CY7C1246V18, CY7C1257V18
CY7C1248V18, CY7C1250V18
Document Number: 001-06348 Rev. *D Page 10 of 27
Write Cycle Descriptions
The write cycle descriptions table for CY7C1246V18 and CY7C1248V18 follows.[2, 8]
BWS0/
NWS0
BWS1/
NWS1KKComments
L L L–H – During the data portion of a write sequence:
CY7C1246V18 − both nibbles (D[7:0]) are written into the device.
CY7C1248V18 − both bytes (D[17:0]) are written into the device.
L L – L-H During the data portion of a write sequence:
CY7C1246V18 − both nibbles (D[7:0]) are written into the device.
CY7C1248V18 − both bytes (D[17:0]) are written into the device.
L H L–H – During the data portion of a write sequence:
CY7C1246V18 − only the lower nibble (D[3:0]) is written into the device, D[7:4] remains unaltered.
CY7C1248V18 − 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:
CY7C1246V18 − only the lower nibble (D[3:0]) is written into the device, D[7:4] remains unaltered.
CY7C1248V18 − 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:
CY7C1246V18 − only the upper nibble (D[7:4]) is written into the device, D[3:0] remains unaltered.
CY7C1248V18 − 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:
CY7C1246V18 − only the upper nibble (D[7:4]) is written into the device, D[3:0] remains unaltered.
CY7C1248V18 − 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 in to the devices during this portion of a write operation.
Write Cycle Descriptions
The write cycle descriptions table for CY7C1257V18 follows.[2, 8]
BWS0K K Comments
L L-H – During the data portion of a write sequence, the single byte (D[8:0]) is written into the device.
L – L-H During the data portion of a write sequence, the single byte (D[8:0]) is written into the device.
H L-H – No data is written into the device during this portion of a write operation.
H – L-H No data is written into the device during this portion of a write operation.
Note
8. Assumes a write cycle was initiated per 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 met.
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