ISL12032 Datasheet, PDF (16/26 Pages) Intersil Corporation – Low Power RTC with Battery Backed SRAM and 50/60 Cycle AC Input and Xtal Back-up

ISL12032
Event Detection Register (EVIC)
TABLE 9. EVENT DETECTION REGISTER (EVIC)
ADDR 7 6
5
4
3
2
1
0
0Eh X EVBATB EVIM EVEN EHYS1 EHYS0 ESMP1 ESMP0
EVENT OUTPUT IN BATTERY MODE ENABLE BIT
(EVBATB)
This bit enables/disables the EVDET pin during battery
backup mode (i.e. VBAT pin supply ON). When the EVBATB
is set to “1”, the Event Detect Output is disabled in battery
backup mode. When the EVBATB is cleared to “0”, the Event
Detect output is enabled in battery backup mode. This
feature can be used to save power during battery mode.
EVENT OUTPUT PULSE MODE (EVIM)
This bit controls the EVDET pin output mode. With EVIM = 0,
the output is in normal mode and when an event is triggered,
the output will be set LOW until reset. With EVIM = 1, the
output is in pulse mode and when an event is triggered, the
device will generate a 200ms to 300ms pulse at the EVDET
output.
EVENT DETECT ENABLE (EVEN)
This bit enables/disables the Event Detect function of the
ISL12032. When this bit is set to “1”, the Event Detect is
active. When this bit is cleared to “0”, the Event Detect is
disabled.
EVENT TIME-BASED HYSTERESIS (EHYS1, EHYS0)
These bits set the amount of time-based hysteresis that is
present at the EVIN pin for deglitching the input signal. The
settings vary from 0ms (hysteresis OFF) to 31.25ms (delay
of 31.25ms to check for change of state at the EVIN pin).
The Hysteresis function and the Event Input Sampling
function work independently.
TABLE 10. EVENT TIME-BASED HYSTERESIS
EHSYS1
EHSYS0
TIME (ms)
0
0
0
0
1
3.9
1
0
16.625
1
1
31.25
EVENT INPUT SAMPLING RATE (ESMP)
These bits set the frequency of sampling of the Event Input
(EVIN). The settings include from 1/4Hz (one sample per 4s)
to 2Hz (twice a second), 1Hz, or continuous sampling
(Always ON). The less frequent the sampling, the lower the
current drain, which can affect battery current drain and
battery life.
.
TABLE 11. EVENT INPUT SAMPLING RATE
ESMP1
ESMP2
SAMPLING RATE
0
0
Always ON
0
1
2 Hz
1
0
1 Hz
1
1
1/4 Hz
Event Index Register (EVIX)
TABLE 12. EVENT INDEX REGISTER (EVIX)
ADDR 7
6
5 432
1
0
0Fh
X
X
X X X X EVIX1 EVIX0
The Event Index Register provides the index for locating an
individual event that has been stored. The Event recording
function allows recalling up to 4 events, although the Event
counting register will count up to 255 events. The 0th
location corresponds to the first event, and the 1st through
3rd locations correspond to the most recent events, with the
3rd location (11b) representing the latest event. Therefore,
setting EVIX to 03h location and reading the TSEVT section
will access the timestamp information for the most recent
(latest) event. Setting this register to another value will allow
reading the corresponding event from the TSEVT section.
EVENT BIT (EVIX <1:0>)
These bits are the Event Counter Register index bits. EVIX1
is the MSB and EVIX0 is the LSB.
Trickle Charge Register (TRICK)
TABLE 13. TRICKLE CHARGE REGISTER (TRICK)
ADDR 7 6 5 4 3 2
1
0
10h X X X X X TRKEN TRKRO1 TRKRO0
The trickle charge function allows charging current to flow
from the V_DD supply to the VBAT pin through a selectable
current limiting resistor. Disabling the trickle charge function
removes this connection and isolates the battery from the
V_DD supply in the case charging is not necessary or harmful
(as in the case with a lithium coin cell battery). Note that
there is no charging diode in series with the trickle charge
resistor, but a switch network that adds a small series
resistance to the charging resistance.
TRICKLE CHARGE BIT (TRKEN)
This bit enables/disables the trickle charge capability for the
backup battery supply. Setting this bit to “1” will enable the
trickle charge. Resetting this bit to “0” will disable the trickle
charge function and isolate the battery from the V_DD supply.
TRICKLE CHARGE RESISTOR (TRKRO<1:0>)
These bits allow the user to change the trickle charge
resistor settings according to the maximum current desired
for the battery or supercapacitor charging.
16
FN6618.2
April 16, 2009