x5323v14zt1 Intersil Corporation, x5323v14zt1 Datasheet - Page 5

• Manufacturer Part Number: x5323v14zt1
• Description: Cpu Supervisor With 32kb Spi Eeprom
• Manufacturer: Intersil Corporation

PRINCIPLES OF OPERATION
Power-on Reset
Application of power to the X5323/X5325 activates a
power-on reset circuit. This circuit goes active at about
1V and pulls the RESET/RESET pin active. This signal
prevents the system microprocessor from starting to
operate with insufficient voltage or prior to stabilization
of the oscillator. As long as RESET/RESET pin is
active, the device will not respond to any Read/Write
instruction. When V
for
RESET/RESET, allowing the processor to begin exe-
cuting code.
Low Voltage Monitoring
During operation, the X5323/X5325 monitors the V
level and asserts RESET/RESET if supply voltage
falls
RESET/RESET signal prevents the microprocessor
from operating in a power fail or brownout condition.
The RESET/RESET signal remains active until the
voltage drops below 1V. It also remains active until
V
Watchdog Timer
The watchdog timer circuit monitors the microprocessor
activity by monitoring the WDI input. The microprocessor
must toggle the CS/WDI pin periodically to prevent a
RESET/RESET signal. The CS/WDI pin must be tog-
gled from HIGH to LOW prior to the expiration of the
watchdog time out period. The state of two nonvolatile
control bits in the status register determine the watch-
dog timer period. The microprocessor can change
these watchdog bits, or they may be “locked” by tying
the WP pin LOW and setting the WPEN bit HIGH.
V
The X5323/X5325 has a standard V
(V
operating and storage conditions. However, in applica-
tions where the standard V
for
X5323/X5325 threshold may be adjusted.
Setting the V
This procedure sets the V
value. For example, if the current V
the new V
the change. If the new setting is lower than the current
setting, then it is necessary to reset the trip point
before setting the new value.
CC
CC
TRIP
returns and exceeds V
Threshold Reset Procedure
higher
200ms
) voltage. This value will not change over normal
below
TRIP
precision
TRIP
is 4.6V, this procedure directly makes
a
(nominal)
Voltage
CC
preset
exceeds the device V
in
5
TRIP
TRIP
TRIP
minimum
the
the
for 200ms.
is not exactly right, or
to a higher voltage
V
TRIP
circuit
TRIP
CC
V
is 4.4V and
TRIP
value,
TRIP
threshold
releases
.
value
X5323, X5325
The
the
CC
To set the new V
threshold to the Vcc pin and tie the CS/WDI pin and
the WP pin HIGH. RESET/RESET and SO pins are
left unconnected. Then apply the programming voltage
V
HIGH. Remove V
Figure 1. Set V
Resetting the V
This procedure sets the V
level. For example, if the current V
V
1.7V. This procedure must be used to set the voltage
to a lower value.
To reset the V
2.7 and 5.5V to the V
WP pin, and the SCK pin HIGH. RESET/RESET and
SO pins are left unconnected. Then apply the pro-
gramming voltage V
CS/WDI LOW then HIGH. Remove V
sequence is complete.
Figure 2. Reset V
P
TRIP
to both SCK and SI and pulse CS/WDI LOW then
is reset, the new V
SCK
SCK
SI
CS
SI
CS
V
V
V
V
P
CC
P
P
TRIP
TRIP
TRIP
TRIP
P
TRIP
and the sequence is complete.
Voltage
voltage, apply a voltage between
P
Voltage
voltage, apply the desired V
CC
to the SI pin ONLY and pulse
Voltage
pin. Tie the CS/WDI pin, the
TRIP
TRIP
is something less than
to a “native” voltage
TRIP
is 4.4V and the
P
October 27, 2005
and the
FN8131.1
TRIP