PCF85163 Real-time clock and calendar - Digikey

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NXP SemiconductorsPCF85163Real-time clock and calendar5. Apply 32 clock pulses to CLKOUT.6. Read time registers to see the first change.7. Apply 64 clock pulses to CLKOUT.8. Read time registers to see the second change.Repeat steps 7 and 8 for additional increments.8.10 STOP bit functionThe function of the STOP bit is to allow for accurate starting of the time circuits. The STOPbit function will cause the upper part of the prescaler (F 2 to F 14 ) to be held in reset andthus no 1 Hz ticks will be generated (see Figure 9). The time circuits can then be set andwill not increment until the STOP bit is released (see Figure 10 and Table 26).OSCILLATOR STOPDETECTORresetOSCILLATOR32768 Hz16384 Hz8192 Hz4096 HzF 0 F 1 F 2F 13RESETRESET2 HzF 14RESET1 Hz tickSTOP1 Hz32 Hz1024 Hz32768 HzCLKOUT source013aaa089Fig 9.STOP bit functional diagramThe STOP bit function will not affect the output of 32.768 kHz on CLKOUT, but will stopthe generation of 1.024 kHz, 32 Hz, and 1 Hz.The lower two stages of the prescaler (F 0 and F 1 ) are not reset; and because the I 2 C-busis asynchronous to the crystal oscillator, the accuracy of re-starting the time circuits will bebetween zero and one 8.192 kHz cycle (see Figure 10).8192 Hzstop released0 μs to 122 μs001aaf912Fig 10.STOP bit release timingPCF85163 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.Product data sheet Rev. 2 — 28 July 2010 18 of 43
NXP SemiconductorsPCF85163Real-time clock and calendarTable 26. First increment of time circuits after STOP bit releaseBit Prescaler bits[1]1Hz tick Time CommentSTOP F 0 F 1 -F 2 to F 14 hh:mm:ssClock is running normally0 01-0 0001 1101 0100 12:45:12 prescaler counting normallySTOP bit is activated by user. F 0 F 1 are not reset and values cannot be predicted externally1 XX-0 0000 0000 0000 12:45:12 prescaler is reset; time circuits are frozenNew time is set by user1 XX-0 0000 0000 0000 08:00:00 prescaler is reset; time circuits are frozenSTOP bit is released by user0 XX-0 0000 0000 0000 08:00:00 prescaler is now running0.507813 to 0.507935 sXX-1 0000 0000 0000 08:00:00 -XX-0 1000 0000 0000 08:00:00 -XX-1 1000 0000 0000 08:00:00 -: : :11-1 1111 1111 1110 08:00:00 -00-0 0000 0000 0001 08:00:01 0 to 1 transition of F 14 increments the time circuits10-0 0000 0000 0001 08:00:01 -: : :1.000000 s11-1 1111 1111 1111 08:00:01 -00-0 0000 0000 0000 08:00:01 -10-0 0000 0000 0000 08:00:01 -: : :11-1 1111 1111 1110 08:00:01 -00-0 0000 0000 0001 08:00:02 0 to 1 transition of F 14 increments the time circuits013aaa076[1] F 0 is clocked at 32.768 kHz.The first increment of the time circuits is between 0.507813 s and 0.507935 s after STOPbit is released. The uncertainty is caused by the prescaler bits F 0 and F 1 not being reset(see Table 26) and the unknown state of the 32 kHz clock.8.11 ResetThe PCF85163 includes an internal reset circuit which is active whenever the oscillator isstopped. In the reset state the I 2 C-bus logic is initialized including the address pointer andall registers are set according to Table 27. I 2 C-bus communication is not possible duringreset.PCF85163 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.Product data sheet Rev. 2 — 28 July 2010 19 of 43
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PCF85163 Real-time clock and calendar - Digikey

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