The following code intends to read from serial port and write the data byte by byte to a 24LC01B EEPROM.
// 24LC01B PINS
// Pin 1, A0: float
// Pin 2, A1: float
// Pin 3, A2: float
// Pin 4, VSS: GND
// Pin 5, SDA: Arduino A4
// Pin 6, SCL: Arduino A5
// Pin 7, WP: Write/Protect = GND
// Pin 8, VCC: +5
#include <Arduino.h>
#include <Wire.h>
// I2C Bus address of 24LC256 EEPROM;
// if more than one eeprom, they will have different addresses (h/w configured);
#define EEPROM_ADDR 0x50
byte m_addr = 0;
#define MAX_ADDRESS 128
byte eeprom_write(byte address, byte *data, byte len)
{
byte r = 0;
for(byte i=0; i<len; )
{
Wire.beginTransmission(EEPROM_ADDR | m_addr);
Wire.write(address + i);
byte l = len > 8 ? 8 : l;
Wire.write(data+i, l);
r |= Wire.endTransmission();
delay(3);
i += l;
}
return r;
}
byte eeprom_read(byte address, byte *data, byte len)
{
Wire.beginTransmission(EEPROM_ADDR | m_addr);
Wire.write(address);
byte tr = Wire.endTransmission();
if(tr)
return tr;
Wire.requestFrom((uint8_t)(EEPROM_ADDR | m_addr), len);
byte avail = Wire.available();
if(avail < len)
return 0xFF;
for(int i=0; i < len; i++)
{
// store data in raw bcd format
data[i] = Wire.read();
}
return 0;
}
void setup()
{
Wire.begin();
Serial.begin(9600);
delay(500);
Serial.println("Type something to store in EEPROM");
}
byte i = 0;
void loop()
{
if(Serial.available())
{
byte data = Serial.read();
int rc = eeprom_write(i, &data, 1);
if(rc==0)
{
Serial.print("EEPROM[0x");
Serial.print(i, HEX);
Serial.print("] = 0x");
Serial.print(data, HEX);
Serial.print(" (");
Serial.print((char)data);
Serial.print(")");
Serial.println();
Serial.println("Reading from EEPROM:");
for(byte j=0;j<MAX_ADDRESS;j++)
{
if(byte rc=eeprom_read(j, &data, 1))
{
Serial.print("Error in reading from EEPROM (rc=0x");
Serial.print(rc, HEX);
Serial.println(")");
}
else
{
Serial.print(data, HEX);
Serial.print(' ');
if((j + 1) % 8 == 0 && j != MAX_ADDRESS - 1)
Serial.print("| ");
}
}
Serial.println("");
}
else
{
Serial.println("Write error.");
}
i++;
}
}
Every time I write one byte to the EEPROM, I read back the data on it.
The result is a bit disappointing for me. I understand that 24LC01B
has a page size of 8 bytes. But, it does not make sense to me why the bytes withing the page rotate right every time I write into it
Type something to store in EEPROM
EEPROM[0x0] = 0x61 (a)
Reading from EEPROM:
61 4 4F 0 80 0 80 4 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x1] = 0x62 (b)
Reading from EEPROM:
4 62 4 4F 0 80 0 80 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x2] = 0x63 (c)
Reading from EEPROM:
80 4 63 4 4F 0 80 0 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x3] = 0x64 (d)
Reading from EEPROM:
0 80 4 64 4 4F 0 80 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x4] = 0x65 (e)
Reading from EEPROM:
80 0 80 4 65 4 4F 0 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x5] = 0x66 (f)
Reading from EEPROM:
0 80 0 80 4 66 4 4F | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x6] = 0x67 (g)
Reading from EEPROM:
4F 0 80 0 80 4 67 4 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x7] = 0x68 (h)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4 45 0 80 4 3 0 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x8] = 0x69 (i)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 69 4 4F 0 80 0 80 4 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x9] = 0x6A (j)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4 6A 4 4F 0 80 0 80 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xA] = 0x6B (k)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 80 4 6B 4 4F 0 80 0 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xB] = 0x6C (l)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 0 80 4 6C 4 4F 0 80 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xC] = 0x6D (m)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 80 0 80 4 6D 4 4F 0 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xD] = 0x6E (n)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 0 80 0 80 4 6E 4 4F | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xE] = 0x6F (o)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4F 0 80 0 80 4 6F 4 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0xF] = 0x70 (p)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4 4F 0 80 0 80 4 70 | 3 F6 0 5B 4 38 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x10] = 0x71 (q)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4 4F 0 80 0 80 4 70 | 71 4 4F 0 80 0 80 4 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF
EEPROM[0x11] = 0x72 (r)
Reading from EEPROM:
4 4F 0 80 0 80 4 68 | 4 4F 0 80 0 80 4 70 | 4 72 4 4F 0 80 0 80 | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF | FF FF FF FF FF FF FF FF