X25401
PIN DESCRIPTIONS
PIN CONFIGURATION
Chip Select (CS)
The Chip Select input must be LOW to enable all read/
write operations. CS must remain LOW following a
Read or Write command until the data transfer is com-
plete. CS HIGH places the X25401 in the low power
standby mode and resets the instruction register. There-
fore, CS must be brought HIGH after the completion of
an operation in order to reset the instruction register in
preparation for the next command.
DIP/SOIC
CS
SCK
SI
1
2
3
4
8
7
6
5
V
CC
AS
X25401
RECALL
SO
V
SS
Serial Clock (SCK)
2051 FHD F02
The Serial Clock input is used to clock all data into and
out of the device.
Serial Data In (SI)
SI is the serial data input.
PIN NAMES
Serial Data Out (SO)
Symbol
CS
SCK
SI
Description
Chip Enable
SO is the serial data output. It is in the high impedance
state except during data output cycles in response to a
READ instruction.
Serial Clock
Serial Data In
Serial Data Out
Recall Input
AUTOSTORE Output
+5V
AUTOSTORE Output (AS)
SO
AS is an open drain output which, when asserted indi-
RECALL
AS
cates V has fallen below the AUTOSTORE thresh-
CC
old (V
). AS may be wire-ORed with multiple open
ASTH
V
V
CC
SS
drain outputs and used as an interrupt input to a micro-
controller or as an input to a low power reset circuit.
Ground
2051 PGM T01
RECALL
RECALL LOW will initiate an internal transfer of data
2
from E PROM to the RAM array.
2
XICOR [ XICOR INC. ]
