SM8578 Nippon_Precision_Circuits America, SM8578 Datasheet
SM8578
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SM8578 Summary of contents
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... OVERVIEW The SM8578BV is a serial interface, real-time clock IC that uses a 32.768 kHz crystal oscillator for its refer- ence timing. It comprises second-counter to year-counter clock and calendar circuits that feature automatic leap-year adjustment, alarm and timer interrupt functions, as well as oscillator stop, timer reloading, and other detection functions ...
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... Serial data transfer data input/output. When CE goes HIGH, the first four bits of write data determine the 7 DATA I/O operating mode (read mode/write mode). 8 VDD – Positive supply voltage connection. A 0.1µF bypass capacitor should be connected between VDD and VSS. SM8578BV VDD VSS Clock and Calendar Divider OSC OSC Control Register Detect ...
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... LOW-level input voltage Input leakage current I LEAK Input resistance 1 R DWN1 Input resistance 2 R DWN2 V V Output voltage Output voltage 2 V Output leakage current I SM8578BV Symbol Condition Input pins IN V INTN OUT1 V DATA OUT2 STG Symbol Condition ...
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... DS Write data hold time t DH Read data output delay time t RD Output disable delay time t RZ Input rise and fall time t RF Abnormal oscillation detection t OSC time SM8578BV = 30k Ω 6pF) unless otherwise noted Condition 1 5.0V ± ...
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... Timing Diagrams t CLK CE 50% Data write Data read CLK DATA CE SM8578BV t CLK 50% 50% CLK t DH 50% DATA 90% 50 CKH t CR 90% Hi−Z 10% NIPPON PRECISION CIRCUITS INC.—5 ...
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... The AF and TF bits have “0” only valid write data values. Note 1. When power is applied, all register values are undefined, hence they must be initialized. Note 2. When Register D is read, the previously preset data value written to the register is read. SM8578BV Bit6 Bit5 ...
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... The seconds and year registers do not have fr flags. Instead, bits 6 and 5 in the seconds register and bits 7 and 6 in the year register are logically-Ored with data “1” (example: year register 00101001 → 11101001). When CE goes LOW, the register values are restored (example: year register 11101001 → 00101001). SM8578BV Bit3 Bit2 ...
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... Note that when the TE bit is set to “0”, fixed-cycle interrupts from output INTN are not generated even when I the fixed-cycle counter (register D) is loaded with zero data. TD1 TD0 SM8578BV Bit4 Bit3 Bit2 Thursday Wednesday Tuesday Source clock 4096Hz 64Hz 1Hz 1/60Hz Bit1 ...
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... AIE is the alarm interrupt enable flag, and TIE is the timer interrupt enable flag. The alarm or timer interrupt is enabled when the corresponding enable bit is set to “1” (both interrupts are output if both bits are set to “1”, so setting both bits to “1” should be avoided). SM8578BV Source clock 32768Hz ...
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... The automatic correction function operates if the HOLD bit is set for less than 1 second. *2. Normal operation for source clocks other than 1/60Hz (1 minute). *3. Normal operation for 4096Hz source clock only. *4. Normal operation for 32768Hz source clock only. SM8578BV Bit4 Bit3 Bit2 Bit1 ...
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... If TIE = “1” when the interrupt occurs, output INTN goes LOW. If TIE = “0”, INTN is in high imped- I ance state. TIE bit INTN output TF bit SM8578BV No output while AIE is "0" Data 0 written output while TIE is "0" Data 0 written to TF NIPPON PRECISION CIRCUITS INC.— ...
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... If TIE = “0” when the interrupt occurs, output INTN stays high impedance and the TF bit is set to “1”, I and this condition is maintained. TIE bit INTN output TF bit * Auto-return: The auto-return time (t SM8578BV t RTN Auto-return Data 0 written determined by the source clock set by register C. RTN ...
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... Read mode Adress select code (C ) select (N) H Note. If the mode set code is neither “C” nor “3”, all subsequent data is ignored and the DATA pin input state is maintained. SM8578BV Data write (adress Data read (adress N) From the point DATA is in output mode ...
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... The output mode setting is set by the TIE, AIE, and FE bits as shown in the following table. I Note that multiple “1” bits are invalid. Mode Timer interrupt output Alarm interrupt output Arbitrary frequency output Output disabled SM8578BV Bit TIE AIE ...
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... By monitoring this output, the oscillator frequency can be adjusted by tuning an external capacitor ( TYPICAL APPLICATION CIRCUIT SM8578BV DD XTN XT INTN VDD CE VSS ≈ 10kΩ) R3 ≈ 10kΩ C1 ≈ 0.1µF SM8578BV VDD INTN XT CE CLK DATA XTN VSS . ). G R3 INTN output (1Hz) VCC VCC Micro controller GND ...
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... Customers are requested not to export or re-export, directly or indirectly, the Products to any country or any entity not in compliance with or in violation of the national export administration laws, treaties, orders and regulations. Customers are requested appropriately take steps to obtain required permissions or approvals from appropriate government agencies. SM8578BV NIPPON PRECISION CIRCUITS INC. 4-3, Fukuzumi 2-chome, Koto-ku, ...