MOSEL VITELIC
V63C31321024
6
V63C31321024 Rev. 0.3 October 1997
Write Mode
The V63C31321024 support different kinds of
write mode operations. The BWE and BW [3:0]
support individual byte writes. The BE [7:0] signals
can be directly connected to the SRAM BW [3:0].
The GW signal is used to override the byte enable
signals and allows the cache controller to write all
bytes to the SRAM, no matter what the byte write
enable signals are. The various write modes are
indicated in the Write Table, below. Note that in
pipelined mode, the byte write enable signals are
not latched by the SRAM with addresses but with
data. In pipelined mode, the cache controller must
ensure the SRAM latches both data and valid byte
enable signals from the processor.
Write Table
Burst Address Sequence
Read/Write Function GW BWE BW3BW2BW1BW0
Read 1 1 XXXX
Read 101111
Write Byte 0, I/O
0
– I/O
7
101110
Write Byte 1, I/O
8
– I/O
15
101101
Write Byte 1, Byte 0 101100
Write Byte 2, I/O
16
– I/O
23
101011
Write Byte 2, Byte 0 101010
Write Byte 2, Byte 1 101001
Write Byte 2, Byte 1, Byte 0 101000
Write Byte 3, I/O
24
– I/O
31
100111
Write Byte 3, Byte 0 100110
Write Byte 3, Byte 1 100101
Write Byte 3, Byte 1, Byte 0 100100
Write Byte 3, Byte 2 100011
Write Byte 3, Byte 2, Byte 0 100010
Write Byte 3, Byte 2, Byte 1 100001
Write All Bytes, I/O
0
– I/O
31
100000
Write All Bytes, I/O
0
– I/O
31
0XXXXX
Intel System (LBO = V
CCQ
) Linear Mode (LBO = GNDQ)
A[1:0] A[1:0] A[1:0] A[1:0] A[1:0] A[1:0] A[1:0] A[1:0]
External Start Address 00 01 10 11 00 01 10 11
Second Address 01 00 11 10 01 10 11 00
Third Address 10 11 00 01 10 11 00 01
Fourth Address 11 10 01 00 11 00 01 10