DS1685 Maxim, DS1685 Datasheet
DS1685
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DS1685 Summary of contents
Page 1
... Real-Time Clocks RAM Clear Input Century Register Date Alarm Register Compatible with Existing BIOS for Original DS1287 Functions Available as Chip (DS1685) or Stand-Alone Encapsulated DIP (EDIP) with Embedded Battery and Crystal (DS1687) Timekeeping Algorithm Includes Leap-Year Compensation Valid Through 2099 Underwriters Laboratory (UL) Recognized ...
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... DS1687-5IND+ -40°C to +85°C +Denotes a lead(Pb)-free/RoHS-compliant device. A “+” anywhere on the top mark indicates a lead-free/RoHS-compliant device “N” or “IND” denotes an industrial temperature grade device. TYPICAL OPERATING CIRCUIT DS1685/DS1687 3V/5V Real-Time Clocks VOLTAGE PIN-PACKAGE ( PDIP (0.600” PDIP (0.600” ...
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... EDIP. The entire unit is fully tested at Maxim such that a minimum of 10 years of timekeeping and data retention in the absence guaranteed. CC OPERATION The block diagram in Figure 1 shows the pin connections with the major internal functions of the DS1685/DS1687. The following paragraphs describe the function of each pin. DS1685/DS1687 3V/5V Real-Time Clocks ...
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... No Connection. Pins missing by design. N.C. Connections for Standard 32.768kHz Quartz Crystal. For greatest accuracy, the DS1685 must be used with a crystal that has a specified load X1 capacitance of either 6pF or 12.5pF. The crystal-select (CS) bit in Extended Control Register 4B is used to select operation with a 6pF or 12.5pF crystal ...
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... NAME Kickstart Input, Active Low. When V DS1685/DS1687, the system can be powered on in response to an active- low transition on the KS pin, as might be generated from a key closure. V must be present and the auxiliary-battery enable bit (ABE) and kick- BAUX KS start enable bit (KSE) must be set the kickstart function is used, and the KS pin must be pulled up to the V KS pin can be used as an interrupt input ...
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... AD0 - AD7 OSCILLATOR CIRCUIT The DS1685 uses an external 32.768kHz crystal. The oscillator circuit does not require any external resistors or capacitors to operate. Table 1 specifies several crystal parameters for the external crystal, and Figure 2 shows a functional schematic of the oscillator circuit. The oscillator is controlled by an enable bit in the control register. ...
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... Refer to Application Note 58: Crystal Considerations with Dallas Real-Time Clocks for detailed information. The DS1685 can also be driven by an external 32.768 kHz oscillator. In this configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is floated. Refer to Application Note 58: Crystal Considerations with Dallas Real-Time Clocks for detailed information about crystal selection and crystal layout ...
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... A). This time period allows the system to stabilize after power is applied. If the oscillator is not enabled, the oscillator enable bit will be enabled on power up, and the device becomes immediately accessible. The DS1685/DS1687 is available in either device. The 5V device is fully accessible and data can be written and read only when V falls below V , read and writes are inhibited ...
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... Date 0 10 Month DV1 DV0 RS3 RS2 AIE UIE SQWE Century 10 Date DS1685/DS1687 3V/5V Real-Time Clocks BIT 1 BIT 0 FUNCTION Seconds Seconds Alarm Minutes Minutes Alarm Hours Hours Hours Hours Alarm Day Day Date Date Month Month Year ...
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... Year DV1 DV0 RS3 RS2 AIE UIE SQWE Century 10 Date DS1685/DS1687 3V/5V Real-Time Clocks BIT 1 BIT 0 FUNCTION Seconds Seconds Alarm Minutes Minutes Alarm Hours Hours Hours Hours Alarm Day Day Date Month Month Year RS1 RS0 ...
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... Enable both at the same time and the same rate Enable neither. Table 3 lists the periodic interrupt rates and the square-wave frequencies that can be chosen with the RS bits. BIT 5 BIT 4 BIT 3 DV1 DV0 RS3 DS1685/DS1687 3V/5V Real-Time Clocks LSB BIT 2 BIT 1 BIT 0 RS2 RS1 RS0 ...
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... When the AIE bit is set to 0, the AF bit does not initiate the IRQ signal. The internal functions of the DS1685/DS1687 do not affect the AIE bit. UIE – The update-ended interrupt-enable (UIE) bit is a read/write bit that enables the update-end flag (UF) bit in Register C to assert IRQ. The SET bit going high clears the UIE bit. SQWE – ...
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... BIT 6, BIT 5, BIT 4, BIT 3, BIT 2, BIT 1, BIT 0 – The remaining bits of Register D are not usable. They cannot be written and when read will always read 0. BIT 4 BIT BIT 5 BIT 4 BIT DS1685/DS1687 3V/5V Real-Time Clocks LSB BIT 2 BIT 1 BIT LSB BIT 2 BIT 1 BIT pin or the ...
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... The IRQF bit in Register whenever the IRQ pin is being driven low as a result of one of the six possible active sources. Therefore, determination that the DS1685/DS1687 initiated an interrupt is accomplished by reading Register C and finding IRQF = 1. IRQF remains set until all enabled interrupt flag bits are cleared to 0 ...
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... However, each function has a separate enable bit in Register B. The SQWE and E32K bits control the square- wave output. Similarly, the periodic interrupt is enabled by the PIE bit in Register B. The periodic interrupt can be used with software counters to measure inputs, create output intervals, or await the next needed software function. DS1685/DS1687 3V/5V Real-Time Clocks . ...
