M41ST85WMX6F STMICROELECTRONICS [STMicroelectronics], M41ST85WMX6F Datasheet
M41ST85WMX6F
Related parts for M41ST85WMX6F
M41ST85WMX6F Summary of contents
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Features ■ Automatic battery switchover and WRITE protect for: – Internal serial RTC and – External low power SRAM (LPSRAM) 2 ■ 400kHz I C serial interface ■ 3.0/3.3V operating voltage – 2.7 to 3.6V CC ■ Ultra-low ...
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Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Description The M41ST85W is a combination Serial Real-Time Clock, Microprocessor Supervisor, and NVRAM Supervisor built in a low power CMOS SRAM process and has a 64-byte memory space with 44 bytes of NVRAM and 20 memory-mapped RTC ...
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M4T28-BR12SH1 (48mAh) and M4T32-BR12SH1 (120mAh). For the extended temperature requirement, the 120mAh M4T32-BR12SH6 is available. For more information, see on page 39. Caution: Do not place the SNAPHAT battery/crystal top in conductive foam, as this will drain the lithium button-cell ...
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Table 1. Signal names E CON EX IRQ/FT/OUT PFI PFO RST RSTIN1 RSTIN2 SCL SDA SQW WDI OUT V SS (1) V BAT For 28-pin, 300mil embedded crystal SOIC only. Figure 2. 28-pin SOIC ...
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Figure 3. 28-pin, 300mil SOIC (MX) connections SQW WDI RSTIN1 RSTIN2 PFO Note: No Function (NF) pins should be tied to V shorted together ...
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Figure 4. Block diagram SDA INTERFACE SCL (2) 32KHz Crystal OSCILLATOR WDI BAT RSTIN1 RSTIN2 EX PFI 1.25V (Internal) 1. Open drain output 2. Crystal integrated into SOIC package for MX package option. 10/41 ...
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Figure 5. Hardware hookup Regulator Unregulated V IN Voltage Pushbutton Reset Required for embedded crystal (MX) package only. M41ST85W SCL SDA WDI RSTIN1 RSTIN2 PFI (1) IRQ/FT/OUT V BAT ...
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Operating modes The M41ST85W clock operates as a slave device on the serial bus. Access is obtained by implementing a start condition followed by the correct slave address (D0h). The 64 bytes contained in the device can then be ...
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Bus not busy Both data and clock lines remain High. 2.1.2 Start data transfer A change in the state of the data line, from High to Low, while the clock is High, defines the START condition. 2.1.3 Stop data ...
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Figure 6. Serial bus data transfer sequence CLOCK DATA START CONDITION Figure 7. Acknowledgement sequence START SCL FROM MASTER DATA OUTPUT BY TRANSMITTER DATA OUTPUT BY RECEIVER Figure 8. Write cycle timing: RTC & external SRAM control signals EX E ...
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Read mode In this mode the master reads the M41ST85W slave after setting the slave address (see Figure 9). Following the WRITE Mode Control Bit (R/W=0) and the Acknowledge Bit, the word address 'An' is written to the on-chip ...
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Figure 10. Read mode sequence BUS ACTIVITY: MASTER SDA LINE S BUS ACTIVITY: SLAVE ADDRESS DATA n+X Figure 11. Alternate read mode sequence BUS ACTIVITY: MASTER SDA LINE S BUS ACTIVITY: SLAVE ADDRESS 16/41 WORD S ADDRESS (An) SLAVE ADDRESS ...
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Write mode In this mode the master transmitter transmits to the M41ST85W slave receiver. Bus protocol is shown in Figure is placed on the bus and indicates to the addressed device that word address An will follow and is ...
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If data retention lifetime is a critical parameter for the system 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 ...
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Clock operation The eight byte clock register (see read the date and time from the clock binary coded decimal format. Tenths/Hundredths of Seconds, Seconds, Minutes, and Hours are contained within the first four registers. Note: A WRITE ...
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Table 2. TIMEKEEPER register map Address 00h 0.1 Seconds 01h ST 10 Seconds 02h 0 10 Minutes 03h CEB CB 10 Hours 04h 05h 0 0 06h 07h 10 Years ...
