Bonjour,
L'horloge de ma voiture a rendu l'âme, je tente d'en refaire une avec une Arduino Nano, un module RTC 1331 et un écran lcd I2C.
J'ai trouvé un modèle qui me convient ici: https://www.instructables.com/Arduino-DS3231-RTC-Clock/
Tout est monté sur breadboard, avec SDA sur A4 et SCL sur A5 (écran et RTC), le tout alimenté en 5V.
Les boutons sur A0, A1, A2 avec résistances pullup.
Au premier montage il y a quelques jours, tout fonctionnait bien. Après avoir finalisé le montage sur un support imprimé convenant au véhicule et la Nano montée sur un "Nano Terminal Adapter" (trouvé sur Amaz*n), le comportement est erratique...
La ligne supérieure n'affiche plus l'heure, les boutons n'ont plus d'action sur les heures, mais seulement sur les minutes.
Alors j'ai besoin de l'aide de quelqu'un qui pourrait faire le montage et voir si mon code merdouille, ou bien si j'ai abîmé un composant (le RTC?, j'ai testé avec 2 Nano et 2 lcd différents).
Je me casse les dent depuis 2 jours à tenter de comprendre ce qui ne va pas 
Je remercie quiquonque voudra bien se pencher sur mon cas. 
Voici le code utilisé:
// ------------------------------------------------------------------------------------
// Simple clock based on a DS3231 RTC and simple 16x2 LCD
// Setup includes 3 push buttons for up, down, and enter
// 15th July 2015, Andrew W. - arwhitus.weebly.com
// Visit arwhitus.weebly.com for more info or to contact author for any reason
// ------------------------------------------------------------------------------------
//#include LCD and Wire library
#include <LiquidCrystal_I2C.h>
#include <LiquidCrystal.h>
#include <Wire.h>
//define button pins
#define enterButtPin A2
#define upButtPin A1
#define downButtPin A0
//define RTC address
#define DS3231_I2C_ADDRESS (0x68)
// Ci dessous code ajouté à l'original
LiquidCrystal_I2C lcd(0x27, 16 , 2 ); ////Instance d'écran
//define LCD pins and initialize LCD library !! Ligne commentée pour désactiver au passage de I2C
//LiquidCrystal lcd(2, 3, 4, 5, 6, 7);
//variables for button states
int enterState = 0;
int enterStateLast = 0;
int upState = 0;
int upStateLast = 0;
int downState = 0;
int downStateLast = 0;
//variables for ui
boolean blinkOn = true; //visibility of ':' between hour and minutes
boolean setVisible = false; //visibility of the set time ui
//variables for new time
int setM = 0; //users new minute value
int setH = 0; //users new hour value
//convert normal decimal numbers to binary coded decimals
byte decToBcd(byte val)
{
return ( (val / 10 * 16) + (val % 10) );
}
//convert binary coded decimal to normal decimal numbers
byte bcdToDec(byte val)
{
return ( (val / 16 * 10) + (val % 16) );
}
//code that runs once at setup
void setup() {
//start wire and lcd
Wire.begin();
lcd.begin(16,2); //(col, rows)
//intialize buttons as inputs
pinMode(enterButtPin, INPUT);
pinMode(upButtPin, INPUT);
pinMode(downButtPin, INPUT);
//Use below code to set time and date once from code
//it will run at every reset and you will lose the time on the RTC
//format is (sec, min, hr, day of week, day of month, month, year)
//setRTCTime(0, 3, 23, 4, 15, 7, 15);
}
//code that runs on a constant loop
void loop() {
checkButtons();
//printTime();
}
//easy and dirty way to clear the LCD
void clearLCD ()
{
lcd.setCursor(0,0);
lcd.print(" ");
lcd.setCursor(0,1);
lcd.print(" ");
lcd.setCursor(0,0);
}
//set the time and date to the RTC
void setRTCTime(byte second, byte minute, byte hour, byte dayOfWeek, byte
dayOfMonth, byte month, byte year)
{
// sets time and date data to DS3231
Wire.beginTransmission(DS3231_I2C_ADDRESS);
Wire.write(0); // set next input to start at the seconds register
