Cypress CY7C1550V18, CY7C1548V18 manual Pin Definitions, Pin Name Pin Description, BWS BWS2, BWS3

CY7C1546V18, CY7C1557V18

CY7C1548V18, CY7C1550V18

Pin Definitions

Pin Name

IO

Pin Description

DQ[x:0]

Input and

Data Input or Output Signals. Inputs are sampled on the rising edge of K and

clocks during valid

K

Output

write operations. These pins drive out the requested data during a read operation. Valid data is driven

Synchronous

out on the rising edge of both the K and K clocks during read operations. When read access is

deselected, Q[x:0] are automatically tri-stated.

CY7C1546V18 − DQ[7:0]

CY7C1557V18 − DQ[8:0]

CY7C1548V18 − DQ[17:0]

CY7C1550V18 − DQ[35:0]

Input

Synchronous Load. Sampled on the rising edge of the K clock. This input is brought LOW when a

LD

Synchronous

bus cycle sequence is defined. This definition includes address and read or write direction. All trans-

actions operate on a burst of 2 data. LD must meet the setup and hold times around edge of K.

0,

1

Input

Nibble Write Select 0, 1 − Active LOW (CY7C1546V18 only). Sampled on the rising edge of the K

NWS

NWS

Synchronous

and K clocks during write operations. Used to select the nibble that is written into the device during

the current portion of the write operations. Nibbles not written remain unaltered.

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 does not write into the device.

0,

1,

Input

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

clocks

BWS

BWS

K

BWS2, BWS3

Synchronous

during write operations. Used to select the byte written into the device during the current portion of

the write operations. Bytes not written remain unaltered.

CY7C1557V18 − BWS0

controls D[8:0]

CY7C1548V18 − BWS0

controls D[8:0] and

BWS

1 controls D[17:9].

CY7C1550V18 − 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 does not write into the device.

A

Input

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

Synchronous

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

organized as 8M x 8 (2 arrays each of 4M x 8) for CY7C1546V18, 8M x 9 (2 arrays each of 4M x 9)

for CY7C1557V18, 4M x 18 (2 arrays each of 2M x 18) for CY7C1548V18, and 2M x 36 (2 arrays

each of 1M x 36) for CY7C1550V18.

Input

Synchronous Read or Write Input. When

is LOW, this input designates the access type (read

R/W

LD

Synchronous

when R/W is HIGH, write when R/W is LOW) for loaded address. R/W must meet the setup and hold

times around edge of K.

QVLD

Valid output

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

indicator

CQ.

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] when in single clock mode. All accesses are initiated on the rising

edge of K.

Input

Negative Input Clock Input.

is used to capture synchronous data presented to the device and to

K

K

Clock

drive out data through Q[x:0] when in single clock mode.

CQ

Clock Output

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

clock (K) of the DDR-II+. The timing for the echo clocks is shown in Switching Characteristics on

page 23.

Clock Output

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

CQ

clock (K) of the DDR-II+. The timing for the echo clocks is shown in Switching Characteristics on

page 23.

Document Number: 001-06550 Rev. *E Page 6 of 28

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