
U631H256
8
March 31, 2006
STK Control #ML0043
Rev 1.0
No. Software Controlled STORE/RECALL
Cycle
l, n
Symbol
Unit
Alt.
IEC
Min.
Max.
25 STORE/RECALL Initiation Time
t
AVAV
t
cR
25
ns
26 Chip Enable to Output Inactive
o
t
ELQZ
t
dis(E)SR
600
ns
27 STORE Cycle Time
p
t
ELQXS
t
d(E)S
10
ms
28 RECALL Cycle Time
q
t
ELQXR
t
d(E)R
20
μ
s
29 Address Setup to Chip Enable
r
t
AVELN
t
su(A)SR
0
ns
30 Chip Enable Pulse Width
r, s
t
ELEHN
t
w(E)SR
20
ns
31 Chip Disable to Address Change
r
t
EHAXN
t
h(A)SR
0
ns
n:
o:
p:
q:
The software sequence is clocked with E controlled READs
Once the software controlled STORE or RECALL cycle is initiated, it completes automatically, ignoring all inputs.
Note that STORE cycles (but not RECALL) are aborted by V
< V
(STORE inhibit).
An automatic RECALL also takes place at power up, starting when V
CC
exceeds V
SWITCH
and takes t
RESTORE
. V
CC
must not drop below
V
SWITCH
once it has been exceeded for the RECALL to function properly.
Noise on the E pin may trigger multiple READ cycles from the same address and abort the address sequence.
If the Chip Enable Pulse Width is less than t
a(E)
(see Read Cycle) but greater than or equal t
w(E)SR
, than the data may not be valid at
the end of the low pulse, however the STORE or RECALL will still be initiated.
r:
s:
Software Controlled STORE/RECALL Cycle
t, u
(E = HIGH after STORE initiation)
ADDREESS 1
ADDRESS 6
t
cR
(25)
t
cR
(25)
t
w(E)SR
t
h(A)SR
(31)
t
su(A)SR
(29)
(30)
VALID
High Impedance
VALID
t
dis(E)SR
(26)
t
d(E)S
(27)
(28)
t
d(E)R
Ai
E
DQi
Output
Software Controlled STORE/RECALL Cycle
r, s, t, u
(E = LOW after STORE initiation)
t
cR
ADDRESS 1
t
w(E)SR
(30)
ADDRESS 6
t
su(A)SR
(29)
(25)
t
h(A)SR
(31)
t
su(A)SR
(29)
t
h(A)SR
(31)
High Impedance
VALID
VALID
(26)
t
d(E)S
(27)
(28)
t
dis(E)SR
t
d(E)R
t:
W must be HIGH when E is LOW during the address sequence in order to initiate a nonvolatile cycle. G may be either HIGH or LOW
throughout. Addresses 1 through 6 are found in the mode selection table. Address 6 determines wheter the U631H256 performs a STORE
or RECALL.
E must be used to clock in the address sequence for the Software controlled STORE and RECALL cycles.
u:
Ai
E
DQi
Output