STK17TA8 128k X 8 AutoStore™ nvSRAM with Real Time Clock Features Description ■ 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 Read/Write 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 3 V +20%, -10% Power Supply ■ Commercial and Industrial Temperatures ■ 48-pin 300-mil SSOP Package (RoHS-Compliant) The Cypress STK17TA8 combines a 1 Mb nonvolatile static RAM (nvSRAM) with a full featured real time clock in a reliable, monolithic integrated circuit. The 1 Mb 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 1024 X 1024 ROW DECODER A5 A6 A7 A8 A9 A12 A13 A14 A15 A16 STORE STATIC RAM ARRAY 1024 X 1024 RECALL VCC VCAP POWER CONTROL STORE/ RECALL CONTROL VRTCbat VRTCcap HSB SOFTWARE DETECT INPUT BUFFERS DQ0 DQ1 DQ2 DQ3 DQ4 DQ5 DQ6 DQ7 A15 – A0 COLUMN I/O COLUMN DEC RTC X1 X2 INT A0 A 1 A 2 A3 A 4 A10 A11 MUX A16 – A0 G E W Cypress Semiconductor Corporation Document #: 001-52039 Rev. ** • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Revised March 02, 2009 [+] Feedback STK17TA8 Pinouts Figure 1. Pin Diagram - 48-PIn SSOP V CAP A 16 A 14 1 48 2 47 V CC A 15 3 46 HSB A 12 A7 4 5 45 44 A6 6 43 W A 13 A8 7 42 A9 INT 8 41 NC A4 A5 9 40 A 11 NC 10 39 NC NC 11 38 NC NC 12 37 V SS NC 13 36 NC 14 35 (TOP) 15 34 V SS NC V RTCcap DQ 0 16 33 DQ 6 A3 17 32 A2 18 31 G A 10 A1 19 30 A0 DQ 1 DQ 2 20 29 DQ 7 21 28 DQ 5 27 DQ 4 X1 22 23 26 DQ 3 X2 24 25 V CC V RTCbat Relative PCB Area Usage[1] E Pin Descriptions Pin Name IO Type Description A16-A0 Input Address: The 17 address inputs select one of 131,072 bytes in the nvSRAM array or one of 16 bytes in the clock register map DQ7-DQ0 I/O E Input Chip Enable: The active low E input selects the device W Input Write Enable: The active low W enables data on the DQ pins to be written to the address location selected on the falling edge of E G Input Output Enable: The active low G input enables the data output buffers during read cycles. De-asserting G high caused the DQ pins to tri-state. X1 Output X2 Input Data: Bi-directional 8-bit data bus for accessing the nvSRAM and RTC Crystal Connection, drives crystal on startup Crystal Connection for 32.768 kHz crystal VRTCcap Power Supply Capacitor supplied backup RTC supply voltage (Left unconnected if VRTCbat is used) VRTCbat Power Supply Battery supplied backup RTC supply voltage (Left unconnected if VRTCcap is used) VCC Power Supply Power: 3.0V, +20%, -10% HSB I/O INT Output Hardware Store Busy: When low this output indicates a Store is in progress. When pulled low external to the chip, it will initiate a nonvolatile STORE operation. A weak pull up resistor keeps this pin high if not connected. (Connection Optional). Interrupt Control: Can be programmed to respond to the clock alarm, the watchdog timer and the power monitor. Programmable to either active high (push/pull) or active low (open-drain) VCAP Power Supply Autostore™ Capacitor: Supplies power to nvSRAM during power loss to store data from SRAM to nonvolatile storage elements. VSS Power Supply Ground NC No Connect Unlabeled pins have no internal connections. Note 1. For detailed package size specifications, See “Package Diagrams” on page 22.. Document #: 001-52039 Rev. ** Page 2 of 23 [+] Feedback STK17TA8 Absolute Maximum Ratings RF (SSOP-48) Package Thermal Characteristics Voltage on Input Relative to Ground ................–0.1V to 4.1V θjc 6.2 C/W; θja 51.1 [0fpm], 44.7 [200fpm], 41.8 C/W [500fpm] Voltage on Input Relative to VSS .........–0.5V to (VCC + 0.5V) Note: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only, and functional operation of the device at conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliablity. Voltage on DQ0-7 or HSB.....................–0.5V to (VCC + 0.5V) Temperature under Bias ............................... –55°C to 125°C Junction Temperature ................................... –55°C to 140°C Storage Temperature .................................... –65°C to 150°C Power Dissipation............................................................. 1W DC Output Current (1 output at a time, 1s duration)..... 15mA DC Electrical Characteristics (VCC = 2.7V-3.6V) Symbol Parameter Commercial Min Max Industrial Min Units Notes Max ICC1 Average VCC Current 65 50 70 55 mA mA tAVAV = 25 ns tAVAV = 45 ns Dependent on output loading and cycle rate. Values obtained without output loads. ICC2 Average VCC Current during STORE 3 3 mA All Inputs Don’t Care, VCC = max Average current for duration of STORE cycle (tSTORE) ICC3 Average VCC Current at tAVAV = 200ns 3V, 25°C, Typical 10 10 mA W ≥ (V CC – 0.2V) All Other Inputs Cycling at CMOS Levels Dependent on output loading and cycle rate. Values obtained without output loads. ICC4 Average VCAP Current during <Emphasis>AutoStore™ Cycle 3 3 mA All Inputs Don’t Care Average current for duration of STORE cycle (tSTORE) ISB VCC Standby Current (Standby, Stable CMOS Levels) 3 3 mA E ≥ (VCC -0.2V) All Others VIN≤ 0.2V or ≥ (VCC-0.2V) Standby current level after nonvolatile cycle complete IILK Input Leakage Current ±1 ±1 mA VCC = max VIN = VSS to VCC IOLK Off-State Output Leakage Current ±1 ±1 mA VCC = max VIN = VSS to VCC, E or G ≥ VIH VIH Input Logic “1” Voltage 2.0 VCC + 0.5 2.0 VCC + 0.5 V All Inputs VIL Input Logic “0” Voltage VSS –0.5 0.8 VSS –0.5 0.8 V All Inputs VOH Output Logic “1” Voltage V IOUT = – 2 mA (except HSB) VOL Output Logic “0” Voltage V IOUT = 4 mA 2.4 2.4 0.4 0.4 Note: The HSB pin has IOUT=-10uA for VOH of 2.4V, this parameter is characterized but not tested. Note: The INT is open-drain and does not source or sink high current when interrupt Register bit D3 is below. Document #: 001-52039 Rev. ** Page 3 of 23 [+] Feedback STK17TA8 DC Electrical Characteristics (continued) (VCC = 2.7V-3.6V) Symbol Parameter Commercial Industrial Min Max Min Max Units Notes TA Operating Temperature 0 70 – 40 85 °C VCC Operating Voltage 2.7 3.6 2.7 3.6 V 3.0V +20%, -10% VCAP Storage Capacitance 17 57 17 57 μF Between VCAP pin and VSS, 5V rated. NVC Nonvolatile STORE operations 200 200 DATAR Data Retention 20 20 K Years At 55 °C AC Test Conditions Input Pulse Levels ....................................................0V to 3V Input Rise and Fall Times ............................................ <5 ns Input and Output Timing Reference Levels .................... 