PCF85263AT datasheet(67/100 Pages) NXP

67 / 100 page

PCF85263A

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Product data sheet

Rev. 4.1 — 27 November 2015

67 of 100

NXP Semiconductors

PCF85263A

Tiny RTC with alarm, battery switch-over, and I2C-bus

11. Application design-in information

In this application, stop-watch mode is used to implement an elapsed time counter. The

TS pin is used with a mechanical switch to start and stop the time. Each time the time is

stopped, timestamp2 is loaded with the current time and an interrupt is generated on the

INTA pin.

The RTC must be configured correctly for this mode of operation. Outlined in Table 66 are

the settings needed for this mode.

In addition, the time must be set and any other configurations like battery switch-over,

quartz oscillator driving mode, etc., which are dependent on the application.

The sampler circuit shown in Figure 35 will hold invalid data until the mechanical switch

detector mode is enabled. It then requires a minimum of one sample period to initialize to

the current TS pin level. It is recommended to enable the mechanical detector mode on

the TS pin at least 62.5 ms before enabling the TS event mode. Failure to do so can result

in a false first event.

Fig 35. Application example

PCF85263AT Datasheet(PDF) 67 Page - NXP Semiconductors