sm55161a-80hkcm Austin Semiconductor, Inc., sm55161a-80hkcm Datasheet - Page 23

• Manufacturer Part Number: sm55161a-80hkcm
• Description: 262144 X 16 Bit Vram Multiport Video Ram
• Manufacturer: Austin Semiconductor, Inc.

split-register programmable stop point
(continued)
initiated. The CBRS operation is enabled by holding CASx\ and
WE\ low and DSF high on the falling edge of RAS\. The falling
edge of RAS\ also latches row addresses A4–A7 which are
used to define the SAM’s partition length. The other row-
address inputs are don’t cares. Stop-point mode should be
initiated after the initialization cycles are performed
(see Table 5).
TABLE 5: Programming Code for Stop-Point Mode
FIGURE 23:
Stop Points
SMJ55161A
Rev. 1.6 03/05
PARTITION
LENGTH
Stop-point mode is not active until the CBRS cycle is
MAX
128
256
16
32
64
A8
X
X
X
X
X
ADDRESS AT RAS\ IN CBRS CYCLE
Austin Semiconductor, Inc.
Example of Split-Register Operation With Programmable
A7
H
L
L
L
L
A6
H
H
L
L
L
A5
H
H
H
L
L
A4
H
H
H
H
L
A0 - A3
X
X
X
X
X
23
register-transfer read cycle determines the SAM partition in
which the serial output begins and at which stop point the
serial output stops coming from one half of the SAM and
switches to the opposite half of the SAM (see Figure 23).
designed to be compatible with both 256-bit SAM and 512-bit
SAM devices like the 55161A.
mode (CBRS) cycle should be initiated immediately after the
power-up initialization cycles are performed.
NUMBER OF
PARTITIONS
In stop-point mode, the tap point loaded during the split-
The stop-point mode of the previous revision 55161 is
IMPORTANT: For proper device operation, a stop-point-
16
8
4
2
1
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
31, 63, 95, 127, 159, 191, 223, 255, 287,
319, 351, 383, 415, 447, 479, 511
63, 127, 191, 255, 319, 383, 447, 511
127, 255, 383, 511
255, 511
255
STOP-POINT LOCATIONS
Production
SM55161A
VRAM