SC138 is a 32k byte I2C memory card.
The memory card contains a 24LC256 (32k by 8 bit) EEPROM. This device can store 32k bytes of data and then retain that data without power.
The device uses a simple 5 volt I2C bus to read and write the data.
The 24LC256 has a fixed address on the I2C bus of binary:
1 0 1 0 1 1 1 x
where x is 1 for read or 0 for write.
In hexadecimal, this is 0xAE for write and 0xAF for read.
Example source code can be found here.
The goal of this project is to add SAVE and LOAD functions to the Small Computer Monitor (SCM) and to ROM BASIC.