DS17285E3 MAXIM [Maxim Integrated Products], DS17285E3 Datasheet
DS17285E3
Related parts for DS17285E3
DS17285E3 Summary of contents
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Rev 0; 4/06 General Description The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (here- after referred to as the DS17x85) provide ...
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Real-Time Clocks ABSOLUTE MAXIMUM RATINGS Voltage Range on V Pin Relative to Ground ....-0.3V to +6.0V CC Operating Temperature Range (Noncondensing) Commercial.........................................................0°C to +70°C Industrial ..........................................................-40°C to +85°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage ...
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DC ELECTRICAL CHARACTERISTICS ( 3.0V Over the operating range, unless otherwise noted.) (Note 1) CC BAT A PARAMETER SYMBOL Current (Oscillator BAT BAUX On +25° 3.0V A ...
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Real-Time Clocks AC ELECTRICAL CHARACTERISTICS (V = +2.7V to +3.7V Over the operating range, unless otherwise noted.) (Note PARAMETER SYMBOL Cycle Time t Pulse Width Low PW Pulse Width ...
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ALE PW ASH t ASD RD PW RWH t ASD ASL AD0–AD7 IRQ PF(MAX) V PF(MIN RECOGNIZED CS, WR, RD VALID AD0–AD7 _____________________________________________________________________ Real-Time Clocks t CYC t ASED PW RWL t ...
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Real-Time Clocks POWER-UP/POWER-DOWN CHARACTERISTICS (T = -40°C to +85°C) (Note 2) A PARAMETER SYMBOL Recovery at Power-Up V Fall Time PF(MAX) V PF(MIN) V Fall Time PF(MAX) V PF(MIN) DATA RETENTION (DS17x87 ONLY) (T ...
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T = +25°C, unless otherwise noted SUPPLY CURRENT vs. INPUT VOLTAGE 400 350 300 250 200 2.5 2.8 3.0 3.3 3.5 V (V) BAT PIN NAME 24 28 Active-Low Power-On Reset. ...
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Real-Time Clocks PIN NAME 24 28 Active-Low Chip-Select Input. This pin must be asserted low during a bus cycle for the device accessed. CS must be kept in the active state during RD and WR. Bus cycles ...
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PIN NAME 24 28 Active-Low RAM Clear Input. This pin is used to clear (set to logic 1) all the 114 bytes of general-purpose RAM but does not affect the RAM associated with the real time clock or extended RAM. ...
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Real-Time Clocks X1 OSCILLATOR X2 DS17x87 ONLY V BAT GND POWER CONTROL BAUX CS BUS WR INTERFACE RD ALE AD0–AD7 DS17x85/87 Figure 1. Functional Diagram 10 ____________________________________________________________________ DIVIDE DIVIDE BY DIVIDE 16:1 MUX ...
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Detailed Description The DS17x85 is a successor to the DS1285 real-time clock (RTC). The device provides 18 bytes of real-time clock/calendar, alarm, and control/status registers and 114 bytes of nonvolatile battery-backed RAM. The device also provides additional extended RAM in ...
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Real-Time Clocks Power-Down/Power-Up Considerations The RTC function continues to operate, and all the RAM, time, calendar, and alarm memory locations remain nonvolatile regardless of the level of the V input must remain within the minimum BAT BAUX ...
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The alarm bytes can be used in two ways. First, when the alarm time is written in the appropriate hours, min- utes, and seconds alarm locations, the alarm interrupt is initiated at the specified time each day, if the alarm ...
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Real-Time Clocks Table 3B. Time, Calendar, and Alarm Data Modes—Binary Mode ( ADDRESS BIT 7 BIT 6 BIT 5 00h 0 0 01h 0 0 02h 0 0 03h 0 0 AM/PM 04h 0 0 AM/PM 05h 0 ...
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Bits Rate Selector Bits (RS3 to RS0). These four rate-selection bits select one of the 13 taps on the 15-stage divider or disable the divider output. The tap selected can be used to generate an output square ...
