BQ32002 Datasheet, PDF (16/29 Pages) Texas Instruments – BQ32002 Real-Time Clock (RTC)

BQ32002
SLUSA96B – AUGUST 2010 – REVISED APRIL 2016
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Address
Name
Initial Value
Description
D7
X
UC
10_YEAR
1_YEAR
Address
Name
Initial Value
Description
D7
OUT
r/w
1
UC
OUT
FT
S
CAL
Table 10. YEARS Register
0x06
YEARS
XXXXXXXXb
Clock year
D6
D5
D4
D3
D2
D1
D0
BIT(S)
10_YEAR
1_YEAR
Name
r/w
r/w
Read/Write
X
X
X
X
X
X
X
Initial
UC
UC
UC
UC
UC
UC
UC
Cycle
BCD of tens of years. The 10_YEAR bits are the BCD representation of the tens of years on the clock. Valid values are 0
to 9. If invalid data is written to 10_YEAR, the clock will update with invalid data in 10_YEAR until the counter rolls over;
thereafter, the data in 10_YEAR 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 year. The 1_YEAR bits are the BCD representation of the years on the clock. Valid values are 0 to 9. If invalid
data is written to 1_YEAR, the clock will update with invalid data in 1_YEAR until the counter rolls over; thereafter, the
data in 1_YEAR 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.
Table 11. CAL_CFG1 Register
0x07
CAL_CFG1
10000000b
Calibration and control
D6
D5
D4
D3
D2
D1
D0
BIT(S)
FT
S
CAL
Name
r/w
r/w
r/w
Read/Write
0
0
0
0
0
0
0
Initial
UC
UC
UC
UC
UC
UC
UC
Cycle
Logic output, when FT = 0. When FT is zero, the logic output of IRQ pin reflects the value of OUT.
0
IRQ is logic 0
1
IRQ is logic 1
Frequency test. The FT bit is used to enable the frequency test signal on the IRQ pin. When FT is 1, a square wave is
produced on the IRQ pin. The FTF bit in the SFR register determines the frequency of the test signal.
0
Disable
1
Enable
Calibration sign. The S bit determines the polarity of the calibration applied to the oscillator. If S is 0, then the calibration
slows the RTC. If S is 1, then the calibration speeds the RTC.
0
Slowing (+)
1
Speeding (–)
Calibration. The CAL bits along with S determine the calibration amount as shown in Table 12.
CAL (DEC)
0
1
N
30
31
Table 12. Calibration
S=0
+0 ppm
+2 ppm
+N / 491520 (per minute)
+61 ppm
+63 ppm
S=1
–0 ppm
–4 ppm
–N / 245760 (per minute)
–122 ppm
–126 ppm
16
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