DS1388 Maxim, DS1388 Datasheet - Page 11

• Manufacturer Part Number: DS1388
• Description: The DS1388 I²C real-time clock (RTC), supervisor, and EEPROM is a multifunction device that provides a clock/calendar, programmable watchdog timer, power-supply monitor with reset, and 512 bytes of EEPROM
• Manufacturer: Maxim

The time and calendar information is obtained by read-
ing the appropriate register bytes. Figure 4 illustrates
the RTC registers. The time and calendar are set or ini-
tialized by writing the appropriate register bytes. The
contents of the time and calendar registers are in the
binary-coded decimal (BCD) format. The end of the
month date is automatically adjusted for months with
fewer than 31 days, including corrections for leap years
through 2099. The day-of-week register increments at
midnight. Values that correspond to the day-of-week
Figure 4. Address Map
Note: Unless otherwise specified, the state of the registers is not defined when power (V
X = General-purpose read/write bit.
0 = Always reads as a zero.
BLK
0h
0h
0h
0h
0h
0h
0h
0h
0h
0h
0h
0h
0h
1h
2h
ADDRESS
00–FFh
00–FFh
WORD
0Ah
0Bh
0Ch
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
I
EOSC
BIT 7
TCS3
OSF
2
0
0
0
0
0
0
Watchdog Tenths of Seconds
Watchdog Tenths of Seconds
C RTC/Supervisor with Trickle Charger
Clock and Calendar
BIT 6
12/24
TCS2
Tenth Seconds
WF
0
0
0
0
10 Year
10 Seconds
10 Minutes
BIT 5
TCS1
AM/
PM
X
0
0
0
____________________________________________________________________
10 Hour
10 Date
10 Hour
Month
BIT 4
TCS0
256 x 8 EEPROM
256 x 8 EEPROM
10
0
0
0
BIT 3
DS1
Watchdog Hundredths of Seconds
X
0
0
Hundredths of Seconds
and 512 Bytes EEPROM
Watchdog Seconds
are user-defined but must be sequential (i.e., if 1
equals Sunday, then 2 equals Monday, and so on).
Illogical time and date entries result in undefined oper-
ation. The DS1388 can be run in either 12-hour or 24-
hour mode. Bit 6 of the hours register is defined as the
12- or 24-hour mode-select bit. When high, the 12-hour
mode is selected. In the 12-hour mode, bit 5 is the
AM/PM bit with logic-high being PM. In the 24-hour
mode, bit 5 is the second 10-hour bit (20–23 hours).
Changing the 12/24 bit requires that the hours data be
re-entered in the proper format.
BIT 2
DS0
0
0
Seconds
Minutes
Month
Hours
Date
Year
ROUT1
BIT 1
WDE
Day
0
CC
WD/RST
ROUT0
BIT 0
and V
0
BACKUP
Trickle Charger
Hundredths of
FUNCTION
Hundredth
Watchdog
Watchdog
EEPROM
EEPROM
Seconds
Seconds
Seconds
Seconds
Minutes
Control
Month
Hours
Date
Year
) is first applied.
Flag
Day
RANGE
00–FFh
00–FFh
AM/PM
1–12+
00–99
00–59
00–59
00–23
01–07
01–31
01–12
00–99
00–99
00–99
—
—
—
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