Rainbow Electronics DS1337 - Manual (Page 8)

DS1337 I 2 C Serial Real-Time Clock
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ADDRESS MAP
Table 2 shows the address map for the DS1337 registers. During a multibyte access, when the address pointer
reaches the end of the register space (0Fh) it wraps around to location 00h. On an I
2 C START, STOP, or address
pointer incrementing to location 00h, the current time is transferred to a second set of registers. The time
information is read from these secondary registers, while the clock may continue to run. This eliminates the need
to re-read the registers in case of an update of the main registers during a read.
Table 2. Timekeeper Registers
ADDRESS BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 FUNCTION RANGE
00H 0 10 Seconds Seconds Seconds 00–59
01H 0 10 Minutes Minutes Minutes 00–59
AM/PM
02H 0 12/ 24
10 Hour
10 Hour Hour Hours
1–12
+AM/PM
00–23
03H 0 0 0 0 0 Day Day 1–7
04H 0 0 10 Date Date Date 01–31
05H Century 0 0 10 Month Month
Month/
Century
01–12 +
Century
06H 10 Year Year Year 00–99
07H A1M1 10 Seconds Seconds
Alarm 1
Seconds
00–59
08H A1M2 10 Minutes Minutes
Alarm 1
Minutes
00–59
AM/PM
09H A1M3 12/ 24
10 Hour
10 Hour Hour
Alarm 1
Hours
1–12 +
AM/PM
00–23
Day
Alarm 1
Day
1–7
0AH A1M4 DY/ DT 10 Date
Date
Alarm 1
Date
1–31
0BH A2M2 10 Minutes Minutes
Alarm 2
Minutes
00–59
AM/PM
0CH A2M3 12/ 24
10 Hour
10 Hour Hour
Alarm 2
Hours
1–12 +
AM/PM
00–23
Day
Alarm 2
Day
1–7
0DH A2M4 DY/ DT 10 Date
Date
Alarm 2
Date
1–31
0EH EOSC 0 0 RS2 RS1 INTCN A2IE A1IE Control —
0FH OSF 0 0 0 0 0 A2F A1F Status —
Note: Unless otherwise specified, the state of the registers is not defined when power is first applied or V
CC
falls below the V
OSC
.