1.5V Output Load..................................See Figure 2 and Figure 3 Capacitance (TA = 25°C, f = 1.0MHz)[2] Symbol Parameter Max Units Conditions CIN Input Capacitance 7 pF ΔV = 0 to 3V COUT Output Capacitance 7 pF ΔV = 0 to 3V Figure 2. AC Output Loading 3.0V 577 Ohms OUTPUT 789 Ohms 30 pF INCLUDING SCOPE AND FIXTURE Figure 3. AC Output Loading for Tristate Specs (tHZ, tLZ, tWLQZ, tWHQZ, tGLQX, tGHQZ 3.0V 577 Ohms OUTPUT 789 Ohms 5 pF INCLUDING SCOPE AND FIXTURE Notes 2. These parameters are guaranteed but not tested. Document #: 001-52039 Rev. ** Page 4 of 23 [+] Feedback STK17TA8 RTC DC Characteristics IBAK VRTCbat RTC Backup Current RTC Battery Pin Voltage Commercial Min Max — 300 1.8 3.3 VRTCcap RTC Capacitor Pin Voltage 1.2 2.7 1.2 2.7 V tOSCS RTC Oscillator time to start — 10 — 10 sec — 5 — 5 sec Symbol Parameter Industrial Min Max — 350 1.8 3.3 Units Notes nA V From either VRTCcap or VRTCbat Typical = 3.0 Volts during normal operation Typical = 2.4 Volts during normal operation At MIN Temperature from Power up or Enable At 25°C from Power up or Enable Y1 C2 RF C1 Figure 4. RTC Recommended Component Configuration X1 X2 Recommended Values Y1 = 32.768 KHz RF = 10M Ohm C1 = 0 (install cap footprint, but leave unloaded) C2 = 56 pF ± 10% (do not vary from this value) Document #: 001-52039 Rev. ** Page 5 of 23 [+] Feedback STK17TA8 SRAM READ Cycles #1 and #2 NO. Symbols #1 1 #2 STK17TA8-25 Parameter Alt. Min Max STK17TA8-45 Min Max Units tELQV tACS Chip Enable Access Time tELEH[3] tAVQV[4] tRC Read Cycle Time tAA Address Access Time 25 45 ns tGLQV tOE Output Enable to Data Valid 12 20 ns tAXQX[4] tOH Output Hold after Address Change 3 3 ns 6 tELQX tLZ Address Change or Chip Enable to Output Active 3 3 ns 7 tEHQZ[5] tHZ Address Change or Chip Disable to Output Inactive 8 tGLQX tOLZ Output Enable to Output Active tOHZ Output Disable to Output Inactive tPA Chip Enable to Power Active tPS Chip Disable to Power Standby 2 3 tAVAV[3] tAVQV[4] 4 5 tAXQX[4] [5] 9 tGHQZ 10 tELICCL[2] 11 tEHICCH [2] 25 25 45 45 10 0 ns 15 0 10 0 ns ns 15 0 25 ns ns ns 45 ns Figure 5. SRAM READ Cycle #1: Address Controlled[3, 4, 6] 2 tAVAV ADDRESS 3 tAVQV 5 tAXQX DQ (DATA OUT) DATA VALID Figure 6. SRAM READ Cycle #2: E and G Controlled[3, 6] 2 29 1 11 6 7 3 4 9 8 10 Notes 3. W must be high during SRAM READ cycles. 4. Device is continuously selected with E and G both low 5. Measured ± 200mV from steady state output voltage. 6. HSB must remain high during READ and WRITE cycles. Document #: 001-52039 Rev. ** Page 6 of 23 [+] Feedback STK17TA8 SRAM WRITE Cycles #1 and #2 Symbols NO. #1 #2 STK17TA8-25 Parameter Alt. Min Max STK17TA8-45 Min Max Units 11 tAVAV tAVAV tWC Write Cycle Time 25 45 ns 13 tWLWH tWLEH tWP Write Pulse Width 20 30 ns 14 tELWH tELEH tCW Chip Enable to End of Write 20 30 ns 15 tDVWH tDVEH tDW Data Set-up to End of Write 10 15 ns 16 tWHDX tEHDX tDH Data Hold after End of Write 0 0 ns 17 tAVWH tAVEH tAW Address Set-up to End of Write 20 30 ns 18 tAVWL tAVEL tAS Address Set-up to Start of Write 0 0 ns 19 tWHAX tEHAX tWR Address Hold after End of Write 0 0 ns 20 tWLQZ5, 7 tWZ Write Enable to Output Disable 21 tWHQX tOW Output Active after End of Write 10 3 15 3 ns ns Figure 7. SRAM WRITE Cycle #1: W Controlled[7, 8] 11 tAVAV ADDRESS 19 tWHAX 14 tELWH E 17 tAVWH 18 tAVWL 13 tWLWH W 15 tDVWH DATA IN 16 tWHDX DATA VALID 20 tWLQZ DATA OUT 21 tWHQX HIGH IMPEDANCE PREVIOUS DATA Figure 8. SRAM WRITE Cycle #2: E Controlled[7, 8] 11 tAVAV ADDRESS 18 tAVEL 14 tELEH 19 tEHAX E 17 tAVEH W 13 tWLEH 15 tDVEH DATA IN DATA OUT 16 tEHDX DATA VALID HIGH IMPEDANCE Notes 7. If W is low when E goes low, the outputs remain in the high-impedance state. 8. E or W must be ≥ VIH during address transitions. Document #: 001-52039 Rev. ** Page 7 of 23 [+] Feedback STK17TA8 AutoStore/Power Up Recall NO. Symbols Standard 22 tHRECALL 23 tSTORE STK17TA8 Parameter Alternate Min Power-up RECALL Duration tHLHZ STORE Cycle Duration 24 VSWITCH Low Voltage Trigger Level 25 VCCRISE VCC Rise Time Units Notes 40 ms 9 12.5 ms 10,11 Max 2.65 150 V μS Figure 9. AutoStore/Power Up RECALL 25 23 22 23 22 NOTE: Read and Write cycles will be ignored during STORE, RECALL and while VCC is below VSWITCH Notes 9. tHRECALL starts from the time VCC rises above VSWITCH 10. If an SRAM WRITE has not taken place since the last nonvolatile cycle, no STORE will take place 11. Industrial Grade Devices require 15 ms MAX. Document #: 001-52039 Rev. ** Page 8 of 23 [+] Feedback STK17TA8 Software-Controlled STORE/RECALL Cycle In the following table, the software controlled STORE and RECALL cycle parameters are listed. [12, 13] NO. Symbols E Cont G Cont STK17TA8-35 Parameter Alternate Min Max STK17TA8-45 Min Max Units Notes 13 26 tAVAV tAVAV tRC STORE / RECALL Initiation Cycle Time 25 45 ns 27 tAVEL tAVGL tAS Address Set-up Time 0 0 ns 28 tELEH tGLGH tCW Clock Pulse Width 20 30 ns 29 tEHAX tGHAX Address Hold Time 1 1 ns 30 tRECALL tRECALL RECALL Duration 100 100 μs Figure 10. Software STORE/RECALL Cycle: E CONTROLLED[13] 26 26 27 28 29 23 30 Figure 11. Software STORE/RECALL Cycle: G Controlled[13] 26 27 26 28 23 30 29 Notes 12. The software sequence is clocked on the falling edge of E controlled READs or G controlled READs 13. The six consecutive addresses must be read in the order listed in the Software STORE/RECALL Mode Selection Table W must be high during all six consecutive cycles. Document #: 001-52039 Rev. ** Page 9 of 23 [+] Feedback STK17TA8 Hardware STORE Cycle NO. Symbols Standard 31 tDELAY 32 tHLHX Parameter Alternate tHLQZ STK17TA8 Min Max Hardware STORE to SRAM Disabled 1 70 Hardware STORE Pulse Width 15 Units Notes μs 14 ns Figure 12. Hardware STORE Cycle 32 23 31 Soft Sequence Commands NO. Symbols Parameter Standard 33 tSS STK17TA8 Min Units Notes μs 15,16 Max Soft Sequence Processing Time 70 Figure 13. Soft Sequence Commands 33 33 Notes 14. On a hardware STORE initiation, SRAM operation continues to be enabled for time tDELAY to allow READ/WRITE cycles to compete. 15. This is the amount of time that it takes to take action on a soft sequence command. Vcc power must remain high to effectively register command. 