Truth table, Write cycle descriptions – Cypress CY7C1312BV18 User Manual
Page 10
CY7C1310BV18, CY7C1910BV18
CY7C1312BV18, CY7C1314BV18
Document #: 38-05619 Rev. *F
Page 10 of 29
Truth Table
The truth table for CY7C1310BV18, CY7C1910BV18, CY7C1312BV18, and CY7C1314BV18 follows.
Operation
K
RPS WPS
DQ
DQ
Write Cycle:
Load address on the rising edge of K;
input write data on K and K rising edges.
L-H
X
L
D(A + 0) at K(t)
↑
D(A + 1) at K(t)
↑
Read Cycle:
Load address on the rising edge of K;
wait one and a half cycle; read data on C and C rising edges.
L-H
L
X
Q(A + 0) at C(t + 1)
↑ Q(A + 1) at C(t + 2) ↑
NOP: No Operation
L-H
H
H
D = X
Q = High-Z
D = X
Q = High-Z
Standby: Clock Stopped
Stopped
X
X
Previous State
Previous State
Write Cycle Descriptions
The write cycle description table for CY7C1310BV18 and CY7C1312BV18 follows.
BWS
0
/
NWS
0
BWS
1
/
NWS
1
K
K
Comments
L
L
L–H
–
During the data portion of a write sequence
:
CY7C1310BV18
− both nibbles (D
[7:0]
) are written into the device.
CY7C1312BV18
− both bytes (D
[17:0]
) are written into the device.
L
L
–
L-H During the data portion of a write sequence
:
CY7C1310BV18
− both nibbles (D
[7:0]
) are written into the device.
CY7C1312BV18
− both bytes (D
[17:0]
) are written into the device.
L
H
L–H
–
During the data portion of a write sequence
:
CY7C1310BV18
− only the lower nibble (D
[3:0]
) is written into the device, D
[7:4]
remains unaltered.
CY7C1312BV18
− 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
:
CY7C1310BV18
− only the lower nibble (D
[3:0]
) is written into the device, D
[7:4]
remains unaltered.
CY7C1312BV18
− 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
:
CY7C1310BV18
− only the upper nibble (D
[7:4]
) is written into the device, D
[3:0]
remains unaltered.
CY7C1312BV18
− 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
:
CY7C1310BV18
− only the upper nibble (D
[7:4]
) is written into the device, D
[3:0]
remains unaltered.
CY7C1312BV18
− 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
2. X = “Don't Care,” H = Logic HIGH, L = Logic LOW,
↑
represents rising edge.
3. Device powers up deselected with the outputs in a tri-state condition.
4. “A” represents address location latched by the devices when transaction was initiated. A + 0, A + 1 represents the internal address sequence in the burst.
5. “t” represents the cycle at which a Read/Write operation is started. t + 1, and t + 2 are the first, and second 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. It is recommended that K = K and C = C = HIGH when clock is stopped. This is not essential, but permits most rapid restart by overcoming transmission line charging
symmetrically.
8. Is based on a write cycle that was initiated in accordance with the
table. NWS
0
, NWS
1
, BWS
0
, BWS
1
,
BWS
2,
and BWS
3
can be altered on
different portions of a write cycle, as long as the setup and hold requirements are achieved.