SM55161A Austin Semiconductor, SM55161A Datasheet - Page 15

• Manufacturer Part Number: SM55161A
• Description: 262144 x 16 BIT VRAM MULTIPORT VIDEO RAM
• Manufacturer: Austin Semiconductor

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block write
written simultaneously to one row of the memory array. This
function is implemented as eight columns by eight DQs and
repeated in two halves. In this manner, each of the two 2M-bit
halves can have up to eight consecutive columns written at a
time with up to eight DQs per column (see Figure 9).
prevent any or all of the eight columns from being written with
FIGURE 9: Block-Write Operation
SMJ55161A
Rev. 1.6 03/05
The block-write feature allows up to 128 bits of data to be
Each 2M-bit half has a 8-bit column mask to mask off and
Austin Semiconductor, Inc.
15
data. Nonpersistent write-per-bit or persistent write-per-bit
functions can be applied to the block-write operation to
provide write-masking options. The DQ data is provided by 8
bits from the on-chip color register. Bits 0–7 from the 16-bit
write-mask register, bits 0 –7 from the 16-bit column-mask
register, and bits 0 –7 from the 16-bit color-data register
configure the block write for the first half, while bits 8 - 15 of the
corresponding register control the other half in a similar
fashion (see Figure 10).
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
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SM55161A
VRAM