Bank 1.2 and the AT24C library for heavy data logging projects
A very useful project from Contesti.eu helping Arduino storing HUGE amount of data usin I2C EEProm:
Searching on the net on Arduino and Arduino web-sites you will find a lot of projects and ideas about the use of EEProm devices as a non-volatile storage method to save data. Arduino is equipped with its own – very small – EEProm memory to save configuration parameters and much more. Arduino boards have about 32 Kb – or even less – storage area and users experience the need to expand it in an affordable and robust way.
The development of a memory bank based on I2C bus EEProm relates to the creation of some kind of software in order to offer at least the possibility to access every memory location regardless of the number and kind of physical devices actually used. Following this way, we developed this memory Bank, aka EEProm 128×8 in respect of these requirements. After having carried out tests and made changes to the first hardware prototype, we are now releasing hardware version 2.1, part of the Bank project 1.2
more after the break.
The diagram is downloadable in pdf format.
As you can see in the diagram above, there are 8 devices stacked with a two-wire connection. As a matter of fact, I2C bus EEprom devices of AT24Cxx series can be stacked up to eight more different devices (in some case only 4 devices can be stacked, but it doesn’t matter). All the eight device address on pins A0, A1, A2 are configured to hardwire the binary values from 000 (all pins low) to 111 (all pins up). The same circuit can work with less than eight devices, as described in the datasheet.
Eagle board layout and electric diagram can be downloaded in zip format here.