X20C16
WE Controlled Software Command Sequence
t
t
STO
WC
Address
OE
555
2AA
555
t
OEST
CE
t
AS
t
t
SPH
SP
WE
t
AH
t
NES
t
NEH
NE
t
t
NHZ
SOE
Data Out
Data In
t
t
DS
DH
AA
55
CMD
AUTOSTORE Feature
The AUTOSTORE instruction (EAS) to the SDP regis-
ter sets the AUTOSTORE enable latch, allowing the
X20C16 to automatically perform a store operation
The AUTOSTORE feature automatically saves the con-
tents of the X20C16’s static RAM to the on-board bit-
for-bit shadow EEPROM at power-down. This circuitry
insures that no data is lost during accidental power-
downs or general system crashes, and is ideal for
microprocessor caching systems, embedded software
systems, and general system back-up memory.
whenever V
falls below the AUTOSTORE threshold
must remain above the AUTOSTORE
CC
(V
). V
ASTH
CC
Cycle End Voltage (V
) for the duration of the
ASEND
store cycle (t
). The detailed timing for this feature
ASTO
is illustrated in the AUTOSTORE timing diagram,
below. Once the AUTOSTORE cycle is initiated, all
other device func-tions are inhibited.
Characteristics subject to change without notice. 12 of 21
REV 1.0 6/21/00
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