AVR Freaks

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

//Modes
unsigned int Mode;
unsigned long lastMil;
int nDevices;

#define logoMode 0
#define titleMode 1
#define chipSelectMode 2

#define btnEnter PIN_PA7
#define romWrite PIN_PA1
#define romCLK PIN_PA3
#define romDATA PIN_PA2
#define ADDR_ROM 0x50
byte address;

U8G2_PCD8544_84X48_F_4W_SW_SPI u8g2(U8G2_R0, /* clock=*/ PIN_PB0, /* data=*/ PIN_PB1, /* cs=*/ PIN_PB2, /* dc=*/ PIN_PB3, /* reset=*/ PIN_PB4);  // Nokia 5110 Display (U8G2_R0, /* clock=*/ PIN_PA5, /* data=*/ PIN_PA6, /* cs=*/ PIN_PA3, /* dc=*/ PIN_PA4, /* reset=*/ PIN_PA2);  // Nokia 5110 Display

void u8g2_prepare(void) {
  u8g2.setFont(u8g2_font_6x10_tf);
  u8g2.setFontRefHeightExtendedText();
  u8g2.setDrawColor(1);
  u8g2.setFontPosTop();
  u8g2.setFontDirection(0);
}

void writePosText(int posX, int posY, String str)
{
  u8g2.setCursor(posX, posY);
  u8g2.print(str);
}


void writeI2CByte(byte i2cAddr, int dAddr, byte data)
{

  Wire.beginTransmission(i2cAddr);
  Wire.write((int)(dAddr >> 8)); // MSB
  Wire.write((int)(dAddr & 0xFF)); // LSB
  delay(5); 
  Wire.write(data);
  Wire.endTransmission();
  delay(1);
}

byte readI2CByte(byte i2cAddr, int dAddr){
  byte data = NULL;
  
  Wire.beginTransmission(i2cAddr); //writing the address to be read
  //Wire.write(dataAddr1);
  //Wire.write(dataAddr2);
  Wire.write((int)(dAddr >> 7)); // MSB
  Wire.write((int)(dAddr & 0xFF)); // LSB
  Wire.endTransmission();
  delay(10);
  Wire.requestFrom(i2cAddr, 1);
  while(Wire.available())
   {
    data = Wire.read();
   }
  Wire.endTransmission();
  return data;
}

void setup(void) 
{
  Wire.begin();
  Mode = logoMode;
  u8g2.begin();
  pinMode(btnEnter, OUTPUT);
  digitalWrite(btnEnter, HIGH);
  pinMode(romWrite, OUTPUT);
  digitalWrite(romWrite, LOW);
  lastMil = millis();
}

void WriteText(long BYTE_ADDR, String txt)
{
  int len = sizeof(txt);
  for(int i = 0; i < len; i++)
  {
    writeI2CByte(ADDR_ROM, BYTE_ADDR + i, txt.charAt(i));
    delay(10);
  }
}


void WriteLocationBytes()
{

int startLoc = 128;
int result;

  //goes up 255 bytes each time
  for(int i = 0; i < 128; i+=2){
     u8g2.clearBuffer();
     u8g2_prepare();
  
     writeI2CByte(ADDR_ROM, i, startLoc >> 8);
     delay(100);
     writeI2CByte(ADDR_ROM, i + 1, startLoc);
     delay(100);
   
    writePosText(0, 0, String(startLoc >> 8, HEX) + " & " + String(startLoc, HEX));

    u8g2.sendBuffer();
    startLoc += 255;
    delay(100);
  }

  u8g2.clearBuffer();
  u8g2_prepare();
  writePosText(0, 0, "DONE");
  u8g2.sendBuffer();
    //locations: first = 128 or 0x80, second = 128 + 255 = 383 or 0x17F, 3rd = 638 or 0x027E, etc. basically adding FF each time
}

void readLocationBytes()
{
 int result;
  for(int i = 0; i < 128; i+=2)
  {
  u8g2.clearBuffer();
  u8g2_prepare();
      result = 0;
      result |= ((int)readI2CByte(ADDR_ROM, i)) << 8;
      result |= ((int)readI2CByte(ADDR_ROM, i + 1));
    writePosText(0, 0, "Loc:" + String(i) + " = " + String((int)result));
    u8g2.sendBuffer();
    delay(100);
  }
  
u8g2.clearBuffer();
u8g2_prepare();
writePosText(0, 0, "DONE!");
u8g2.sendBuffer();

}

void getChipName(int chipNum)
{
  char tmp;
  int chipAddr;
  String tmpName;
  
  chipAddr = getChipAddr(chipNum);
  //for(int i = 0; i < 20; i++)
  //{
    tmp = readI2CByte(ADDR_ROM, 128);// + i);
    //tmpName += String(tmp, HEX);
    u8g2.clearBuffer();
  u8g2_prepare();
   writePosText(0, 0, String(tmp, HEX));
  u8g2.sendBuffer();
    delay(1000);
  //}
 
}

int getChipAddr(int chipNum)
{
  int result = 0;
  result |= ((int)readI2CByte(ADDR_ROM, chipNum)) << 8;
  result |= ((int)readI2CByte(ADDR_ROM, chipNum + 1));
  return result;
}

void ReadText(int len)
{
  char tmp;
  u8g2.clearBuffer();
  u8g2_prepare();
  for(int i = 0; i < len; i++)
  {
    tmp = readI2CByte(ADDR_ROM, i);
    u8g2.print(tmp);
  }
  
  u8g2.sendBuffer();
  delay(1000);
}

void writeChipName(int chipNum, String chipName)
{
  //always 20 characters
  //chip num = 0, 2, 4 , 6...etc to 126
  u8g2.clearBuffer();
  u8g2_prepare();
  
  int nameAddr;
  char tmpChar;
 
  nameAddr = getChipAddr(chipNum);
  writePosText(0,0, String(nameAddr));
  
  //for(int i = 0; i < chipName.length(); i++)
   //{
    //tmpChar = chipName.charAt(i);
      writeI2CByte(ADDR_ROM, 700, 0xAB);
     // delay(1000);
     //u8g2.clearBuffer();
     delay(50);
  //u8g2_prepare();
  byte tmp;
   tmp = readI2CByte(ADDR_ROM, 700);
   writePosText(0,10, String(tmp));
  u8g2.sendBuffer();
     delay(1000);
    
  // }
  
}

void deleteEeprom()
{
  for(int i = 0; i < 32000; i++)
  {
    u8g2.clearBuffer();
    u8g2_prepare();
    writeI2CByte(ADDR_ROM, i, 0x00);
    writePosText(0,0, String(i));
    delay(1);
    u8g2.sendBuffer();
  }
  u8g2.clearBuffer();
    writePosText(0,0, "Done!");
    delay(2);
    u8g2.sendBuffer();
}

void loop(void) 
{
  //start at byte zero for two byte chip info addresses, 0&1 == chip 1, 2&3 == chip 2, etc.
  
      digitalWrite(romWrite, LOW);
  
   if(digitalRead(btnEnter) == LOW)
         {
             //WriteLocationBytes();
             //readLocationBytes();
              //writeChipName(0, "4116 Ram");
           // getChipName(0);
            //deleteEeprom();
         }
  
  delay(100);
}

Some of it might be all over the place because I've taken some stuff out and added stuff to try different things and to debug using the LCD. Anyway, I've been messing with the read and writeChipName, but it doesn't matter. No matter what I do, I've made small real quick functions and no address over 127 will write.