X1242 – Preliminary Information
Characteristics subject to change without notice.
4 of 24
REV 1.1.3 10/15/00
www.xicor.com
The alarm enable bits are located in the MSB of the
particular register. When all enable bits are set to ‘0’,
there are no alarms.
Table 1. Clock/Control Memory Map
Addr.
Type
Reg
Name
Bit
Range
F
S
7
6
5
4
3
2
1
0
(optional)
003F
Status
SR
BAT
AL1
AL0
0
0
RWEL
WEL
RTCF
01h
0037
RTC
(SRAM)
Y2K
0
0
Y2K21
Y2K20
Y2K13
0
0
Y2K10
20
20h
0036
DW
0
0
0
0
0
DY2
DY1
DY0
0-6
00h
0035
YR
Y23
Y22
Y21
Y20
Y13
Y12
Y11
Y10
0-99
00h
0034
MO
0
0
0
G20
G13
G12
G11
G10
1-12
00h
0033
DT
0
0
D21
D20
D13
D12
D11
D10
1-31
00h
0032
HR
MIL
0
H21
H20
H13
H12
H11
H10
0-23
00h
0031
MN
0
M22
M21
M20
M13
M12
M11
M10
0-59
00h
0030
SC
0
S22
S21
S20
S13
S12
S11
S10
0-59
00h
0010
Control
(EEPROM)
BL
BP2
BP1
BP0
WD1
WD0
0
0
0
00h
000F
Alarm1
(EEPROM)
Y2K
0
0
A1Y2K21
A1Y2K20
A1Y2K13
0
0
A1Y2K10
20
20h
000E
DWA
EDW1
0
0
0
0
DY2
DY1
DY0
0-6
00h
000D
YRA
Unused - Default = RTC Year value
000C
MOA
EMO1
0
0
A1G20
A1G13
A1G12
A1G11
A1G10
1-12
00h
000B
DTA
EDT1
0
A1D21
A1D20
A1D13
A1D12
A1D11
A1D10
1-31
00h
000A
HRA
EHR1
0
A1H21
A1H20
A1H13
A1H12
A1H11
A1H10
0-23
00h
0009
MNA
EMN1
A1M22
A1M21
A1M20
A1M13
A1M12
A1M11
A1M10
0-59
00h
0008
SCA
ESC1
A1S22
A1S21
A1S20
A1S13
A1S12
A1S11
A1S10
0-59
00h
0007
Alarm0
(EEPROM)
Y2K0
0
0
A0Y2K21
A0Y2K20
A0Y2K13
0
0
A0Y2K10
20
20h
0006
DWA0
EDW0
0
0
0
0
DY2
DY1
DY0
0-6
0h
0005
YRA0
Unused - Default = RTC Year value
0004
MOA0
EMO0
0
0
A0G20
A0G13
A0G12
A0G11
A0G10
1-12
00h
0003
DTA0
EDT0
0
A0D21
A0D20
A0D13
A0D12
A0D11
A0D10
1-31
00h
0002
HRA0
EHR0
0
A0H21
A0H20
A0H13
A0H12
A0H11
A0H10
0-23
00h
0001
MNA0
EMN0
A0M22
A0M21
A0M20
A0M13
A0M12
A0M11
A0M10
0-59
00h
0000
SCA0
ESC0
A0S22
A0S21
A0S20
A0S13
A0S12
A0S11
A0S10
0-59
00h
REAL TIME CLOCK REGISTERS
Year 2000 (Y2K)
The X1242 has a century byte that “rolls over” from 19
to 20 when the years byte changes from 99 to 00. The
Y2K byte can contain only the values of 19 or 20.
Day of the Week Register (DW)
This register provides a Day of the Week status and
uses three bits DY2 to DY0 to represent the seven
days of the week. The counter advances in the cycle
0-1-2-3-4-5-6-0-1-2-... The assignment of a numerical
value to a specific day of the week is arbitrary and may
be decided by the system software designer. The
Clock Default values define 0 = Sunday.