
STK11C88-3
July 1999
5-17
The STK11C88-3 is a versatile 3.3V V
CC
 memory
chip that provides several modes of operation. The
STK11C88-3 can operate as a standard 32K x 8
SRAM
. It has a 32K x 8 
EEPROM
 shadow to which
the 
SRAM
 information can be copied or from which
the 
SRAM
 can be updated in nonvolatile mode. 
NOISE CONSIDERATIONS
Note that the STK11C88-3 is a high-speed memory
and so must have a high frequency bypass capaci-
tor of approximately 0.1
μ
F connected between V
CC
and V
SS
, using leads and traces that are as short as
possible. As with all high-speed 
CMOS
 ICs, normal
careful routing of power, ground and signals will
help prevent noise problems.
SRAM READ
The STK11C88-3 performs a 
READ
 cycle whenever
E and G are low and W is high. The address speci-
fied on pins A
0-14
 determines which of the 32,768
data bytes will be accessed. When the 
READ
 is initi-
ated by an address transition, the outputs will be
valid after a delay of t
AVQV
 (
READ
 cycle #1). If the
READ
 is initiated by E or G, the outputs will be valid
at t
ELQV
 or at t
GLQV
, whichever is later (
READ 
cycle #2).
The data outputs will repeatedly respond to address
changes within the t
AVQV
 access time without the need
for transitions on any control input pins, and will
remain valid until another address change or until E
or G is brought high.
SRAM WRITE
A 
WRITE
 cycle is performed whenever E and W are
low. The address inputs must be stable prior to
entering the 
WRITE
 cycle and must remain stable
until either E or W goes high at the end of the cycle.
The data on the common I/O pins DQ
0-7
 will be writ-
ten into the memory if it is valid t
DVWH
 before the end
of a W controlled 
WRITE
 or t
DVEH
 before the end of an
E controlled 
WRITE
. 
It is recommended that G be kept high during the
entire 
WRITE
 cycle to avoid data bus contention on
the common I/O lines. If G is left low, internal circuitry
will turn off the output buffers t
WLQZ
 after W goes low.
SOFTWARE NONVOLATILE 
STORE
The STK11C88-3 software 
STORE
 cycle is initiated
by executing sequential 
READ
 cycles from six spe-
cific address locations. During the 
STORE
 cycle an
erase of the previous nonvolatile data is first per-
formed, followed by a program of the nonvolatile
elements. The program operation copies the 
SRAM
data into nonvolatile memory. Once a 
STORE
 cycle
is initiated, further input and output are disabled until
the cycle is completed.
Because a sequence of reads from specific
addresses is used for 
STORE
 initiation, it is impor-
tant that no other 
READ
 or 
WRITE
 accesses inter-
vene in the sequence, or the sequence will be
aborted and no 
STORE
 or 
RECALL
 will take place.
To initiate the software 
STORE
 cycle, the following
READ
 sequence must be performed:
1.
2.
3.
4.
5.
6.
Read address
Read address
Read address
Read address
Read address
Read address
0E38 (hex)
31C7 (hex)
03E0 (hex)
3C1F (hex)
303F (hex)
0FC0 (hex)
Valid READ
Valid READ
Valid READ
Valid READ
Valid READ
Initiate 
STORE
 cycle
The software sequence is clocked with E controlled
READ
s.
Once the sixth address in the sequence has been
entered, the 
STORE
 cycle will commence and the
chip will be disabled. It is important that 
READ
 cycles
and not 
WRITE
 cycles be used in the sequence,
although it is not necessary that G be low for the
sequence to be valid. After the t
STORE
 cycle time has
been fulfilled, the 
SRAM
 will again be activated for
READ
 and 
WRITE
 operation.
SOFTWARE NONVOLATILE 
RECALL
A software 
RECALL
 cycle is initiated with a sequence
of 
READ
 operations in a manner similar to the soft-
ware 
STORE
 initiation. To initiate the 
RECALL
 cycle,
the following sequence of 
READ
 operations must be
performed:
1.
2.
3.
4.
5.
6.
Read address
Read address
Read address
Read address
Read address
Read address
0E38 (hex)
31C7 (hex)
03E0 (hex)
3C1F (hex)
303F (hex)
0C63 (hex)
Valid READ
Valid READ
Valid READ
Valid READ
Valid READ
Initiate 
RECALL
 cycle
DEVICE OPERATION