DS3232 Maxim, DS3232 Datasheet - Page 13

• 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

The DS3232 has two additional registers (control and
control/status) that control the real-time clock, alarms,
and square-wave output.
Bit 7: Enable Oscillator (EOSC). When set to logic 0,
the oscillator is started. When set to logic 1, the oscilla-
tor is stopped when the DS3232 switches to battery
power. This bit is clear (logic 0) when power is first
applied. When the DS3232 is powered by V
oscillator is always on regardless of the status of the
EOSC bit. When EOSC is disabled, all register data is
static.
Bit 6: Battery-Backed Square-Wave Enable
(BBSQW). When set to logic 1 with INTCN = 0 and V
< V
is logic 0, the INT/SQW pin goes high impedance when
V
first applied.
Bit 5: Convert Temperature (CONV). Setting this bit to
1 forces the temperature sensor to convert the temper-
ature into digital code and execute the TCXO algorithm
to update the capacitance array to the oscillator. This
can only happen when a conversion is not already in
progress. The user should check the status bit BSY
before forcing the controller to start a new TCXO exe-
cution. A user-initiated temperature conversion does
not affect the internal 64-second (default interval)
update cycle.
A user-initiated temperature conversion does not affect
the BSY bit for approximately 2ms. The CONV bit
remains at a 1 from the time it is written until the conver-
sion is finished, at which time both CONV and BSY go
to 0. The CONV bit should be used when monitoring
the status of a user-initiated conversion.
Bits 4 and 3: Rate Select (RS2 and RS1). These bits
control the frequency of the square-wave output when
* POR is defined as the first application of power to the device, either V
NAME:
POR*:
CC
PF
< V
, this bit enables the square wave. When BBSQW
PF
. This bit is disabled (logic 0) when power is
Special-Purpose Registers
EOSC
BIT 7
0
BBSQW
BIT 6
Control Register (0Eh)
0
Extremely Accurate I
____________________________________________________________________
CONV
BIT 5
0
Integrated Crystal and SRAM
CC
, the
CC
BIT 4
RS2
1
the square wave has been enabled. The following table
shows the square-wave frequencies that can be select-
ed with the RS bits. These bits are both set to logic 1
(8.192kHz) when power is first applied.
Bit 2: Interrupt Control (INTCN). This bit controls the
INT/SQW signal. When the INTCN bit is set to logic 0, a
square wave is output on the INT/SQW pin. When the
INTCN bit is set to logic 1, a match between the time-
keeping registers and either of the alarm registers acti-
vates the INT/SQW (if the alarm is also enabled). The
corresponding alarm flag is always set regardless of
the state of the INTCN bit. The INTCN bit is set to logic
1 when power is first applied.
Bit 1: Alarm 2 Interrupt Enable (A2IE). When set to
logic 1, this bit permits the alarm 2 flag (A2F) bit in the
status register to assert INT/SQW (when INTCN = 1).
When the A2IE bit is set to logic 0 or INTCN is set to
logic 0, the A2F bit does not initiate an interrupt signal.
The A2IE bit is disabled (logic 0) when power is first
applied.
Bit 0: Alarm 1 Interrupt Enable (A1IE). When set to
logic 1, this bit permits the alarm 1 flag (A1F) bit in the
status register to assert INT/SQW (when INTCN = 1).
When the A1IE bit is set to logic 0 or INTCN is set to
logic 0, the A1F bit does not initiate the INT/SQW sig-
nal. The A1IE bit is disabled (logic 0) when power is
first applied.
SQUARE-WAVE OUTPUT FREQUENCY
BAT
RS2
or V
0
0
1
1
BIT 3
RS1
1
CC
.
RS1
0
1
0
1
INTCN
BIT 2
Control Register (0Eh)
1
2
SQUARE-WAVE OUTPUT
C RTC with
BIT 1
A2IE
FREQUENCY
0
1.024kHz
4.096kHz
8.192kHz
1Hz
BIT 0
A1IE
0
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