M41ST95Y* M41ST95W
5.0 or 3.0V, 512 bit (64 bit x8) Serial RTC (SPI) SRAM and NVRAM Supervisor
FEATURES SUMMARY
5.0 OR 3.0V OPERATING VOLTAGE SERIAL PERIPHERAL INTERFACE (SPI) N VRAM SUPERVISOR FOR EXTERNAL LPSRAM 2.5 TO 5.5V OSCILLATOR OPERATING VOLTAGE AUTOMATIC SWITCH-OVER AND DESELECT CIRCUITRY C HOICE OF POWER-FAIL DESELECT VOLTAGES: M41ST95Y*: VCC = 4.5 to 5.5V 4.20V VPFD 4.50V M41ST95W: VCC = 2.7 to 3.6V 2.55V VPFD 24.70V 1.25V REFERENCE (FOR PFI/PFO) C OUNTERS FOR TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES, HOURS, DAY, DATE, MONTH, YEAR, AND CENTURY 44 BYTES OF GENERAL PURPOSE RAM PROGRAMMABLE ALARM and INTERRUPT FUNCTION (VALID EVEN DURING BATTERY BACK-UP MODE) W ATCHDOG TIMER MICROPROCESSOR POWER-ON RESET BATTERY LOW FLAG 32kHz FREQUENCY OUTPUT AVAILABLE IMMEDIATELY UPON POWER-ON (300mil SO28 MX PACKAGE ONLY) AUTOMATICALLY RECORDS TIME WHEN POWER-FAIL OCCURS U LTRA-LOW BATTERY SUPPLY CURRENT OF 550nA (MAX) PACKAGING INCLUDES A 28-LEAD SOIC and SNAPHAT TOP (to be ordered separately) SOIC PACKAGE PROVIDES DIRECT CONNECTION FOR A SNAPHAT TOP WHICH CONTAINS THE BATTERY and CRYSTAL
Figure 1. 28-pin SOIC Package*
SNAPHAT (SH) Battery & Crystal
28 1
SOH28 (MH)
Figure 2. 28-pin (300mil) SOIC Package
Embedded Crystal
SOX28 (MX)
* Contact Local Sales Office
September 2004 1/35
M41ST95Y*, M41ST95W
TABLE OF CONTENTS
FEATUR ES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Figure 1. 28-pin SOIC Package*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Figure 2. 28-pin (300mil) SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 3. Table 1. Figure 4. Figure 5. Figure 6. Figure 7. Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-pin SOIC Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-pin, 300mil SOIC (MX) Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hardware Hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. . . .. . . .. . . .. . . .. . . .5 . . .5 . . .6 . . .6 . . .7 . . .8
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 SPI Bus Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Signal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Table 2. Function Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 8. Data and Clock Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 9. Input Timing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 10.Output Timing Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 11.WRITE Cycle Timing: RTC and External SRAM Control Signals . . . . . . . . . . . . . . . . . . 11 Table 3. AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 R EAD and WRITE Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 12.READ Mode Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 13.WRITE Mode Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 D ata Retention Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 CLOCK OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Power-down Time-Stamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 TIMEKEEPER Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 4. TIMEKEEPER Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 C alibrating the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Setting Alarm Clock Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 14.Alarm Interrupt Reset Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 5. Alarm Repeat Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 15.Back-up Mode Alarm Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 W atchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Square Wave Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Table 6. Square Wave Output Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Full-time F32k Square Wave Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 (Available only in 28-pin, 300mil SOIC (MX) package). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 R eset Input (RSTIN1 and RSTIN2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Figure 16.RSTIN1 and RSTIN2 Timing Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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Table 7. Reset AC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Power-fail INPUT/OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Figure 17.Power-Fail Comparator Hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 C entury Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Output Driver Pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 B attery Low Warning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 tREC Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Preferred Power-on Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 8. tREC Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 9. Default Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Figure 18.Crystal Accuracy Across Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Figure 19.Calibration Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 MAXIMU M RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Table 10. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Table 11. DC and AC Measurement Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 20.AC Testing Input/Output Waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Table 12. Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Table 13. DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 21.Power Down/Up Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Table 14. Power Down/Up AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 PAC KAGE MECHANICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Figure 22.SOH28 28-lead Plastic Small Outline, Battery SNAPHAT, Package Outline . . . . . . . . 29 Table 15. SOH28 28-lead Plastic Small Outline, battery SNAPHAT, Package Mechanical Data 29 Figure 23.SH 4-pin SNAPHAT Housing for 48mAh Battery & Crystal, Package Outline . . . . . . . 30 Table 16. SH 4-pin SNAPHAT Housing for 48mAh Battery & Crystal, Package Mechanical Data30 Figure 24.SH 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Outline . . . . . . 31 Table 17. SH 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Mech. Data. . . 31 Figure 25.SOX28 28-lead Plastic Small Outline, 300mils, Embedded Crystal, Outline . . . . . . . . 32 Table 18. SOX28 28-lead Plastic Small, 300mils, Embedded Crystal, Package Mech. Data . . . 32 PAR T NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Table 19. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Table 20. SNAPHAT Battery Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 REVISION HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Table 21. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
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M41ST95Y*, M41ST95W
SUMMARY DESCRIPTION
The M41ST95Y/W Serial TIMEKEEPER SRAM is a low power, 512-bit static CMOS SRAM organized as 64 words by 8 bits. A built-in 32,768Hz oscillator (external crystal controlled) and 8 bytes of the SRAM (see Table 4., page 16) are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. An additional 12 bytes of RAM provide status/control of Alarm, Watchdog and Square Wave functions. Addresses and data are transferred serially via a serial SPI interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41ST95Y/W has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the SRAM and clock operations can be supplied by a small lithium buttoncell supply when a power failure occurs. Functions available to the user include a non-volatile, timeof-day clock/calendar, Alarm interrupts, Watchdog Timer and programmable Square Wave output. Other features include a Power-On Reset as well as two additional debounced inputs (RSTIN1 and RSTIN2) which can also generate an output Reset (RST). The eight clock address locations contain the century, year, month, date, day, hour, minute, second and tenths/hundredths of a second in 24 hour BCD format. Corrections for 28, 29 (leap year - valid until year 2100), 30 and 31 day months are made automatically. The M41ST95Y/W is supplied in a 28-lead SOIC SNAPHAT (MH) package (which integrates both crystal and battery in a single SNAPHAT top), or a 28-pin, 300mil SOIC package (MX) which includes an embedded 32kHz crystal. The 28-pin, 330mil SOIC provides sockets with gold plated contacts at both ends for direct connection to a separate SNAPHAT housing containing the battery and crystal. The unique design allow s the SNAPHAT battery/crystal package to be mounted on top of the SOIC package after the completion of the surface mount process. Insertion of the SNAPHAT housing after reflow prevents potential battery and crystal damage due to the high temperatures required for device surface-mounting. The SNAPHAT housing is also keyed to prevent reverse insertion. The SNAPHAT SOIC and battery/crystal packages are shipped separately in plastic anti-static tubes or in Tape & Reel form. For the 28-lead SOIC, the battery/crystal package (e.g., SNAPHAT) part number is "M4TXX-BR12SH" (see Table 20. , page 33) . Caution: Do not place the SNAPHAT battery/crystal top in conductive foam, as this will drain the lithium button-cell battery. The 300mil, embedded crystal SOIC requires only a user-supplied battery to provide non-volatile operation.