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... ensure that data is not read during the update cycle. PI BUC DS1685/DS1687 3V/5V Real-Time Clocks SQW OUTPUT FREQUENCY None 256Hz 128Hz 8.192kHz 4.096kHz 2.048kHz 1.024kHz 512Hz 256Hz 128Hz 64Hz 32Hz 16Hz 8Hz 4Hz 2Hz 32 ...
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... PF EXTENDED FUNCTIONS The extended functions provided by the DS1685/DS1687 that are new to the RAMified RTC family are accessed by a software-controlled bank-switching scheme, as illustrated in Figure 5. In bank 0, the clock/calendar registers and 50 bytes of user RAM are in the same locations as for the DS1287 result, existing routines implemented within BIOS, DOS, or application software packages can gain access to the DS1685/DS1687 clock registers with no changes ...
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... Figure 5. DS1685/DS1687 Register Map and Extended Register Bank Definition BANK 0 DV0 MSB = 0 00 TIMEKEEPING AND CONTROL BYTES-USER RAM 3F 64 BYTES-USER RAM 7F When bank 1 is selected, the clock/calendar registers and the original 50 bytes of user RAM still appear as bank 0. However, the registers that provide control and status for the extended functions are accessed in place of the additional 64 bytes of user RAM ...
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... In the DS1685/DS1687, this auxiliary battery can be used as the primary backup-power source for maintaining the clock/calendar, user RAM, and extended external RAM functions. This occurs if the V than the DS1685 backed-up using a single battery with the auxiliary features enabled, then V BAUX should be used and V should be grounded ...
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... At the beginning of Interval 3, the system processor has begun code execution and clears the interrupt condition of WF and/ writing 0’s to both of these control bits. As long as no other interrupt within the DS1685/DS1687 is pending, the IRQ line is taken inactive once these bits are reset. Execution of the application software can proceed. ...
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... Two extended control registers are provided to supply controls and status information for the extended features offered by the DS1685/DS1687. These are designated as extended control registers 4A and 4B and are located in register bank 1, locations 04AH and 04BH, respectively. The functions of the bits within these registers are described as follows ...
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... RAM. When RCE = 0, RCLR and the RAM clear function are disabled. PRS – PAB Reset-Select Bit. When set the PWR pin is set high-Z when the DS1685 goes into power-fail. When set the PWR pin remains active upon entering power-fail. ...
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... RTC address 4Eh is latched and the address from “1” is pushed to location “4Eh,” “RTC Address-2” while 0Ah is pushed to the “RTC Address-1” location. The data in this register, 4Eh, is the RTC address lost due to the SMI DS1685/DS1687 3V/5V Real-Time Clocks 4 ...
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... A A PARAMETER (-5) Power-Supply Voltage (-3) Input Logic 1 PWR Pullup Voltage IRQ Input Logic 0 Battery Voltage (-5) Auxiliary Battery Voltage (-3) SYMBOL MIN TYP 4.5 5 2.7 3 PUPWR V -0 2.5 BAT 2.5 V BAUX 2 DS1685/DS1687 3V/5V Real-Time Clocks MAX UNITS NOTES 5 0.2 CC 0.6 V 3.7 V 5 ...
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... CC1 I CC2 BATLKG OLPWR I OLIRQ = -40C to +85C.) SYMBOL MIN I BAT1 I BAT2 DS1685/DS1687 3V/5V Real-Time Clocks TYP MAX UNITS 0.5 2 A +1 0.4 V 4.37 4.5 V 2.6 2 BAT V V BAUX 10 100 nA ...
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... DHR t 0 DHW t 30 ASL t 15 AHL t 30 ASD PW 80 ASH t 30 ASED t 20 DDR t 60 DSW t IRD DS1685/DS1687 3V/5V Real-Time Clocks MAX UNITS NOTES ...
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... DHR t 0 DHW t 30 ASL t 15 AHL t 25 ASD PW 40 ASH t 30 ASED t 20 DDR t 60 DSW t IRD DS1685/DS1687 3V/5V Real-Time Clocks MAX UNITS NOTES ...
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... DS1685/DS1667 BUS TIMING FOR READ CYCLE TO RTC AND RTC REGISTERS DS1685/DS1687 BUS TIMING FOR WRITE CYCLE TO RTC AND RTC REGISTERS DS1685/DS1687 3V/5V Real-Time Clocks ...
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... 2.7V V 2. SYMBOL MIN OUT SYMBOL MIN TYP t 2 KSPW t 2 POTO DS1685/DS1687 3V/5V Real-Time Clocks TYP MAX UNITS 0 ns 150 ms s s s years TYP MAX UNITS 0 ns 150 ms s s years TYP MAX UNITS 12 ...
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... POWER-UP CONDITION—3V CS 2.6V 2. POWER FAIL POWER-DOWN CONDITION— POWER FAIL REC 2. 2.7V 2.6V 2. DS1685/DS1687 3V/5V Real-Time Clocks ...
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... POWER-UP CONDITION—5V CS 4.5V 4.25V 4. POWER FAIL POWER-DOWN CONDITION— DS1685/DS1687 3V/5V Real-Time Clocks REC 4.5V FB 4.25V 4.0V 3. ...
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... Post solder cleaning with water washing techniques is acceptable, if ultrasonic vibration is not used. Note 12: I and I are measured at V BAT1 BAT2 and V . BAT BAUX 3.5V and with recommended crystal type on X1 and X2. BAT BAUX DS1685/DS1687 3V/5V Real-Time Clocks . DR ...
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... RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE 24 PDIP 28 PLCC 24 TSSOP EDIP DS1685/DS1687 3V/5V Real-Time Clocks PACKAGE CODE P24+3 Q28+4 U24+1 W24+7 MDP24 DOCUMENT NO ...
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... Maxim is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Maxim Integrated Products, Inc. DS1685/DS1687 3V/5V Real-Time Clocks DESCRIPTION © ...