FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Register Description
Address Description
0Eh
Alarm & WP Control
D7
D6
D5
D4
D3
D2
D1
D0
AL/SW
F1
F0
WP1
WP0
VBC
FC
TST
AL/SW
F(1:0)
Alarm/Square Wave Select: When set to 1, the alarm controls the ACS pin as well as the AF flag. When set to 0,
the selected Square Wave Freq will be driven on the ACS pin, and an alarm match only sets the AF flag. Battery-
backed, read/write.
Square Wave Freq Select: These bits select the frequency on the ACS pin when the CAL and AL/SW bits are
both 0. Battery-backed.
Setting
1 Hz
12 Hz
F(1:0)
00 (default)
01
Setting
F(1:0)
10
4096 Hz
32768 Hz
5
11
WP1,WP0 Write Protect. These bits control the write protection of the memory array. Battery-backed, read/write.
Write-Protect addresses
None
WP1
WP0
0
0
1
1
0
1
0
1
Bottom 1/4
Bottom 1/2
Full array
VBC
FC
VBAK Charger Control: Setting VBC to 1 (and FC=0) causes approx. 80 µA (1mA if FC=1) trickle charge
current to be supplied on VBAK. Clearing VBC to 0 disables the charge current. Battery-backed, read/write.
Fast Charge: Setting FC to 1 (and VBC=1) causes approx. 1mA trickle charge current to be supplied on VBAK
.
Clearing VBC to 0 disables the charge current. Battery-backed, read/write.
Invokes factory test mode. Users should always set this bit to 0.
TST
0Dh
Alarm – Month
D7
D6
D5
D4
D3
D2
D1
D0
M
0
0
10 Month
Month.3
Month.2
Month.1
Month.0
Contains the alarm value for the month and the mask bit to select or deselect the Month value.
Match. Setting this bit to a ‘0’ causes the Month value to be used in the alarm match logic. Setting this bit to a
/M
‘1’ causes the match circuit to ignore the Month value. Battery-backed, read/write.
0Ch
Alarm – Date
D7
D6
D5
D4
D3
D2
D1
D0
M
0
10 date.1
10 date.0
Date.3
Date.2
Date.1
Date.0
Contains the alarm value for the date and the mask bit to select or deselect the Date value.
/M
Match: Setting this bit to a ‘0’ causes the Date value to be used in the alarm match logic. Setting this bit to a ‘1’
causes the match circuit to ignore the Date value. Battery-backed, read/write.
0Bh
Alarm – Hours
D7
D6
D5
D4
D3
D2
D1
D0
M
0
10 hours.1
10 hours.0
Hours.3
Hours2
Hours.1
Hours.0
Contains the alarm value for the hours and the mask bit to select or deselect the Hours value.
/M
Match: Setting this bit to a ‘0’ causes the Hours value to be used in the alarm match logic. Setting this bit to a ‘1’
causes the match circuit to ignore the Hours value. Battery-backed, read/write.
0Ah
Alarm – Minutes
D7
D6
D5
D4
D3
D2
D1
D0
M
10 min.2
10 min.1
10 min.0
Min.3
Min.2
Min.1
Min.0
Contains the alarm value for the minutes and the mask bit to select or deselect the Minutes value
/M
Match: Setting this bit to a ‘0’ causes the Minutes value to be used in the alarm match logic. Setting this bit to a
‘1’ causes the match circuit to ignore the Minutes value. Battery-backed, read/write.
Rev. 1.2
Feb. 2009
Page 9 of 21
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