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Figure 3. Logic Diagram Table 1. Signal Names
ECON EX E IRQ/FT/OUT RST Conditioned Chip Enable Output External Chip Enable Chip Enable Interrupt/Frequency Test/Out Output (Open Drain) Reset Output (Open Drain) Reset 1 Input Reset 2 Input Serial Clock Input Serial Data Input Serial Data Output Square Wave Output 32kHz Square Wave Output Watchdog Input Power-Fail Input Power-Fail Output Voltage Output Battery Supply Voltage Supply Voltage Ground No Connect No Function
VCC VBAT(1)
RSTIN1 RSTIN2
E SCL SDI EX RSTIN1 RSTIN2 WDI PFI M41ST95Y/W
ECON RST(2) IRQ/FT/OUT SQW SDO PFO VOUT F32k(3)
(2)
S CL S DI S DO SQW F32k(2) W DI P FI P FO
VSS
VOUT
AI06369
VBAT(1) V CC VSS NC NF
Note: 1. For SOX28 package only. 2. Open drain 3. Available only in 28-pin, 300mil SOIC (MX) package.
Note: 1. For SOX28 package only. 2. Available only in 28-pin, 300mil SOIC (MX) package.
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Figure 4. 28-pin SOIC Connections
SQW NC NC NC NC NC NC WDI RSTIN1 RSTIN2 NC NC PFO VSS 28 1 2 27 3 26 4 25 5 24 6 23 7 M41ST95Y 22 8 M41ST95W 21 9 20 10 19 11 18 12 17 13 16 14 15 VCC E IRQ/FT/OUT VOUT NC NC PFI NC SCL EX RST SDI SDO ECON
AI06370
Figure 5. 28-pin, 300mil SOIC (MX) Connections
NF(1) NF(1) NF(1) (1) NF NC NC NC SQW WDI RSTIN1 RSTIN2 PFO NC VSS 28 1 2 27 3 26 4 25 5 24 6 23 7 M41ST95Y 22 8 M41ST95W 21 9 20 10 19 11 18 12 17 13 16 14 15 VCC E IRQ/FT/OUT VOUT NC PFI SCL F32k EX RST SDI SDO ECON VBAT
AI06370b
Note: 1. No Function (NF) pins (1, 2, 3, and 4) pins must be tied to VSS, and are internally shorted together.
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Figure 6. Block Diagram
REAL TIME CLOCK CALENDAR E SDO SDI SCL SPI INTERFACE 44 BYTES USER RAM RTC w/ALARM & CALIBRATION OUTPUT DRIVER FREQUENCY TEST 32kHz OSCILLATOR WATCHDOG SQUARE WAVE AFE OUT FT WDS IRQ/FT/OUT
(1)
Crystal
SQW F32k VOUT
(2)
WDI VCC
VBAT VBL COMPARE BL
VSO
COMPARE
VPFD RSTIN1 RSTIN2
COMPARE
POR RST(1)
EX PFI COMPARE 1.25V (Internal)
ECON
PFO
AI06371
Note: 1. Open Drain Output 2. Available only in 28-pin, 300mil SOIC (MX) package.
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Figure 7. Hardware Hookup
SPI Interface with (CPOL, CPHA)(1) = ('0','0') or ('1','1')
D Q C
Master (ST6, ST7, ST9, ST10, Others) CS3 CS2 CS1
C
Q
D
C
Q XXXXX
D
C
Q XXXXX
D
M41ST95Y/W E E
E
AI06372
Note: 1. CPOL (Clock Polarity) and CPHA (Clock Phase) are bits that may be set in the SPI Control Register of the MCU.
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OPERATION
The M41ST95Y/W clock operates as a slave device on the SPI serial bus. Each memory device is accessed by a simple serial interface that is SPI bus compatible. The bus signals are SCL, SDI and SDO (see Table 1., page 5 and Figure 7., page 8). The device is selected when the Chip Enable input (E) is held low. All instructions, addresses and data are shifted serially in and out of the chip. The most significant bit is presented first, with the data input (SDI) sampled on the first rising edge of the clock (SCL) after the Chip Enable (E) goes low. The 64 bytes contained in the device can then be accessed sequentially in the following order: 1. Tenths/Hundredths of a Second Register 2. Seconds Register 3. Minutes Register 4. C entury/Hours Register 5. D ay Register 6. D ate Register 7. Month Register 8. Year Register 9. C ontrol Register 10. W atchdog Register 11 - 16.Alarm Registers 17 - 19.Reserved 20. Square Wave Register 21 - 64.User RAM The M41ST95Y/W clock continually monitors VCC for an out-of tolerance condition. Should VCC fall below VPFD, the device terminates an access in progress and resets the device address counter. Inputs to the device will not be recognized at this time to prevent erroneous data from being written to the device from a an out-of-tolerance system. When VCC falls below VSO, the device automatically switches over to the battery and powers down into an ultra low current mode of operation to conserve battery life. As system power returns and VCC rises above VSO , the battery is disconnected, and the power supply is switched to external VCC. Write protection continues until VCC reaches VPFD (min) plus tREC (min). For more information on Battery Storage Life refer to Application Note AN1012. SPI Bus Characteristics The Serial Peripheral interface (SPI) bus is intended for synchronous communication between different ICs. It consists of four signal lines: Serial Data Input (SDI), Serial Data Output (SDO), Serial Clock (SCL) and a Chip Enable (E). By definition a device that gives out a message is called "transmitter," the receiving device that gets the message is called "receiver." The device that controls the message is called "master." The devices that are controlled by the master are called "slaves." The E input is used to initiate and terminate a data transfer. The SCL input is used to synchronize data transfer between the master (micro) and the slave (M41ST95Y/W) devices. The SCL input, which is generated by the microcontroller, is active only during address and data transfer to any device on the SPI bus (see Figure 7., page 8). The M41ST95Y/W can be driven by a microcontroller with its SPI peripheral running in either of the two following modes: (CPOL, CPHA) = ('0', '0') or (CPOL, CPHA) = ('1', '1'). For these two modes, input data (SDI) is latched in by the low-to-high transition of clock SCL, and output data (SDO) is shifted out on the high-to-low transition of SCL (see Table 2., page 10 and Figure 8., page 10). There is one clock for each bit transferred. Address and data bits are transferred in groups of eight bits. Due to memory size the second most significant address bit is a Don't Care (address bit 6).
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Signal Description Serial Data Output (SDO). The output pin is used to transfer data serially out of the Memory. Data is shifted out on the falling edge of the serial clock. Serial Data Input (SDI). The input pin is used to transfer data serially into the device. Instructions, addresses, and the data to be written, are each received this way. Input is latched on the rising edge of the serial clock. Serial Clock (SCL). The serial clock provides the timing for the serial interface (as shown in Figure 9., page 11 and Figure 10., page 11). The W/R Bit, addresses, or data are latched, from the input pin, on the rising edge of the clock input. The output data on the SDO pin changes state after the falling edge of the clock input. Table 2. Function Table
Mo de Disable Reset E H SCL Input Disabled SDI Input Disabled SDO High Z
The M41ST95Y/W can be driven by a microcontroller with its SPI peripheral running in either of the two following modes: (CPOL, CPHA) = ('0', '0') or (CPOL, CPHA) = ('1', '1'). For these two modes, input data (SDI) is latched in by the low-to-high transition of clock SCL, and output data (SDO) is shifted out on the high-to-low transition of SCL (see Table 2 and Figure 8). Chip Enable (E). When E is high, the memory device is deselected, and the SDO output pin is held in its high impedance state. After power-on, a high-to-low transition on E is required prior to the start of any operation.
