Arduino library for Microchip (former Atmel) AT24MAC402/602 EEPROM with build in MAC address and serial number.
The chip uses internally two I2C addresses for different memory areas.
Only 1k bit can used for R/W operations by the user.

• 0x50 - 0x57 (7bit address) for R/W operations of the first 128 bytes of the EEPROM
• 0x58 - 0x5F (7bit address) for Read Only operations to get the MAC (EUI-48) address and the 128 bit serial number (UUID), also the EUI-64 only for the AT24MAC602 EEPROM type
• Depending of the package you can set 8 different I2C start addresses, beware that the address pins set I2C address of both memory areas

Here is a simple example which shows the capabilities of the library

#include "AT24MAC402.h"

AT24MAC402 at24mac402;
uint8_t mac[6];
uint8_t uuid[16];

void setup() {
  Serial.begin(9600);
  delay(2000);
  at24mac402.begin();
  at24mac402.readMac(mac);
  Serial.print("MAC address ");
  Serial.println(MACtoString(mac));
  at24mac402.readUUID(uuid);
  Serial.print("UUID ");
  Serial.println(UUIDtoString(mac));
  for (uint8_t i = 0; i < 6; i++) {
    at24mac402.writebyte(i, i);
    }
  for (uint8_t i = 0; i < 6; i++) {
    Serial.print("Byte ");
    Serial.print(i);
    Serial.print(" Value ");
    Serial.println(at24mac402.readbyte(i));
    }
  }
  
void loop() {
  }

AT24MAC402(uint8_t a0 = 0, uint8_t a1 = 0, uint8_t a2 = 0);

• a0 set address pin A0 to HIGH or LOW
• a1 set address pin A1 to HIGH or LOW
• a2 set address pin A2 to HIGH or LOW

Create an EEPROM object with an optional settings of the address pins A0, A1 and A2.

Example

AT24MAC402 at24mac402; // all address pins to GND using Wire
AT24MAC402 at24mac402(0, 0, 1); // address pin A2 high using Wire

void begin(TwoWire &wire = Wire);

• wire set optional Wire class to use (Wire, Wire1, Wire2 ...)

Initialize the Wire (I2C) communication of the EEPROM.
This must done in setup()

Example

setup() {
  at24mac402.begin();
  at24mac402.begin(Wire1); // for use with e.g. Wire1
  }

void writeByte(uint8_t address, uint8_t data);

• address set the EEPROM address
• data set the data

Write a single byte into the EEPROM.

Example

at24mac402.writeByte(2, 23); // write the value 23 to EEPROM address 2

uint8_t readByte(uint8_t address)

• address set the EEPROM address

Read a single byte from the EEPROM.
Returns the stored value of the given address.

Example

uint8_t data = at24mac402.readByte(2); // read the value from EEPROM address 2

void readMac(uint8_t mac[]);
uint8_t* readMac();

• mac pointer to the mac address

Returns the MAC (EUI-48) address.

Example

uint8_t mac[6];
at24mac402.readMac(mac);

void readEUI64(uint8_t eui64[]);
uint8_t* readEUI64();

• eui64address pointer to the EUI64 address

Returns the EUI-64 address. Only for AT24MAC602!

Example

uint8_t eui64[8];
at24mac402.readEUI64(eui64);

void readUUID(uint8_t uuid[]);
uint8_t* readUUID();

• uuid pointer to the UUID address

Returns the UUID (128bit serial number).

Example

uint8_t uuid[16];
at24mac402.readUUID(uuid);

void MACtoString(uint8_t mac[], char macString[]);
char* MACtoString(uint8_t mac[]);

• mac pointer to the MAC address
• macString pointer to the formated string

Returns the MAC address as a formated string.

Example

Serial.println(MACtoString(mac));

void UUIDtoString(uint8_t uuid[], char uuidString[]);
char* UUIDtoString(uint8_t uuid[]);

• uuid pointer to the UUID
• uuidString pointer to the formated string

Returns the UUID as a formated string.

Example

Serial.println(UUIDtoString(uuid));