pcf2123 NXP Semiconductors, pcf2123 Datasheet - Page 33

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

NXP Semiconductors
Table 40.
[1]
PCF2123_1
Product data sheet
Bit
STOP
Clock is running normally
0
STOP bit is activated by user. F
1
New time is set by user
1
STOP bit is released by user
0
F
0
is clocked at 32.768 kHz.
Prescaler bits
F
01-0 0001 1101 0100
XX-0 0000 0000 0000
XX-0 0000 0000 0000
XX-0 0000 0000 0000
XX-1 0000 0000 0000
XX-0 1000 0000 0000
XX-1 1000 0000 0000
:
11-1 1111 1111 1110
00-0 0000 0000 0001
10-0 0000 0000 0001
:
11-1 1111 1111 1111
00-0 0000 0000 0000
10-0 0000 0000 0000
:
11-1 1111 1111 1110
00-0 0000 0000 0001
First increment of time circuits after STOP bit release
0
F
1
-F
2
to F
14
The first increment of the time circuits is between 0.499888 s and 0.500000 s after STOP
bit is released. The uncertainty is caused by the prescaler bits F
(see
Fig 21. STOP bit release timing
Table
[1]
0
F
1
40).
are not reset and values cannot be predicted externally
stop released
1 Hz tick
001aaf913
8192 Hz
Rev. 01 — 19 November 2008
Time
hh:mm:ss
12:45:12
12:45:12
08:00:00
08:00:00
08:00:00
08:00:00
08:00:00
:
08:00:00
08:00:01
08:00:01
:
08:00:01
08:00:01
08:00:01
:
08:00:01
08:00:02
Comment
prescaler counting normally
prescaler is reset; time circuits are frozen
prescaler is reset; time circuits are frozen
prescaler is now running
-
-
-
:
-
0 to 1 transition of F
-
:
-
-
-
-
-
0 to 1 transition of F
0 s to 122 s
14
14
SPI Real time clock/calendar
increments the time circuits
increments the time circuits
0
and F
PCF2123
001aaf912
© NXP B.V. 2008. All rights reserved.
1
not being reset
33 of 54