small delay is required after setting the channel
      AccData[i] = read_adc(); //starts the conversion
   }

   lcd_gotoxy(1,1);
   printf(lcd_putc, "x = %u y = %u ", AccData[0], AccData[1]);
   lcd_gotoxy(1,2);
   printf(lcd_putc, "z = %u ", AccData[2]);
delay_ms(10);

valuey = AccData[1];
timery= (valuey^2)/376;
valuex = AccData[0];
timerx = (valuex^10)/794000000000000000;

enable_interrupts(int_timer2);
enable_interrupts(GLOBAL);

}

#int_timer2
void ISR_Timer2()
{
disable_interrupts(int_timer2);
//disable_interrupts(GLOBAL);
output_high(PIN_B0);
delay_us(timery);
output_high(PIN_B1);
delay_us(timerx);
enable_interrupts(int_timer2);
// enable_interrupts(GLOBAL);
}

Quote:

this code i tried before the code i shown at top, this code is pull up the PIN_B0 with the delay with calculation, but the simulation result output is totally different with my calculation, why?)

because i failed to use the delay, so i change to the SET_DUTY_PWM.
but i wanted to know what problem in this, so i shown this code to you all, so i can learned it Very Happy

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