Data in 2D array is Gone

Question

I'm having a hard time with this 2D array in CPP. I tried following this link, but it did not solve my problem.

In the saveApToEeprom() function I save two strings. This works fine. Then i want to read from the EEPROM using getConfigForEeprom(). This is where things go wrong.

The function getConfigForEeprom() prints 2 times 32 bytes, that matches with what I see in saveApToEeprom(). But when the program goes into dumbDataEeprom() all the data in valueEeprom[1] seem to be gone, except for valueEeprom[0] is there.

Does anyone know how to solve this issue?

See below for my code

main.cpp

#include <eeprom_handler.h>
void setup(){
  initEeprom();

  String ssid = "test";
  String psw = "tset";
 
  saveApToEeprom(ssid, psw);

  uint8_t** valuesOutEeprom = getConfigForEeprom();
  dumbDataEeprom(valuesOutEeprom);
}

void loop() {
}

eeprom_handler.h

#ifndef eeprom_handler_H
#define eeprom_handler_H

#include <Arduino.h>
#include <String.h>
#include <EEPROM.h>

/* PARAMETERS EEPROM*/
#define PARAMETER_SIZE_IN_BYTES          32
#define PARAMETERS_EEPROM                2
#define BYTES_NEEDED_FROM_EEPROM         (PARAMETER_SIZE_IN_BYTES*PARAMETERS_EEPROM)

/* FUNCTIONS EEPROM */
void initEeprom(uint8_t nmrOfBytes = BYTES_NEEDED_FROM_EEPROM);
uint8_t saveApToEeprom(String apSsid, String ApPsw);
uint8_t** getConfigForEeprom(uint8_t nmrOfBytes = BYTES_NEEDED_FROM_EEPROM);
void dumbDataEeprom(uint8_t** valuesOutEeprom);
void clearEeprom(uint8_t nmrOfBytes = BYTES_NEEDED_FROM_EEPROM);

#endif // eeprom_handler_H

eeprom_handler.cpp

/**************************************************************************/
/*!
  @brief    Read data from the EEPROM
  @param    nmrOfBytes              uint8_t: total number of bytes of the EEPROM to read
  @return   valueEeprom             uint8_t[][]: 
                                    [0-32][]) 32 bytes, should contain SSID
                                    [][0-32]) 32 bytes, should contain SSID
*/
/**************************************************************************/
//  TODO reconstruct uint8_t to chars
uint8_t** getConfigForEeprom(uint8_t nmrOfBytes){
    if (Serial){
        Serial.println("Class eeprom_handler, function: getConfigForEeprom");
    }

    // init the 2D array
    uint8_t** valueEeprom = new uint8_t* [PARAMETERS_EEPROM];

    for (uint8_t m = 0; m < PARAMETERS_EEPROM; m++){
        valueEeprom[m] = new uint8_t[BYTES_NEEDED_FROM_EEPROM];
    }

    for(uint8_t i = 0; i < PARAMETER_SIZE_IN_BYTES; i ++ ) {
        valueEeprom[0][i] = EEPROM.read(i);
        Serial.println(valueEeprom[0][i]);
    }

    for(uint8_t j = PARAMETER_SIZE_IN_BYTES; j < BYTES_NEEDED_FROM_EEPROM; j ++ ) {
        valueEeprom[1][j] = EEPROM.read(j);
        Serial.println(valueEeprom[1][j]);
    }  

    return valueEeprom;
}

/**************************************************************************/
/*!
  @brief    Serial print the data read from the EEPROM
  @param    valuesOutEeprom         uint8_t**: pointer to a uint8_t 2D array
*/
/**************************************************************************/
void dumbDataEeprom(uint8_t** valuesOutEeprom){
    if (Serial){
        Serial.println("Class eeprom_handler, function: dumbDataEeprom");
        for (uint8_t i = 0; i < PARAMETERS_EEPROM; i++){
            for (uint8_t j = 0; j < PARAMETER_SIZE_IN_BYTES; j++){
                Serial.print(valuesOutEeprom[i][j]);
            }
        Serial.println();
        }
    }
}

output (Serial)

Class eeprom_handler, function: initEeprom    
Class eeprom_handler, function: saveApToEeprom
Class eeprom_handler, function: clearEeprom
0  
116
1  
101
2  
115
3  
116
32 
116
33 
115
34
101
35
116

Class eeprom_handler, function: getConfigForEeprom
116
101
115
116
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

116
115
101
116
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Class eeprom_handler, function: dumbDataEeprom
1161011151160000000000000000000000000000
00000000000000000000000000000000

Stefan de Kraker · Accepted Answer · 2021-09-26T14:12:43.403

Solved

I had a fault in my for loop in the function. I was writing the data of the EEPROM index [32-63] also to array index [32-62], but that needed to go array index [0-32]

orginal:

    for(uint8_t j = PARAMETER_SIZE_IN_BYTES; j < BYTES_NEEDED_FROM_EEPROM; j ++ ) {
        valueEeprom[1][j] = EEPROM.read(j);
        Serial.println(valueEeprom[1][j]);
    }

correct:

    for(uint8_t j = PARAMETER_SIZE_IN_BYTES; j < BYTES_NEEDED_FROM_EEPROM; j ++ ) {
        valueEeprom[1][j - PARAMETER_SIZE_IN_BYTES] = EEPROM.read(j);
        Serial.println(valueEeprom[1][j - PARAMETER_SIZE_IN_BYTES]);
    }

Data in 2D array is Gone

1 Answers1

Solved