Strange problem with on-chip EEPROM

Other Hardware Storage
1

I have a strange issue with a sketch I've written to test some code I'm working on for a project, a HVAC control system.

This specific code is to pull some data from the onboard EEPROM and display it on a LCD screen.

The values were written to EEPROM in another sketch as follows:

  EEPROM.write(41,0);
  EEPROM.write(42,1);
  EEPROM.write(43,9);
  EEPROM.write(44,30);

When I read out the values in a sketch and send them to the serial monitor, they are correct, but when I run the sketch I'm working on, I only get the following on the serial monitor:

41
memstate is 0
memday is 0
memhour is 0
memmin is 0

My sketch is as follows:

// Switch Times Setting test
#include <EEPROM.h>
#include <OneWire.h>
#include <Wire.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
#define I2C_ADDR    0x27 // <<----- Add your address here.  Find it from I2C Scanner
#define BACKLIGHT_PIN     3
#define En_pin  2
#define Rw_pin  1
#define Rs_pin  0
#define D4_pin  4
#define D5_pin  5
#define D6_pin  6
#define D7_pin  7
LiquidCrystal_I2C	lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);
int memPin = 1;
int dayPin = 2;
int hrPin = 3;
int minPin = 4;
int statePin = 5;
int backPin = 6;
int memSlot = 4;
int memstate;
int memday;
int memhour;
int memmin;
int i;

void setup ()
{
  Serial.begin(9600);
  pinMode(memPin,INPUT_PULLUP);
  pinMode(dayPin,INPUT_PULLUP);
  pinMode(hrPin,INPUT_PULLUP);
  pinMode(minPin,INPUT_PULLUP);
  pinMode(statePin,INPUT_PULLUP);
  pinMode(backPin,INPUT_PULLUP);
  lcd.begin (20,4);
  lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
  lcd.setBacklight(HIGH);
}
void loop ()
{
  //code
  lcd.clear();
  if (digitalRead(memPin) == 0){
    lcd.home();
    lcd.print(F("Set Switch Times"));
    delay(2000);
    lcd.home();
    lcd.print("                    ");
    while (digitalRead(backPin) == 1){
      i = (memSlot * 10) + 1;
      Serial.println(i);
      memstate == EEPROM.read(i);
      Serial.print("memstate is ");Serial.println(memstate);
      i = i++;
      memday == EEPROM.read(i);
      Serial.print("memday is ");Serial.println(memday);
      i = i++;
      memhour == EEPROM.read(i);
      Serial.print("memhour is ");Serial.println(memhour);
      i = i++;
      memmin == EEPROM.read(i);
      Serial.print("memmin is ");Serial.println(memmin);
      
      lcd.home();
      lcd.print("Memory Slot ");lcd.print(memSlot);
      lcd.setCursor(0,1);
      lcd.print("Heating: "); 
      if (memstate == 0) {
       lcd.print("Off");
      }
      else {
       lcd.print("On");
      }
      lcd.setCursor(0,2);
      lcd.print("Day: ");
      switch (memday) {
        case 0:
          lcd.print("Every Day");
          break;
        case 1:
          lcd.print("Sunday");
          break;
        case 2:
          lcd.print("Monday");
          break;
        case 3:
          lcd.print("Tuesday");
          break;
        case 4:
          lcd.print("Wednesday");
          break;
        case 5:
          lcd.print("Thursday");
          break;
        case 6:
          lcd.print("Friday");
          break;
        case 7:
          lcd.print("Saturday");
          break;
        case 8:
          lcd.print("Weekdays");
          break;
        case 9:
          lcd.print("Weekends");
          break;
      }
      lcd.setCursor(0,3);
      lcd.print("Time: ");
      if (memhour < 10) lcd.print("0");
      lcd.print(memhour); lcd.print(":");
      if (memmin < 10) lcd.print("0");
      lcd.print(memmin);
    }
  }
}

Can anyone point me where I should be looking to troubleshoot this?

Thanks and regards,
Stefan

2

I also tried the following for the EEPROM.read() code, but it didn't work either, I'm pretty sure there is no issue with how I'm passing the addresses to the EEPROM.read command:

      Serial.println((memSlot * 10) + 1);
      memstate == EEPROM.read((memSlot * 10) + 1);
      Serial.print("memstate is ");Serial.println(memstate);
      memday == EEPROM.read((memSlot * 10) + 2);
      Serial.print("memday is ");Serial.println(memday);
      memhour == EEPROM.read((memSlot * 10) + 3);
      Serial.print("memhour is ");Serial.println(memhour);
      memmin == EEPROM.read((memSlot * 10) + 4);
      Serial.print("memmin is ");Serial.println(memmin);
3 
      memstate == EEPROM.read(i);

Eh?
== ?
I don't think so :slight_smile:

Pete

4

DOH!!!

Thanks man, that was it.

I reckoned it was something simple......

TypoKing strikes again.