Cypress CY7C1424BV18 manual Truth Table, Write Cycle Descriptions, Ld R/W, BWS0/ BWS1 NWS0 NWS1

CY7C1422BV18, CY7C1429BV18

CY7C1423BV18, CY7C1424BV18

Truth Table

The truth table for CY7C1422BV18, CY7C1429BV18, CY7C1423BV18, and CY7C1424BV18 follows. [2, 3, 4, 5, 6, 7]

Operation

K

LD R/W

DQ

DQ

Write Cycle:			L-H	L	L	D(A + 0) at K(t + 1)↑		D(A + 1) at	K(t + 1)↑
Load address; wait one cycle;
input write data on consecutive K and	K	rising edges.
Read Cycle:			L-H	L	H	Q(A + 0) at		Q(A + 1) at C(t + 2)↑
							C(t + 1)↑
Load address; wait one and a half cycle;
read data on consecutive C and C rising edges.
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 CY7C1422BV18 and CY7C1423BV18 follows. [2, 8]

BWS0/ BWS1/

NWS0 NWS1

K

K

Comments

L	L	L–H	–	During the data portion of a write sequence :
				CY7C1422BV18 − both nibbles (D[7:0]) are written into the device,
				CY7C1423BV18 − both bytes (D[17:0]) are written into the device.
L	L	–	L-H	During the data portion of a write sequence :
				CY7C1422BV18 − both nibbles (D[7:0]) are written into the device,
				CY7C1423BV18 − both bytes (D[17:0]) are written into the device.
L	H	L–H	–	During the data portion of a write sequence :
				CY7C1422BV18 − only the lower nibble (D[3:0]) is written into the device, D[7:4]		remains unaltered.
				CY7C1423BV18 − 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 :
				CY7C1422BV18 − only the lower nibble (D[3:0]) is written into the device, D[7:4]		remains unaltered.
				CY7C1423BV18 − 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 :
				CY7C1422BV18 − only the upper nibble (D[7:4]) is written into the device, D[3:0]		remains unaltered.
				CY7C1423BV18 − 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 :
				CY7C1422BV18 − only the upper nibble (D[7:4]) is written into the device, D[3:0]		remains unaltered.
				CY7C1423BV18 − 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 Write Cycle Descriptions table. NWS0, NWS1, BWS0, BWS1, BWS2 and BWS3 can be altered on different portions of a write cycle, as long as the setup and hold requirements are achieved.

Document #: 001-07035 Rev. *D Page 10 of 30

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