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DS1603 Dataheets PDF



Part Number DS1603
Manufacturers Maxim Integrated
Logo Maxim Integrated
Description Elapsed Time Counter
Datasheet DS1603 DatasheetDS1603 Datasheet (PDF)

www. maxim-i c.com www.maxim-ic.com DS1603 Elapsed Time Counter Module FEATURES § Two 32-bit counters keep track of real-time and elapsed time § Counters keep track of seconds for over 125 years § Battery powered counter counts seconds from the time battery is attached until VBAT is less than 2.5V § VCC powered counter counts seconds while VCC is above VTP and retains the count in the absence of VCC under battery backup power § Clear function resets selected counter to 0 § Read/write serial po.

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www. maxim-i c.com www.maxim-ic.com DS1603 Elapsed Time Counter Module FEATURES § Two 32-bit counters keep track of real-time and elapsed time § Counters keep track of seconds for over 125 years § Battery powered counter counts seconds from the time battery is attached until VBAT is less than 2.5V § VCC powered counter counts seconds while VCC is above VTP and retains the count in the absence of VCC under battery backup power § Clear function resets selected counter to 0 § Read/write serial port affords low pin count § Powered internally by a lithium energy cell that provides over 10 years of operation § One-byte protocol defines read/write, counter address and software clear function § Self-contained crystal provides an accuracy of ±2 min per month § Operating temperature range of 0°C to +70°C § Low-profile SIP module § Underwriters Laboratory (UL) recognized PIN ASSIGNMENT VCC RST DQ NC CLK OSC GND 1 2 3 4 5 6 7 PIN DESCRIPTION RST CLK DQ GND VCC OSC NC - Reset - Clock - Data Input/Output - Ground - +5V - 1Hz Oscillator Output - No Connect DESCRIPTION The DS1603 is a real-time clock/elapsed time counter designed to count seconds when VCC power is applied and continually count seconds under battery backup power with an additional counter regardless of the condition of VCC. The continuous counter can be used to derive time of day, week, month, and year by using a software algorithm. The VCC powered counter will automatically record the amount of time that VCC power is applied. This function is particularly useful in determining the operational time of equipment in which the DS1603 is used. Alternatively, this counter can also be used under software control to record real-time events. Communication to and from the DS1603 takes place via a 3-wire serial port. A 1-byte protocol selects read/ write functions, counter clear functions and oscillator trim. The device contains a 32.768kHz crystal that will keep track of time to within ±2 min/mo. An internal lithium energy source contains enough energy to power the continuous seconds counter for over 10 years. OPERATION The main elements of the DS1603 are shown in Figure 1. As shown, communications to and from the elapsed time counter occur over a 3-wire serial port. The port is activated by driving RST to a high state. Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata. 1 of 8 093002 DS1603 With RST at high level 8 bits are loaded into the protocol shift register providing read/write, register select, register clear, and oscillator trim information. Each bit is serially input on the rising edge of the clock input. After the first eight clock cycles have loaded the protocol register with a valid protocol additional clocks will output data for a read or input data for a write. VCC must be present to access the DS1603. If VCC < VTP, the DS1603 will switch to internal power and disable the serial port to conserve energy. When running off of the internal power supply, only the continuous counter will continue to count and the counter powered by VCC will stop, but retain the count, which had accumulated when VCC power was lost. The 32-bit VCC counter is gated by VCC and the internal 1Hz signal. PROTOCOL REGISTER The protocol bit definition is shown in Figure 2. Valid protocols and the resulting actions are shown in Table 1. Each data transfer to the protocol register designates what action is to occur. As defined, the MSB (bit 7 which is designated ACC) selects the 32-bit continuous counter for access. If ACC is a logical 1 the continuous counter is selected and the 32 clock cycles that follow the protocol will either read or write this counter. If the counter is being read, the contents will be latched into a different register at the end of protocol and the latched contents will be read out on the next 32 clock cycles. This avoids reading garbled data if the counter is clocked by the oscillator during a read. Similarly, if the counter is to be written, the data is buffered in a register and all 32 bits are jammed into the counter simultaneously on the rising edge of the 32nd clock. The next bit (bit 6 which is designated AVC) selects the 32–bit VCC active counter for access. If AVC is a logical 1 this counter is selected and the 32 clock cycles that follow will either read or write this counter. If both bit 7 and bit 6 are written to a logic high, all clock cycles beyond the protocol are ignored and bit 5, 4, and 3 are loaded into the oscillator trim register. A value of binary 3 (011) will give a clock accuracy of ±120 seconds per month at +25°C. Increasing the binary number towards 7 will cause the real- time clock to run faster. Conversely, lowering the binary number towards 0 will cause the clock to run slo.


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