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dunque questo e' il programma che sto compilando ( un prog di prova)/** C O N F I G U R A T I O N B I T S ******************************/
#pragma config FOSC = INTIO67, FCMEN = OFF, IESO = OFF // CONFIG1H
#pragma config PWRT = OFF, BOREN = OFF, BORV = 30 // CONFIG2L
#pragma config WDTEN = OFF, WDTPS = 32768 // CONFIG2H
#pragma config MCLRE = ON, LPT1OSC = OFF, PBADEN = OFF, CCP2MX = PORTC // CONFIG3H
#pragma config STVREN = ON, LVP = OFF, XINST = OFF // CONFIG4L
#pragma config CP0 = OFF, CP1 = OFF, CP2 = OFF, CP3 = OFF // CONFIG5L
#pragma config CPB = OFF, CPD = OFF // CONFIG5H
#pragma config WRT0 = OFF, WRT1 = OFF, WRT2 = OFF, WRT3 = OFF // CONFIG6L
#pragma config WRTB = OFF, WRTC = OFF, WRTD = OFF // CONFIG6H
#pragma config EBTR0 = OFF, EBTR1 = OFF, EBTR2 = OFF, EBTR3 = OFF // CONFIG7L
#pragma config EBTRB = OFF // CONFIG7H
/** I N C L U D E S **************************************************/
#include "p18f45k20.h"
#include "delays.h"
#include "PWM.h" // header file
/** V A R I A B L E S *************************************************/
#pragma idata // declare statically allocated initialized variables
/** D E C L A R A T I O N S *******************************************/
#pragma code // declare executable instructions
void main (void)
{
unsigned char brightness = 125; // = 0x7D
// Set RD7/P1D pin output so P1D PWM output drives LED7
TRISDbits.TRISD7 = 0;
// Set up 8-bit Timer2 to generate the PWM period (frequency)
T2CON = 0b00000111;// Prescale = 1:16, timer on, postscale not used with CCP module
PR2 = 249; // Timer 2 Period Register = 250 counts
// Thus, the PWM frequency is:
// 1MHz clock / 4 = 250kHz instruction rate.
// (250kHz / 16 prescale) / 250) = 62.5Hz, a period of 16ms.
// The Duty Cycle is controlled by the ten-bit CCPR1L<7,0>:DC1B1:DC1B0
// 50% Duty Cycle = 0.5 * (250 * 4) = 500
CCPR1L = 0x7D; // The 8 most significant bits of the value 500 = 0x1F4 are 0x7D
// The 2 least significant bits of the value (0b00) are written
// to the DC1B1 and DC1B0 bits in CCP1CON
CCP1CON = 0b01001100;
// P1Mx = 01 Full-Bridge output forward, so we get the PWM
// signal on P1D to LED7. Only Single Output (00) is needed,
// but the P1A pin does not connect to a demo board LED
// CCP1Mx = 1100, PWM mode with P1D active-high.
// The LED brightness is affected by by the Duty Cycle, which determines how much
// of each 16ms period it is on and how much it is off. As the duty cycle gets
// less than 50%, it is off more than it is on so the LED becomes dimmer. As the
//duty cycle increases above 50%, it is on more than off, so it gets brighter.
//
// This increases the brightness over 2 seconds, then decreases it over the next 2 seconds
// Updating the CCPR1L value more than once per 16ms period has no benefit, so we'll update
// it a total of 125 times, once per period, which works out to 2 seconds.
//
// Although we have nearly ten bits of resolution in the duty cycle (1000 counts)
// we'll increment the duty cycle by 8 each time as we only have 125 levels over the
// 2 second period.
while(1)
{
// increase brightness over 2 seconds.
do
{
brightness += 2;
CCPR1L = brightness; // + 8 including 2 bits DC1Bx in CCP1CON
PIR1bits.TMR2IF = 0; // clear interrupt flag; set on every TMR2 = PR2 match
while (PIR1bits.TMR2IF == 0); // watch for match, which is end of period.
} while (brightness < 250);
Delay1KTCYx(63); // delay about 250ms at peak brightness, just for effect!
// decrease brightness over 2 seconds.
do
{
brightness -= 2;
CCPR1L = brightness; // - 8 including 2 bits DC1Bx in CCP1CON
PIR1bits.TMR2IF = 0; // clear interrupt flag; set on every TMR2 = PR2 match
while (PIR1bits.TMR2IF == 0); // watch for match, which is end of period.
} while (brightness > 1);
Delay1KTCYx(63); // delay about 250ms at dimmest, it gives a better effect!
};
}
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- internet + cabernet
- V8 Power
l'esperienza non si compra ma si paga
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