FM3130 Integrated RTC/Alarm with 64Kb FRAM
24
25
26
27
28
29
30
31
511.9478
511.9456
511.9433
511.9411
511.9389
511.9367
511.9344
511.9322
511.9456
511.9433
511.9411
511.9389
511.9367
511.9344
511.9322
511.9300
102.00
106.34
110.68
115.02
119.36
123.70
128.04
132.38
106.33
110.67
115.01
119.35
123.69
128.03
132.37
136.71
111000
111001
111010
111011
111100
111101
111110
111111
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Negative Calibration for fast clocks: Calibration will achieve
2.17 PPM after calibration
Measured Frequency Range
Error Range (PPM)
Min
Max
Min
Max
Program Calibration Register to:
512.0000
512.0011
0
2.17
000000
512.0011
512.0033
2.18
6.51
000001
512.0033
512.0056
6.52
10.85
000010
512.0056
512.0078
10.86
15.19
000011
512.0078
512.0100
15.20
19.53
000100
512.0100
512.0122
19.54
23.87
000101
512.0122
512.0144
23.88
28.21
000110
512.0144
512.0167
28.22
32.55
000111
512.0167
512.0189
32.56
36.89
001000
512.0189
512.0211
36.90
41.23
001001
512.0211
512.0233
41.24
45.57
001010
512.0233
512.0256
45.58
49.91
001011
512.0256
512.0278
49.92
54.25
001100
512.0278
512.0300
54.26
58.59
001101
512.0300
512.0322
58.60
62.93
001110
512.0322
512.0344
62.94
67.27
001111
512.0344
512.0367
67.28
71.61
010000
512.0367
512.0389
71.62
75.95
010001
512.0389
512.0411
75.96
80.29
010010
512.0411
512.0433
80.30
84.63
010011
512.0433
512.0456
84.64
88.97
010100
512.0456
512.0478
88.98
93.31
010101
512.0478
512.0500
93.32
97.65
010110
512.0500
512.0522
97.66
101.99
010111
512.0522
512.0544
102.00
106.33
011000
512.0544
512.0567
106.34
110.67
011001
512.0567
512.0589
110.68
115.01
011010
512.0589
512.0611
115.02
119.35
011011
512.0611
512.0633
119.36
123.69
011100
512.0633
512.0656
123.70
128.03
011101
512.0656
512.0678
128.04
132.37
011110
512.0678
512.0700
132.38
136.71
011111
Alarm
The alarm function compares user-programmed
alarm values to the corresponding RTC time/date
values. When a match occurs, an alarm event occurs.
The alarm event sets an internal flag AF (register
00h, bit 6) and drives the ACS pin low, if the
appropriate control bits are set in registers 00h and
0Eh. See Table 3. The alarm condition on the ACS
pin and the AF bit are cleared by reading register
00h.
The alarm operates under V
DD
or V
BAK
power. If the
system controller is being used to detect an alarm
while the FM3130 is powered on V
BAK
only, the ACS
pin may cause extra I
BAK
current when the alarm is
activated. To avoid battery drain, the ACS pin can be
E
T
ent
E
cem 64
L
pla 31
O
t Re : FM
S
irec tive
B
o D rna
O
N Alte
tri-stated by reading the AF flag, located in the
RTC/Alarm Control register 00h.
There are five alarm match fields. They are Month,
Date, Hours, Minutes, and Seconds. Each of these
fields also has a Match bit that is used to determine if
the field is used in the alarm match logic. Setting the
Match bit to „0‟ indicates that the corresponding field
will be used in the match process.
Depending on the Match bits, the alarm can occur as
specifically as one particular second on one day of
the month, or as frequently as once per second
continuously. The MSB of each Alarm register is a
Match bit. Examples of the Match bit settings are
shown in
Table 4. Alarm Match Bit Examples.
Selecting none of the match bits (all „1‟s) indicates
that no match is required. The alarm occurs every
Rev. 3.2
Sept. 2011
Page 6 of 22
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
