FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Register Map
The RTC, alarm, and other functions are accessed via 15 special function registers mapped to a separate 2-wire
device ID. The interface protocol is described below. The registers contain timekeeping data, control bits, or
information flags. A description of each register follows the summary table below.
Register Map Summary Table
Address
0Eh
0Dh
0Ch
0Bh
0Ah
09h
08h
07h
06h
05h
04h
03h
02h
01h
00h
D7
AL/SW
/Match
/Match
/Match
/Match
/Match
0
0
0
0
0
0
/OSCEN
LB
D6
F1
0
0
0
D4
WP1
10 mo
10 date
Alarm 10 hours
Alarm 10 minutes
Alarm 10 seconds
10 years
0
0
10 mo
0
10 date
0
0
0
0
10 hours
10 minutes
10 seconds
-
CALS
CAL4
AF
CF
POR
D5
F0
0
D3
WP0
D2
D1
VBC
FC
Alarm months
Alarm date
Alarm hours
Alarm minutes
Alarm seconds
years
months
date
day
hours
minutes
seconds
CAL2
CAL1
CAL
W
D0
TST
Function
Alarm & WP Control
Alarm Month
Alarm Date
Alarm Hours
Alarm Minutes
Alarm Seconds
RTC Years
Range
01-12
01-31
00-23
00-59
00-59
00-99
1-12
1-31
1-7
0-23
0-59
0-59
0
CAL3
AEN
CAL0
R
RTC Month
RTC Date
RTC Day
RTC Hours
RTC Minutes
RTC Seconds
CAL/Control
RTC/Alarm Control
Note: When the device is first powered up, all registers should be treated as unknown and must be written.
Otherwise, unpredictable behavior may result.
Rev. 1.2
Feb. 2009
Page 8 of 21
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
