M48T86PC1 STMicroelectronics, M48T86PC1 Datasheet
M48T86PC1
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M48T86PC1 Summary of contents
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Features ■ Drop-in replacement for PC computer clock/calendar ■ Counts seconds, minutes, hours, days, day of the week, date, month, and year with leap year compensation ■ Clock accuracy better than 1 minute per month ■ Interfaced with software as ...
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Contents Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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M48T86 3.11.2 3.11.3 3.11.4 3.11.5 3.11.6 3.11.7 3.11.8 3.12 Register ...
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List of tables List of tables Table 1. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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M48T86 List of figures Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Description 1 Description The M48T86 is an industry standard real-time clock (RTC). The M48T86 is composed of a lithium energy source, quartz crystal, write protection circuitry, and a 128-byte RAM array. This provides the user with a complete subsystem packaged ...
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M48T86 Table 1. Signal names AD0-AD7 E R RST RCL MOT SQW IRQ Figure 2. 24-pin DIP connections Multiplexed address/data bus Chip enable input WRITE enable input Data strobe input Address strobe input ...
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Description Figure 3. 28-pin SOIC connections Figure 4. Block diagram BAT DS R/W AS AD0-AD7 8/ MOT AD0 5 AD1 6 AD2 7 M48T86 AD3 8 AD4 9 AD5 ...
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M48T86 2 Operation The M48T86 clock is driven by a quartz-controlled oscillator with a nominal frequency of 32,768 Hz. The devices are tested not to exceed 23 ppm (parts per million) oscillator frequency error at 25°C, which equates to approximately ...
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Operation 2.1.5 MOT (mode select) The MOT pin offers the flexibility to choose between two bus types (see page 12). When connected left disconnected, Intel bus timing is selected. The pin has an internal pull-down resistance of ...
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M48T86 2.1.11 R/W (read/write input) The R/W pin is used to latch data into the M48T86 and provides functionality similar other memory systems. 2.1.12 Non-volatile RAM The 114 general-purpose non-volatile RAM bytes are not dedicated to any ...
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Operation Figure 7. Motorola bus read/write mode AC waveforms AS tDAS DS R/W E AD0-AD7 (Write) AD0-AD7 (Read) 12/36 tASW tASD tCYC tDSL tDSH tRWS tCS tAH tAS tAS tOD tAH M48T86 tRWH tCH tDW tDHW tDHR AI01649 ...
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M48T86 Table 2. AC characteristics Symbol t Cycle time CYC t Pulse width, data strobe low or R/W high DSL t Pulse width, data strobe high or R/W low DSH t R/W hold time RWH t R/W setup time RWS ...
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Clock operations 3 Clock operations 3.1 Address map The address map of the M48T86 is shown in 10 bytes of RAM that contain the RTC time, calendar and alarm data, and 4 bytes which are used for control and status. ...
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M48T86 Figure 8. Address map 0 14 CLOCK AND CONTROL BYTES STATUS REGISTERS 13 14 114 STORAGE REGISTERS BYTES 127 Table 3. Time, calendar, and alarm formats Address RTC bytes 0 Seconds 1 Seconds alarm 2 Minutes 3 Minutes alarm ...
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Clock operations 3.3 Interrupts The RTC plus RAM includes three separate, fully automatic sources of interrupt (alarm, periodic, update-in-progress) available to a processor. The alarm interrupt can be programmed to occur at rates from once per second to once per ...
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M48T86 3.5 Alarm interrupt The alarm interrupt provides the system processor with an interrupt when a match is made between the RTC's hours, minutes, and seconds bytes and the corresponding alarm bytes. The three alarm bytes can be used in ...
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Clock operations should avoid interrupt service routines that would cause the time needed to read valid time/calendar data to exceed 244 µs. The third method uses a periodic interrupt to determine if an update cycle is in progress. The UIP ...
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M48T86 3.10 Register A 3.10.1 UIP update in progress The Update in Progress (UIP) bit is a status flag that can be monitored. When the UIP bit is '1,' the update transfer will soon occur (see will not occur for ...
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Clock operations 3.11 Register B 3.11.1 SET When the SET bit is a '0,' the update transfer functions normally by advancing the counts once per second. When the SET bit is written to a '1,' any update transfer is inhibited ...
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M48T86 3.11.7 24/12 The 24/12 Control bit establishes the format of the hours byte. A '1' indicates the 24-hour mode and a '0' indicates the 12-hour mode. This bit is READ/WRITE and is not affected by internal functions or RST. ...
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... VRT: valid RAM and time The Valid RAM and Time (VRT) bit is set to the '1' state by STMicroelectronics prior to shipment. This bit is not writable and should always be a '1' when read '0' is ever present, an exhausted internal lithium cell is indicated and both the contents of the RTC data and RAM data are questionable ...
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M48T86 3.14 V noise and negative going transients CC I transients, including those produced by output switching, can produce voltage CC fluctuations, resulting in spikes on the V capacitors are used to store energy which stabilizes the V bypass capacitors ...
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... 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 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. Table 9. ...
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M48T86 5 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 ...
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DC and AC parameters Figure 13. AC testing load circuit (with IRQ) Table 11. Capacitance Symbol C Input capacitance IN (3) C Input / output capacitance IO 1. Effective capacitance measured with power supply sampled only, not ...
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M48T86 Figure 14. Power down/up mode AC waveforms V CC 4.5V V PFD Table 13. Power down/up mode AC characteristics Symbol Parameter ( fall time rise time ...
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Package mechanical data 6 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available ...
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M48T86 Figure 15. PCDIP24 – 24-pin plastic DIP, battery CAPHAT™, package outline Note: Drawing is not to scale. Table 15. PCDIP24 – 24-pin plastic DIP, battery CAPHAT™, package mechanical data Symb ...
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Package mechanical data Figure 16. SOH28 – 28-lead plastic small outline, 4-socket SNAPHAT outline Note: Drawing is not to scale. Table 16. SOH28 – 28-lead plastic small outline, 4-socket battery SNAPHAT mechanical data Symb ...
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M48T86 Figure 17. SH – 4-pin SNAPHAT outline Note: Drawing is not to scale. Table 17. SH – 4-pin SNAPHAT mechanical data Symb ® housing for 48 mAh battery and ...
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Package mechanical data Figure 18. SH – 4-pin SNAPHAT outline Note: Drawing is not to scale. Table 18. SH – 4-pin SNAPHAT mechanical data Symb 32/36 ® housing for 120 ...
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M48T86 7 Part numbering Table 19. Ordering information scheme Example: Device type M48T Supply voltage and write protect voltage 4 Package PC = PCDIP24 ( SOH28 Temperature range 1 ...
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Environmental information 8 Environmental information Figure 19. Recycling symbols This product contains a non-rechargeable lithium (lithium carbon monofluoride chemistry) button cell battery fully encapsulated in the final product. Recycle or dispose of batteries in accordance with the battery manufacturer's instructions ...
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M48T86 9 Revision history Table 21. Document revision history Date Revision Mar-1999 04-May-2000 31-Jul-2001 20-May-2002 01-Apr-2003 02-Apr-2004 20-Feb-2007 05-Jul-2007 04-Dec-2008 1 First Issue 1.1 Page layout changed 2 Reformatted; temp/voltage info. added to tables 2.1 Modify reflow time and temperature ...
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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 time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...