WRITE
L
AI04630
Data Bit latch
High Z
READ
L
AI04631
X
Next data bit shift (1)
Note: 1. SDO remains at High Z until eight bits of data are ready to be shifted out during a READ.
Figure 8. Data and Clock Timing
CPOL CPHA
0
0
SCL
1
1
SCL
SDI
MSB
LSB
SDO
MSB
LSB
AI06368
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Figure 9. Input Timing Requirements
tEHEL E tELCH SCL tDVCH tCHDX SDI MSB IN tDLDH tDHDL tCLCH LSB IN tCHCL tCHEH tEHCH
SDO
HIGH IMPEDANCE
AI04633
Figure 10. Output Timing Requirements
E tCH SCL tCLQV tCLQX SDO
MSB OUT
tCL
tEHQZ
LSB OUT tQLQH tQHQL
SDI
ADDR. LSB IN AI04634
Figure 11. WRITE Cycle Timing: RTC and External SRAM Control Signals
EX tEXPD tEXPD ECON
AI03663
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M41ST95Y*, M41ST95W
Table 3. AC Characteristics
Symbol fSCL tCH(2) tCHCL(3) tCHDX tCHEH tCL(2) tCLCH(3) tCLQV tCLQX tDHDL(3) tDLDH(3) tDVCH tEHCH tEHEL tEHQZ(3) tELCH tQHQL(3) tQLQH(3) tEXPD Parameter(1) Serial Clock Input Frequency Clock High Clock Transition (Fall Time) Serial Clock Input High to Input Data Transition Serial Clock Input High to Chip Enable High Clock Low Clock Transition (Rise Time) Serial Clock Input Low to Output Valid Serial Clock Input Low to Output Data Transition Input Data Transition (Fall Time) Input Data Transition (Rise Time) Input Data to Serial Clock Input High Chip Enable High to Serial Clock Input High Chip Enable High to Chip Enable Low Chip Enable High to Output High-Z Chip Enable Low to Serial Clock Input High Output Data Transition (Fall Time) Output Data Transition (Rise Time) M41ST95Y EX to ECON Propagation Delay M41ST95W 15 ns 200 100 100 10 40 200 200 250 0 1 1 50 200 200 1 150 Min DC 200 1 Max 2 Unit MHz ns s ns ns ns s ns ns s s ns ns ns ns ns ns ns ns
Note: 1. Valid for Ambient Operating Temperature: TA = 40 to 85C; VCC = 4.5 to 5.5V or 2.7 to 3.6V (except where noted). 2. tCH + tCL 1/fSCL 3. Value guaranteed by design, not 100% tested in production.
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M41ST95Y*, M41ST95W
REA D and WRITE Cycles Address and data are shifted MSB first into the Serial Data Input (SDI) and out of the Serial Data Output (SDO). Any data transfer considers the first bit to define whether a READ or WRITE will occur. This is followed by seven bits defining the address to be read or written. Data is transferred out of the SDO for a READ operation and into the SDI for a WRITE operation. The address is always the second through the eighth bit written after the Enable (E) pin goes low. If the first bit is a '1,' one or more WRITE cycles will occur. If the first bit is a '0,' one or more READ cycles will occur (see Figure 12 and Figure 13., page 14). Data transfers can occur one byte at a time or in multiple byte burst mode, during which the address pointer will be automatically incremented. For a single byte transfer, one byte is read or written and then E is driven high. For a multiple byte transfer all that is required is that E continue to remain low. Under this condition, the address pointer will continue to increment as stated previously. Incrementing will continue until the device is deselected by taking E high. The address will wrap to 00h after incrementing to 3Fh. Figure 12. READ Mode Sequence
E 0 SCL W/R BIT 7 BIT ADDRESS 1 2 3 4 5 6 7 8 9 12 13 14 15 16 17 22
The system-to-user transfer of clock data will be halted whenever the address being read is a clock address (00h to 07h). Although the clock continues to maintain the correct time, this will prevent updates of time and date during either a READ or WRITE of these address locations by the user. The update will resume either due to a deselect condition or when the pointer increments to an non-clock or RAM address (08h to 3Fh). Note: This is true both in READ and WRITE mode.
SDI
7 MSB
6
5
4
3
2
1
0 DATA OUT (BYTE 1) 7 MSB 6 5 4 3 2 1 0 7 MSB
AI04635
DATA OUT (BYTE 2) 6 5 4 3 2 1 0
SDO
HIGH IMPEDANCE
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M41ST95Y*, M41ST95W
Figure 13. WRITE Mode Sequence
E 0 SCL 1 2 3 4 5 6 7 8 9 10 15
W/R BIT
7 BIT ADDR
DATA BYTE
SDI
7 MSB
6
5
4
3
2
1
0
7 MSB
6
5
4
3
2
1
0
7
SDO HIGH IMPEDANCE
AI04636
Data Retention Mode With valid VCC applied, the M41ST95Y/W can be accessed as described above with READ or WRITE Cycles. Should the supply voltage decay, the M41ST95Y/W will automatically deselect, write protecting itself (and any external SRAM) when VCC falls between VPFD(max) and VPFD(min). This is accomplished by internally inhibiting access to the clock registers. At this time, the Reset pin (RST) is driven active and will remain active until VCC returns to nominal levels. External RAM access is inhibited in a similar manner by forcing ECON to a high level. This level is within 0.2 volts of the VBAT. ECON will remain at this level as long as VCC remains at an out-of-tolerance condition. When VCC falls below the Battery Back-up Switchover Voltage (VSO), power input is switched from the VCC pin to the SNAPHAT battery, and the clock registers and external SRAM are maintained from the attached battery supply. All outputs become high impedance. The VOUT pin is capable of supplying 100 A of current to the attached memory with less than 0.3 volts drop under this condition. On power up, when VCC returns to a nominal value, write protection continues for tREC by inhibiting ECON. The RST signal also remains active during this time (see Figure 21. , page 28) . Note: Most low power SRAMs on the market today can be used with the M41ST95Y/W RTC SUPERVISOR. There are, however some criteria which should be used in making the final choice of an SRAM to use.
The SRAM must be designed in a way where the chip enable input disables all other inputs to the SRAM. This allows inputs to the M41ST95Y/W and SRAMs to be "Don't Care" once VCC falls below VPFD(min). The SRAM should also guarantee data retention down to VCC = 2.0 volts. The chip enable access time must be sufficient to meet the system needs with the chip enable output propagation delays included. If the SRAM includes a second chip enable pin (E2), this pin should be tied to VOUT. If data retention lifetime is a critical parameter for the system, it is important to review the data retention current specifications for the particular SRAMs being evaluated. Most SRAMs specify a data retention current at 3.0 volts. Manufacturers generally specify a typical condition for room temperature along with a worst case condition (generally at elevated temperatures). The system level requirements will determine the choice of which value to use. The data retention current value of the SRAMs can then be added to the IBAT value of the M41ST95Y/W to determine the total current requirements for data retention. The available battery capacity for the SNAPHAT of your choice can then be divided by this current to determine the amount of data retention available (see 20). For a further more detailed review of lifetime calculations, please see Application Note AN1012.
