129 lines
4.3 KiB
C
129 lines
4.3 KiB
C
/*
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* File: main.c
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* Author: clement
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*
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* Created on July 14, 2025, 3:54 PM
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <xc.h>
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// Configuration bits
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#pragma config FOSC = INTOSC // Oscillator Selection bits (INTOSC oscillator: I/O function on CLKIN pin)
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#pragma config WDTE = OFF // Watchdog Timer Enable (WDT disabled)
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#pragma config PWRTE = OFF // Power-up Timer Enable (PWRT disabled)
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#pragma config MCLRE = ON // MCLR Pin Function Select (MCLR/VPP pin function is digital input)
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#pragma config CP = OFF // Flash Program Memory Code Protection (Program memory code protection is disabled)
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#pragma config BOREN = OFF // Brown-out Reset Enable (Brown-out Reset disabled)
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#pragma config CLKOUTEN = OFF // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
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#pragma config LVP = OFF
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#pragma config DEBUG = ON
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#pragma config PLLEN = 0
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#define DHT22_PIN_DIR TRISAbits.TRISA4
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#define DHT22_DATA PORTAbits.RA4
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#define CTRL_1 PORTAbits.RA5
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#define CTRL_2 PORTAbits.RA2
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#define _XTAL_FREQ 8000000
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void startSignal() {
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__delay_ms(5); // Attendre 5 ms pour stabiliser. Durée trame = 4ms
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// Signal de départ : bas pendant au moins 1 ms
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DHT22_PIN_DIR = 0; // 0 = sortie donc à 0
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__delay_ms(1); // Attendre 1 ms
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// Signal de départ : haut pendant 20-40 µs
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DHT22_PIN_DIR = 1; // 1 = entrée donc haut grace au pullup
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__delay_us(30); // Attendre 30 µs
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}
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// Fonction pour lire un octet du DHT22
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uint8_t readByte(int n) {
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uint8_t byte = 0;
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for (uint8_t i = 0; i < 8; i++) {
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TMR1H = 0; // Réinitialise le Timer1
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TMR1L = 0;
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while (!DHT22_DATA);
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CTRL_1 = 1;
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//T1CONbits.TMR1ON = 1;
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TMR0 = 0;
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while (DHT22_DATA);
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//T1CONbits.TMR1ON = 0;
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CTRL_1 = 0;
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//uint16_t pulseWidth = (uint16_t) (TMR1H << 8) | (uint16_t) TMR1L; // Lit la valeur du Timer1
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//byte <<= 1; // Décale le byte de 1 bit à gauche
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if (TMR0 > 50) { // Si l'impulsion est supérieure à 50 µs, c'est un 1
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byte |= 1;
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}
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}
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return byte;
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}
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// Fonction pour lire l'humidité et la température
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uint8_t lire(signed char* humidite, signed char* temp) {
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startSignal();
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uint8_t humidityHigh = readByte(1);
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uint8_t humidityLow = readByte(2);
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uint8_t temperatureHigh = readByte(3);
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uint8_t temperatureLow = readByte(4);
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uint8_t checksum = readByte(5);
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if (checksum != (humidityHigh + humidityLow + temperatureHigh + temperatureLow)) {
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return 1; // Erreur de checksum
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}
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uint16_t humidity = (uint16_t) (humidityHigh << 8) | (uint16_t) humidityLow;
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*humidite = (signed char)(humidity / 10);
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uint16_t temperature = (uint16_t) (temperatureHigh << 8) | (uint16_t) temperatureLow;
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if (temperature & 0x8000) { // Si le bit de signe est à 1, la température est négative
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temperature = -(temperature & 0x7FFF);
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}
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*temp = (signed char)(temperature / 10);
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return 0; // Lecture réussie
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}
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void main() {
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// Configuration de l'horloge interne à 1MHz
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OSCCON = 0b01110000;
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// Configuration des broches
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APFCONbits.T1GSEL = 0b0; // Timer1 sur RA4
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TRISA = 0b11011011; // Configure RA2 et RA5 en sortie 0 = sortie
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ANSELA = 0b00000011; // Configure les broches utiles digital I/O
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WPUA = 0b00010000; // Active la résistance de pull-up sur RA4
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LATAbits.LATA4 = 0b0; // RA4 est en sortie
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// Configuration du Timer1
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T1CON = 0b00000000; // Timer1 est éteint initialement
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T1CONbits.TMR1CS = 0b01; // Source d'horloge est Fosc => 1MHz
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T1CONbits.T1CKPS = 0b11; // Pas de division de l'horloge
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T1GCONbits.T1GSS = 0b00; // Timer1 gate pin T1G
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T1GCONbits.T1GPOL = 0b1; // Polarité du gate control est active haut
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T1GCONbits.T1GTM = 0b0; // Mode du gate toggle désactivé
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T1GCONbits.T1GSPM = 0b1; // Single gate désactivé
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T1GCONbits.TMR1GE = 0; // Pas de gate control
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T1CONbits.TMR1ON = 0; // Démarrage du Timer1
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PIR1bits.TMR1GIF = 0; // Efface le flag d'interruption du gate control
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OPTION_REGbits.PSA = 0; // Prescaler pour T0
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// Boucle principale
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while (1) {
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signed char humidite = 0;
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signed char temperature = 0;
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lire(&humidite, &temperature);
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int x = 0;
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__delay_ms(100);
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}
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}
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