CY7C149

The CY7C148 and CY7C149 are high-performance CMOS static RAMs organized as 1024 by 4 bits. Easy memory expansion is provided by an active LOW chip select (CS) input and three-state outputs. The CY7C148 remains in a low-power mode as long as the device remains unselected; i.e., (CS) is HIGH, thus reducing the average power requirements of CY7C148 and CY7C149 . The chip select (CS) of the CY7C149 does not affect the power dissipation of the device.

Writing to CY7C148 and CY7C149 are accomplished when the chip select (CS) and write enable (WE) inputs are both LOW. Data on the I/O pins (I/O0 through I/O3) is written into the memory locations specified on the address pins (A₀ through A₉).

Reading CY7C148 and CY7C149  are accomplished by taking chip select (CS) LOW while write enable (WE) remains HIGH. Under these conditions, the contents of the location specified on the address pins will appear on the four data I/O pins.

The I/O pins of CY7C148 and CY7C149 remain in a high-impedance state when chip select (CS) is HIGH or write enable (WE) is LOW.