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M41ST95Y*, M41ST95W
CLOCK OPERATION
The eight byte clock register (see Table 4., page 16) is used to both set the clock and to read the date and time from the clock, in a binary coded decimal format. Tenths/Hundredths of Seconds, Seconds, Minutes, and Hours are contained within the first four registers. Note: The Tenths/Hundredths of Seconds cannot be written to any value other than "00." Bits D6 and D7 of Clock Register 03h (Century/ Hours Register) contain the CENTURY ENABLE Bit (CEB) and the CENTURY Bit (CB). Setting CEB to a '1' will cause CB to toggle, either from '0' to '1' or from '1' to '0' at the turn of the century (depending upon its initial state). If CEB is set to a '0,' CB will not toggle. Bits D0 through D2 of Register 04h contain the Day (day of week). Registers 05h, 06h, and 07h contain the Date (day of month), Month and Years. The ninth clock register is the Control Register (this is described in the Clock Calibration section). Bit D7 of Register 01h contains the STOP Bit (ST). Setting this bit to a '1' will cause the oscillator to stop. If the device is expected to spend a significant amount of time on the shelf, the oscillator may be stopped to reduce current drain. When reset to a '0' the oscillator restarts within one second. The eight Clock Registers may be read one byte at a time, or in a sequential block. The Control Register (Address location 08h) may be accessed independently. Provision has been made to assure that a clock update does not occur while any of the eight clock addresses are being read. If a clock address is being read, an update of the clock registers will be halted. This will prevent a transition of data during the READ. Power-down Time-Stamp When a power failure occurs, the Halt Update Bit (HT) will automatically be set to a '1.' This will prevent the clock from updating the clock registers, and will allow the user to read the exact time of the power-down event. Resetting the HT Bit to a '0' will allow the clock to update the clock registers with the current time. TIMEKEEPER Registers The M41ST95Y/W offers 20 internal registers which contain Clock, Alarm, Watchdog, Flag, Square Wave and Control data (see Table 4., page 16). These registers are memory locations which contain external (user accessible) and internal copies of the data (usually referred to as BiPORTTM TIMEKEEPER cells). The external copies are independent of internal functions except that they are updated periodically by the simultaneous transfer of the incremented internal copy. The internal divider (or clock) chain will be reset upon the completion of a WRITE to any clock address. The system-to-user transfer of clock data will be halted whenever the clock addresses (00h to 07h) are being written. The update will resume either due to a deselect condition or when the pointer increments to a non-clock or RAM address. TIMEKEEPER and Alarm Registers store data in BCD . Control, Watchdog and Square Wave Registers store data in Binary format.
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Table 4. TIMEKEEPER Register Map
A ddr D7 00h 01h 02h 03h 04h 05h 06h 07h 08h 09h 0Ah 0Bh 0 Ch 0 Dh 0Eh 0 Fh 10h 11h 12h 13h OUT WDS AFE RPT4 RPT3 RPT2 RPT1 W DF 0 0 0 RS3 ST 0 CEB TR 0 0 CB 0 0 0 0 D6 D5 D4 D3 D2 D1 D0 Function/Range BCD Format 10ths/100ths of Seconds Seconds Minutes Century/Hours Day Date Month Year Control RB1 RB 0 Watchdog Al Month Al Date Al Hour Al Min Al Sec 0 0 0 0 0 Flags Reser ved Reser ved Reser ved SQW 01-12 01-31 00-23 00-59 00-59 00-99 00-59 00-59 0-1/00-23 01-7 01-31 01-12 00-99
0.1 Seconds 10 Seconds 10 Minutes 10 Hours 0 10 Date 10M 0 0
0.01 Seconds Seconds Minutes Hours (24 Hour Format) Day of Week Date: Day of Month Month Year Calibration BMB2 Al 10M BMB1 BMB0
10 Years FT BMB4 SQWE RPT5 HT S BMB3 ABE
Alarm Month Alarm Date Alarm Hour Alarm Minutes Alarm Seconds 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
AI 10 Date AI 10 Hour
Alarm 10 Minutes Alarm 10 Seconds AF 0 0 0 RS2 0 0 0 0 RS1 BL 0 0 0 RS0
Keys: S = Sign Bit FT = Frequency Test Bit ST = Stop Bit 0 = Must be set to '0' BL = Battery Low Flag (Read only) BMB0-BMB4 = Watchdog Multiplier Bits CEB = Century Enable Bit CB = Century Bit OUT = Output level AFE = Alarm Flag Enable Flag
RB0-RB1 = Watchdog Resolution Bits WDS = Watchdog Steering Bit ABE = Alarm in Battery Back-Up Mode Enable Bit RPT1-RPT5 = Alarm Repeat Mode Bits WDF = Watchdog flag (Read only) AF = Alarm flag (Read only) SQWE = Square Wave Enable RS0-RS3 = SQW Frequency HT = Halt Update Bit TR = tREC Bit
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M41ST95Y*, M41ST95W
Calibrating the Clock The M41ST95Y/W is driven by a quartz-controlled oscillator with a nominal frequency of 32,768Hz. Uncalibrated clock accuracy will not exceed 35 ppm (parts per million) oscillator frequency error at 25C, which equates to about 1.53 minutes per month. When the Calibration circuit is properly employed, accuracy improves to better than 2 ppm at 25C. The oscillation rate of crystals changes with temperature (see Figure 18., page 24). Therefore, the M41ST95Y/W design employs periodic counter correction. The calibration circuit adds or subtracts counts from the oscillator divider circuit at the divide by 256 stage, as shown in Figure 19., page 24. The number of times pulses are blanked (subtracted, negative calibration) or split (added, positive calibration) depends upon the value loaded into the five Calibration Bits found in the Control Register. Adding counts speeds the clock up, subtracting counts slows the clock down. The Calibration Bits occupy the five lower order bits (D4-D0) in the Control Register (8h). These bits can be set to represent any value between 0 and 31 in binary form. Bit D5 is a Sign Bit; '1' indicates positive calibration, '0' indicates negative calibration. Calibration occurs within a 64 minute cycle. 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 in the 64 minute cycle will be 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. Assuming that the oscillator is running at exactly 32,768Hz, each of the 31 increments in the Calibration byte would represent +10.7 or 5.35 seconds per month which corresponds to a total range of +5.5 or 2.75 minutes per month. Two methods are available for ascertaining how much calibration a given M41ST95Y/W may require. The first involves setting the clock, letting it run for a month and comparing it to a known accurate reference and recording deviation over a fixed period of time. Calibration values, including the number of seconds lost or gained in a given period, can be found in Application Note AN934: TIMEKEEPER CALIBRATION. This allows the designer to give the end user the ability to calibrate the clock as the environment requires, even if the final product is packaged in a non-user serviceable enclosure.
