read errors

[K0rkunc]

only this variable gives �������D

I2C_eeprom ee(0x51, I2C_DEVICESIZE_24LC512);

if (request->argName(i) == "setname")
{
if (strcmp(cihaz_adi, request->arg(i).c_str()) != 0)
{
strcpy(cihaz_adi, request->arg(i).c_str());
pass_len1 = strlen(cihaz_adi);
ee.writeBlock(670, (uint8_t *)&cihaz_adi, sizeof(pass_len1));
ee.writeByte(350, pass_len1);
}
}

[RobTillaart]

I do not understand the problem you have.
You make a statement about "only this variable gives �������D"
and provides some uncompilable code.

Please provide a minimal sized sketch that shows the problem.

[K0rkunc]

Hello

I am writing eeprom a char variable in uint8_t format as in the codes below.

then I read this data at boot and it gives irrelevant values.

**I don't have this problem in other reading and writing areas, but I'm having this problem in "device_name" variable, **

please can you help me with this?

I get the device name from the esp32 async web server interface and save it.

by the way, the recording function returns a value of 4.

if (request->argName(i) == "setname")
{
if (strcmp(cihaz_adi, request->arg(i).c_str()) != 0)
{
snprintf(cihaz_adi,sizeof(cihaz_adi),"%c",request->arg(i).c_str());
pass_len1 = strlen(cihaz_adi);
ee.writeBlock(600, (uint8_t *)&cihaz_adi, 4);
ee.writeByte(350, pass_len1);
}
}

then I try to read this value at device startup.

pass_len1 = ee.readByte(350);
ee.readBlock(600, (uint8_t *)cihaz_adi, pass_len1);

but this is how the value I read comes in. �������

[RobTillaart]

Please provide a minimal sized sketch that shows the problem.

Are you sure that

• there is a value written to EEPROM?
• it is the right value?

[RobTillaart]

by the way, the recording function returns a value of 4.

such remark does not tell me anything if I do not have a complete minimal sketch to verify

[K0rkunc]

full project codes https://www.paste.tc/code-84118

yes after transferring the values ​​I get from the interface to the char variable

I am reading with serial print the value is correct

but unfortunately when i save and restart, bad value comes

[RobTillaart]

minimal sketch

...

[K0rkunc]

#include "I2C_eeprom.h"

char cihaz_adi[50]={"TwinsLED"};

I2C_eeprom ee(0x51, I2C_DEVICESIZE_24LC512);

Setup()
{
Wire.begin();
Wire.setClock(400000);
ee.begin();

strcpy(cihaz_adi, request->arg(i).c_str());
pass_len1 = strlen(cihaz_adi);
cihaz_adi[5]='\0';
ee.writeBlock(600, (uint8_t *)&cihaz_adi, 4);
ee.writeByte(350, pass_len1);

pass_len1 = ee.readByte(350);
ee.readBlock(600, (uint8_t *)cihaz_adi, pass_len1);

}

[RobTillaart]

Not tested code, no time today to elaborate on this, but should get you started how to store a text in EEPROM

//    FILE: I2C_eeprom_store_text.ino
//  AUTHOR: Rob Tillaart
// PURPOSE: demo I2C_EEPROM library

// uses a 24LC256 (32KB) EEPROM
// might need adaptions for other EEPROMS (page size etc)

#include "Wire.h"
#include "I2C_eeprom.h"

I2C_eeprom ee(0x50, I2C_DEVICESIZE_24LC256);

void setup()
{
  Serial.begin(115200);
  while (!Serial);      // wait for Serial port to connect.
  Serial.println(__FILE__);

  ee.begin();
  if (! ee.isConnected())
  {
    Serial.println("ERROR: Can't find eeprom\nstopped...");
    while (1);
  }

  Serial.print("I2C_EEPROM_VERSION: ");
  Serial.print(I2C_EEPROM_VERSION);
  Serial.println("\n");

  Serial.println("\nwrite string");
  ee.setBlock(600, 0, 128);
  dumpEEPROM(600, 128);
  char data[] = "hello world";
  ee.writeBlock(600, (uint8_t*) data, strlen(data) + 1);  // add the \0 char to be sure   <<<<<<<<<<<<<<<
  dumpEEPROM(600, 128);

  Serial.println("\nread string");
  char dataRead[100];
  memset(dataRead, 0, 100);
  ee.readBlock(600, (uint8_t*)dataRead, 12);
  Serial.println(dataRead);

  Serial.println("\tDone...");
}

void loop()
{
}

void dumpEEPROM(uint16_t memoryAddress, uint16_t length)
{
  const int BLOCK_TO_LENGTH = 10;
  
  Serial.print("\t  ");
  for (int x = 0; x < 10; x++)
  {
    if (x != 0) Serial.print("    ");
    Serial.print(x);
  }
  Serial.println();

  // block to defined length
  memoryAddress = memoryAddress / BLOCK_TO_LENGTH * BLOCK_TO_LENGTH;
  length = (length + BLOCK_TO_LENGTH - 1) / BLOCK_TO_LENGTH * BLOCK_TO_LENGTH;

  byte b = ee.readByte(memoryAddress);
  for (unsigned int i = 0; i < length; i++)
  {
    char buf[6];
    if (memoryAddress % BLOCK_TO_LENGTH == 0)
    {
      if (i != 0) Serial.println();
      sprintf(buf, "%05d", memoryAddress);
      Serial.print(buf);
      Serial.print(":\t");
    }
    sprintf(buf, "%03d", b);
    Serial.print(buf);
    b = ee.readByte(++memoryAddress);
    Serial.print("  ");
  }
  Serial.println();
}

// END OF FILE

[RobTillaart]

#include "I2C_eeprom.h"

char cihaz_adi[50]={"TwinsLED"};

I2C_eeprom ee(0x51, I2C_DEVICESIZE_24LC512);

Setup()
{
Wire.begin();
Wire.setClock(400000);
ee.begin();

strcpy(cihaz_adi, request->arg(i).c_str());
pass_len1 = strlen(cihaz_adi);
cihaz_adi[5]='\0';
ee.writeBlock(600, (uint8_t *)&cihaz_adi, 4);
ee.writeByte(350, pass_len1);

pass_len1 = ee.readByte(350);
ee.readBlock(600, (uint8_t *)cihaz_adi, pass_len1);

}

Does not compile

[K0rkunc]

Why

[RobTillaart]

Why

It does not compile because the code you posted is an incomplete half sketch.

Please provide a minimal sketch that shows the problem.
(or if it is solved you may close the issue)

[RobTillaart]

As there is no answer I assume the problem is solved, therefor I close the issue. If the issue still exists you can reopen the issue, or better ask on https://forum.arduino.cc/ for help on your sketch as your problem does not appear to be a library problem.