16. Commands like Store and Recall lock out I/O until operation is complete which further increases this time. See specific command. Document #: 001-52039 Rev. ** Page 10 of 23 [+] Feedback STK17TA8 MODE Selection E W G A16-A0 Mode I/O Power H L L L X H L H X L X L X X X 0x04E38 0x0B1C7 0x083E0 0x07C1F 0x0703F 0x08FC0 0x04E38 0x0B1C7 0x083E0 0x07C1F 0x0703F 0x04C63 Not Selected Read SRAM Write SRAM Read SRAM Read SRAM Read SRAM Read SRAM Read SRAM Nonvolatile Store Read SRAM Read SRAM Read SRAM Read SRAM Read SRAM Nonvolatile Recall Output High Z Output Data Input Data Output Data Output Data Output Data Output Data Output Data Output High Z Output Data Output Data Output Data Output Data Output Data Output High Z Standby Active Active L H L Active Notes 17, 18, 19 ICC2 Active 17, 18, 19 Notes 17. The six consecutive addresses must be in the order listed. W must be high during all six consecutive cycles to enable a nonvolatile cycle. 18. While there are 17 addresses on the STK17TA8, only the lower 16 are used to control software modes 19. I/O state depends on the state of G. The I/O table shown assumes G low Document #: 001-52039 Rev. ** Page 11 of 23 [+] Feedback STK17TA8 nvSRAM Operation The STK17TA8 nvSRAM is made up of two functional components paired in the same physical cell. These are the SRAM memory cell and a nonvolatile QuantumTrap cell. The SRAM memory cell operates like a standard fast static RAM. Data in the SRAM can be transferred to the nonvolatile cell (the STORE operation), or from the nonvolatile cell to SRAM (the RECALL operation). This unique architecture enables all cells to be stored and recalled in parallel. During the STORE and RECALL operations SRAM READ and WRITE operations are inhibited. The STK17TA8 supports unlimited read and writes like a typical SRAM. In addition, it provides unlimited RECALL operations from the nonvolatile cells and up to 200K STORE operations. SRAM READ The STK17TA8 performs a READ cycle whenever E and G are low while W and HSB are high. The address specified on pins A0-16 determine which of the 131,072 data bytes are accessed. When the READ is initiated by an address transition, the outputs are valid after a delay of tAVQV (READ cycle #1). If the READ is initiated by E and G, the outputs are valid at tELQV or at tGLQV, whichever is later (READ cycle #2). The data outputs repeatedly respond to address changes within the tAVQV access time without the need for transitions on any control input pins, and remain valid until another address change or until E or G is brought high, or W and HSB is brought low. Figure 14. AutoStore Mode W 0.1µF VCAP VCC 10k Ohm VCC VCAP SRAM WRITE A WRITE cycle is performed whenever E and W are low and HSB is high. The address inputs must be stable prior to entering the WRITE cycle and must remain stable until either E or W goes high at the end of the cycle. The data on the common I/O pins DQ0-7 is written into memory if it is valid tDVWH before the end of a W controlled WRITE or tDVEH before the end of an E controlled WRITE. It is recommended that G be kept high during the entire WRITE cycle to avoid data bus contention on common I/O lines. If G is left low, internal circuitry turns off the output buffers tWLQZ after W goes low. AutoStore Operation The STK17TA8 stores data to nvSRAM using one of three storage operations. These three operations are Hardware Store Document #: 001-52039 Rev. ** (activated by HSB), Software Store (activated by an address sequence), and AutoStore (on power down). AutoStore operation, a unique feature of Cypress QuanumTrap technology is a standard feature on the STK17TA8. During normal operation, the device draws current from VCC to charge a capacitor connected to the VCAP pin. This stored charge is used by the chip to perform a single STORE operation. If the voltage on the VCC pin drops below VSWITCH, the part automatically disconnects the VCAP pin from VCC. A STORE operation is initiated with power provided by the VCAP capacitor. Figure 14 shows the proper connection of the storage capacitor (VCAP) for automatic store operation. Refer to the DC Electrical Characteristics on page 3 for the size of the capacitor. The voltage on the VCAP pin is driven to 5V by a charge pump internal to the chip. A pull up should be placed on W to hold it inactive during power up. To reduce unneeded nonvolatile stores, AutoStore and Hardware Store operations are ignored unless at least one WRITE operation has taken place since the most recent STORE or RECALL cycle. Software initiated STORE cycles are performed regardless of whether a WRITE operation has taken place. The HSB signal can be monitored by the system to detect an AutoStore cycle is in progress. Hardware STORE (HSB) Operation The STK17TA8 provides the HSB pin for controlling and acknowledging the STORE operations. The HSB pin can be used to request a hardware STORE cycle. When the HSB pin is driven low, the STK17TA8 conditionally initiates a STORE operation after tDELAY. An actual STORE cycle only begins if a WRITE to the SRAM took place since the last STORE or RECALL cycle. The HSB pin has a very resistive pullup and is internally driven low to indicate a busy condition while the STORE (initiated by any means) is in progress. This pin should be externally pulled up if it is used to drive other inputs. SRAM READ and WRITE operations that are in progress when HSB is driven low by any means are given time to complete before the STORE operation is initiated. After HSB goes low, the STK17TA8 continues to allow SRAM operations for tDELAY. During tDELAY, multiple SRAM READ operations may take place. If a WRITE is in progress when HSB is pulled low, it is allowed a time, tDELAY, to complete. However, any SRAM WRITE cycles requested after HSB goes low is inhibited until HSB returns high. If HSB is not used, it should be left unconnected. Hardware RECALL (POWER-UP) During power up or after any low power condition (VCC<VSWITCH), an internal RECALL request is latched. When VCC once again exceeds the sense voltage of VSWITCH, a RECALL cycle is automatically initiated and takes tHRECALL to complete. Software STORE Data can be transferred from the SRAM to the nonvolatile memory by a software address sequence. The STK17TA8 software STORE cycle is initiated by executing sequential E controlled or G controlled READ cycles from six specific