Rainbow Electronics DS1393 - Manual (Page 13)

Address Map
Table 2 shows the address map for the DS1390–
DS1393 RTC and RAM registers. The RTC registers are
located in address locations 00h to 0Fh in read mode,
and 80h to 8Fh in write mode. During a multibyte
access, when the address pointer reaches 0Fh, it
wraps around to location 00h. On the falling edge of the
CS pin (DS1390/DS1391) or the rising edge of CE
(DS1392/DS1393), 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 if the main registers update during a read. To
avoid rollover issues when writing to the time and date
registers, all registers should be written before the hun-
dredths-of-seconds registers reaches 99 (BCD).
DS1390/DS1391/DS1392/DS1393
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
____________________________________________________________________ 13
WRITE
ADDRESS
READ
ADDRESS
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 FUNCTION RANGE
80h 00h Tenths of Seconds Hundredths of Seconds
Hundredths
of Seconds
0–99 BCD
81h 01h 0 10 Seconds Seconds Seconds 00–59 BCD
82h 02h 0 10 Minutes Minutes Minutes 00–59 BCD
AM/PM
83h 03h 0 12/24
10 Hour
10
Hour
Hour Hours
1–12 +AM/PM
00–23 BCD
84h 04h 0 0 0 0 0 Day Day 1–7 BCD
85h 05h 0 0 10 Date Date Date 01–31 BCD
86h 06h Century 0 0
10
Month
Month
Month/
Century
01–12 +
Century BCD
87h 07h 10 Year Year Year 00–99 BCD
88h 08h Tenths of Seconds Hundredths of Seconds
Alarm
Hundredths
of Seconds
0–99 BCD
89h 09h AM1 10 Seconds Seconds Alarm 00–59 BCD
8Ah 0Ah AM2 10 Minutes Minutes Alarm 00–59 BCD
AM/PM
8Bh 0Bh AM3 12/24
10 Hour
10
Hour
Hour Alarm Hours
1–12 +
AM/PM
00–23 BCD
Day Alarm Day 1–7 BCD
8Ch 0Ch AM4 DY/DT 10 Date
Date Alarm Date 1–31 BCD
0 BBSQI RS2 RS1 INTCN 0 AIE DS1390/93
0 X X X X 0 X DS1391 8Dh 0Dh EOSC
0 BBSQI RS2 RS1 ESQW 0 AIE
Control
DS1392
8Eh 0Eh OSF 0 0 0 0 0 0 AF Status —
8Fh 0Fh TCS3 TCS2 TCS1 TCS0 DS1 DS0 ROUT1 ROUT0
Trickle
Charger
—
Table 2. Address Map
Note: Unless otherwise specified, the state of the registers is not defined when power (V CC and V BACKUP ) is first applied.
X = General-purpose read/write bit.
0 = Always reads as zero.