Escribí el siguiente código para medir la frecuencia de una onda cuadrada usando el módulo de captura del PIC16f1788. Escribí el código siguiendo paso a paso lo que se requiere en la hoja de datos de este PIC. Me gustaría saber si he omitido algún paso importante al hacerlo y si mi código tiene sentido. Esta es la primera vez que uso el módulo de captura, así que cualquier sugerencia es bienvenida. Gracias
#include <xc.h>
// Config word
#define frequ 2
#define _XTAL_FREQ 32000000
// CONFIG1
#pragma config FOSC = INTOSC // Oscillator Selection (INTOSC oscillator: I/O function on CLKIN pin)
#pragma config WDTE = ON // Watchdog Timer Enable (WDT enabled)
#pragma config PWRTE = OFF // Power-up Timer Enable (PWRT disabled)
#pragma config MCLRE = ON // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config CP = OFF // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config CPD = OFF // Data Memory Code Protection (Data memory code protection is disabled)
#pragma config BOREN = ON // Brown-out Reset Enable (Brown-out Reset enabled)
#pragma config CLKOUTEN = OFF // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
#pragma config IESO = ON // Internal/External Switchover (Internal/External Switchover mode is enabled)
#pragma config FCMEN = ON // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is enabled)
// CONFIG2
#pragma config WRT = OFF // Flash Memory Self-Write Protection (Write protection off)
#pragma config VCAPEN = OFF // Voltage Regulator Capacitor Enable bit (Vcap functionality is disabled on RA6.)
#pragma config PLLEN = ON // PLL Enable (4x PLL enabled)
#pragma config STVREN = ON // Stack Overflow/Underflow Reset Enable (Stack Overflow or Underflow will cause a Reset)
#pragma config BORV = LO // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config LPBOR = OFF // Low Power Brown-Out Reset Enable Bit (Low power brown-out is disabled)
#pragma config LVP = ON // Low-Voltage Programming Enable (Low-voltage programming enabled)
void main(void)
{
int count=0;
float rise1=0,rise2=0,frequency,period;
OSCCON = 0b11111010;
// clear the interrupts at beginning that way we are sure that our calculations will be exact no previous interrupt present
PIR1.CCP1IF=0;
PIE1.CCP1IE=0;
// output
TRISBbits.TRISB0 = 1; // set it to input
APFCON1bits.CCP1SEL=1;// toggle the CCP port output to RB0 from RC2
// configure CCP1
CCP1CONbits.CCP1M = 0x05; // set it to Capture mode; on every rising edge
While (count=! 2){
count +=1; // increment the value of count
// configure Timer 1
T1CONbits.TMR1CS = 0; //set the timer 1 clock to instruction clock Fosc/4 as mentioned in page300
T1CONbits.TMR1ON = 1; // set Timer 1 on
delay_us(10); //aquisition time
T1GCON.T1GO/nDONE=1; // aquisition is ready wait for a rising edge
while (T1GCON.T1GO/nDONE=1); //wait untill the aquisition is complete
if (count==1) {
rise1=CCPR1; } //capture the first rising edge and store that value in rise1
if count ==2) {
rise2=CCPR1; } // capture the second rising edge and store the value in rise2
}
period = rise2-rise1; // subtracte both values to get the period of the signal
frequency=1/period;
// clear any interrupts that are set
PIR1.CCP1IF=0;
PIE1.CCP1IE=0;
}