address locations in exact order. During the STORE cycle, previous data is erased and then the new data is programmed into the nonvol- Page 12 of 23 [+] Feedback STK17TA8 atile elements. Once a STORE cycle is initiated, further memory inputs and outputs are disabled until the cycle is completed. To initiate the Software STORE cycle, the following read sequence must be performed: 1. Read Address 0x4E38 Valid READ 2. Read Address 0xB1C7 Valid READ 3. Read Address 0x83E0 Valid READ 4. Read Address 0x7C1F Valid READ 5. Read Address 0x703F Valid READ 6. Read Address 0x8FC0 Initiate STORE Cycle Preventing AutoStore Because of the use of nvSRAM to store critical RTC data, the AutoStore function cannot be disabled on the STK17TA8. Best Practices nvSRAM products have been used effectively for over 15 years. While ease-of-use is one of the product’s main system values, experience gained working with hundreds of applications has resulted in the following suggestions as best practices: ■ The nonvolatile cells in an nvSRAM are programmed on the test floor during final test and quality assurance. Incoming inspection routines at customer or contract manufacturer’s sites sometimes reprogram these values. Final NV patterns are typically repeating patterns of AA, 55, 00, FF, A5, or 5A. End product’s firmware should not assume an NV array is in a set programmed state. Routines that check memory content values to determine first time system configuration, cold or warm boot status, should always program a unique NV pattern (for example, complex 4-byte pattern of 46 E6 49 53 hex or more random bytes) as part of the final system manufacturing test to ensure these system routines work consistently. ■ Power up boot firmware routines should rewrite the nvSRAM into the desired state (autostore enabled and so on). While the nvSRAM is shipped in a preset state, best practice is to again rewrite the nvSRAM into the desired state as a safeguard against events that might flip the bit inadvertently (program bugs, incoming inspection routines, and so on. ■ The OSCEN bit in the Calibration register at 0x1FFF8 should be set to 1 to preserve battery life when the system is in storage (see “Stopping And Starting The RTC Oscillator” on page 14). ■ The Vcap value specified in this data sheet includes a minimum and a maximum value size. Best practice is to meet this requirement and not exceed the max Vcap value because the nvSRAM internal algorithm calculates Vcap charge time based on this max Vcap value. Customers that want to use a larger Vcap value to make sure there is extra store charge and store time should discuss their Vcap size selection with Cypress to understand any impact on the Vcap voltage level at the end of a tRECALL period. Once the sixth address in the sequence has been entered, the STORE cycle starts and the chip is disabled. It is important that READ cycles and not WRITE cycles be used in the sequence and that G is active. After the tSTORE cycle time has been fulfilled, the SRAM is again activated for READ and WRITE operation. Software RECALL Data is transferred from nonvolatile memory to the SRAM by a software address sequence. A Software RECALL cycle is initiated with a sequence of READ operations in a manner similar to the Software STORE initiation. To initiate the RECALL cycle, the following sequence of E or G controlled or READ operations must be performed: 1. Read Address 0x4E38 Valid READ 2. Read Address 0xB1C7 Valid READ 3. Read Address 0x83E0 Valid READ 4. Read Address 0x7C1F Valid READ 5. Read Address 0x703F Valid READ 6. Read Address 0x4C63 Initiate RECALL Cycle Internally, RECALL is a two-step procedure. First, the SRAM data is cleared, and second, the nonvolatile information is transferred into the SRAM cells. After the tRECALL cycle time, the SRAM is once again be ready for READ or WRITE operations. The RECALL operation in no way alters the data in the nonvolatile storage elements. Data Protection The STK17TA8 protects data from corruption during low-voltage conditions by inhibiting all externally initiated STORE and WRITE operations. The low voltage condition is detected when VCC<VSWITCH. If the STK17TA8 is in a WRITE mode (both E and W low) at power-up, after a RECALL, or after a STORE, the WRITE will be inhibited until a negative transition on E or W is detected. This protects against inadvertent writes during power up or brown out conditions. Noise Considerations The STK17TA8 is a high speed memory and so must have a high frequency bypass capacitor of 0.1 µF connected between both VCC pins and VSS ground plane with no plane break to chip VSS. Use leads and traces that are as short as possible. As with all high speed CMOS ICs, careful routing of power, ground, and signals reduces circuit noise. Document #: 001-52039 Rev. ** Low Average Active Power CMOS technology provides the STK17TA8 with the benefit of power supply current that scales with cycle time. Less current is drawn as the memory cycle time becomes longer than 50 ns. Figure 15 shows the relationship between ICC and READ/WRITE cycle time. Worst-case current consumption is shown for commercial temperature range, VCC=3.6V, and chip enable at maximum frequency. Only standby current is drawn when the chip is disabled. The overall average current drawn by the STK17TA8 depends on the following items: 1. The duty cycle of chip enable. 2. The overall cycle rate for accesses. 3. The ration of READs to WRITEs. 4. The operating temperature. 5. The VCC level. 