U635H256 Datasheet, PDF (7/13 Pages) Simtek Corporation – PowerStore 32K x 8 nvSRAM

NONVOLATILE MEMORY OPERATIONS
MODE SELECTION
U635H256
E
W
A13 - A0
(hex)
Mode
I/O
H
X
X
Not Selected
Output High Z
L
H
X
Read SRAM
Output Data
L
L
X
Write SRAM
Input Data
L
H
0E38
31C7
03E0
3C1F
303F
0FC0
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile STORE
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
L
H
0E38
31C7
03E0
3C1F
303F
0C63
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile RECALL
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
Power
Standby
Active
Active
Active
Active
Notes
m
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k, l
k: The six consecutive addresses must be in order listed. W must be high during all six consecutive cycles. See STORE cycle and RECALL
cycle tables and diagrams for further details.
The following six-address sequence is used for testing purposes and should not be used: 0E38, 31C7, 03E0, 3C1F, 303F, 339C.
l: While there are 15 addresses on the U635H256, only the lower 14 are used to control software modes.
Activation of nonvolatile cycles does not depend on the state of G.
m: I/O state assumes that G ≤ V_IL.
No.
PowerStore
Power Up RECALL
24 Power Up RECALL Durationⁿ
Symbol
Alt.
IEC
t_RESTORE
25 STORE Cycle Duration^{f, e}
t_PDSTORE
26
Time allowed to Complete SRAM
Cycle^f
Low Voltage Trigger Level
t_DELAY
V_SWITCH
Conditions
Min. Max. Unit
the power supply
voltage must be stay
above 3.6 V for at least
10 ms after the start of
the STORE operation
650 µs
10 ms
1
µs
4.0 4.5 V
n: t_RESTORE starts from the time V_CC rises above V_SWITCH.
December 12, 1997
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