The ISSI IS62/65WVS2568FALLFBLL are 2M bit Serial static RAMs organized as 256K bytes by 8 bits. It is fabricated using ISSI's high-performance CMOS technology.
The device is accessed via a simple Serial Peripheral Interface (SPI) compatible serial bus. The bus signals required are a clock input (SCK) plus separate data in (SI) and data out (SO) lines. Access the device is controlled through a Chip Select (CS#) input. Additionally, SDI (Serial Dual Interface) and SQI (Serial Quad Interface) is supported if your application needs faster data rates.