6. I/O loading. Page 13 of 23 [+] Feedback STK17TA8 Figure 15. Current versus Cycle Time You can power the real time clock with either a capacitor or a battery. Factors to be considered when choosing a backup power source include the expected duration of power outages and the cost and reliability trade-off of using a battery versus a capacitor. If you select a capacitor power source, connect the capacitor to the VRTCcap pin and leave the VRTCbat pin unconnected. Capacitor backup time values based on maximum current specs are shown below. Nominal times are approximately three times longer. RTC Operations Real Time Clock The clock registers maintain time up to 9,999 years in one second increments. The user can set the time to any calendar time and the clock automatically keeps track of days of the week and month, leap years, and century transitions. There are eight registers dedicated to the clock functions which are used to set time with a write cycle and to read time during a read cycle. These registers contain the Time of Day in BCD format. Bits defined as "0" are currently not used and are reserved for future use by Cypress. Reading The Clock The user should halt internal updates to the real time clock registers before reading clock data to prevent the reading of data in transition. Stopping the internal register updates does not affect clock accuracy. Write a “1” to the read bit "R" (in the Flags register at 0x1FFF0) captures the current time in holding registers. Clock updates will not restart until a “0” is written to the read bit. The RTC registers can then be read while the internal clock continues to run. Within 20ms after a “0” is written to the read bit, all real time clock registers are simultaneously updated. Setting The Clock Set the write bit “W” (in the Flags register at 0x1FFF0) to a "1" to enable the time to be set. The correct day, date and time can then be written into the real time clock registers in 24-hour BCD format. The time written is referred to as the "Base Time." This value is stored in nonvolatile registers and used in calculation of the current time. Reset the write bit to "0" to transfer the time to the actual clock counters. The clock starts counting at the new base time. Backup Power The RTC in intended to keep time even when system power is lost. When primary power, VCC, drops below VSWITCH, the real time clock switches to the backup power supply connected to either the VRTCcap or VRTCbat pin. The clock oscillator uses a maximum of 300 nanoamps at 2 volts to maximize the backup time available from the backup source. Document #: 001-52039 Rev. ** Capacitor Value Backup Time 0.1 F 72 hours 0.47 F 14 days 1.0 F 30 days A capacitor has the obvious advantage of being more reliable and not containing hazardous materials. The capacitor is recharged every time the power is turned on so that real time clock continues to have the same backup time over years of operation. If you select a battery power source, connect the battery to the VRTCbat pin and leave the VRTCcap pin unconnected. A 3V lithium battery is recommended for this application. The battery capacity should be chosen for the total anticipated cumulative down-time required over the life of the system. The real time clock is designed with a diode internally connected to the VRTCbat pin. This prevents the battery from ever being charged by the circuit. Stopping And Starting The RTC Oscillator The OSCEN bit in Calibration register at 0x1FFF8 enables RTC oscillator operation. This bit is nonvolatile and shipped to customers in the “enabled” state (set to 0). OSCEN should be set to a 1 to preserve battery life while the system is in storage. This turns off the oscillator circuit extending the battery life. If the OSCEN bit goes from disabled to enabled, it typically takes 5 seconds (10 seconds max) for the oscillator to start. The STK17TA8 has the ability to detect oscillator failure due to loss of backup power. The failure is recorded by the OSCF (Oscillator Failed) bit of the Flags register (at address 0x1FFF0). When the device is powered on (VCC goes above VSWITCH), the OSCEN bit is checked for "enabled" status. If the OSCEN bit is enabled and the oscillator is not active within the first 5 ms, the OSCF bit is set. The user should check for this condition and then write a 0 to clear the flag. When the OSCF flag bit is set, the real time clock registers are reset to the “Base Time” (see the section "Setting the Clock"), the value last written to the real time clock registers. The value of OSCF should be reset to 0 when the real time clock registers are written for the first time. This initializes the state of this bit which may have become set when the system was first powered on. To reset OSCF, set the write bit “W” (in the Flags register at 0x1FFF0) to a "1" to enable writes to the Flag register. Write a “0” to the OSCF bit. and thenreset the write bit to "0" to disable writes. Page 14 of 23 [+] Feedback STK17TA8 Calibrating The Clock The RTC is driven by a quartz controlled oscillator with a nominal frequency of 32.768 KHz. Clock accuracy will depend on the quality of the crystal, specified (usually 35 ppm at 25 C). This error could equate to 1.53 minutes gain or loss per month. The STK17TA8 employs a calibration circuit that can improve the accuracy to +1/-2 ppm at 25 C. The calibration circuit adds or subtracts counts from the oscillator divider circuit. The number of time pulses are added or substracted depends upon the value loaded into the five calibration bits found in Calibration register (at 0x1FFF8). Adding counts speeds the clock up; subtracting counts slows the clock down. The Calibration bits occupy the five lower order bits of the register. These bits can be set to represent any value between 0 and 31 in binary form. Bit D5 is a Sign bit, where a “1” indicates positive calibration and a “0” indicates negative calibration. Calibration occurs during a 64 minute period. The first 62 minutes in the cycle may, once per minute, have one second either shortened by 128 or lengthened by 256 oscillator cycles. If a binary “1” is loaded into the register, only the first 2 minutes of the 64 minute cycle is modified; if a binary 6 is loaded, the first 12 will be affected, and so on. Therefore each calibration step has the effect of adding 512 or subtracting 256 oscillator cycles for every 125,829,120 actual oscillator cycles. That is +4.068 or -2.034 ppm of adjustment per calibration step in the calibration register. The calibration register value is determined during system test by setting the CAL bit in the Flags register (at 0x1FFF0) to 1. This causes the INT pin to toggle at a nominal 512 Hz. This frequency can be measured with a frequency counter. Any deviation measured from the 512 Hz will indicate the degree and direction of the required correction. For example, a reading of 512.01024 Hz would indicate a +20 ppm error, requiring a -10 (001010) to be loaded into the Calibration register. Note that setting or changing the calibration