pcf2123 NXP Semiconductors, pcf2123 Datasheet - Page 27

• Manufacturer Part Number: pcf2123
• Description: Spi Real Time Clock/calendar
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2123_1
Product data sheet
9.9.3.1 Correction pulse interrupts
9.9.3 Alarm interrupts
The timing shown for clearing bit TF in
mode i.e. when bit TI_TP = 0, INT may be shortened by setting bit TIE to logic 0.
The generation of interrupts from the alarm function is controlled via bit AIE (see
If bit AIE is enabled, the INT pin follows the condition of bit AF. Clearing bit AF will
immediately clear INT. No pulse generation is possible for alarm interrupts (see
Figure
Interrupt pulses generated by correction events can be shortened by writing a logic 1 to bit
CIE in register Control_1.
Fig 18. Example of shortening the INT pulse by clearing the TF flag
Fig 19. AF timing
(1) Indicates normal duration of INT pulse (bit TI_TP = 1).
19).
Example where only the minute alarm is used and no other interrupts are enabled.
countdown counter
minute counter
minute alarm
instruction
instruction
Rev. 01 — 19 November 2008
SCL
INT
AF
SCL
INT
TF
44
45
01
45
n
Figure 18
CLEAR INSTRUCTION
CLEAR INSTRUCTION
is also valid for the non-pulsed interrupt
SPI Real time clock/calendar
8th clock
8th clock
001aaf910
001aaf909
PCF2123
© NXP B.V. 2008. All rights reserved.
(1)
Table
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6).