X4165 INTERSIL [Intersil Corporation], X4165 Datasheet - Page 7

• Manufacturer Part Number: X4165
• Description: CPU Supervisor with 16K EEPROM
• Manufacturer: INTERSIL [Intersil Corporation]

Figure 4. V
Control Register
The Control Register provides the user a mechanism
for changing the Block Lock and Watchdog Timer set-
tings. The Block Lock and Watchdog Timer bits are
nonvolatile and do not change when power is
removed.
The Control Register is accessed at address FFFFh. It
can only be modified by performing a byte write opera-
tion directly to the address of the register and only one
data byte is allowed for each register write operation.
Prior to writing to the 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.
TRIP
Emax = Maximum Allowed V
Programming Sequence
Old V
New V
CC
CC
Applied + Error
Applied =
7
Error ≤ –Emax
TRIP
Error
NO
Set V
X4163, X4165
(V
V
TRIP
Apply 5V to V
CC
Measured V
Decrement V
CC
Desired V
goes active?
Desired V
Reset V
RESET pin
Sequence
Sequence
Set V
= V
Execute
Execute
= V
Programming
DONE
CC
CC
TRIP
- 50mV)
YES
–Emax < Error < Emax
TRIP
Applied =
TRIP
TRIP
TRIP
The user must issue a stop after sending this byte to
the register to initiate the nonvolatile cycle that stores
WD1, and WD0. The X4163, X4165 will not acknowl-
edge any data bytes written after the first byte is
entered.
The state of the Control Register can be read at any
time by performing a random read at address FFFFh.
Only one byte is read by each register read operation.
The X4163, X4165 resets itself after the first byte is
CC
CC
-
Error ≥ Emax
Old V
New V
CC
Reset V
Sequence
CC
Execute
Applied - Error
Applied =
TRIP
May 12, 2006
FN8120.1