register does not affect the frequency test output frequency. To set or clear CAL, set the write bit “W” (in the Flags register at 0x1FFF0) to a "1" to enable writes to the Flag register. Write a value to CAL. and then reset the write bit to "0" to disable writes. The alarm value should be initialized on power-up by software since the alarm registers are not nonvolatile. To set or clear Alarm registers, set the write bit “W” (in the Flags register at 0x1FFF0) to a "1" to enable writes to the Alarm registers. Write an alarm value to the alarm registers and then reset the write bit to "0" to disable writes. Watchdog Timer The watchdog timer is designed to interrupt or reset processor should the program get hung in a loop and respond in a timely manner. The software must reload watchdog timer before it counts down to zero to prevent interrupt or reset. the not the this The watchdog timer is a free running down counter that uses the 32 Hz clock (31.25 ms) derived from the crystal oscillator. The watchdog timer function does no operate unless the oscillator is running. The watchdog counter is loaded with a starting value from the load register and then counts down to zero setting the watchdog flag (WDF) and generating an interrupt if the watchdog interrupt is enabled. The watchdog flag bit is reset when the flag register is read. The operating software would normally reload the counter by setting the watchdog strobe bit (WDS) to 1 within the timing interval programmed into the load register. To use the watchdog timer to reset the processor on timeout, the INT is tied to processor master reset and Interrupt register is programmed to 24h to enable interrupts to pulse the reset pin on timeout. To load the watch dog timer, set a new value into the load register by writing a “0” to the watchdog write bit (WDW) of the watchdog register (at 01x1FFF7). Then load a new value into the load register. Once the new value is loaded, the watchdog write bit is then set to 1 to disable watchdog writes. The watchdog strobe bit (WDS) is then set to 1 to load this value into the watchdog timer. Note Setting the load register to zero disables the watchdog timer function. The default Calibration register value from the factory is 00h. The user calibration value loaded is retained during a power loss. The system software should initialize the watchdog load register on power-up to the desired value since the register is not nonvolatile. Alarm Power Monitor The alarm function compares a user-programmable alarm time/date (stored in registers 0x1FFF1-5) with the real time clock time-of-day/date values. When a match occurs, the alarm flag (AF) is set and an interrupt is generated if the alarm interrupt is enabled. The alarm flag is automatically reset when the Flags register is read. The STK17TA8 provides a power monitor function. The power monitor is based on an internal band-gap reference circuit that compares the VCC voltage to VSWITCH. Each of the alarm registers has a match bit as its MSB. Setting the match bit to a 1 disables this alarm register from the alarm comparison. When the match bit is 0, the alarm register is compared with the equivalent real time clock register. Using the match bits, the alarm can occur as specifically as one particular second on one day of the month or as frequently as once per minute. Note The product requires the match bit for seconds(1x1FFF2 D7) be set to 0 for proper operation of the Alarm Flag and Interrupt. Document #: 001-52039 Rev. ** When the power supply drops below VSWITCH, the real time clock circuit is switched to the backup supply (battery or capacitor) . When operating from the backup source, no data may be read or written to the nvSRAM and the clock functions are not available to the user. The clock continues to operate in the background. Updated clock data is available to the user tHRECALL delay after VCC has been restored to the device. When power is lost, the PF flag in the Flags Register is set to indicate the power failure and an interrupt is generated if the power fail interrupt is enabled (interrupt register=20h). This line would normally be tied to the processor master reset input for perform power-off reset. Page 15 of 23 [+] Feedback STK17TA8 Interrupts The STK17TA8 has a Flags register, Interrupt Register, and interrupt logic that can interrupt a microcontroller or generate a power-up master reset signal. There are three potential interrupt sources: the watchdog timer, the power monitor, and the clock alarm. Each can be individually enabled to drive the INT pin by setting the appropriate bit in the Interrupt register. In addition, each has an associated flag bit in the Flags register that the host processor can read to determine the interrupt source. Two bits in the Interrupt register determine the operation of the INT pin driver. A functional diagram of the interrupt logic is shown below: Figure 16. Interrupt Block Diagram Power Monitor WIE PF P/L PFE Pin Driver H/L VINT VCC INT VSS AF Clock Alarm High/Low (H/L). When set to a 1, the INT pin is active high and the driver mode is push-pull. The INT pin can drive high only when VCC>VSWITCH. When set to a 0, the INT pin is active low and the drive mode is open-drain. The active low (open drain) output is maintained even when power is lost . Pulse/Level (P/L). When set to a 1, the INT pin is driven for approximately 200 ms when an interrupt occurs. The pulse is reset when the Flags register is read. When P/L is set to a 0, the INT pin is driven high or low (determined by H/L) until the Flags register is read. The Interrupt register is loaded with the default value 00h at the factory. The user should configure the Interrupt register to the value desired for their desired mode of operation. Once configured, the value is retained during power failures. WDF Watchdog Timer Power Fail Interrupt Enable (PFE). When set to 1, the INT pin is driven by a power fail signal from the power monitor circuit. When set to 0, only the PF flag is set. AIE Interrupt Register Flags Register The Flags register has three flag bits: WDF, AF, and PF. These flags are set by the watchdog time-out, alarm match, or power fail monitor respectively. The processor can either poll this register or enable interrupts to be