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Calibrating the clock The M41ST85W is driven by a quartz controlled oscillator with a nominal frequency of 32,768 Hz. The devices are tested not exceed +/–35 ppm (parts per million) oscillator frequency error at 25 Calibration circuit is properly ...
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Figure 13. Crystal accuracy across temperature Frequency (ppm –20 –40 –60 –80 –100 –120 –140 –160 –40 –30 –20 Figure 14. Calibration waveform NORMAL POSITIVE CALIBRATION NEGATIVE CALIBRATION 3.4 Setting alarm clock registers Address locations 0Ah-0Eh contain the ...
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Bits RPT5–RPT1 put the alarm in the repeat mode of operation. 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 ...
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Figure 16. Back-up mode alarm waveform PFD V SO ABE, AFE Bits in Interrupt Register AF bit in Flags Register IRQ/FT/OUT 3.5 Watchdog timer The watchdog timer can be used to detect an out-of-control microprocessor. The user ...
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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 ...
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Reset inputs (RSTIN1 & RSTIN2) The M41ST85W 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 5 and Figure 17 ...
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PFI. If the comparator is unused, PFI should be connected to V unconnected. 3.10 Century bit Bits D7 and D6 of Clock Register 03h contain the CENTURY ENABLE Bit (CEB) and the CENTURY Bit (CB). Setting CEB to a ...
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Bit D7 of Clock Register 04h contains the t continuation of the deselect time after V time before WRITEs may again be performed to the device after a power-down condition. The t Bit will allow the ...
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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 ...
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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 ...
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Table 11. DC characteristics Sym Parameter Battery current OSC ON (2) I BAT Battery current OSC OFF I Supply current CC1 I Supply current (standby) CC2 Input leakage current ( Input leakage current (PFI) (4) I Output leakage ...
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Figure 19. Bus timing requirements sequence SDA tBUF SCL P S Table 12. AC characteristics Symbol f SCL Clock Frequency SCL t Time the bus must be free before a new transmission can start BUF Propagation ...
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Figure 20. Power down/up mode AC waveforms PFD (max) V PFD (min tPD PFO INPUTS RECOGNIZED RST OUTPUTS VALID (PER CONTROL INPUT) E CON Table 13. Power down/up AC characteristics Symbol ( ...
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Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect. The category of second Level Interconnect is marked on the package and on the inner ...
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Table 14. SOH28 – 28-lead plastic small outline, battery SNAPHAT, package mechanical data Symbol Typ 1. millimeters Min Max 3.05 0.05 0.36 2.34 2.69 0.36 0.51 ...
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Figure 22. SH – 4-pin SNAPHAT housing for 48mAh battery & crystal, package outline Note: Drawing is not to scale. Table 15. SH – 4-pin SNAPHAT housing for 48mAh battery & crystal, mechanical data Symbol Typ ...
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Figure 23. SH – 4-pin SNAPHAT housing for 120mAh battery & crystal, package outline Note: Drawing is not to scale. Table 16. SH – 4-pin SNAPHAT housing for 120mAh battery & crystal, mechanical data Symbol Typ ...
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Figure 24. SOX28 – 28-lead plastic small outline, 300mils, embedded crystal, package outline SO-E Note: Drawing is not to scale. Table 17. SOX28 – 28-lead plastic small outline, 300mils, embedded crystal, mechanical data Symbol Typ A ...
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Part numbering Table 18. Ordering information scheme Example: Device type M41ST Supply voltage and write protect voltage 85W = V = 2.7 to 3.6V; 2.55V V CC Package ( SOH28 ( SOX28 Temperature range 6 ...
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Revision history Table 20. Document revision history Date Revision Aug-2000 1.0 First issue 24-Aug-2000 1.1 Block Diagram added 12-Oct-2000 1.2 t Table removed, cross references corrected rec 18-Dec-2000 2.0 Reformatted, TOC added, and PFI Input Leakage Current added Addition ...
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Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any ...