PCF2127 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCF2127' PDF : 101 Pages View PDF
NXP Semiconductors
PCF2127
Accurate RTC with integrated quartz crystal for industrial applications
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Fig 16. Dependency between POR and oscillator
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After POR, the following mode is entered:
• 32.768 kHz CLKOUT active
• Power-On Reset Override (PORO) available to be set
• 24-hour mode is selected
• Battery switch-over is enabled
• Battery low detection is enabled
• Extra power fail detection is enabled
The register values after power-on are shown in Table 5 on page 8.
8.8.2 Power-On Reset Override (PORO)
The POR duration is directly related to the crystal oscillator start-up time. Due to the long
start-up times experienced by these types of circuits, a mechanism has been built in to
disable the POR and therefore speed up the on-board test of the device.
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Fig 17. Power-On Reset (POR) system
The setting of the PORO mode requires that POR_OVRD in register Control_1 is set
logic 1 and that the signals at the interface pins SDA/CE and SCL are toggled as
illustrated in Figure 18. All timings shown are required minimum.
PCF2127
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 8 — 19 December 2014
© NXP Semiconductors N.V. 2014. All rights reserved.
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