- **bool begin()** initializes the I2C bus and checks if the device is available on the I2C bus.
- **bool begin(uint8_t sda, uint8_t scl)** idem for ESP32 / ESP8266 and alike.
- **bool isConnected()** test to see if device is on the bus.
### Core functions
- **int writeByte(uint32_t memoryAddress, uint8_t value)** write a single byte to the specified memory address.
- **int updateByte(uint32_t memoryAddress, uint8_t value)** write a single byte, but only if changed. Returns 0 if value was same or write succeeded.
- **int writeBlock(uint32_t memoryAddress, uint8_t \* buffer, uint32_t length)** write a buffer starting at the specified memory address.
- **int updateBlock(uint32_t memoryAddress, uint8_t \* buffer, uint32_t length)** write a buffer starting at the specified memory address, but only if changed
- **int setBlock(uint32_t memoryAddress, uint8_t value, uint32_t length)** writes the same byte to length places starting at the specified memory address. Returns 0 if OK.
- **uint8_t readByte(uint32_t memoryAddress)** read a single byte from a given address
- **uint16_t readBlock(uint32_t memoryAddress, uint8_t \* buffer, uint32_t length)** read length bytes into buffer starting at specified memory address. Returns the number of bytes read, which should be length.
### Other
- **uint32_t getDeviceSize()** idem
- **uint8_t getPageSize()** idem
- **uint32_t getLastWrite()** idem
#### UpdateBlock()
(new since 0.1.3)
The function **updateBlock()** reads the block of data and compares it with the new values
to see if it needs rewriting.
As the function reads/writes the data in blocks with a maximum length of **I2C_TWIBUFFERSIZE**
(== 30 AVR limitation; 128 for ESP32) it does this comparison in chuncks if the length exceeds this number.
The result is that an **updateBlock()** call can result e.g. in 4 reads and only 2 writes under the hood.
If data is changed often between writes, **updateBlock()** is slower than **writeBlock()**.
So you should verify if your sketch can make use of the advantages of **updateBlock()**
## Limitation
The library does not offer multiple EEPROMS as one continuous storage device.
