Spartan-3E FPGA Family: Functional Description
X-Ref Target - Figure 34
Internal
Memory
DO
Data_in
CLK
Prior stored data
DI
WE
DI
XXXX
aa
1111
2222
XXXX
ADDR
DO
bb
cc
dd
0000
MEM(aa)
old MEM(bb)
old MEM(cc)
MEM(dd)
EN
DISABLED
READ
WRITE
MEM(bb)=1111
WRITE
MEM(cc)=2222
READ
DS312-2_06_020905
Figure 34: Waveforms of Block RAM Data Operations with READ_FIRST Selected
X-Ref Target - Figure 35
Internal
Memory
DO
Data_in
No change during write
DI
CLK
WE
DI
XXXX
aa
1111
2222
cc
XXXX
ADDR
DO
bb
dd
0000
MEM(aa)
MEM(dd)
EN
DISABLED
READ
WRITE
MEM(bb)=1111
WRITE
MEM(cc)=2222
READ
DS312-2_07_020905
Figure 35: Waveforms of Block RAM Data Operations with NO_CHANGE Selected
Setting the WRITE_MODE attribute to a value of
NO_CHANGE, puts the DO outputs in a latched state when
asserting WE. Under this condition, the DO outputs retain
the data driven just before WE is asserted. NO_CHANGE
timing is shown in the portion of Figure 35 during which WE
is High.
DS312 (v4.2) December 14, 2018
www.xilinx.com
Product Specification
42
XILINX [ XILINX, INC ]
