VRAM
SMJ44C251B
MT42C4256
Austin Semiconductor, Inc.
FIGURE 23: Block-Write-Cycle Timing (Delayed-Write)
BLOCK-WRITE-CYCLE STATE TABLE
STATE
CYCLE
1
L
2
L
L
3
4
Write-mask load/use, Block write
Write Mask Column Mask
Don't Care Column Mask
Don't Care Column Mask
Use previous write mask, Block write
Write mask disable, Block write to all I/Os
H
L
H
Write mask data 0: I/O write disable
1: I/O write enable
DQ0 — column 0 (addressA1 = 0,A0 = 0)
DQ1 — column 1 (addressA1 = 0,A0 = 1)
DQ2 — column 2 (addressA1 = 1,A0 = 0)
DQ3 — column 3 (addressA1 = 1,A0 = 1)
Column mask data DQn =
(n = 0, 1, 2, 3)
0 column write disable
1 column write enable
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
SMJ44C251B/MT42C4256
Rev. 0.1 12/03
33
AUSTIN [ AUSTIN SEMICONDUCTOR ]