Wire.write(decToBcd(second)); // set seconds
Wire.write(decToBcd(minute)); // set minutes
Wire.write(decToBcd(hour)); // set hours
Wire.write(decToBcd(dayOfWeek)); // set day of week (1=Sunday, 7=Saturday)
Wire.write(decToBcd(dayOfMonth)); // set date (1 to 31)
Wire.write(decToBcd(month)); // set month
Wire.write(decToBcd(year)); // set year (0 to 99)
Wire.endTransmission();
}
//read the time and date from the RTC
void readRTCTime(byte *second, byte *minute, byte *hour, byte *dayOfWeek,
byte *dayOfMonth, byte *month, byte *year)
{
Wire.beginTransmission(DS3231_I2C_ADDRESS);
Wire.write(0); // set DS3231 register pointer to 00h
Wire.endTransmission();
Wire.requestFrom(DS3231_I2C_ADDRESS, 7);
// request seven bytes of data from DS3231 starting from register 00h
*second = bcdToDec(Wire.read() & 0x7f);
*minute = bcdToDec(Wire.read());
*hour = bcdToDec(Wire.read() & 0x3f);
*dayOfWeek = bcdToDec(Wire.read());
*dayOfMonth = bcdToDec(Wire.read());
*month = bcdToDec(Wire.read());
*year = bcdToDec(Wire.read());
}
//reads the RTC time and prints it to the top of the LCD
void printTime()
{
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
//retrieve time
readRTCTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
//print to lcd top
lcd.setCursor(0,0);
lcd.print(" Il est ");
if (hour<10)
{
lcd.print("0");
}
lcd.print(hour, DEC);
if (blinkOn == true)
{
lcd.print(" ");
blinkOn = false;
}
else if (blinkOn == false)
{
lcd.print(":");
blinkOn = false;
}
if (minute<10)
{
lcd.print("0");
}
lcd.print(minute, DEC);
delay(100);
}
//checks if buttons are pressed and responds accordingly
void checkButtons()
{
//check enter
enterState = digitalRead(enterButtPin);
if (enterState != enterStateLast)
{
if (enterState == HIGH)
{
if (setVisible == true)
{
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
readRTCTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
setRTCTime(0, setM, setH, dayOfWeek, dayOfMonth, month, year);
hideSet();
}
else if (setVisible == false)
{
showSet();
}
}
}
enterStateLast = enterState;
//check up
upState = digitalRead(upButtPin);
if (upState != upStateLast)
{
if (upState == HIGH)
{
if (setVisible == true)
{
addMin();
printSetTime();
}
else if (setVisible == false)
{
showSet();
}
}
}
upStateLast = upState;
//check down
downState = digitalRead(downButtPin);
if (downState != downStateLast)
{
if (downState == HIGH)
{
if (setVisible == true)
{
subMin();
printSetTime();
}
else if (setVisible == false)
{
showSet();
}
}
}
downStateLast = downState;
}
//displays the new time interface in the bottom of the LCD
void showSet ()
{
//update new time variables to current RTC values
byte second, minute, hour, dayOfWeek, dayOfMonth, month, year;
readRTCTime(&second, &minute, &hour, &dayOfWeek, &dayOfMonth, &month, &year);
setH = hour, DEC;
setM = minute, DEC;
//pints to the LCD
lcd.setCursor(0,1);
lcd.print(" New: ");
printSetTime();
setVisible = true;
}
//hides the new time interface
void hideSet ()
{
clearLCD();
setVisible = false;
}
//adds a minute to new time
void addMin()
{
if (setM < 59)
{
setM++;
}
else if (setM == 59)
{
setM = 0;
addHr();
}
}
//subtracts a minute from new time
void subMin()
{
if (setM > 0)
{
setM--;
}
else if (setM == 0)
{
setM = 59;
subHr();
}
}
//adds an hour to new time
void addHr ()
{
if (setH < 23)
{
setH++;
}
else if (setH == 23)
{
setH = 0;
}
}
//subtracts an hour from new time
void subHr ()
{
if (setH > 0)
{
setH--;
}
else if (setH == 0)
{
setH = 23;
}
}
//prints the new time values on the bottom of the LCD
void printSetTime()
{
lcd.setCursor(8,1);
if (setH<10)
{
lcd.print("0");
}
lcd.print(setH);
lcd.print(":");
if (setM<10)
{
lcd.print("0");
}
lcd.print(setM);
}
