X5043S8ZT1 Datasheet, PDF (6/21 Pages) Intersil Corporation – CPU Supervisor with 4K SPI EEPROM

X5043, X5045
no microprocessor action, the watchdog timer control bits
remain unchanged, even during total power failure.
V_CC Threshold Reset Procedure
The X5043, X5045 are shipped with a standard V_CC
threshold (V_TRIP) voltage. This value will not change over
normal operating and storage conditions. However, in
applications where the standard V_TRIP is not exactly right, or
if higher precision is needed in the V_TRIP value, the X5043,
X5045 threshold may be adjusted. The procedure is
described below, and uses the application of a high voltage
control signal.
Setting the V_TRIP Voltage
This procedure is used to set the V_TRIP to a higher voltage
value. For example, if the current V_TRIP is 4.4V and the new
V_TRIP is 4.6V, this procedure will directly make the change. If
the new setting is to be lower than the current setting, then it
is necessary to reset the trip point before setting the new
value.
To set the new V_TRIP voltage, apply the desired V_TRIP
threshold voltage to the V_CC pin and tie the WP pin to the
programming voltage V_P. Then send a WREN command,
followed by a write of Data 00h to address 01h. CS going
HIGH on the write operation initiates the V_TRIP programming
sequence. Bring WP LOW to complete the operation.
Note: This operation also writes 00h to array address 01h.
Resetting the V_TRIP Voltage
This procedure is used to set the V_TRIP to a “native” voltage
level. For example, if the current V_TRIP is 4.4V and the new
V_TRIP must be 4.0V, then the V_TRIP must be reset. When
V_TRIP is reset, the new V_TRIP is something less than 1.7V.
This procedure must be used to set the voltage to a lower
value.
To reset the V_TRIP voltage, apply at least 3V to the V_CC pin
and tie the WP pin to the programming voltage V_P. Then
send a WREN command, followed by a write of Data 00h to
address 03h. CS going HIGH on the write operation initiates
the V_TRIP programming sequence. Bring WP LOW to
complete the operation.
Note: This operation also writes 00h to array address 03h.
WP
V_P = 15-18V
CS
SCK
SI
0 1 23 4 56 7
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
8 Bits
06h
WREN
02h
Write
01h
Address
FIGURE 1. SET V_TRIP LEVEL SEQUENCE (V_CC = DESIRED V_TRIP VALUE.)
00h
Data
6
FN8126.2
March 16, 2006