Cypress CY7C1568V18 Manual De Usuario
CY7C1566V18, CY7C1577V18
CY7C1568V18, CY7C1570V18
CY7C1568V18, CY7C1570V18
Document Number: 001-06551 Rev. *E
Page 10 of 28
Truth Table
The truth table for CY7C1566V18, CY7C1577V18, CY7C1568V18, and CY7C1570V18 follows.
Operation
K
LD
R/W
DQ
DQ
Write Cycle:
Load address; wait one cycle;
input write data on consecutive K and K rising edges.
Load address; wait one cycle;
input write data on consecutive K and K rising edges.
L-H
L
L
D(A) at K(t + 1)
↑
D(A+1) at K(t + 1)
↑
Read Cycle: (2.5 cycle Latency)
Load address; wait two and half cycle;
read data on consecutive K and K rising edges.
Load address; wait two and half cycle;
read data on consecutive K and K rising edges.
L-H
L H
Q(A)
at
K(t + 2)
↑
Q(A+1) at K(t + 3)
↑
NOP: No Operation
L-H
H
X
High Z
High Z
Standby: Clock Stopped
Stopped
X
X
Previous State
Previous State
Write Cycle Descriptions
The write cycle description table for CY7C1566V18 and CY7C1568V18 follows.
BWS
0
/
NWS
0
BWS
1
/
NWS
1
K
K
Comments
L
L
L–H
–
During the data portion of a write sequence
:
CY7C1566V18
− both nibbles (D
[7:0]
) are written into the device.
CY7C1568V18
− both bytes (D
[17:0]
) are written into the device.
L
L
–
L-H During the data portion of a write sequence
:
CY7C1566V18
− both nibbles (D
[7:0]
) are written into the device.
CY7C1568V18
− both bytes (D
[17:0]
) are written into the device.
L
H
L–H
–
During the data portion of a write sequence
:
CY7C1566V18
− only the lower nibble (D
[3:0]
) is written into the device, D
[7:4]
remains unaltered.
CY7C1568V18
− only the lower byte (D
[8:0]
) is written into the device, D
[17:9]
remains unaltered.
L
H
–
L–H During the data portion of a write sequence
:
CY7C1566V18
− only the lower nibble (D
[3:0]
) is written into the device, D
[7:4]
remains unaltered.
CY7C1568V18
− only the lower byte (D
[8:0]
) is written into the device, D
[17:9]
remains unaltered.
H
L
L–H
–
During the data portion of a write sequence
:
CY7C1566V18
− only the upper nibble (D
[7:4]
) is written into the device, D
[3:0]
remains unaltered.
CY7C1568V18
− only the upper byte (D
[17:9]
) is written into the device, D
[8:0]
remains unaltered.
H
L
–
L–H During the data portion of a write sequence
:
CY7C1566V18
− only the upper nibble (D
[7:4]
) is written into the device, D
[3:0]
remains unaltered.
CY7C1568V18
− only the upper byte (D
[17:9]
) is written into the device, D
[8:0]
remains unaltered.
H
H
L–H
–
No data is written into the devices during this portion of a write operation.
H
H
–
L–H No data is written into the devices during this portion of a write operation.
Notes
3. X = “Don’t Care,” H = Logic HIGH, L = Logic LOW,
↑
represents rising edge.
4. Device powers up deselected with the outputs in a tri-state condition.
5. “A” represents address location latched by the devices when transaction was initiated. A + 1 represents the address sequence in the burst.
6. “t” represents the cycle at which a read/write operation is started. t + 1 and t + 2 are the first and second clock cycles succeeding the “t” clock cycle.
7. Data inputs are registered at K and K rising edges. Data outputs are delivered on K and K rising edges.
8. Cypress recommends that K = K = HIGH when clock is stopped. This is not essential but permits most rapid restart by overcoming transmission line charging
5. “A” represents address location latched by the devices when transaction was initiated. A + 1 represents the address sequence in the burst.
6. “t” represents the cycle at which a read/write operation is started. t + 1 and t + 2 are the first and second clock cycles succeeding the “t” clock cycle.
7. Data inputs are registered at K and K rising edges. Data outputs are delivered on K and K rising edges.
8. Cypress recommends that K = K = HIGH when clock is stopped. This is not essential but permits most rapid restart by overcoming transmission line charging
symmetrically.
9. Is based on a write cycle is initiated per the
table. NWS
0
, NWS
1
,
BWS
0
, BWS
1
, BWS
2
,
and BWS
3
are altered on different portions of a write
cycle, as long as the setup and hold requirements are met.