PCF2129AT datasheet(44/86 Pages) PHILIPS

44 / 86 page

PCF2129

All information provided in this document is subject to legal disclaimers.

Product data sheet

Rev. 7 — 19 December 2014

44 of 86

NXP Semiconductors

PCF2129

Accurate RTC with integrated quartz crystal for industrial applications

8.11.4 Dependency between Battery switch-over and timestamp

The timestamp function depends on the control bit BTSE in register Control_3:

[1]

Default value.

8.12 Interrupt output, INT

PCF2129 has an interrupt output pin INT which is open-drain, active LOW (requiring a

pull-up resistor if used). Interrupts may be sourced from different places:

• second or minute timer

• watchdog timer

• alarm

• timestamp

• battery switch-over

• battery low detection

The control bit TI_TP (register Watchdg_tim_ctl) is used to configure whether the

interrupts generated from the second/minute timer (flag MSF in register Control_2) are

pulsed signals or a permanently active signal. All the other interrupt sources generate a

permanently active interrupt signal which follows the status of the corresponding flags.

When the interrupt sources are all disabled, INT remains high-impedance.

• The flags MSF, AF, TSFx, and BF can be cleared by command.

• The flag WDTF is read only. How it can be cleared is explained in Section 8.10.5.

• The flag BLF is read only. It is cleared automatically from the battery low detection

circuit when the battery is replaced.

Table 71.

Battery switch-over and timestamp

BTSE

Description

[1] the battery switch-over does not affect the

timestamp registers

If a battery switch-over event occurs:

[1]

the timestamp registers store the time and

date when the switch-over occurs;

after this event occurred BF is set logic 1

the timestamp registers are not modified;

in this condition subsequent battery

switch-over events or falling edges on pin TS

are not registered

PCF2129AT датащи(PDF) 44 Page - NXP Semiconductors

PCF2129AT датащи(HTML) 44 Page - NXP Semiconductors

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

датащи скачать

ссылки URL