X4003/X4005
Figure 4. V
Programming Sequence
TRIP
V
Programming
Execute
TRIP
Reset V
TRIP
Sequence
Set V
= V
Applied =
TRIP
CC
CC
Desired V
Execute
TRIP
Sequence
New V
Applied =
applied + Error
New V
Applied =
Applied - Error
CC
CC
Set V
Old V
Old V
CC
CC
Execute
Apply 5V to V
CC
Reset V
TRIP
Sequence
Decrement V
(V
CC
= V –50mV)
CC
CC
NO
RESET pin
goes active?
YES
Error ≥ Emax
Error ≤ –Emax
Measured V
-
TRIP
TRIP
Desired V
-Emax < Error < Emax
DONE
Emax = Maximum Allowable V
Error
TRIP
Control Register
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 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 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.
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
Characteristics subject to change without notice. 5 of 18
REV 1.1.3 4/30/02
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