The designer could provide a simple utility that accesses the Calibration Byte. The second approach is better suited to a manufacturing environment, and involves the use of the IRQ/FT/OUT pin. The pin will toggle at 512Hz, when the Stop Bit (ST, D7 of 1h) is '0,' the Frequency Test Bit (FT, D6 of 8h) is '1,' the Alarm Flag Enable Bit (AFE, D7 of Ah) is '0,' and the Watchdog Steering Bit (WDS, D7 of 9h) is '1' or the Watchdog Register (9h = 0) is reset. Any deviation from 512Hz indicates the degree and direction of oscillator frequency shift at the test temperature. For example, a reading of 512.010124Hz would indicate a +20 ppm oscillator frequency error, requiring a 10 (XX001010) to be loaded into the Calibration Byte for correction. Note: Setting or changing the Calibration Byte does not affect the Frequency Test output frequenc y . The IRQ/FT/OUT pin is an open drain output which requires a pull-up resistor for proper operation. A 500 to 10k resistor is recommended in order to control the rise time. The FT Bit is cleared on power-down. Setting Alarm Clock Registers Address locations 0Ah-0Eh contain the alarm settings. The alarm can be configured to go off at a prescribed time on a specific month, date, hour, minute, or second, or repeat every year, month, day, hour, minute, or second. It can also be programmed to go off while the M41ST95Y/W is in the battery back-up to serve as a system wake-up call. Bits RPT5-RPT1 put the alarm in the repeat mode of operation. Table 5., page 18 shows the possible configurations. Codes not listed in the table default to the once per second mode to quickly alert the user of an incorrect alarm setting. When the clock information matches the alarm clock settings based on the match criteria defined by RPT5-RPT1, the AF (Alarm Flag) is set. If AFE (Alarm Flag Enable) is also set, the alarm condition activates the IRQ/FT/OUT pin. Note: If the address pointer is allowed to increment to the Flag Register address, an alarm condition will not cause the Interrupt/Flag to occur until the address pointer is moved to a different address. It should also be noted that if the last address written is the "Alarm Seconds," the address pointer will increment to the Flag address, causing this situation to occur.
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M41ST95Y*, M41ST95W
To disable the alarm, write '0' to the Alarm Date Register and to RPT1-5. The IRQ/FT/OUT output is cleared by a READ to the Flags Register as shown in Figure 14. A subsequent READ of the Flags Register is necessary to see that the value of the Alarm Flag has been reset to '0.' The IRQ/FT/OUT pin can also be activated in the battery back-up mode. The IRQ/FT/OUT will go low if an alarm occurs and both ABE (Alarm in Battery Back-up Mode Enable) and AFE are set. Figure 14. Alarm Interrupt Reset Waveform The ABE and AFE Bits are reset during power-up, therefore an alarm generated during power-up will only set AF. The user can read the Flag Register at system boot-up to determine if an alarm was generated while the M41ST95Y/W was in the deselect mode during power-up. Figure 15., page 19 illustrates the back-up mode alarm timing.
0Eh
0Fh
10h
ACTIVE FLAG
IRQ/FT/OUT
HIGH-Z
AI03664
Table 5. Alarm Repeat Mode
RPT5 1 1 1 1 1 0 RPT4 1 1 1 1 0 0 RPT3 1 1 1 0 0 0 RPT2 1 1 0 0 0 0 RPT1 1 0 0 0 0 0 Alarm Setting Once per Second Once per Minute Once per Hour Once per Day Once per Month Once per Year
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M41ST95Y*, M41ST95W
Figure 15. Back-up Mode Alarm Waveforms
VCC VPFD
VSO tREC ABE, AFE Bits in Interrupt Register
AF bit in Flags Register
IRQ/FT/OUT HIGH-Z HIGH-Z
AI03920
Watchdog Timer The watchdog timer can be used to detect an outof-control microprocessor. The user programs the watchdog timer by setting the desired amount of time-out into the Watchdog Register, address 09h. Bits BMB4-BMB0 store a binary multiplier and the two lower order bits RB1-RB0 select the resolution, where 00 = 1/16 second, 01 = 1/4 second, 10 = 1 second, and 11 = 4 seconds. The amount of time-out is then determined to be the multiplication of the five-bit multiplier value with the resolution. (For example: writing 00001110 in the Watchdog Register = 3*1 or 3 seconds). Note: Accuracy of timer is within the selected resolution. If the processor does not reset the timer within the specified period, the M41ST95Y/W sets the WDF (Watchdog Flag) and generates a watchdog interrupt or a microprocessor reset. WDF is reset by reading the Flags Register (0Fh). The most significant bit of the Watchdog Register is the Watchdog Steering Bit (WDS). When set to a '0,' the watchdog will activate the IRQ/FT/OUT pin when timed-out. When WDS is set to a '1,' the watchdog will output a negative pulse on the RST pin for tREC. The Watchdog register and the AFE, ABE, SQWE, and FT Bits will reset to a '0' at the end of a Watchdog time-out when the WDS Bit is set to a '1.'
The watchdog timer can be reset by two methods: 1. a transition (high-to-low or low-to-high) can be applied to the Watchdog Input pin (WDI), or 2. the microprocessor can perform a WRITE of the Watchdog Register. The time-out period then starts over. The WDI pin should be tied to VSS if not used. In order to perform a software reset of the watchdog timer, the original time-out period can be written into the Watchdog Register, effectively restarting the count-down cycle. Should the watchdog timer time-out, and the WDS Bit is programmed to output an interrupt, a value of 00h needs to be written to the Watchdog Register in order to clear the IRQ/FT/OUT pin. This will also disable the watchdog function until it is again programmed correctly. A READ of the Flags Register will reset the Watchdog Flag (Bit D7; Register 0Fh). The watchdog function is automatically disabled upon power-up and the Watchdog Register is cleared. If the watchdog function is set to output to the IRQ/FT/OUT pin and the Frequency Test (FT) function is activated, the watchdog function prevails and the Frequency Test function is denied.
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M41ST95Y*, M41ST95W
Square Wave Output The M41ST95Y/W offers the user a programmable square wave function which is output on the SQW pin. RS3-RS0 bits located in 13h establish the square wave output frequency. These frequencies are listed in Table 6. Once the selection Table 6. Square Wave Output Frequency
Square Wave Bits RS3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 RS 2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 RS1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 RS0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Square Wave Frequency None 32.768 8.192 4.096 2.048 1.024 512 256 128 64 32 16 8 4 2 1 Units kHz kHz kHz kHz kHz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz
of the SQW frequency has been completed, the SQW pin can be turned on and off under software control with the Square Wave Enable Bit (SQWE) located in Register 0Ah.
Full-time F32k Square Wave Output (Available only in 28-pin, 300mil SOIC (MX) package). and can only be disabled by setting the ST Bit to The M41ST95Y/W offers the user a special 32kHz '1,' or while the device is in back-up. If not used, square wave function which is always output on the F32k pin should be disconnected and allowed the F32k pin (Pin 21) as long as VCC VSO, and the oscillator is running (ST Bit = '0'). This function is to float. available within four seconds of initial power-up
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M41ST95Y*, M41ST95W
Power-on Reset The M41ST95Y/W continuously monitors VCC. When VCC falls to the power fail detect trip point, the RST pulls low (open drain) and remains low on power-up for tREC after VCC passes VPFD (max). The RST pin is an open drain output and an appropriate pull-up resistor should be chosen to control rise time. Reset Input (RSTIN1 and RSTIN2) The M41ST95Y/W provides two independent inputs which can generate an output reset. The duration and function of these resets is identical to a reset generated by a power cycle. Table 7 and Figure 16 illustrate the AC reset characteristics of this function. Pulses shorter than tRLRH1 and tRLRH2 will not generate a reset condition. RSTIN1 and RSTIN2 are each internally pulled up to VCC through a 100k resistor.
