DS3232 Maxim, DS3232 Datasheet - Page 14

• Manufacturer Part Number: DS3232
• Description: The DS3232 is a low-cost temperature-compensated crystal oscillator (TCXO) with a very accurate, temperature-compensated, integrated real-time clock (RTC) and 236 bytes of battery-backed SRAM
• Manufacturer: Maxim

Bit 7: Oscillator Stop Flag (OSF). A logic 1 in this bit
indicates that the oscillator either is stopped or was
stopped for some period and may be used to judge the
validity of the timekeeping data. This bit is set to logic 1
any time that the oscillator stops. The following are
examples of conditions that can cause the OSF bit to
be set:
1) The first time power is applied.
2) The voltages present on both V
3) The EOSC bit is turned off in battery-backed mode.
4) External influences on the crystal (i.e., noise, leak-
This bit remains at logic 1 until written to logic 0.
Bit 6: Battery-Backed 32kHz Output (BB32kHz). This
bit enables the 32kHz output when powered from V
(provided EN32kHz is enabled). If BB32kHz = 0, the
32kHz output is low when the part is powered by V
Bits 5 and 4: Conversion Rate (CRATE1 and
CRATE0). These two bits control the sample rate of the
TCXO. The sample rate determines how often the tem-
perature sensor makes a conversion and applies com-
pensation to the oscillator. Decreasing the sample rate
decreases the overall power consumption by decreas-
ing the frequency at which the temperature sensor
operates. However, significant temperature changes
that occur between samples may not be completely
compensated for, which reduce overall accuracy.
When a new conversion rate is written to the register, it
may take up to the new conversion rate time before the
conversions occur at the new rate.
Extremely Accurate I
Integrated Crystal and SRAM
* POR is defined as the first application of power to the device, either V
14
NAME:
POR*:
insufficient to support oscillation.
age, etc.).
CRATE1
____________________________________________________________________
0
0
1
1
BIT 7
OSF
1
Control/Status Register (0Fh)
CRATE0
0
1
0
1
BB32kHz
BIT 6
1
SAMPLE RATE
CC
(seconds)
CRATE1
BIT 5
and V
128
256
512
0
64
BAT
BAT
2
BAT
CRATE0
are
BIT 4
.
C RTC with
0
Bit 3: Enable 32kHz Output (EN32kHz). This bit indi-
cates the status of the 32kHz pin. When set to logic 1,
the 32kHz pin is enabled and outputs a 32.768kHz
square-wave signal. When set to logic 0, the 32kHz pin
goes low. The initial power-up state of this bit is logic 1,
and a 32.768kHz square-wave signal appears at the
32kHz pin after a power source is applied to the DS3232
(if the oscillator is running).
Bit 2: Busy (BSY). This bit indicates the device is busy
executing TCXO functions. It goes to logic 1 when the
conversion signal to the temperature sensor is asserted
and then is cleared when the conversion is complete.
Bit 1: Alarm 2 Flag (A2F). A logic 1 in the alarm 2 flag
bit indicates that the time matched the alarm 2 regis-
ters. If the A2IE bit is logic 1 and the INTCN bit is set to
logic 1, the INT/SQW pin is also asserted. A2F is
cleared when written to logic 0. This bit can only be
written to logic 0. Attempting to write to logic 1 leaves
the value unchanged.
Bit 0: Alarm 1 Flag (A1F). A logic 1 in the alarm 1 flag
bit indicates that the time matched the alarm 1 regis-
ters. If the A1IE bit is logic 1 and the INTCN bit is set to
logic 1, the INT/SQW pin is also asserted. A1F is
cleared when written to logic 0. This bit can only be
written to logic 0. Attempting to write to logic 1 leaves
the value unchanged.
BAT
EN32kHz
or V
BIT 3
1
CC
Control/Status Register (0Fh)
.
BIT 2
BSY
0
BIT 1
A2F
0
BIT 0
A1F
0