SRM2AW216LLBT
1/7
6
● Reading data
It is possible to control the data width by LB and UB pins.
(1) Reading data from lower byte
Data is able to be read when the address is set while holding CS ="Low", OE= "Low", LB ="Low" and WE =
"High".
(2) Reading data from upper byte
Data is able to be read when the address is set while holding CS = "Low", OE = "Low", UB = "Low" and WE
="High".
(3) Reading data from both bytes
Data is able to be read when the address is set while holding CS = "Low", OE ="Low", UB ="Low", LB =
"Low", and WE = "High"
Since I/O pins are in "Hi-Z" state when OE = "High", the data bus line can be used for any other objective, then
access time apparently is able to be cut down.
● Writing data
(1) Writing data into lower byte
There are the following three ways of writing data into memory.
i) Hold WE = "Low", UB = "High" and LB = "Low", set address and give "Low" pulse to CS.
ii) Hold CS = "Low", UB = "High" and LB = "Low", set address and give "Low" pulse to WE.
iii) Set address and give "Low" pulse to CS, UB = "High" and "Low" pulse to WE, LB.
Anyway, data on I/O pins are latched up into the memory cell during CS ="Low", WE ="Low", and LB = "Low".
(2) Writing data into upper byre
There are the following three ways of writing data into the memory.
i) Hold WE = "Low", LB = "High" and UB = "Low", set address and give "Low" pulse to CS.
ii) Hold CS = "Low", LB = "High" and UB = "Low", set address and give "Low" pulse to WE.
iii) Set address and give "Low" pulse to CS, LB = "High" and "Low" pulse to WE, UB.
Anyway, data on I/O pins are latched up into the memory cell during CS = "Low", WE = "Low", and UB = "Low".
(3)Writing data into both bytes
There are the following three ways of writing data into the memory.
i) Hold WE = "Low", LB and UB = "Low", set address and give "Low" pulse to CS.
ii) Hold CS = "Low", LB and UB = "Low", set address and give "Low" pulse to WE.
iii) Set address give "Low" pulse to both pins of LB and UB, "Low" pulse to CS and "Low" pulse to WE.
CS
H
L
L
L
L
L
L
L
L
X
H
L
H
L
L
H
L
X
LB X
H
H
L
L
H
L
L
X
UB X
X
X
X
X
L
L
L
H
OE X
X
L
L
L
H
H
H
H
WE I/O1 to 8 I
DD
MODE I
DDS,
I
DDS1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
I
DDA,
I
DDA1
High-Z
High-Z
Data In
High-Z
Data In
DataOut
High-Z
Data Out
High-Z
I/O9 to 16
High-Z
High-Z
High-Z
Data In
Data In
High-Z
DataOut
Data Out
High-Z
Not Selected
Output disable
Lower Byte Write
Upper Byte Write
All Byte Write
Lower Byte Read
Upper Byte Read
All Byte Read
Output disable
X : Hi
h or Low
■ FUNCTIONS
● Truth Table