pca2125 NXP Semiconductors, pca2125 Datasheet - Page 7

• Manufacturer Part Number: pca2125
• Description: Spi Real Time Clock / Calendar Semiconductors
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA2125_00
Preliminary data sheet
6.2 Reset
The PCA2125 includes an internal reset circuit (see
the oscillator is stopped. The oscillator may be stopped, for example, by grounding one of
the oscillator pins, OSCI or OSCO. The oscillator is also considered to be stopped during
the time between power-up and stable crystal resonance. This time may be in the range of
200ms to 2s depending on crystal type, temperature and supply voltage. Whenever an
internal reset occurs, the RF flag is set.
The SPI interface is initialized whenever the chip enable line CE is inactive.
Table 6:
[1]
[2]
After reset, the following mode is entered:
Address Register name
00
01
02
03
04
05
06
07
08
09
0A
0B
0C
0D
0E
0F
Fig 4. Power on reset
32768Hz CLKOUT active
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
HEX
registers marked ‘x’ are undefined at power up and unchanged by subsequent resets.
registers marked ‘-’ are not implemented.
oscillation
internal
control 1
control 2
seconds
minutes
hours
days
weekdays
months
years
minute alarm
hour alarm
day alarm
weekday alarm
CLKOUT control
timer control
countdown timer
Register reset value
reset
V
DD
Rev. 00.11 — 30 January 2007
Bit 7
0
0
1
-
-
-
-
-
x
1
1
1
1
-
0
x
chip in reset
Bit 6
0
0
x
x
-
-
-
-
x
x
-
-
-
-
-
x
Bit 5
0
0
x
x
x
x
-
-
x
x
x
x
-
-
-
x
Figure
Bit 4
-
0
x
x
x
x
-
x
x
x
x
x
-
-
-
x
SPI Real time clock / calendar
4) which is active whenever
Bit 3
1
0
x
x
x
x
-
x
x
x
x
x
-
-
-
x
chip not in reset
Bit 2
0
0
x
x
x
x
x
x
x
x
x
x
x
0
-
x
PCA2125
© NXP B.V. 2007. All rights reserved.
001aaf897
Bit 1
0
0
x
x
x
x
x
x
x
x
x
x
x
0
1
x
t
Bit 0
0
0
x
x
x
x
x
x
x
x
x
x
x
0
1
x
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