PCF8523 NXP [NXP Semiconductors], PCF8523 Datasheet - Page 13

• Manufacturer Part Number: PCF8523
• Description: Real-Time Clock (RTC) and calendar
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF8523
Product data sheet
Fig 8.
SECONDS COUNTER
TAC = 10
TAC = 01
TBC = 1
When SIE, CTAIE, WTAIE, CTBIE, AIE, CIE, BSIE, BLIE, and clock-out are disabled, then INT1 will remain high-impedance.
When CTBIE is disabled, then INT2 will remain high-impedance.
Interrupt block diagram
add/subtract pulse
watchdog counter
circuit: clear BLF
or reading WTAF
ENABLE
WATCHDOG
COUNTER A
from interface:
from interface:
from interface:
COUNTDOWN
COUNTDOWN
ENABLE
ENABLE
low detection
low flag, BLF
COUNTER A
COUNTER B
from interface:
from interface:
from interface:
offset circuit:
MCU loading
from battery
set battery
set battery
clear BSF
clear CTAF
clear CTBF
set alarm
clear CIE
flag, BSF
clear AF
flag, AF
clear SF
SIE
SET
SET
SET
SET
GENERATOR 5
SET
BSF: BATTERY
SET
BLF: BATTERY
SET
SECOND FLAG
SET
TIMER A FLAG
TIMER B FLAG
COUNTDOWN
WATCH DOG
COUNTDOWN
TIMER FLAG
AF: ALARM
LOW FLAG
PULSE
WTAF:
FLAG
FLAG
CTAF:
CTBF:
All information provided in this document is subject to legal disclaimers.
SF:
CLEAR
CLEAR
CLEAR
CLEAR
CLEAR
CLEAR
CLEAR
CLEAR
Rev. 3 — 30 March 2011
TRIGGER CLEAR
TRIGGER CLEAR
TRIGGER CLEAR
TRIGGER CLEAR
GENERATOR 3
GENERATOR 1
GENERATOR 2
GENERATOR 4
to interface:
read SF
to interface:
read CTAF
to interface:
read WTAF
to interface:
read CTBF
to interface:
read AF
to interface:
read BSF
to interface:
read BLF
PULSE
PULSE
PULSE
PULSE
0
1
0
1
0
1
0
1
TAM
TAM
TAM
TBM
Real-Time Clock (RTC) and calendar
013aaa330
WTAIE
CTAIE
CTBIE
BSIE
BLIE
AIE
SIE
CIE
CLKOUT
INT1
INT2
PCF8523
© NXP B.V. 2011. All rights reserved.
INT1/CLKOUT
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