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Application example, Truth table – Cypress Perform CY7C1513KV18 User Manual

Page 10

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CY7C1511KV18, CY7C1526KV18

CY7C1513KV18, CY7C1515KV18

Document Number: 001-00435 Rev. *E

Page 10 of 31

Application Example

Figure 1

shows four QDR-II used in an application.

Figure 1. Application Example

Truth Table

The truth table for CY7C1511KV18, CY7C1526KV18, CY7C1513KV18, and CY7C1515KV18 follows.

[2, 3, 4, 5, 6, 7]

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

[8]

L

[9]

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:

Load address on the rising

edge of K; wait one and a

half cycle; read data on

two consecutive C and C

rising edges.

L-H

L

[9]

X

Q(A) at C(t + 1)

↑ Q(A + 1) at C(t + 2)↑ Q(A + 2) at C(t + 2)↑ Q(A + 3) at C(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

R = 250

ohms

Vt

R

R = 250

ohms

Vt

Vt

R

Vt = Vddq/2

R = 50

ohms

R

C C#

D
A

SRAM #4

R
P
S
#

W

P
S
#

B

W

S
#

K

ZQ

CQ/CQ#

Q

K#

C C#

D
A

K

SRAM #1

R
P
S
#

W

P
S
#

B

W

S
#

ZQ

CQ/CQ#

Q

K#

BUS

MASTER

(CPU

or

ASIC)

DATA IN

DATA OUT

Address

RPS#

WPS#
BWS#

Source K

Source K#

Delayed K

Delayed K#

CLKIN/CLKIN#

Notes

2. X = “Don't Care,” H = Logic HIGH, L = Logic LOW,

represents rising edge.

3. Device powers up deselected with the outputs in a tristate 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 C and C rising edges, except when in single clock mode.
7. Ensure that when the clock is stopped K = K and C = C = HIGH. 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 or write request.

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