informed when a flag is set. The flags are automatically reset once the register is read. The Flags register is automatically loaded with the value 00h on power up (with the exception of the OSCF bit). Watchdog Interrupt Enable (WIE). When set to 1, the watchdog timer drives the INT pin when a watchdog time-out occurs. When WIE is set to 0, the watchdog time-out only sets the WDF flag bit. Alarm Interrupt Enable (AIE). When set to 1, the INT pin is driven when an alarm match occurs. When set to 0, the alarm match only sets the AF flag bit. Document #: 001-52039 Rev. ** Page 16 of 23 [+] Feedback STK17TA8 RTC Register Register BCD Format Data D7 D6 0x1FFFF D5 D4 D3 D2 10s Years 0x1FFFE 0 0 0 10s Months 0x1FFFD 0 0 10s Day of Month 0x1FFFC 0 0 0 0x1FFFB 0 0 0 0 D1 D0 Years Years: 00-99 Months Months: 01-12 Day of Month Day of Month: 01-31 Day of Week 10s Hours Function / Range Day of week: 01-07 Hours Hours: 00-23 0x1FFFA 0 10s Minutes Minutes Minutes: 00-59 0x1FFF9 0 10s Seconds Seconds Seconds: 00-59 0x1FFF8 OSCEN [0] 0 0x1FFF7 WDS WDW 0x1FFF6 WIE [0] AIE [0] Cal Sign Calibration[00000] Calibration values* WDT PFE [0] 0 H/L [1] Watchdog* P/L [0] 0 0 Interrupts* 0x1FFF5 M 0 10s Alarm Date Alarm Day Alarm, Day of Month: 01-31 0x1FFF4 M 0 10s Alarm Hours Alarm Hours Alarm, hours: 00-23 0x1FFF3 M 10 Alarm Minutes Alarm Minutes Alarm, minutes: 00-59 0x1FFF2 M 10 Alarm Seconds Alarm Seconds Alarm, seconds: 00-59 0x1FFF1 0x1FFF0 10s Centuries WDF AF PF Centuries OSCF 0 CAL[0] W[0] Centuries: 00-99 R[0] Flags* * A binary value, not a BCD value. 0 - Not implemented, reserved for future use. Default Settings of nonvolatile Calibration and Interrupt registers from factory Calibration Register=00h Interrupt Register=00h The User should configure to desired value at startup or during operation and the value is then retained during a power failure. [ ] designates values shipped from the factory. See “Stopping And Starting The RTC Oscillator” on page 14 . Document #: 001-52039 Rev. ** Page 17 of 23 [+] Feedback STK17TA8 Register Map Detail 0x1FFFF 0x1FFFE 0x1FFFD 0x1FFFC 0x1FFFB 0x1FFFA 0x1FFF9 0x1FFF8 OSCEN Calibration Sign Calibration D7 D6 D5 Real Time Clock – Years D4 D3 D2 D1 D0 10s Years Years Contains the lower two BCD digits of the year. Lower nibble contains the value for years; upper nibble contains the value for 10s of years. Each nibble operates from 0 to 9. The range for the register is 0-99. Real Time Clock – Months D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 10s Month Months Contains the BCD digits of the month. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble (one bit) contains the upper digit and operates from 0 to 1. The range for the register is 1-12. Real Time Clock – Date D7 D6 D5 D4 D3 D2 D1 D0 0 0 10s Day of month Day of month Contains the BCD digits for the date of the month. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble contains the upper digit and operates from 0 to 3. The range for the register is 1-31. Leap years are automatically adjusted for. Real Time Clock – Day D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 0 0 Day of week Lower nibble contains a value that correlates to day of the week. Day of the week is a ring counter that counts from 1 to 7 then returns to 1. The user must assign meaning to the day value, as the day is not integrated with the date. Real Time Clock – Hours D7 D6 D5 D4 D3 D2 D1 D0 0 0 10s Hours Hours Contains the BCD value of hours in 24 hour format. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble (two bits) contains the upper digit and operates from 0 to 2. The range for the register is 0-23. Real Time Clock – Minutes D7 D6 D5 D4 D3 D2 D1 D0 0 10s Minutes Minutes Contains the BCD value of minutes. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble contains the upper minutes digit and operates from 0 to 5. The range for the register is 0-59. Real Time Clock – Seconds D7 D6 D5 D4 D3 D2 D1 D0 0 10s Seconds Seconds Contains the BCD value of seconds. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble contains the upper digit and operates from 0 to 5. The range for the register is 0-59. Calibration D7 D6 D5 D4 D3 D2 D1 D0 OSCEN 0 Calibration Calibration Sign Oscillator Enable. When set to 1, the oscillator is disabled. When set to 0, the oscillator is enabled. Disabling the oscillator saves battery/capacitor power during storage. Determines if the calibration adjustment is applied as an addition (1) to or as a subtraction (0) from the time-base. These five bits control the calibration of the clock. Document #: 001-52039 Rev. ** Page 18 of 23 [+] Feedback STK17TA8 Register Map Detail (continued) 0x1FFF7 WDS WDW WDT 0x1FFF6 WIE AIE PFIE 0 H/L P/L 0x1FFF5 M 0x1FFF4 M 0x1FFF4 M Watchdog Timer D7 D6 D5 D4 D3 D2 D1 D0 WDS WDW WDT Watchdog Strobe. Setting this bit to 1 reloads and restarts the watchdog timer. The bit is cleared automatically once the watchdog timer is reset. The WDS bit is write only. Reading it always will return a 0. Watchdog Write Enable. Set this bit to 1 to disable writing of the watchdog time-out value (WDT5-WDT0). This allows the user to strobe the watchdog stobe bit without disturbing the time-out value. Set this bit to 0 to allow bits 5-0 to be written. Watchdog time-out selection. The watchdog timer interval is selected by the 6-bit value in this register. It represents a multiplier of the 32 Hz count (31.25 ms). The range of time-out values is 31.25 ms (a setting of 1) to 2 seconds (setting of 3Fh). Setting the watchdog timer register to 0 disables the timer. These bits can be written only if the WDW bit was cleared to 0 on a previous cycle. Interrupt D7 D6 D5 D4 D3 D2 D1 D0 WIE AIE PFIE ABE H/L P/L 0 0 Watchdog Interrupt Enable. When set to 1 and a watchdog time-out occurs, the watchdog timer drives the INT pin as well as setting the WDF flag. When set to 0, the watchdog time-out only sets the WDF flag. Alarm Interrupt Enable. When set to 1, the alarm match drives the INT pin as well as setting the AF flag. When set to 0, the alarm match only affects the AF flag. Power-Fail Enable. When set to 1, a power failure drives the INT pin as well as setting the PF flag. When set to 0, the power failure only sets the PF flag. Reserved For Future Used High/Low. When