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Real-Time Clocks Register B (0Bh) MSB BIT 7 BIT 6 BIT 5 SET PIE AIE Bit 7: SET. When the SET bit is 0, the update transfer functions normally by advancing the counts once per second. When the SET bit ...
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Register C (0Ch) MSB BIT 7 BIT 6 IRQF PF Bit 7: Interrupt Request Flag (IRQF). This bit is set to 1 when any of the following are true PIE = WIE = 1 AF ...
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Real-Time Clocks Nonvolatile RAM The user RAM bytes are not dedicated to any special function within the DS17x85. They can be used by the processor program as battery-backed memory and are fully available during the update cycle. The user RAM ...
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Periodic Interrupt Selection The periodic interrupt causes the IRQ pin active state from once every 500ms to once every 122µs. This function is separate from the alarm inter- rupt, which can be output from once per ...
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Real-Time Clocks Extended Functions The extended functions provided by the DS17x85/ DS17x87 that are new to the RAMified RTC family are accessed by a software-controlled bank-switching scheme, as illustrated in Table 5. In bank 0, the clock/calendar registers and 50 ...
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Table 5. Extended Bank Register Bank Definition Bank 0 DV0 = 0 00h Timekeeping and Control 0Dh 0Eh 50 Bytes – User RAM 3Fh 40h 64 Bytes – User RAM 7Fh Note: Reserved bits can be written to any value, ...
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Real-Time Clocks Century Counter A register has been added in bank 1, location 48H, to keep track of centuries. The value is read in either bina BCD according to the setting of the DM bit. RTC Write Counter ...
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The timing associated with both the wake-up and kick- starting sequences is illustrated in the Wake- Up/Kickstart Timing Diagram (Figure 6). The timing associated with these functions is divided into five inter- vals, labeled the diagram. ...
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Real-Time Clocks At the beginning of interval 3, the system processor has begun code execution and clears the interrupt condi- tion of WF and/ writing zeros to both of these control bits. As long as no other interrupt ...
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AS CS AD0-7 53H DS OR R/W Figure 7. Burst Mode Timing Waveform Extended Control Registers Two extended control registers are provided to supply control and status information for the extended func- tions offered by the DS17x85/DS17x87. These are des- ...
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Real-Time Clocks Extended Control Register (4Bh) MSB BIT 7 BIT 6 BIT 5 ABE E32k Bit 7: Auxiliary Battery Enable (ABE). When written to logic 1, this bit enables the V BAUX functions. Bit 6: Enable 32.768kHz Output (E32k). When ...
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System Maintenance Interrupt (SMI) Recovery Stack An SMI recovery register stack is located in the extend- ed register bank, locations 4Eh and 4Fh. This register stack, shown below, can be used by the BIOS to recov- er from an SMI ...
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Real-Time Clocks TOP VIEW PWR AD0 4 AD1 5 DS17285 AD2 6 DS17485 AD3 7 DS17885 AD4 8 AD5 9 AD6 10 AD7 11 GND 12 SO, PDIP IRQ V BAT RCLR V BAUX SQW ...
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... Note: A “-5” suffix denotes 5V±10% device, and a “-3” suffix denotes PART TOP MARK* DS17285-3 DS17485SN-5 DS17285-5 DS17487-3 DS17285E3 DS17285E3 DS17487-3IND DS17285E5 DS17285E5 DS17487-5 DS17285E3 DS17285N5 DS17487-5IND DS17285S-3 DS17885-3 DS17885-5 DS17285SN3 DS17885E-3 DS17885E-3+ DS17285S-5 DS17885E-5 DS17885E-5+ DS17285SN3 DS17885S-3 DS17285SN5 ...
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Real-Time Clocks Typical Operating Circuit CRYSTAL IRQ ALE WR DS17285 DS17485 RD DS17885 DS83C520 CS AD0–AD7 V SB SUPPLY PWR CONTROL GND CIRCUIT V CC Maxim cannot assume responsibility for use of any circuitry other than ...