Figure 16. RSTIN1 and RSTIN2 Timing Waveforms
RSTIN1 tRLRH1 RSTIN2 tRLRH2 RST
(1)
tR1HRH
tR2HRH
AI03665
Note: 1. Open Drain Output
Table 7. Reset AC Characteristics
Symbol tRLRH1(2) tRLRH2(3) tR1HRH(4) tR2HRH(4,5)
Note: 1. 2. 3. 4. 5.
Parameter(1) RSTIN1 Low to RSTIN1 High RSTIN2 Low to RSTIN2 High RSTIN1 High to RST High RSTIN2 High to RST High
Min 200 100 96 96
Ma x
Unit ns ms
98 98
ms ms
Valid for Ambient Operating Temperature: TA = 40 to 85C; VCC = 4.5 to 5.5V or 2.7 to 3.6V (except where noted). Pulse width less than 50ns will result in no RESET (for noise immunity). Pulse width less than 20ms will result in no RESET (for noise immunity). Programmable (see Table 8., page 23) After crystal oscillator has started
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M41ST95Y*, M41ST95W
Power-fail INPUT/OUTPUT The Power-Fail Input (PFI) is compared to an internal reference voltage (1.25V). If PFI is less than the power-fail threshold (VPFI), the Power-Fail Output (PFO) will go low. This function is intended for use as an under-voltage detector to signal a failing power supply. Typically PFI is connected through an external voltage divider (see Figure 17) to either the unregulated DC input (if it is available) or the regulated output of the VCC regulator. The voltage divider can be set up such that the voltage at PFI falls below VPFI several milliseconds before the regulated VCC input to the M41ST95Y/W or the microprocessor drops below the minimum operating voltage. Figure 17. Power-Fail Comparator Hookup
Regulator Unregulated Voltage VIN VCC VCC M41ST95Y/W VOUT ECON EX From MCU E SDI SCL WDI RST RSTIN1 R1 RSTIN2 Pushbutton Reset PFI IRQ/FT/OUT R2 VBAT F32k VSS To INT
(1)
During battery back-up, the power-fail comparator turns off and PFO goes (or remains) low. This occurs after VCC drops below VPFD(min). When power returns, PFO is forced high, irrespective of VPFI for the write protect time (tREC), which is the time from VPFD(max) until the inputs are recognized. At the end of this time, the power-fail comparator is enabled and PFO follows PFI. If the comparator is unused, PFI should be connected to VSS and PFO left unconnected.
VCC VCC E
SDO To RST To LED Display To NMI
SQW PFO
AI06373
Note: 1. Available only in 28-pin, 300mil SOIC (MX) package.
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M41ST95Y*, M41ST95W
Century Bit Bits D7 and D6 of Clock Register 03h contain the CEN TURY ENABLE Bit (CEB) and the CENTURY Bit (CB). Setting CEB to a '1' will cause CB to toggle, either from a '0' to '1' or from '1' to '0' at the turn of the century (depending upon its initial state). If CEB is set to a '0,' CB will not toggle. Output Driver Pin When the FT Bit, AFE Bit and Watchdog Register are not set, the IRQ/FT/OUT pin becomes an output driver that reflects the contents of D7 of the Control Register. In other words, when D7 (OUT Bit) and D6 (FT Bit) of address location 08h are a '0,' then the IRQ/FT/OUT pin will be driven low. Note: The IRQ/FT/OUT pin is an open drain which requires an external pull-up resistor. Battery Low Warning The M41ST95Y/W automatically performs battery voltage monitoring upon power-up and at factoryprogrammed time intervals of approximately 24 hours. The Battery Low (BL) Bit, Bit D4 of Flags Register 0Fh, will be asserted if the battery voltage is found to be less than approximately 2.5V. The BL Bit will remain asserted until completion of battery replacement and subsequent battery low monitoring tests, either during the next power-up sequence or the next scheduled 24-hour interval. If a battery low is generated during a power-up sequence, this indicates that the battery is below approximately 2.5 volts and may not be able to maintain data integrity in the SRAM. Data should be considered suspect and verified as correct. A fresh battery should be installed. Table 8. tREC Definitions
tREC Bit (TR) 0 0 1 STOP Bit (ST) Min 0 1 X 96 40 50 tREC Time Max 98(1) 200 2000 ms ms s Un its
If a battery low indication is generated during the 24-hour interval check, this indicates that the battery is near end of life. However, data is not compromised due to the fact that a nominal VCC is supplied. In order to insure data integrity during subsequent periods of battery back-up mode, the battery should be replaced. The SNAPHAT top may be replaced while VCC applied to the device. The M41ST95Y/W only monitors the battery when a nominal VCC is applied to the device. Thus applications which require extensive durations in the battery back-up mode should be powered-up periodically (at least once every few months) in order for this technique to be beneficial. Additionally, if a battery low is indicated, data integrity should be verified upon power-up via a checksum or other technique. tREC Bit Bit D7 of Clock Register 04h contains the tREC Bit (TR). tREC refers to the automatic continuation of the deselect time after VCC reaches VPFD. This allows for a voltage setting time before WRITEs may again be performed to the device after a powerdown condition. The tREC Bit will allow the user to set the length of this deselect time as defined by Table 8. Preferred Power-on Defaults Upon initial application of power to the device, the following register bits are set to a '0' state: Watchdog Register, TR, FT, AFE, ABE, and SQWE. The following bits are set to a '1' state: OUT and HT (see Table 9).
Note: 1. Default Setting; after oscillator has started
Table 9. Default Values
Cond ition Initial Power-up (Battery Attach for SNAPHAT)(2) Subsequent power-up (with battery back-up)(3) TR 0 UC ST 0 UC HT 1 1 Out 1 UC FT 0 0 AFE 0 0 A BE 0 0 SQWE 0 0 WATCHDOG Register(1) 0 0
Note: 1. WDS, BMB0-BMB4, RB0, RB1. 2. State of other control bits undefined. 3. UC = Unchanged.
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Figure 18. Crystal Accuracy Across Temperature
Frequency (ppm) 20 0 20 40 60 80 100 120 140 160 40 30 20 10 0 10 20 30 40 50 60 70 80 F = K x (T T )2 O F
2 2 K = 0.036 ppm/C 0.006 ppm/C
TO = 25C 5C
Temperature C
AI07888
Figure 19. Calibration Waveform
NORMAL
POSITIVE CALIBRATION
NEGATIVE CALIBRATION
AI00594B
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M41ST95Y*, M41ST95W
MAXIMUM RATING
Stressing the device above the rating listed in the "Absolute Maximum Ratings" table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the Operating sections of this specification is Table 10. Absolute Maximum Ratings
Symbol TSTG VCC Parameter Storage Temperature (VCC Off, Oscillator Off) M41ST95Y Supply Voltage M41ST95W Lead-free lead finish(1) TSLD Lead Solder Temperature for 10 seconds Standard (SnPb) lead finish(2,3) 0.3 to 4.6 260 240 260 0.3 to VCC+0.3 20 1 V C C C V mA W Value 55 to 125 0.3 to 7 Unit C V
not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents.
