Cypress CY7C1556V18 manual Pin Definitions, Pin Name Pin Description, Negative Input Clock Input

CY7C1541V18, CY7C1556V18

CY7C1543V18, CY7C1545V18

Pin Definitions

Pin Name

IO

Pin Description

D[x:0]

Input-

Data Input Signals. Sampled on the rising edge of K and

clocks when valid write operations are active.

K

Synchronous

CY7C1541V18 − D[7:0]

CY7C1556V18 − D[8:0]

CY7C1543V18 − D[17:0]

CY7C1545V18 − D[35:0]

Input-

Write Port Select − Active LOW. Sampled on the rising edge of the K clock. When asserted active, a

WPS

Synchronous

write operation is initiated. Deasserting deselects the write port. Deselecting the write port ignores D[x:0].

0,

Input-

Nibble Write Select 0, 1 − Active LOW (CY7C1541V18 Only). Sampled on the rising edge of the K and

NWS

NWS1,

Synchronous

K clocks when write operations are active. Used to select which nibble is written into the device during

the current portion of the write operations. NWS0 controls D[3:0] and NWS1 controls D[7:4].

All the Nibble Write Selects are sampled on the same edge as the data. Deselecting a Nibble Write Select

ignores the corresponding nibble of data and it is not written into the device.

0,

Input-

Byte Write Select 0, 1, 2 and 3 − Active LOW. Sampled on the rising edge of the K and

clocks when

BWS

K

BWS1,

Synchronous

write operations are active. Used to select which byte is written into the device during the current portion

BWS2,

of the write operations. Bytes not written remain unaltered.

BWS3

CY7C1556V18 − BWS0

controls D[8:0]

CY7C1543V18 − BWS0

controls D[8:0] and BWS1 controls D[17:9].

CY7C1545V18 − BWS0

controls D[8:0], BWS1 controls D[17:9],

BWS2 controls D[26:18] and BWS3 controls D[35:27].

All the Byte Write Selects are sampled on the same edge as the data. Deselecting a Byte Write Select

ignores the corresponding byte of data and it is not written into the device.

A

Input-

Address Inputs. Sampled on the rising edge of the K clock during active read and write operations. These

Synchronous

address inputs are multiplexed for both read and write operations. Internally, the device is organized as

8M x 8 (4 arrays each of 2M x 8) for CY7C1541V18, 8M x 9 (4 arrays each of 2M x 9) for CY7C1556V18,

4M x 18 (4 arrays each of 1M x 18) for CY7C1543V18 and 2M x 36 (4 arrays each of 512K x 36) for

CY7C1545V18. Therefore, only 21 address inputs are needed to access the entire memory array of

CY7C1541V18 and CY7C1556V18, 20 address inputs for CY7C1543V18 and 19 address inputs for

CY7C1545V18. These inputs are ignored when the appropriate port is deselected.

Q[x:0]

Outputs-

Data Output Signals. These pins drive out the requested data when the read operation is active. Valid

Synchronous

data is driven out on the rising edge of the K and K clocks during read operations. On deselecting the

read port, Q[x:0]

are automatically tri-stated.

CY7C1541V18

− Q[7:0]

CY7C1556V18 − Q[8:0]

CY7C1543V18 − Q[17:0]

CY7C1545V18 − Q[35:0]

Input-

Read Port Select − Active LOW. Sampled on the rising edge of positive input clock (K). When active, a

RPS

Synchronous

read operation is initiated. Deasserting deselects the read port. When deselected, the pending access is

allowed to complete and the output drivers are automatically tri-stated following the next rising edge of

the K clock. Each read access consists of a burst of four sequential transfers.

QVLD

Valid output

Valid Output Indicator. The Q Valid indicates valid output data. QVLD is edge aligned with CQ and

CQ.

indicator

K

Input-

Positive Input Clock Input. The rising edge of K is used to capture synchronous inputs to the device

Clock

and to drive out data through Q[x:0]. All accesses are initiated on the rising edge of K.

Input-

Negative Input Clock Input.

is used to capture synchronous inputs being presented to the device and

K

K

Clock

to drive out data through Q[x:0].

CQ

Echo Clock

Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the input clock

(K) of the QDR-II+. The timings for the echo clocks are shown in the Switching Characteristics on page 23.

Echo Clock

Synchronous Echo Clock Outputs. This is a free running clock and is synchronized to the input clock

CQ

(K) of the QDR-II+.The timings for the echo clocks are shown in the Switching Characteristics on page 23.

Document Number: 001-05389 Rev. *F Page 6 of 28

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