X4003 Xicor, X4003 Datasheet - Page 5

• Manufacturer Part Number: X4003
• Description: CPU Supervisor
• Manufacturer: Xicor

X4003/X4005
Figure 4. V
Control Register
The control register provides the user a mechanism for
changing the watchdog timer settings. watchdog timer
bits are nonvolatile and do not change when power is
removed.
The control register is accessed with a special pream-
ble in the slave byte (1011) and is located at address
1FFh. It can only be modified by performing a control
register write operation. Only one data byte is allowed
for each register write operation. Prior to writing to the
REV 1.1.3 4/30/02
TRIP
Old V
New V
Programming Sequence
CC
Reset V
Sequence
CC
Execute
Applied - Error
Applied =
TRIP
Error ≥ Emax
-Emax < Error < Emax
Set V
V
(V
Measured V
TRIP
Apply 5V to V
Decrement V
Desired V
CC
CC
Desired V
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goes active?
Reset V
YES
RESET pin
Sequence
Sequence
Set V
= V
Execute
Execute
= V
DONE
Programming
CC
CC
TRIP
TRIP
–50mV)
TRIP
TRIP
TRIP
Applied =
CC
CC
control register, the WEL and RWEL bits must be set
using a two step process, with the whole sequence
requiring 3 steps. See "Writing to the Control Register"
below.
The user must issue a stop after sending the control
byte to the register to initiate the nonvolatile cycle that
stores WD1 and WD0. The X4003/X4005 will not
acknowledge any data bytes written after the first byte
is entered.
-
NO
Error ≤ –Emax
Emax = Maximum Allowable V
Old V
New V
Characteristics subject to change without notice.
CC
CC
applied + Error
Applied =
TRIP
Error
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