ISL1218 Datasheet, PDF (10/21 Pages) Intersil Corporation – Low Power RTC with Battery Backed SRAM

ISL1218
Write capability is allowable into the RTC registers (00h to
06h) only when the WRTC bit (bit 4 of address 07h) is set to
“1”. A multi-byte read or write operation is limited to one
section per operation. Access to another section requires a
new operation. A read or write can begin at any address
within the section.
A register can be read by performing a random read at any
address at any time. This returns the contents of that register
location. Additional registers are read by performing a
sequential read. For the RTC and Alarm registers, the read
instruction latches all clock registers into a buffer, so an
update of the clock does not change the time being read. A
sequential read will not result in the output of data from the
memory array. At the end of a read, the master supplies a
stop condition to end the operation and free the bus. After a
read, the address remains at the previous address +1 so the
user can execute a current address read and continue
reading the next register.
It is not necessary to set the WRTC bit prior to writing into
the control and status, alarm, and user SRAM registers.
TABLE 1. REGISTER MEMORY MAP
BIT
REG
ADDR. SECTION NAME
7
6
5
4
3
2
00h
SC
0
SC22
SC21
SC20
SC13
SC12
01h
MN
0
MN22 MN21 MN20 MN13 MN12
02h
HR
MIL
0
HR21 HR20 HR13 HR12
03h
RTC
DT
0
0
DT21
DT20
DT13
DT12
04h
MO
0
0
0
MO20 MO13 MO12
05h
YR
YR23
YR22
YR21
YR20
YR13
YR12
06h
DW
0
0
0
0
0
DW2
07h
SR ARST XTOSCB Reserved WRTC Reserved ALM
08h
INT
IM
ALME LPMODE FOBATB FO3
Control
09h
and
Reserved
Status
0Ah
ATR BMATR1 BMATR0 ATR5
ATR4
ATR3
FO2
ATR2
0Bh
DTR Reserved
DTR2
0Ch
SCA ESCA ASC22 ASC21 ASC20 ASC13 ASC12
0Dh
MNA EMNA AMN22 AMN21 AMN20 AMN13 AMN12
0Eh
HRA EHRA
Alarm
0Fh
DTA EDTA
0
AHR21 AHR20 AHR13 AHR12
0
ADT21 ADT20 ADT13 ADT12
10h
MOA EMOA
0
0
AMO20 AMO13 AMO12
11h
DWA EDWA
0
0
0
0
ADW12
12h
USR1 USR17 USR16 USR15 USR14 USR13 USR12
13h
USR2 USR27 USR26 USR25 USR24 USR23 USR22
14h
USR3 USR37 USR36 USR35 USR34 USR33 USR32
15h
USR4 USR47 USR46 USR45 USR44 USR43 USR42
User
16h
USR5 USR57 USR56 USR55 USR54 USR53 USR52
17h
USR6 USR67 USR66 USR65 USR64 USR63 USR62
18h
USR7 USR77 USR76 USR75 USR74 USR73 USR72
19h
USR8 USR87 USR86 USR85 USR84 USR83 USR82
1
SC11
MN11
HR11
DT11
MO11
YR11
DW1
BAT
FO1
ATR1
DTR1
ASC11
AMN11
AHR11
ADT11
AMO11
ADW11
USR11
USR21
USR31
USR41
USR51
USR61
USR71
USR81
0
SC10
MN10
HR10
DT10
MO10
YR10
DW0
RTCF
FO0
ATR0
DTR0
ASC10
AMN10
AHR10
ADT10
AMO10
ADW10
USR10
USR20
USR30
USR40
USR50
USR60
USR70
USR80
RANGE DEFAULT
0-59
00h
0-59
00h
0-23
00h
1-31
00h
1-12
00h
0-99
00h
0-6
00h
N/A
01h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
00-59
00h
00-59
00h
0-23
00h
1-31
00h
1-12
00h
0-6
00h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
N/A
00h
10
FN6313.0
June 22, 2006