Cypress STK17T88 manual Features, Description, Logic Block Diagram

STK17T88

32K x 8 AutoStore™ nvSRAM with Real Time Clock

Features

■nvSRAM Combined With Integrated Real-Time Clock Functions (RTC, Watchdog Timer, Clock Alarm, Power Monitor)

■Capacitor or Battery Backup for RTC

■25, 45 ns Read Access and R/W Cycle Time

■Unlimited Read/Write Endurance

■Automatic Nonvolatile STORE on Power Loss

■Nonvolatile STORE Under Hardware or Software Control

■Automatic RECALL to SRAM on Power Up

■Unlimited RECALL Cycles

■200K STORE Cycles

■20-Year Nonvolatile Data Retention

■Single 3V +20%, -10% Power Supply

■Commercial and Industrial Temperatures

■48-pin 300-mil SSOP Package (RoHS-Compliant)

Description

The Cypress STK17T88 combines a 256 Kb nonvolatile static RAM (nvSRAM) with a full-featured real-time clock in a reliable, monolithic integrated circuit.

The 256 Kb nvSRAM is a fast static RAM with a nonvolatile Quantum Trap storage element included with each memory cell.

The SRAM provides the fast access and cycle times, ease of use and unlimited read and write endurance of a normal SRAM. Data transfers automatically to the nonvolatile storage cells when power loss is detected (the STORE operation). On power up, data is automatically restored to the SRAM (the RECALL operation). Both STORE and RECALL operations are also available under software control.

The real time clock function provides an accurate clock with leap year tracking and a programmable, high accuracy oscillator. The Alarm function is programmable for one-time alarms or periodic minutes, hours, or days alarms. There is also a programmable watchdog timer for processor control.

Logic Block Diagram
			Quantum Trap		VCC	VCAP
			512 X 512		POWER		VRTCbat
A5
	DECODER				CONTROL		VRTCcap
A6				STORE
A7
A8			STATIC RAM	RECALL	STORE/
A9			ARRAY		RECALL		HSB
A11	ROW		512 X 512		CONTROL
A12
A13
A14						SOFTWARE		A13 – A0
						DETECT
DQ0	BUFFERS		COLUMN I/O
DQ1								X1
DQ2			COLUMN DEC			RTC
DQ3								X2
DQ4								INT
	INPUT
DQ5			A0 A1 A2 A3 A4 A10
DQ6						MUX		A14 – A0
DQ7
								G
								E
								W
Cypress Semiconductor Corporation		•	198 Champion Court		•	San Jose, CA 95134-1709			• 408-943-2600
Document Number: 001-52040 Rev. *A								Revised March 17, 2009

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