Application example, Truth table – Cypress CY7C1143V18 User Manual
Page 10
CY7C1141V18, CY7C1156V18
CY7C1143V18, CY7C1145V18
Document Number: 001-06583 Rev. *D
Page 10 of 28
Application Example
shows the four QDR-II+ used in an application.
Figure 1. Appliation Example
Truth Table
The truth table for the CY7C1141V18, CY7C1156V18, CY7C1143V18, and CY7C1145V18 follows.
Operation
K
RPS WPS
DQ
DQ
DQ
DQ
Write Cycle:
Load address on the rising
edge of K; input write data
on two consecutive K and
K rising edges
L-H
H
L
D(A) at K(t + 1)
↑ D(A + 1) at K(t + 1) ↑ D(A + 2) at K(t + 2) ↑ D(A + 3) at K(t + 2) ↑
Read Cycle:
(2.0 cycle Latency)
Load address on the rising
edge of K; wait one and a
half cycle; read data on
two consecutive K and K
rising edges
L-H
L
X
Q(A) at K(t + 2)
↑ Q(A + 1) at K(t + 2) ↑ Q(A + 2) at K(t + 3)↑ Q(A + 3) at K(t + 3) ↑
NOP: No Operation
L-H
H
H
D = X
Q = High-Z
D = X
Q = High-Z
D = X
Q = High-Z
D = X
Q = High-Z
Standby: Clock Stopped
Stopped
X
X
Previous State
Previous State
Previous State
Previous State
BUS MASTER
(CPU or ASIC)
DATA IN
DATA OUT
Address
Source K
Source K
Vt
Vt
Vt
R
R
CLKIN/CLKIN
D
A
K
SRAM #4
RQ = 250ohms
ZQ
CQ/CQ
Q
K
RPS WPS BWS
D
A
K
SRAM #1
RQ = 250ohms
ZQ
CQ/CQ
Q
K
RPS WPS BWS
RPS
WPS
BWS
R = 50ohms, Vt = V /2
DDQ
R
Notes
2. X = “Don't Care,” H = Logic HIGH, L = Logic LOW,
↑
represents rising edge.
3. Device powers up deselected and the outputs in a tri-state condition.
4. “A” represents address location latched by the devices when transaction was initiated. A + 1, A + 2, and A + 3 represents the address sequence in the burst.
5. “t” represents the cycle at which a Read/Write operation is started. t + 1, t + 2, and t + 3 are the first, second, and third clock cycles respectively succeeding the “t” clock
cycle.
6. Data inputs are registered at K and K rising edges. Data outputs are delivered on K and K rising edges.
7. IDo K = K = HIGH when clock is stopped. This is not essential, but permits most rapid restart by overcoming transmission line charging symmetrically.
8. If this signal was LOW to initiate the previous cycle, this signal becomes a “Don’t Care” for this operation.
9. This signal was HIGH on previous K clock rise. Initiating consecutive read or write operations on consecutive K clock rises is not permitted. The device ignores the
second read orwrite request.