PCF2123BS/1,518 NXP Semiconductors, PCF2123BS/1,518 Datasheet - Page 38

• Manufacturer Part Number: PCF2123BS/1,518
• Description: IC RTC/CALENDAR SPI BUS 16HVQFN
• Manufacturer: NXP Semiconductors
• Type: Clock/Calendar/Alarmr

Specifications of PCF2123BS/1,518

• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 1.1 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-VQFN Exposed Pad, 16-HVQFN, 16-SQFN, 16-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant
• Other names: 935286382518

NXP Semiconductors
PCF2123
Product data sheet
Fig 25. Serial bus read example
address
counter
SDO
SCL
SDI
CE
8.12.1 Interface watchdog timer
R/W
b7
xx
1
b6
0
b5
0
During read/write operations, the time counting circuits are frozen. To prevent a situation
where the accessing device becomes locked and does not clear the interface by setting
pin CE LOW, the PCF2123 has a built in watchdog timer. Should the interface be active
for more than 1 s from the time a valid subaddress is transmitted, then the PCF2123 will
automatically clear the interface and allow the time counting circuits to continue counting.
CE must return LOW once more before a new data transfer can be executed.
Fig 26. Interface watchdog timer
b4
1
a. Correct data transfer: read or write
b. Incorrect data transfer; read or write
b3
0
addr 07
b2
1
WD timer
WD timer
counters
counters
b1
HEX
1
data
time
data
time
CE
CE
All information provided in this document is subject to legal disclaimers.
b0
1
b7
Rev. 4 — 22 December 2010
0
07
b6
valid sub-address
valid sub-address
0
months data 11
running
running
b5
0
b4
1
b3
0
BCD
b2
data
data
0
time counters frozen
WD timer running
b1
t
0
w(CE)
data
data
time counters frozen
b0
WD timer running
1 s < t
1
< 1 s
b7
data
data
0
08
w(CE)
b6
0
< 2 s
data transfer fail
b5
years data 06
0
SPI Real time clock/calendar
b4
0
running
b3
0
BCD
b2
1
WD trips
PCF2123
© NXP B.V. 2010. All rights reserved.
running
001aai563
001aai564
b1
1
001aaf916
b0
0
09
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