Instruction/ maintenance manual of the product CY14B256K Cypress Semiconductor
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CY14B256K 256 Kbit (32K x 8) nvSRAM with Real T ime Clock Cypress Semiconductor Corpora tion • 198 Champion Court • San Jose , CA 95134-1709 • 408-943-2600 Document Number: 001-06431 Rev .
CY14B256K Document Number: 001-06431 Rev . *H Page 2 of 28 Pin Configurations Figure 1. 48-Pin SSOP Pin Definitions Pin Name Alt IO T ype Description A 0 –A 14 Input Address Inputs. Used to select one of the 32,768 bytes of the nvSRAM. DQ0-DQ7 Input or Output Bidirectional Dat a IO lines .
CY14B256K Document Number: 001-06431 Rev . *H Page 3 of 28 Device Operation The CY14B256K nvSRAM consists of two functional components paired in the same physical cell. Th e component s are SRAM memory cell and a nonvolatile QuantumTrap cell. The SRAM memory cell operates as a standard fast static RAM.
CY14B256K Document Number: 001-06431 Rev . *H Page 4 of 28 t DELA Y , multi ple SRAM READ operations take place. If a WRITE is in progress when HSB is pulled LOW , it allows a time, t DELA Y , to complete. However , any SRAM WRITE cycles requested after HSB goes LOW are inhibited until HSB retu rns HIGH.
CY14B256K Document Number: 001-06431 Rev . *H Page 5 of 28 Low A verage Active Power CMOS technology provides the CY14B25 6K the benefit of drawing significantly le ss current when it is cycled at times longer than 50 ns. Figure 3 shows the relation ship between I CC and READ and/or WRITE cycle time.
CY14B256K Document Number: 001-06431 Rev . *H Page 6 of 28 T able 1. Mode Selection CE WE OE A13–A0 Mode IO Power H X X X Not Selected Output High Z S tandby L H L X Read SRAM Output Data Active L L.
CY14B256K Document Number: 001-06431 Rev . *H Page 7 of 28 Real Time Clock Operation nvTIME Operation The CY14B256K consists of internal registe rs that contain clock, alarm, watchdog, interrupt, and co ntro l functions. RTC registers use the last 16 address locati ons of the SRAM .
CY14B256K Document Number: 001-06431 Rev . *H Page 8 of 28 Calibrating the Clock The RTC is driven by a quartz controlled oscillator with a nominal frequency of 32.768 kHz. Clock accu racy depends on the quality of the crystal and calibration. The crystal oscillators typically have an error of + 20ppm to + 35ppm.
CY14B256K Document Number: 001-06431 Rev . *H Page 9 of 28 Power Monitor The CY14B256K provides a power management sch eme with power fail interru pt capability . It also controls the inte rnal switch to backup po wer for the cl ock and prot ects t he memory from lo w V CC access.
CY14B256K Document Number: 001-06431 Rev . *H Page 10 of 28 Figure 5. Interrupt Block Diagram Figure 6. RTC Recommende d Componen t Configurati on WDF - W atchdog T imer Flag WIE - W atchdog I nterrup.
CY14B256K Document Number: 001-06431 Rev . *H Page 1 1 of 28 T able 3. RTC Register Map [5, 6] Register BCD Format Data [5 ] Fu nction/Range D7 D6 D5 D4 D3 D2 D1 D0 0x7FFF 10s Y ears Y ears Y ears: 00.
CY14B256K Document Number: 001-06431 Rev . *H Page 12 of 28 T able 4. Register Map Detail 0x7FFF Time Keeping - Y ears D7 D6 D5 D4 D3 D2 D1 D0 10s Y ears Y ears Contains the lower two BCD digits of the year . Lower nibble (four bits) contains the value for years; upper nibble (four bits) contains the value for 10s of years.
CY14B256K Document Number: 001-06431 Rev . *H Page 13 of 28 0X7FF8 Calibration/Con trol D7 D6 D5 D4 D3 D2 D1 D0 OSCEN 0 Calibration Sign Calibration OSCEN Oscillator Enable. When set to 1, the oscillator is stopped . When set to 0, the oscillator runs.
