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PCA2125TS/1,112

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33P34-P36
PCA2125_1 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 01 — 28 July 2008 7 of 36
NXP Semiconductors
PCA2125
SPI Real-time clock/calendar
8.3 Control registers
Table 6. Control_1 register (address 00h) bit description
Bit Symbol Value Description Reference
7 EXT_TEST 0 normal mode
Section 8.9
1 external clock test mode
6 - 0 unused
5 STOP 0 RTC source clock runs
Section 8.10
1 RTC divider chain flip-flops are asynchronously set
to logic 0; the RTC clock is stopped (CLKOUT at
32.768 kHz, 16.384 kHz or 8.192 kHz is still
available)
4 - 0 unused -
3 POR_OVRD 0 power-on reset override facility is disabled; set to
logic 0 for normal operation
Section 8.2.1
1 power-on reset override is enabled
2 12_24 0 24 hour mode is selected
Table 11
1 12 hour mode is selected
1 to 0 - 0 unused -
Table 7. Control_2 register (address 01h) bit description
Bit Symbol Value Description Reference
7 MI 0 minute interrupt is disabled
Section 8.6.1
1 minute interrupt is enabled
6 SI 0 second interrupt is disabled
1 second interrupt is enabled
5 MSF 0 no minute or second interrupt generated
Section 8.6
1 flag set when minute or second interrupt generated;
flag must be cleared to clear interrupt
4 TI_TP 0 interrupt pin follows timer flags
Section 8.7.2
1 interrupt pin generates a pulse
3 AF 0 no alarm interrupt generated
Section 8.5.1
1 flag set when alarm triggered; flag must be cleared
to clear interrupt
2 TF 0 no countdown timer interrupt generated -
1 flag set when countdown timer interrupt generated;
flag must be cleared to clear interrupt
-
1 AIE 0 no interrupt generated from the alarm flag
Section 8.7.3
1 interrupt generated when alarm flag set
0 TIE 0 no interrupt generated from the countdown timer
flag
Section 8.7
1 interrupt generated when countdown timer flag set
PCA2125_1 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 01 — 28 July 2008 8 of 36
NXP Semiconductors
PCA2125
SPI Real-time clock/calendar
8.4 Time and date function
The majority of the registers are coded in the Binary Coded Decimal (BCD) format. BCD
is used to simplify application use.
An example is shown for register Minutes in Table 8.
[1] Hour mode is set by bit 12_24 in register Control_1.
Table 8. BCD example
Minutes value
(decimal)
Double-digit Digit
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
2
3
2
2
2
1
2
0
2
3
2
2
2
1
2
0
00 00000000
01 00000001
02 00000010
: ::::::::
09 00001001
10 00010000
: ::::::::
58 01011000
59 01011001
Table 9. Register Seconds (address 02h) bit description
Bit Symbol Value Description
7 RF 0 clock integrity is guaranteed
1 clock integrity is not guaranteed; chip reset has
occurred since flag was last cleared
6 to 0 SECONDS[6:0] 00 to 59 this register holds the current seconds value coded in
BCD format
Table 10. Register Minutes (address 03h) bit description
Bit Symbol Value Description
7 - 0 unused
6 to 0 MINUTES[6:0] 00 to 59 this register holds the current minutes value coded in
BCD format
Table 11. Register Hours (address 04h) bit description
Bit Symbol Value Description
6 and 7 - 0 unused
12 hour mode
[1]
5 AMPM 0 indicates AM
1 indicates PM
4 to 0 HOURS[4:0] 01 to 12 this register holds the current hours value coded in
BCD format for 12 hour mode
24 hour mode
[1]
5 to 0 HOURS[5:0] 00 to 23 this register holds the current hours value coded in
BCD format for 24 hour mode
PCA2125_1 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 01 — 28 July 2008 9 of 36
NXP Semiconductors
PCA2125
SPI Real-time clock/calendar
[1] The RTC compensates for leap years by adding a 29th day to February if the year counter contains a value
which is exactly divisible by 4, including the year 00.
[1] The weekday assignments can be re-defined by the user.
Table 12. Register Days (address 05h) bit description
Bit Symbol Value Description
6, 7 - 0 unused
5 to 0 DAYS[5:0] 01 to 31 this register holds the current day value coded in BCD
format
[1]
Table 13. Register Weekdays (address 06h) bit description
Bit Symbol Value Description
3 to 7 - 0 unused
2 to 0 WEEKDAYS[2:0] 0 to 6 this register holds the current weekday value; see
Table 14
Table 14. Weekday assignments
Day
[1]
Double-digit Digit
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Sunday X XXXX000
Monday X XXXX001
Tuesday X XXXX010
Wednesday X XXXX011
Thursday X XXXX100
Friday XXXXX101
Saturday X XXXX110
Table 15. Register Months (address 07h) bit description
Bit Symbol Value Description
5 to 7 - 0 unused
4 to 0 MONTHS[4:0] 01 to 12 this register holds the current month value coded in BCD
format; see
Table 16
Table 16. Month assignments
Month Double-digit Digit
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
January XXX00001
February X X X 0 0 0 1 0
March X X X 0 0 0 1 1
April X X X 0 0 1 0 0
May XXX00101
June X X X 0 0 1 1 0
July X X X 0 0 1 1 1
August X X X 0 1 0 0 0
September X X X 0 1 0 0 1
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PCA2125TS/1,112

Mfr. #:
Buy PCA2125TS/1,112
Manufacturer:
NXP Semiconductors
Description:
IC RTC CLK/CALENDAR SPI 14-TSSOP
Lifecycle:
New from this manufacturer.
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