VG4616321B/VG4616322B
262,144x32x2-Bit
Preliminary
CMOS Synchronous Graphic RAM
VIS
•
Mode field (A8~A7)
A7 and A8 must be programmed to “00” in normal operation.
A8
0
A7
0
Test Mode
normal mode
0
1
Vendor Use Only
Vendor Use Only
1
x
•
Single Write Mode (A9)
This bit is used to select the write mode. When the A9 bit is “0”, Burst Read and Burst Write mode is
selected. When the A9 bit is ”1”, Burst Read and Single Write mode is Selected.
A9
0
Single Write Mode
Burst Read and Burst Write
Burst Read and Single Write
1
12 Special Mode Register Set command
(RAS = ”L”, CAS = ”L”, WE = ”L”, DSF = ”H”, BS, A0-A9 = Register Data)
The special mode register is used to load the Color and Mask registers, which are used in Block
Write and masked Write cycles. The control information being written to the Special Mode register is
applied to the address inputs and the data to be written to either the Color register or the Mask register is
applied to the DQs. When A6 is “high” during a Special Mode Register Set cycle, the Color register will be
loaded with the data on the DQs. Similarly, when A5 is “high” during a Special Mode Register Set cycle,
the Mask register will be loaded with the data on the DQs. A6 = A5 = 1 in the Special Mode Register Set
cycle is illegal.
Functions
Leave Unchanged
Load Mask Register
Load Color Register
Illegal
BS
X
A9~A7
A6
0
A5
0
A4~A0
X
X
X
X
X
X
X
X
X
0
1
X
1
0
X
1
1
One clock cycle is required to complete the write in the Special Mode register. This command can
be issued at the active state. As in write operation, this command accepts the data needed through DQ
pins. Therefore it should be attended not to induce bus contention.
13 No-Operation command
(RAS = ”H”, CAS = ”H”, WE = ”H”)
The No-Operation command is used to perform a NOP to SGRAM which is selected (CS is Low).
This prevents unwanted commands from being registered during idle or wait states.
14 Burst Stop command
(RAS = ”H”, CAS = ”H”, WE = ”L’, DSF = ”L”)
Burst Stop command is used to terminate either fixed-length or full-page bursts. This command is
only effective in a read/write burst without auto precharge function. The terminated read burst ends after
a delay equal to the CAS latency (refer to the following figure). The termination of a write burst is shown
in the following figure.
Document:1G5-0145
Rev.1
Page18
VML [ VANGUARD INTERNATIONAL SEMICONDUCTOR ]