TSLD(1,2) VIO IO PD
Lead Solder Temperature for 10 seconds Input or Output Voltage Output Current Power Dissipation
Note: 1. For SOH28 package, Lead-free (Pb-free) lead finish: Reflow at peak temperature of 260C (total thermal budget not to exceed 245C for greater than 30 seconds). 2. For SOH28 package, standard (SnPb) lead finish: Reflow at peak temperature of 225C (total thermal budget not to exceed 180C for between 90 to 150 seconds). 3. The SOX28 package has Lead-free (Pb-free) lead finish, but cannot be exposed to peak reflow temperature in excess of 240C (use same reflow profile as standard (SnPb) lead finish).
CAUTION: Negative undershoots below 0.3V are not allowed on any pin while in the Battery Back-up mode. CAUTION: Do NOT wave solder SOIC to avoid damaging SNAPHAT sockets.
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M41ST95Y*, M41ST95W
DC AND AC PARAMETERS
This section summarizes the operating and measurement conditions, as well as the DC and AC characteristics of the device. The parameters in the following DC and AC Characteristic tables are derived from tests performed under the MeasureTable 11. DC and AC Measurement Conditions
Parameter VCC Supply Voltage Ambient Operating Temperature Load Capacitance (CL) Input Rise and Fall Times Input Pulse Voltages Input and Output Timing Ref. Voltages
Note: Output Hi-Z is defined as the point where data is no longer driven.
ment Conditions listed in the relevant tables. Designers should check that the operating conditions in their projects match the measurement conditions when using the quoted parameters.
M41ST95Y 4.5 to 5.5V 40 to 85C 100pF 50ns 0.2 to 0.8VCC 0.3 to 0.7VCC
M41ST95W 2.7 to 3.6V 40 to 85C 50pF 50ns 0.2 to 0.8VCC 0.3 to 0.7VCC
Figure 20. AC Testing Input/Output Waveforms
0.8VCC
0.7VCC 0.3VCC
AI02568
0.2VCC
Table 12. Capacitance
Symbol CIN COUT(3) tLP Input Capacitance Output Capacitance Low-pass filter input time constant (SDI and SCL) Parameter(1,2) Min Max 7 10 50 Unit pF pF ns
Note: 1. Effective capacitance measured with power supply at 5V; sampled only, not 100% tested. 2. At 25C, f = 1MHz. 3. Outputs are deselected.
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M41ST95Y*, M41ST95W
Table 13. DC Characteristics
Sym Parameter Battery Current OSC ON Battery Current OSC OFF Supply Current Supply Current (Standby) Input Leakage Current ILI(3) Input Leakage Current (PFI) Output Leakage Current 0V VIN VCC VOUT1 > VCC 0.3V VOUT2 > VBAT 0.3V 0.7VC C 0.3 2.5 IOH = 1.0mA IRQ/FT/OUT, RST IOUT2 = 1.0A IOL = 3.0mA IOL = 10mA 4.20 VCC = 5V(Y) VCC = 3V(W) PFI Rising 1.225 4.40 1.250 20 2.5 2.5 2.9 2.4 5.5 3.5 0.4 0.4 4.50 1.275 70 2.55 1.225 2.60 1.250 20 2.5 2.5 2.9 3.0 Test Condition(1) TA = 25C, VCC = 0V, VBAT = 3V f = 2MHz SCL, SDI = VCC 0.3V 0V VIN VCC 25 2 M41ST95Y Min Typ 400 50 2 1.4 1 25 1 175 100 VCC + 0.3 0.3VCC 3.5(6) 0.7VCC 0.3 2.5 2.4 3.6 3.5 0.4 0.4 2.70 1.275 70 3.0 25 2 Max 550 Min M41ST95W Typ 400 50 2 1.4 1 25 1 100 100 VCC + 0.3 0.3VCC 3.5(6) Max 550 nA nA mA mA A nA A mA A V V V V V V V V V V mV V Unit
IBAT
(2)
ICC1 ICC2
ILO(4)
IOUT1(5) VOUT Current (Active) IOUT2 VIH VIL VBAT VOH VOUT Current (Battery Back-up) Input High Voltage Input Low Voltage Battery Voltage Output High Voltage(7) Power Supply Voltage (Open Drain) VOHB(8) VOH (Battery Back-up) Output Low Voltage VOL Output Low Voltage (Open Drain)(9) Power Fail Deselect PFI Input Threshold PFI Hysteresis VSO
Note: 1. 2. 3. 4. 5. 6. 7. 8.
VPFD VPFI
Battery Back-up Switchover
Valid for Ambient Operating Temperature: TA = 40 to 85C; VCC = 4.5 to 5.5V or 2.7 to 3.6V (except where noted). Measured with VOUT and ECON open. RSTIN1 and RSTIN2 internally pulled-up to VCC through 100K resistor. WDI internally pulled-down to VSS through 100K resistor. Outputs Deselected. External SRAM must match RTC SUPERVISOR chip VCC specification. For rechargeable back-up, VBAT(max) may be considered VCC. For PFO, F32k, and SQW pins (CMOS). Conditioned output (ECON) can only sustain CMOS leakage current in the battery back-up mode. Higher leakage currents will reduce battery life. 9. For IRQ/FT/OUT, RST pins (Open Drain); if pulled-up to supply other than VCC, this supply must be equal to, or less than 3.0V when VCC = 0V (during battery back-up mode).
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M41ST95Y*, M41ST95W
Figure 21. Power Down/Up Mode AC Waveforms
VCC VPFD (max) VPFD (min) VSO tF tFB tPD PFO tDR tRB tREC tR
INPUTS
RECOGNIZED
DON'T CARE
RECOGNIZED
RST HIGH-Z OUTPUTS VALID
(PER CONTROL INPUT)
VALID
(PER CONTROL INPUT)
ECON
AI03661
Table 14. Power Down/Up AC Characteristics
Symbol tF(2) tFB(3) tR tRB tPFD tREC(4,5) Parameter(1) VPFD (max) to VPFD (min) VCC Fall Time VPFD (min) to VSS VCC Fall Time VPFD (min) to VPFD (max) VCC Rise Time VSS to VPFD (min) VCC Rise Time PFI to PFO Propagation Delay Power up Deselect Time 96 Min 300 10 10 1 15 25 98 Typ Max Unit s s s s s ms
Note: 1. Valid for Ambient Operating Temperature: TA = 40 to 85C; VCC = 4.5 to 5.5V or 2.7 to 3.6V (except where noted). 2. VPFD (max) to VPFD (min) fall time of less than tF may result in deselection/write protection not occurring until 200s after VCC passes VPFD (min). 3. VPFD (min) to VSS fall time of less than tFB may cause corruption of RAM data. 4. Programmable (see Table 8., page 23) 5. After crystal oscillator has started
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M41ST95Y*, M41ST95W
PACKAGE MECHANICAL INFORMATION
Figure 22. SOH28 28-lead Plastic Small Outline, Battery SNAPHAT, Package Outline
A2 B e
A C eB CP
D
N
E
H A1 L
1 SOH-A
Note: Drawing is not to scale.
Table 15. SOH28 28-lead Plastic Small Outline, battery SNAPHAT, Package Mechanical Data
millimeters Symbol Typ A A1 A2 B C D E e eB H L N CP 1.27 0.05 2.34 0.36 0.15 17.71 8.23 3.20 11.51 0.41 0 28 0.10 Min Ma x 3.05 0.36 2.69 0.51 0.32 18.49 8.89 3.61 12.70 1.27 8 0.050 0.002 0.092 0.014 0.006 0.697 0.324 0.126 0.453 0.016 0 28 0.004 Typ Min Max 0.120 0.014 0.106 0.020 0.012 0.728 0.350 0.142 0.500 0.050 8 inches
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M41ST95Y*, M41ST95W
Figure 23. SH 4-pin SNAPHAT Housing for 48mAh Battery & Crystal, Package Outline
A1
A2 A A3
eA D
B eB
L
E
SHTK-A
Note: Drawing is not to scale.
