CY7C144 CY7C1458K x 8/9 Dual-Port Static RAM with SEM, INT, BUSY

CY7C145, CY7C144

8K x 8/9 Dual-Port Static RAM with SEM, INT, BUSY

Features

■True Dual-Ported memory cells that enable simultaneous reads of the same memory location

■8K x 8 organization (CY7C144)

■8K x 9 organization (CY7C145)

■0.65-micron CMOS for optimum speed and power

■High speed access: 15 ns

■Low operating power: ICC = 160 mA (max.)

■Fully asynchronous operation

■Automatic power down

■TTL compatible

■Master/Slave select pin enables bus width expansion to 16/18 bits or more

■Busy arbitration scheme provided

■Semaphores included to permit software handshaking between ports

■INT flag for port-to-port communication

■Available in 68-pin PLCC, 64-pin and 80-pin TQFP

■Pb-free packages available

Functional Description

The CY7C144 and CY7C145 are high speed CMOS 8K x 8 and 8K x 9 dual-port static RAMs. Various arbitration schemes are included on the CY7C144/5 to handle situations when multiple processors access the same piece of data. Two ports are provided permitting independent, asynchronous access for reads and writes to any location in memory. The CY7C144/5 can be used as a standalone 64/72-Kbit dual-port static RAM or multiple devices can be combined in order to function as a 16/18-bit or wider master/slave dual-port static RAM. An M/S pin is provided for implementing 16/18-bit or wider memory applications without the need for separate master and slave devices or additional discrete logic. Appli- cation areas include interprocessor/multiprocessor designs, communications status buffering, and dual-port video/graphics memory.

Each port has independent control pins: chip enable (CE), read or write enable (R/W), and output enable (OE). Two flags, BUSY and INT, are provided on each port. BUSY signals that the port is trying to access the same location currently being accessed by the other port. The interrupt flag (INT) permits communication between ports or systems by means of a mail box. The semaphores are used to pass a flag, or token, from one port to the other to indicate that a shared resource is in use. The semaphore logic is comprised of eight shared latches. Only one side can control the latch (semaphore) at any time. Control of a semaphore indicates that a shared resource is in use. An automatic power down feature is controlled independently on each port by a chip enable (CE) pin or SEM pin.

Logic Block Diagram

R/ W L

R/ W R

CE L

CE R

OE L

OE R

(7C145) I /O8L

 

 

I/O 8R(7C14 5)

I /O7L

I/ O

I /O

I/O 7R

 

 

 

 

I /O0L

CONT ROL

CONT ROL

I/O 0R

 

 

 

 

 

 

 

 

B US Y [1, 2]

 

 

BUS Y R

[1, 2]

L

 

 

 

A 12L

 

 

 

A 12R

 

ADDRE SS

M EM ORY

A DDRES S

 

A 0L

A RRA Y

A 0R

DE CODE R

DECODE R

SE M L I NTL[2]

CEL

OE L

R/ W L

INT ERRUP T SE MA P HORE ARB I TRAT IO N

M /S

CE R

OE R

R/W R

SE MR

INTR [2]

Notes

 

 

 

 

1.

BUSY

is an output in master mode and an input in slave mode.

 

 

 

 

2.

Interrupt: push-pull output and requires no pull-up resistor.

 

 

 

 

Cypress Semiconductor Corporation • 198 Champion Court

•

San Jose, CA 95134-1709

•

408-943-2600

Document #: 38-06034 Rev. *D

 

Revised December 10, 2008

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Cypress CY7C145, CY7C144 manual Features, Functional Description, Logic Block Diagram
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CY7C145, CY7C144 specifications

Cypress Semiconductor is renowned for its advanced memory solutions, and two of its noteworthy products are the CY7C144 and CY7C145, both of which serve as emerging leaders in the field of synchronous dynamic random-access memory (SDRAM). These memory chips provide high-speed data access, making them ideal for various applications, including networking, automotive, and industrial electronics.

The CY7C144 is a 4-Mbit SRAM, while its counterpart, the CY7C145, is an 8-Mbit SRAM. Both chips utilize a synchronous interface, which allows them to operate at clock rates that significantly enhance data retrieval speeds. Designed for low power consumption, these devices feature several power-saving modes, making them suitable for battery-operated applications.

One of the main features of the CY7C144 and CY7C145 is their support for burst read and write operations. This function enables the memory to deliver multiple bits of data sequentially with a single command, substantially increasing throughput. Additionally, both models come with a wide data bus, typically 16 bits, allowing for efficient data handling and alignment with a variety of systems.

The technology behind these chips includes static CMOS processes, which promote high performance and reliability under various operating environments. The CY7C144 and CY7C145 both guarantee a high level of data integrity, thanks to advanced error detection and correction features. This makes them especially valuable in applications where data accuracy is critical.

Another critical aspect is the integration of an on-chip address decoder for efficient memory addressing, minimizing delays during data access. This characteristic plays a crucial role in optimizing the overall system performance, particularly in high-bandwidth applications.

In terms of environmental resilience, these memories are designed to withstand a range of temperatures, making them robust enough for industrial applications. The CY7C144 and CY7C145 also comply with several industry standards, ensuring compatibility with a wide array of devices and systems.

In summary, the CY7C144 and CY7C145 by Cypress Semiconductor stand out due to their blend of high speed, low power consumption, and robust reliability. With advanced features like burst read/write capabilities, error detection, and temperature resilience, these memory chips are exceptional choices for modern electronic applications demanding speed and efficiency. Their continued evolution reflects Cypress's commitment to innovation in the semiconductor industry, catering to the growing needs of a data-driven world.
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