BQ32002 Datasheet, PDF (13/29 Pages) Texas Instruments – BQ32002 Real-Time Clock (RTC)

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BQ32002
SLUSA96B – AUGUST 2010 – REVISED APRIL 2016
7.6.2 Normal Register Descriptions
Address
Name
Initial Value
Description
D7
STOP
r/w
0
UC
STOP
10_SECOND
1_SECOND
Table 4. SECONDS Register
0x00
SECONDS
0XXXXXXb
Clock seconds and STOP bit
D6
D5
D4
D3
D2
D1
D0
BIT(S)
10_SECOND
1_SECOND
Name
r/w
r/w
Read/Write
X
X
X
X
X
X
X
Initial
UC
UC
UC
UC
UC
UC
UC
Cycle
Oscillator stop. The STOP bit is used to force the oscillator to stop oscillating. STOP is set to 0 on initial application of
power, on all subsequent power cycles STOP remains unchanged. On initial power application STOP can be written to 1
and then written to 0 to force start the oscillator.
0
Normal
1
Stop
BCD of tens of seconds. The 10_SECOND bits are the BCD representation of the number of tens of seconds on the
clock. Valid values are 0 to 5. If invalid data is written to 10_SECOND, the clock will update with invalid data in
10_SECOND until the counter rolls over; thereafter, the data in 10_SECOND is valid. Time keeping registers can take up
to 1 second to update after the RTC switches from backup power supply to main power supply.
BCD of seconds. The 1_SECOND bits are the BCD representation of the number of seconds on the clock. Valid values
are 0 to 9. If invalid data is written to 1_SECOND, the clock will update with invalid data in 1_SECOND until the counter
rolls over; thereafter, the data in 1_SECOND is valid. Time keeping registers can take up to 1 second to update after the
RTC switches from backup power supply to main power supply.
Address
Name
Initial Value
Description
D7
OF
r/w
1
0
OF
10_MINUTE
1_MINUTE
Table 5. MINUTES Register
0x01
MINUTES
1XXXXXXb
Clock minutes
D6
D5
D4
D3
D2
D1
D0
BIT(S)
10_MINUTE
1_MINUTE
Name
r/w
r/w
Read/Write
X
X
X
X
X
X
X
Initial
UC
UC
UC
UC
UC
UC
UC
Cycle
Oscillator fail flag. The OF bit is a latched flag indicating when the 32.768-kHz oscillator has dropped at least four
consecutive pulses. The OF flag is always set on initial power-up, and it can be cleared through the serial interface.
When OF is 0, no oscillator failure has been detected. When OF is 1, the oscillator fail detect circuit has detected at least
four consecutive dropped pulses.
0
No failure detected
1
Failure detected
BCD of tens of minutes. The 10_MINUTE bits are the BCD representation of the number of tens of minutes on the clock.
Valid values are 0 to 5. If invalid data is written to 10_MINUTE, the clock will update with invalid data in 10_MINUTE until
the counter rolls over; thereafter, the data in 10_MINUTE is valid. Time keeping registers can take up to 1 second to
update after the RTC switches from backup power supply to main power supply.
BCD of minutes. The 1_MINUTE bits are the BCD representation of the number of minutes on the clock. Valid values are
0 to 9. If invalid data is written to 1_MINUTE, the clock will update with invalid data in 1_MINUTE until the counter rolls
over; thereafter, the data in 1_MINUTE is valid. Time keeping registers can take up to 1 second to update after the RTC
switches from backup power supply to main power supply.
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