BQ4802YDWRG4 Datasheet, PDF (12/26 Pages) Texas Instruments – PARALLEL REAL-TIME CLOCK WITH CPU SUPERVISOR

bq4802Y
bq4802LY
SLUS464C – AUGUST 2000 – REVISED JUNE 2002
FUNCTIONAL DESCRIPTION
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The following sections describe the bq4802Y/bq4802LY functional operation including clock interface, data-retention
modes, power-on reset timing, watchdog timer activation, and interrupt generation.
Table 1. Operational Truth Table
VCC
CS
OE
WE
CEOUT
VOUT
MODE
DQ
POWER
< VCC(MAX)
VIH
X
X
CEIN
VOUT1 Deselect
High Z
Standby
VIL
X
VIL
CEIN
VOUT1
Write
DIN
Active
> VCC(MIN)
VIL
VIL
VIH
CEIN
VOUT1
Read
DOUT
Active
VIL
VIH
VIH
CEIN
VOUT1
Read
High-Z
Active
<VPFD(MIN>VSO
X
X
X
VOH
VOUT1
Deselect
High-Z
CMOS standby
≤ VSO
X
X
X
VOHB
VOUT2
Deselect
High-Z
Battery-backup mode
ADDRESS MAP
The bq4802Y/bq4802LY provides 16 bytes of clock and control status registers. Table 1 is a map of the bq4802Y/bq4802LY
registers, and Table 2 describes the register bits.
Table 2. Clock and Control Register Map
Addr
(h)
D7
D6
D5
D4
D3
D2
D1
D0
0
0
10-second digit
1-second digit
ALM0
1
ALM1
10-second digit
1-second digit
2
0
10-minute digit
1-minute digit
ALM0
3
ALM1
10-minute digit
1-minute digit
4
PM/AM
0
10-hour digit
1-hour digit
ALM1
5
ALM0
PM/AM
10-hour digit
1-hour digit
6
0
0
10-day digit
1-day digit
7
ALM1
ALM0
10-day digit
1-day digit
8
0
0
0
0
0
day of week digit
9
0
0
0
10 mo.
1-month digit
A
10-year digit
1-year digit
B
(1)
WD2
WD1
WD0
RS3
RS2
RS1
RS0
C
(1)
(1)
(1)
(1)
AIE
PIE
PWRIE
ABE
D
(1)
(1)
(1)
(1)
AF
PF
PWRF
BVF
E
(1)
(1)
(1)
(1)
UTI
STOP
24/12
DSE
F
10-century digit
1-century digit
(1) _{Unused bits; cannot be written to and read as 0.}
(2) _{Internal write-protection period after VCC passes VPFD on power up.}
(3) _{Clock calendar data in BCD. Automatic leap year adjustment up to year 2100.}
(4) _{PM/AM = 1 for PM and 0 for AM.}
(5) _{DSE = 1 to enable daylight savings adjustment.}
(6) _{24/12 = 1 to enable 24–hour data representation and 0 for 12–hour data representation.}
(7) _{Day of week coded as Sunday = 1 through Saturday = 7}
(8) _{BVF = 1 for valid BC input}
(9) _{STOP = 1 to turn the RTC on and 0 stops the RTC in battery-backup mode}
Range (h)
00–59
Register
Seconds
00–59 Seconds alarm
00–59
Minutes
00–59
Minutes alarm
01–12AM
81–92PM
01–12AM
81–92PM
01–31
01–31
01–07
01–12
00–99
–
–
–
–
00–99
Hours
Hours alarm
Day
Day alarm
Day of Week
Month
Year
Rates
Enables
Flags
Control
Century
12