Projet 2 A / Mbed 2 deprecated Projet_2A

First Upload

Dependencies:   mbed

main.cpp@0:41d540d48633, 2016-06-08 (annotated)

Committer:
azer136
Date:
Wed Jun 08 11:55:23 2016 +0000
Revision:
0:41d540d48633
first upload

Who changed what in which revision?

UserRevisionLine numberNew contents of line
azer136 0:41d540d48633 1 #include "mbed.h"
azer136 0:41d540d48633 2
azer136 0:41d540d48633 3 AnalogIn adc(A0); // Objet (ADC) utilisé pour effectuer la démodulation
azer136 0:41d540d48633 4 Timer timer;
azer136 0:41d540d48633 5
azer136 0:41d540d48633 6 bool wait_zero(void); //Cette fonction est nécessaire pour commencer la démodulation, elle permet de différencier 1 zéro d'un niveau logique bas lors de la modulation d'un 1
azer136 0:41d540d48633 7 char decale_mot(char mot); //Cette fonction effectue une rotation des bits d'un caractère: utile pour la vérification du mot reçu
azer136 0:41d540d48633 8 char get_word(void); // Permet d'obtenir le mot démodulé; utilise la fonction: get_bit()
azer136 0:41d540d48633 9 char get_bit(void); //Permet de démoduler un bit du mot émis
azer136 0:41d540d48633 10
azer136 0:41d540d48633 11 #define delay_bit 119
azer136 0:41d540d48633 12 #define DELAY_ZERO 10
azer136 0:41d540d48633 13 #define SEUIL_MOYEN 0.56
azer136 0:41d540d48633 14
azer136 0:41d540d48633 15 int main() {
azer136 0:41d540d48633 16 printf("Debut\n");
azer136 0:41d540d48633 17 char mot;
azer136 0:41d540d48633 18 int i;
azer136 0:41d540d48633 19 printf("Attente presence tension.\n");
azer136 0:41d540d48633 20 while(adc.read() > SEUIL_MOYEN); //On attend un zéro
azer136 0:41d540d48633 21 while (adc.read() < SEUIL_MOYEN); //On attend la fin du zéro
azer136 0:41d540d48633 22 // Démodulation
azer136 0:41d540d48633 23 mot=get_word(); // Récupération du bit démodulé
azer136 0:41d540d48633 24 /* Vérification du mot reçu en utilisant le décalage binaire */
azer136 0:41d540d48633 25 for (i=0; i<7; i++){
azer136 0:41d540d48633 26 printf("%x\n", mot);
azer136 0:41d540d48633 27 mot=decale_mot(mot);
azer136 0:41d540d48633 28 }
azer136 0:41d540d48633 29 printf("%x\n", mot);
azer136 0:41d540d48633 30 printf("Fin\n");
azer136 0:41d540d48633 31 while(1);
azer136 0:41d540d48633 32
azer136 0:41d540d48633 33 }
azer136 0:41d540d48633 34
azer136 0:41d540d48633 35
azer136 0:41d540d48633 36 bool wait_zero(void){
azer136 0:41d540d48633 37 int valeur;
azer136 0:41d540d48633 38 valeur=0;
azer136 0:41d540d48633 39 while (adc.read() < DELAY_ZERO){
azer136 0:41d540d48633 40 valeur++;
azer136 0:41d540d48633 41 wait_us(5);
azer136 0:41d540d48633 42 }
azer136 0:41d540d48633 43 return (valeur < SEUIL_MOYEN)?true:false;
azer136 0:41d540d48633 44 }
azer136 0:41d540d48633 45
azer136 0:41d540d48633 46 char decale_mot(char mot){ //Cette fonction effectue un décalage du mot de 1 cran vers la gauche
azer136 0:41d540d48633 47 mot=((mot&0x7F)<<1)|((mot&0x80)>>7);
azer136 0:41d540d48633 48 return mot;
azer136 0:41d540d48633 49 }
azer136 0:41d540d48633 50
azer136 0:41d540d48633 51 char get_word(void){
azer136 0:41d540d48633 52 int i,time[2];
azer136 0:41d540d48633 53 char word; //Mots acquis
azer136 0:41d540d48633 54 word=0x00;
azer136 0:41d540d48633 55 timer.reset();
azer136 0:41d540d48633 56 timer.start();
azer136 0:41d540d48633 57 time[0]=timer.read_us();
azer136 0:41d540d48633 58 for(i=7;i>=0;i--){
azer136 0:41d540d48633 59 word |= get_bit()<<i;
azer136 0:41d540d48633 60 }
azer136 0:41d540d48633 61 time[1]=timer.read_us();
azer136 0:41d540d48633 62 printf("La difference des deux est: %d %d\n", time[1],time[0]);
azer136 0:41d540d48633 63 return word;
azer136 0:41d540d48633 64 }
azer136 0:41d540d48633 65
azer136 0:41d540d48633 66 char get_bit(void){
azer136 0:41d540d48633 67 float moyenne, delai;
azer136 0:41d540d48633 68 char retour; //Valeur retournée
azer136 0:41d540d48633 69 moyenne = 0; //Variable pour contenir la valeur moyenne d'un bit de la trame
azer136 0:41d540d48633 70 delai=0; //Variable permettant de vérifier une variable;
azer136 0:41d540d48633 71 while(delai < delay_bit){
azer136 0:41d540d48633 72 moyenne += adc.read();
azer136 0:41d540d48633 73 wait_us(5);
azer136 0:41d540d48633 74 delai += 5;
azer136 0:41d540d48633 75 }
azer136 0:41d540d48633 76 moyenne /= 24;
azer136 0:41d540d48633 77 retour=(moyenne > SEUIL_MOYEN)?0x01:0x00;
azer136 0:41d540d48633 78 return retour;
azer136 0:41d540d48633 79 }
azer136 0:41d540d48633 80
azer136 0:41d540d48633 81