Table 16. SH 4-pin SNAPHAT Housing for 48mAh Battery & Crystal, Package Mechanical Data
millimeters Symbol Typ A A1 A2 A3 B D E eA eB L 0.46 21.21 14.22 15.55 3.20 2.03 6.73 6.48 Min Ma x 9.78 7.24 6.99 0.38 0.56 21.84 14.99 15.95 3.61 2.29 0.0181 0.8350 0.5598 0.6122 0.1260 0.0799 0.2650 0.2551 Typ Min Max 0.3850 0.2850 0.2752 0.0150 0.0220 0.8598 0.5902 0.6280 0.1421 0.0902 inches
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M41ST95Y*, M41ST95W
Figure 24. SH 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Outline
A1
A2 A A3
eA D
B eB
L
E
SHTK-A
Note: Drawing is not to scale.
Table 17. SH 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Mech. Data
millimeters Symbol Typ A A1 A2 A3 B D E eA eB L 0.46 21.21 14.22 15.55 3.20 2.03 6.73 6.48 Min Ma x 10.54 7.24 6.99 0.38 0.56 21.84 14.99 15.95 3.61 2.29 0.0181 0.8350 0.5598 0.6122 0.1260 0.0799 0.2650 0.2551 Typ Min Max 0.4150 0.2850 0.2752 0.0150 0.0220 0.8598 0.5902 0.6280 0.1421 0.0902 inches
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M41ST95Y*, M41ST95W
Figure 25. SOX28 28-lead Plastic Small Outline, 300mils, Embedded Crystal, Outline
D
14 1
h x 45
C E H
15
28
A2 B SO-E
Note: Drawing is not to scale.
A e A1 ddd A1 L
Table 18. SOX28 28-lead Plastic Small, 300mils, Embedded Crystal, Package Mech. Data
millimeters Symbol Typ A A1 A2 B C D ddd E e H L N 1.27 7.57 10.16 0.51 0 28 Min 2.44 0.15 2.29 0.41 0.20 17.91 Ma x 2.69 0.31 2.39 0.51 0.31 18.01 0.10 7.67 10.52 0.81 8 0.050 0.298 0.400 0.020 0 28 Typ Min 0.096 0.006 0.090 0.016 0.008 0.705 Max 0.106 0.012 0.094 0.020 0.012 0.709 0.004 0.302 0.414 0.032 8 inches
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M41ST95Y*, M41ST95W
PART NUMBERING
Table 19. Ordering Information Scheme
Example: M41ST 95Y MH 6
Device Type M41ST
Supply Voltage and Write Protect Voltage 95Y(1) = VCC = 4.5 to 5.5V; 4.20V VPFD 4.50V 95W = VCC = 2.7 to 3.6V; 2.55V VPFD 2.70V
Package MH(1,2) = SOH28 MX(3) = SOX28
Temperature Range 6 = 40 to 85C
Shipping Method For SOH28: blank = Tubes (Not for New Design - Use E) E = Lead-free Package (ECO F = Lead-free Package (ECO PACK), Tubes PACK), Tape & Reel
TR = Tape & Reel (Not for New Design - Use F) For SOX28: blank = Tubes TR = Tape & Reel
Note: 1. Contact Local Sales Office 2. The SOIC package (SOH28) requires the SNAPHAT battery package which is ordered separately under the part number "M4TXXBR12SH" in plastic tube or "M4TXX-BR12SHTR" in Tape & Reel form (see Table 20). 3. The SOX28 package includes an embedded 32,768Hz crystal. Caution : Do not place the SNAPHAT battery package "M4TXX-BR12SH" in conductive foam as it will drain the lithium button-cell battery.
For other options, or for more information on any aspect of this device, please contact the ST Sales Office nearest you. Table 20. SNAPHAT Battery Table
Part Number M4T28-BR12SH M4T32-BR12SH Description Lithium Battery (48mAh) and Crystal SNAPHAT Lithium Battery (120mAh) and Crystal SNAPHAT Package SH SH
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REVISION HISTORY
Table 21. Document Revision History
Date February 2002 27-Mar-02 01-Apr-02 12-Apr-02 21-Jan-03 25-Feb-03 20-Mar-03 27-Mar-03 06-May-03 15-Jun-04 13-Sep-04 Rev. # 1.0 1.1 1.2 2.0 2.1 2.2 3.0 3.1 3.2 4.0 5.0 First draft Change tREC Definition (Table 8) Addition of new package option and inherent features Document promoted Add marketing note; (Figure 1); modify logic, signals (Figure 3; Table 1); modify block diagram (Figure 6) Update Definitions (Table 8); correct mechanical dimensions (Figure 25; Table 18) Document promoted Add marketing status (Table 19) Update 32kHz information (Figure 3, 5, 6, 17; Table 1, 13, 14, 7) Reformatted; update characteristics; added Lead-free information (Figure 5, 6, 18; Table 1, 4, 7, 8, 10, 13, 14, 19) Update Maximum ratings (Table 10) Revision Details
M4 1S T 95 , 41ST95, ST95, M41ST95Y, 41ST95Y, ST95Y, M41ST95W, 41ST95W, ST95W, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, S erial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, Serial, S erial, Serial, Serial, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, A cce ss , Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Acce ss, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, Access, A cce ss , Access, Access, Access, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, S PI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, S PI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, S PI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, SPI, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clo ck , Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clo ck , Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clo ck , Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, Clock, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, RTC, Oscillator, Oscillator, Oscillator, Oscillator, Osc illator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscilla tor, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Oscillator, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Micro pro ce sso r, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Micropro ce ss or, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Microprocessor, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Res et, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Res et, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Res et, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Reset, Res et, Reset, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write P ro tec t, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Write Protect, Wri te Protect, Write Protect, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, A la rm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, A la rm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, A la rm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Alarm, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, In terru pt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrup t, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, In terru pt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrup t, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, In terru pt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrup t, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, In terru pt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrup t, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Interrupt, Watchdog, Wa tch do g, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Wa tch do g, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Wa tch do g, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Watchdog, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Low, Lo w, Low, Low, Low, Low, Low, Low, Low, Low, Low, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, B attery , Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, B attery , Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Battery, Switchover, Switchover, Switchover, Switchover, Switchover, S witch o ve r, Switchover, Switchover, Switchover, Switchover, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Com pa rato r, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Com pa rato r, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Comparator, Power-fail, Power-fail, Power-fail, Power-fail, Power-fail, Power-fail, Power-fail, Power-fail, Power-fail, P ow e r-fa il, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, S R AM , SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SRAM, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, S N AP H A T , SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, S N AP H A T , SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SNAPHAT, SOIC, SOIC, SOIC, SOIC, SOIC, SOIC, S OIC, SOIC, SOIC, SOIC, SOIC, SOIC, SOIC, SOIC, SOIC, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 2.7V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V , 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V, 5V
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M41ST95Y*, M41ST95W
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners 2004 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com
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