DS1678S Maxim Integrated Products, DS1678S Datasheet
DS1678S
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... Two-wire serial interface allows for a simple connection to your system § Three resolution options are available to trade off accuracy versus maximum time between events § Underwriters Laboratory (UL) recognized ORDERING INFORMATION DS1678 8-Pin DIP (300-mil) DS1678S 8-Pin SOIC (208-mil) Real-Time Event Recorder PIN ASSIGNMENT ...
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DESCRIPTION The DS1678 Real-Time Clock Event Recorder records the time and date of a non-periodic, asynchronous event each time the pin is activated. The device records the seconds, minutes, hours, date, day of the INT week, month, year, and century ...
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The block diagram in Figure 1 shows the main elements of the RTC event recorder. The device has four major components: 1) 64-bit RTC and control block, 2) 32-byte user NV RAM, 3) 2048 bytes of event log memory (1024 ...
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DS1678 BLOCK DIAGRAM Figure 1 32.768 kHz X2 OSCILLATOR AND DIVIDER CONTROL INT LOGIC 2-WIRE SERIAL SCL INTERFACE SDA V CC POWER V BAT CONTROL GND SIGNAL DESCRIPTIONS The following paragraphs describe the function of each pin. V – V ...
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Input/Output) – The INT signify an event has occurred and should be logged. Once the pin is activated, the event will be recorded in the event log memory and the event counter register will be incremented by one. The ...
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CLOCK ACCURACY The accuracy of the clock is dependent upon the accuracy of the crystal and the accuracy of the match between the capacitive load of the oscillator circuit and the capacitive load for which the crystal was trimmed. Additional ...
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Entering a value greater than 07FFh will result in the address location associated with the value of the lowest 11 bits of the address. The RTC and control registers (See Figure 2a for more detail.) are located in the main ...
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DS1678 RTC AND CONTROL PAGE Figure 2a ADDRESS BIT 7 BIT 12/ YEAR 07 10 CENTURY SECONDS ALARM 09 ...
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DS1678 EVENT ELAPSED TIME DURATION Figure 2b ADDRESS 0000 Event 1 Elapsed Time from Last Event Counter LSB 0001 Event 1 Elapsed Time from Last Event Counter MSB 0002 Event 2 Elapsed Time from Last Event Counter LSB 0003 Event ...
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The value in the MIP and ME bits will remain a 1 until the mission has completed, even if they are written Upon initiation of an event log ...
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When this rollover ...
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TIME-OF-DAY ALARM BITS Table 1 ALARM REGISTER MASK BITS (bit 7) SECONDS MINUTES (MS) (MM The DS1678 also contains a time-of-day alarm. The alarm registers are located in registers 08h ...
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CLR - Clear Enable – This bit enables the memory to be cleared. When this bit is set to a one and the clear memory (CM) bit in the status register is subsequently written the event log ...
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With the DIS0 bit set to a zero and the DIS1 bit set to a one, the ETC will increment every time the single minutes byte in the RTC is incremented. This will give a medium resolution between events, but ...
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Likewise, subsequent samples will increment through the event log registers, overwriting their data. The event 0 elapsed time from last event bytes will have the elapsed time since the last event in ...
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MIP - Mission in Progress – This bit indicates the sampling status of the DS1678. If MIP is logic 1, the device is currently on a “mission” in which it is operating in the event logging mode. The MIP bit ...
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MSB (40h). These will be helpful in recovering all of the data if a rollover occurs. The address pointer will point to the oldest event in the memory after a rollover. This is the memory location that would be over ...
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START and STOP conditions. The DS1678 operates as a slave on the 2-wire bus. Connections to the bus are made via the open-drain I/O lines SDA and SCL. The following bus protocol has been defined (See Figure ...
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Figure 4 details how data transfer is accomplished on the 2-wire bus. Depending upon the state of the R/ bit, two types of data transfer are possible Data transfer from a master transmitter to a slave receiver. The ...
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ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the ...
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AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL SCL Clock Frequency Bus Free Time Between a STOP and START Condition Hold Time (Repeated) t START Condition. LOW Period of SCL HIGH Period of SCL Set-Up Time for a t Repeated START Data Hold ...
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SERIAL COMMUNICATION WITH DS1678 Figure 4 W rite ...
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EVENT RECOGNITION TIMING DIAGRAM Figure ven ven ven / ...
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START MISSION FLOW CHART Figure 7 Start via Computer no Mem Clr =1 yes Write the MIP bit The ME bit is Automatically Written Time/Date Stamp is Written ETC Starts Incrementing EC is Incremented ...
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ROLL OVER FLOW CHART Figure Incremented INT Input Activated yes Memory Full yes Rollover Enable = 1 yes ETC Written to Event 0 and Time/Date Stamp is Written ETC is Cleared no Continue to Monitor Input no ...
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NOTES: 1. After this period, the first clock pulse is generated device must initially provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined region of the falling edge of ...