set to a 1, the INT pin is driven active high. When set to 0, the INT pin is open drain, active low. Pulse/Level. When set to a 1, the INT pin is driven active (determined by H/L) by an interrupt source for approximately 200 ms. When set to a 0, the INT pin is driven to an active level (as set by H/L) until the Flags register is read. Alarm – Day D7 D6 D5 D4 D3 D2 D1 D0 M 0 10s Alarm Date Alarm Date Contains the alarm value for the date of the month and the mask bit to select or deselect the date value. Match. Setting this bit to 0 causes the date value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the date value. Alarm – Hours D7 D6 D5 D4 D3 D2 D1 D0 M 0 10s Alarm Hours Alarm Hours Contains the alarm value for the hours and the mask bit to select or deselect the hours value. Match. Setting this bit to 0 causes the hours value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the hours value. Alarm – Hours D7 D6 D5 D4 D3 D2 D1 D0 M 0 10s Alarm Hours Alarm Hours Contains the alarm value for the hours and the mask bit to select or deselect the hours value. Match. Setting this bit to 0 causes the hours value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the hours value. Document #: 001-52039 Rev. ** Page 19 of 23 [+] Feedback STK17TA8 Register Map Detail (continued) 0x1FFF2 M 0x1FFF1 0x1FFF0 WDF AF PF OSCF CAL W R Alarm – Seconds D7 D6 D5 D4 D3 D2 D1 D0 M 10s Alarm Seconds Alarm Seconds Contains the alarm value for the seconds and the mask bit to select or deselect the seconds’ value. Match. Setting this bit to 0 causes the seconds’ value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the seconds value. Real Time Clock – Centuries D7 D6 D5 D4 D3 D2 D1 D0 10s Centuries Centuries Contains the BCD value of centuries. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble contains the upper digit and operates from 0 to 9. The range for the register is 0-99 centuries. Flags D7 D6 D5 D4 D3 D2 D1 D0 WDF AF PF OSCF 0 CAL W R Watchdog Timer Flag. This read-only bit is set to 1 when the watchdog timer is allowed to reach 0 without being reset by the user. It is cleared to 0 when the Flags register is read or on power-up. Alarm Flag. This read-only bit is set to 1 when the time and date match the values stored in the alarm registers with the match bits = 0. It is cleared when the Flags register is read or on power-up. Power-fail Flag. This read-only bit is set to 1 when power falls below the power-fail threshold VSWITCH. It is cleared to 0 when the Flags register is read or on power-up. Oscillator Fail Flag. Set to 1 on power-up only if the oscillator is enabled and not running in the first 5ms of operation. This indicates that RTC backup power failed and clock value is no longer valid. The user must reset this bit to 0 to clear this condition. Calibration Mode. When set to 1, a 512Hz square wave is output on the INT pin. When set to 0, the INT pin resumes normal operation. This bit defaults to 0 (disabled) on power up. Write Enable. Setting the W bit to 1 freezes updates of the RTC registers and enables writes to RTC registers, Alarm registers, Calibration register, Interrupt register and Flags register. Setting the W bit to 0 causes the contents of the RTC registers to be transferred to the timekeeping counters if the time has been changed (a new base time is loaded). This bit defaults to 0 on power up. Read Time. Set R to 1 to captures the current time in holding registers so that clock updates are not seen during the reading process. Set R to 0 to enable the holding register to resume clock updates. This bit defaults to 0 on power up. Document #: 001-52039 Rev. ** Page 20 of 23 [+] Feedback STK17TA8 Ordering Information STK17TA8-R F 45 ITR Packing Option Blank=Tube TR=Tape and Reel Temperature Range Blank=Commercial (0 to +70 C) I= Industrial (-45 to +85 C) Access Time 25=25 ns 45=45 ns Lead Finish F=100% Sn (Matte Tin) RoHS Compliant Package R=Plastic 48-pin 300 mil SSOP (25 mil pitch) Ordering Codes Ordering Code Description Access Times (ns) Temperature STK17TA8-RF25 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 25 Commercial STK17TA8-RF45 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 45 Commercial STK17TA8-RF25TR 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 25 Commercial STK17TA8-RF45TR 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 45 Commercial STK17TA8-RF25I 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 25 Industrial STK17TA8-RF45I 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 45 Industrial STK17TA8-RF25ITR 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 25 Industrial STK17TA8-RF45ITR 3V 128Kx8 AutoStore nvSRAM+RTC SSOP48-300 45 Industrial Document #: 001-52039 Rev. ** Page 21 of 23 [+] Feedback STK17TA8 Package Diagrams Figure 17. 48-Pin SSOP (51-85061) 51-85061 *C Document #: 001-52039 Rev. ** Page 22 of 23 [+] Feedback STK17TA8 Document History Page Document Title: STK17TA8 128k X 8 AutoStore™ nvSRAM with Real Time Clock Document Number: 001-52039 Orig. of Submission Rev. ECN No. Description of Change Change Date ** 2668660 GVCH/PYRS 03/04/2009 New Data Sheet Sales, Solutions, and Legal Information Worldwide Sales and Design Support Cypress maintains a worldwide network of offices, solution centers, manufacturer’s representatives, and distributors. To find the office closest to you, visit us at cypress.com/sales. Products PSoC Clocks & Buffers PSoC Solutions psoc.cypress.com clocks.cypress.com General Low Power/Low Voltage psoc.cypress.com/solutions psoc.cypress.com/low-power Wireless wireless.cypress.com Precision Analog Memories memory.cypress.com LCD Drive psoc.cypress.com/lcd-drive image.cypress.com CAN 2.0b psoc.cypress.com/can USB psoc.cypress.com/usb Image Sensors psoc.cypress.com/precision-analog © Cypress Semiconductor Corporation, 2009. The information contained herein is subject to change without notice. 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Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. Document #: 001-52039 Rev. ** Revised March 02, 2009 Page 23 of 23 AutoStore and QuantumTrap are registered trademarks of Cypress Semiconductor Corporation. All products and company names mentioned in this document are the trademarks of their respective holders. [+] Feedback