DS1340 Maxim, DS1340 Datasheet - Page 8

• Manufacturer Part Number: DS1340
• Description: The DS1340 is a real-time clock (RTC)/calendar that is pin compatible and functionally equivalent to the ST M41T00, including the software clock calibration
• Manufacturer: Maxim

I
Table 3 shows the DS1340 address map. The RTC reg-
isters are located in address locations 00h to 06h, and
the control register is located at 07h. The trickle-charge
and flag registers are located in address locations 08h
to 09h. During a multibyte access of the timekeeping
registers, when the address pointer reaches 07h—the
end of the clock and control register space—it wraps
around to location 00h. Writing the address pointer to
the corresponding location accesses address locations
08h and 09h. After accessing location 09h, the address
pointer wraps around to location 00h. On a I
Figure 5. Functional Diagram
X = Read/Write bit
Note: Unless otherwise specified, the state of the registers is not defined when power is first applied.
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Table 3. Address Map
ADDRESS
2
_______________________________________________________________________________________
00H
01H
02H
03H
04H
05H
06H
07H
08H
09H
C RTC with Trickle Charger
EOSC
BIT 7
TCS3
OUT
CEB
OSF
X
X
X
X
"C" VERSION ONLY
V
BACKUP
BIT 6
TCS2
CB
SDA
SCL
FT
V
X
X
X
0
CC
10 Year
X1
X2
10 Seconds
10 Minutes
BIT 5
TCS1
X
X
S
0
Address Map
10 Hours
10 Date
C
C
AND ADDRESS
L
L
INTERFACE
CONTROL
REGISTER
10 Month
POWER
SERIAL
BIT 4
CAL4
TCS0
X
0
2
C START,
BIT 3
CAL3
DS1
X
0
32,768Hz
DS1340
CALIBRATION
DIVIDER AND
CONTROL
CIRCUIT
LOGIC
BIT 2
CAL2
DS0
STOP, or address pointer incrementing to location 00h,
the current time is transferred to a second set of regis-
ters. The time information is read from these secondary
registers, while the clock may continue to run. This
eliminates the need to reread the registers in case the
main registers update during a read.
The time and calendar information is obtained by read-
ing the appropriate register bytes. Table 3 shows the
RTC registers. The time and calendar data are set or
initialized by writing the appropriate register bytes. The
contents of the time and calendar registers are in the
0
Seconds
Minutes
Hours
Month
512Hz
Date
Year
1Hz
Day
ROUT1
CAL1
BIT 1
0
USER BUFFER
CLOCK AND
CALENDAR
REGISTERS
(7 BYTES)
BUFFER
MUX/
ROUT0
BIT 0
CAL0
0
Clock and Calendar
Trickle Charger
N
Century/Hours
FUNCTION
Seconds
Minutes
Control
Month
Date
Year
Flag
Day
FT/OUT
0–1; 00–23
RANGE
00–59
00–59
01–07
01–31
01–12
00–99
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—
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