The Storage library for Arduino is designed to abstract handling of external memory, and allow block read/write and streaming of data. The library includes device drivers for SPI SRAM (23LC512/1024), 2-Wire EEPROM (AT24CXX) and internal EEPROM.

Device driver for external storage such as EEPROM and SRAM should implement the Storage class virtual member functions and supply the number of bytes on the device.

The Storage class supports linear allocation. The Storage::Block class handles the allocated block and provides functions to read and write to the block.

In many cases the external block contains data that mirrors data used in the applications. The Storage::Cache handles read and write between the block on external storage and data/variables. The Storage::Cache class also allows handling of large vectors on external storage and element/member access.

Version: 1.0

• Abstract Storage Manager, Storage
• Storage Block, Storage::Block
• Storage Cache, Storage::Cache
• Storage Stream, Storage::Stream

• 2-Wire EEPROM, AT24CXX
• 512 Kbit Serial SRAM, 23LC512
• 1 Mbit Serial SRAM, 23LC1024
• Internal EEPROM, EEPROM

• Benchmarks measurement of characteristics.
• Block read/write eeprom blocks.
• Cache cache local variable.
• Persistent read/write configuration.
• Stream storage as a print stream.
• Vector handling large sample vectors.

Note: 1) The read/write operations have a three byte header (8-bit command, and 16-bit address). 2) Write performance increases up to page size. When the block size is larger than the page size the write operation will wait for the device to complete the page write. Typical max 5-10 ms per page. 3) 400 KHz (and even 800 KHz) clock can be used.

Note: The read/write operations have a four byte header (8-bit command, and 24-bit address).

Note: The internal eeprom has a single byte buffer and write of multiple bytes will wait for the device to complete previous write. Typical 3 ms.

• Arduino-GPIO
• Arduino-TWI
• Arduino-SPI