X40011 XICOR [Xicor Inc.], X40011 Datasheet - Page 4

• Manufacturer Part Number: X40011
• Description: Dual Voltage Monitor with Integrated CPU Supervisor
• Manufacturer: XICOR [Xicor Inc.]

X40010/X40011/X40014/X40015 – Preliminary
Figure 2. V
WATCHDOG TIMER
The Watchdog Timer circuit monitors the microproces-
sor activity by monitoring the SDA and SCL pins. The
microprocessor must toggle the SDA pin HIGH to LOW
periodically, while SCL also toggles from HIGH to LOW
(this is a start bit) followed by a stop condition prior to
the expiration of the watchdog time out period to pre-
vent a WDO signal going active. The state of two non-
volatile control bits in the Status Register determines
the watchdog timer period. The microprocessor can
change these watchdog bits by writing to the X40010/
11/14/15 control register (also refer to page 19).
Figure 3. Watchdog Restart
V1 AND V2 THRESHOLD PROGRAM PROCEDURE
(OPTIONAL)
The X40010/11/14/15is shipped with standard V1 and
V2 threshold (V
will not change over normal operating and storage con-
ditions. However, in applications where the standard
thresholds are not exactly right, or if higher precision is
needed in the threshold value, the X40010/11/14/15trip
REV 1.3.4 7/12/02
SCL
SDA
WDO
SCL
SDA
TRIPX
.6µs
TRIP1,
Set/Reset Conditions
0
A0h
V
TRIPX
V
TRIP2
1.3µs
) voltages. These values
(X = 1, 2)
Timer Start
7
0
www.xicor.com
V
CC
/V2MON
7
points may be adjusted. The procedure is described
below, and uses the application of a high voltage control
signal.
Setting a V
There are two procedures used to set the threshold
voltages (V
be stored is higher or lower than the present value. For
example, if the present V
V
into the V
lower than the present setting, then it is necessary to
“reset” the V
Setting a Higher V
To set a V
higher than the present threshold, the user must apply
the desired V
sponding input pin Vcc(V1MON), or V2MON. The
Vcc(V1MON) and V2MON must be tied together during
this sequence. Then, a programming voltage (Vp) must
be applied to the WDO pin before a START condition is
set up on SDA. Next, issue on the SDA pin the Slave
Address A0h, followed by the Byte Address 01h for
V
order to program V
valid write operation initiates the programming
sequence. Pin WDO must then be brought LOW to
complete the operation.
Note: This operation does not corrupt the memory
array.
TRIPx
TRIP1
V
P
0
is 3.2 V, the new voltage can be stored directly
00h
and 09h for V
TRIPx
TRIPx
TRIPx
TRIPx
TRIPx
TRIPx
cell. If however, the new setting is to be
), depending if the threshold voltage to
threshold to a new voltage which is
Voltage (x=1, 2)
voltage before setting the new value.
Characteristics subject to change without notice.
TRIPx
TRIPx
7
threshold voltage to the corre-
TRIP2
Voltage (x=1, 2)
. The STOP bit following a
TRIPx
, and a 00h Data Byte in
t
WC
is 2.9 V and the new
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