CY14B256K Document Number: 001-06431 Rev . *H Page 14 of 28 0x7FF4 Alarm - Hours D7 D6 D5 D4 D3 D2 D1 D0 M 10s Alarm Hours Alarm Hours Contains the alarm value for the hours and the ma sk bit to select or desele ct the hours value. M Match. When this bit is set to 0, the hours valu e is used in the alarm match.
CY14B256K Document Number: 001-06431 Rev . *H Page 15 of 28 Maximum Ratings Exceeding maximum ratin gs may impair the useful life of the device. These user guidelines are not teste d. S torage T emperature ............. .............. ...... –65 ° C to +150 ° C Ambient T emper ature wit h Power Applied .
CY14B256K Document Number: 001-06431 Rev . *H Page 16 of 28 Dat a Retention and Endurance Parameter Description Min Unit DA T A R Data Retention 20 Y ears NV C Nonvolatile STORE Operations 200 K Cap acitance These parameters are guaranteed but not tested.
CY14B256K Document Number: 001-06431 Rev . *H Page 17 of 28 AC Switching Ch aracteristics Parameter Description 25 ns 35 ns 45 ns Unit Min Max Min Max Min Max Cypress Parameter Alt.
CY14B256K Document Number: 001-06431 Rev . *H Page 18 of 28 AC Switching Ch aracteristics (continued) Parameter Description 25 ns 35 ns 45 ns Unit Min Max Min Max Min Max Cypress Parameter Alt.
CY14B256K Document Number: 001-06431 Rev . *H Page 19 of 28 AutoStore or Power Up RECALL Parameter Descrip tion CY14B256K Unit Min Max t HRECALL [17] Power Up RECALL Duration 40 ms t STORE [18, 19] STORE Cycle Duration Commercial 12.5 ms Industrial 15 ms V SWITCH Low V oltage T rigger Level 2.
CY14B256K Document Number: 001-06431 Rev . *H Page 20 of 28 Sof tware Con trolled STORE/RECALL Cycles [20, 21] Parameter Alt. Parameter Descriptio n 25 ns 35 ns 45 ns Unit Min Max Min Max Min Max t RC.
CY14B256K Document Number: 001-06431 Rev . *H Page 21 of 28 Hardware STORE Cycle Parameter Alt. Parameter Description CY14B256K Unit Min Max t DELA Y [22] Time Allowed to Comp lete SRAM Cycle 1 70 μ s t PHSB t HLHX Hardware STORE Pulse Width 15 ns Figure 15.
CY14B256K Document Number: 001-06431 Rev . *H Page 22 of 28 RTC Characteristics Parameter Description T est Conditions Min Max Unit I BAK [25] RTC Backup Current Commercial 300 nA Industrial 350 nA V RTCbat [26] R TC Battery Pin V oltage 1.8 3.3 V V RTCca p [27] RTC Capacitor Pin V oltage 1.
CY14B256K Document Number: 001-06431 Rev . *H Page 23 of 28 Part Numbering Nomenclature CY 14 B 256 K - SP 25 X C T Option: T -T ape and Reel Blank - S td.
CY14B256K Document Number: 001-06431 Rev . *H Page 24 of 28 Ordering Information All the below mentioned parts are Pb-free. Contact your local Cypress sales representative for availability of these parts.
CY14B256K Document Number: 001-06431 Rev . *H Page 25 of 28 Package Diagrams Figure 17. 48-Pin Shrunk Small Outline Package (51-85061) 51-85061-* C [+] Feedback.
CY14B256K Document Number: 001-06431 Rev . *H Page 26 of 28 Document History Page Document Title: CY14B256K 256 Kbit (32K x 8) nvSRAM with Real Time Clock Document Number: 001-06431 Rev .
CY14B256K Document Number: 001-06431 Rev . *H Page 27 of 28 *H 2663934 GVCH/PYRS 02/24/09 U pdated Features section Updated pin definition o f WE pin Updated “Reading the clock”, “Backup Power”, “S topping and starting the Oscillator” and “Alarm” descriptions under R TC operation Modified “Figure 4.
Document Number: 001-06431 Rev . *H Revised February 24, 2009 Page 28 of 28 All product s and comp any names mentioned in thi s document ar e the tradem arks of their re spective holder s. CY14B256K © Cypress Sem iconductor Corp oration, 2006-2009. The informatio n contained herein is su bject to change without notice.
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