PCA2125TS/1-T NXP Semiconductors, PCA2125TS/1-T Datasheet - Page 13

• Manufacturer Part Number: PCA2125TS/1-T
• Description: Real Time Clock AUTO RL TME CLCK/CAL
• Manufacturer: NXP Semiconductors

Specifications of PCA2125TS/1-T

• Bus Type: Serial (3-Wire, SPI)
• Package Type: TSSOP
• Operating Supply Voltage (max): 5.5V
• Operating Temperature (min): -40C
• Mounting: Surface Mount
• Date Format: DW:DM:M:Y
• Time Format: HH:MM:SS
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-14
• Lead Free Status / RoHS Status: Compliant
• Other names: PCA2125TS/1,118

NXP Semiconductors
Table 25.
PCA2125_1
Product data sheet
Bit
7 to 0 COUNTDOWN_TIMER[7:0]
Symbol
Register Countdown_timer (address 0Fh) bit description
8.6.1 Second and minute interrupt
8.6 Timer functions
To prevent the timer flags being overwritten while clearing bit AF, a logic AND is performed
during a write access. The flag is reset by writing a logic 0 but its value is not affected by
writing a logic 1.
Table 22.
Table 23
bit TF are unaffected.
Table 23.
The countdown timer has four selectable source clocks allowing for countdown periods in
the range from less than 1 ms to more than 4 hours. There are also two pre-defined timers
which can be used to generate an interrupt once per second or once per minute.
Registers Control_2 (01h), Timer_control (0Eh) and Countdown_timer (0Fh) are used to
control the timer function and output.
Table 24.
The second and minute interrupts (bits SI and MI) are pre-defined timers for generating
periodic interrupts. The timers can be enabled independently of one another, however a
minute interrupt enabled on top of a second interrupt will not be distinguishable since it will
occur at the same time; see
Register
Control_2
Register
Control_2
Bit
7
6 to 2
1 to 0
shows what instruction must be sent to clear bit AF. In this example, bit MSF and
Symbol
TE
-
CTD[1:0]
Flag location in register Control_2
Example to clear only AF (bit 3) in register Control_2
Register Timer_control (address 0Eh) bit description
Value
00h to FFh
Bit 7
-
Bit 7
-
Value
0
1
0
00
01
10
11
Rev. 01 — 28 July 2008
Bit 6
-
Bit 6
-
Description
countdown value = n.
CountdownPeriod
Figure
Description
countdown timer is disabled
countdown timer is enabled
unused
4096 Hz countdown timer source clock
64 Hz countdown timer source clock
1 Hz countdown timer source clock
1
60
Bit 5
MSF
Bit 5
1
Hz countdown timer source clock
9.
Bit 4
-
Bit 4
-
=
-------------------------------------------------------------- -
SourceClockFrequency
Bit 3
AF
Bit 3
0
n
SPI Real-time clock/calendar
Bit 2
TF
Bit 2
1
PCA2125
© NXP B.V. 2008. All rights reserved.
Bit 1
-
Bit 1
-
Reference
Section 8.6.2
Reference
Section 8.6.2
Bit 0
-
Bit 0
-
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