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Chapter 3: Memory Blocks in Cyclone IV Devices
3–11
Memory Modes
November 2011
Altera Corporation
True Dual-Port Mode
True dual-port mode supports any combination of two-port operations: two reads,
two writes, or one read and one write, at two different clock frequencies.
shows Cyclone IV devices true dual-port memory configuration.
1
The widest bit configuration of the M9K blocks in true dual-port mode is 512 × 16-bit
(18-bit with parity).
lists the possible M9K block mixed-port width configurations.
In true dual-port mode, M9K memory blocks support separate
wren
and
rden
signals.
You can save power by keeping the
rden
signal low (inactive) when not reading.
Read-during-write operations to the same address can either output “New Data” at
that location or “Old Data”. To choose the desired behavior, set the
Read-During-
Write
option to either
New Data
or
Old Data
in the RAM MegaWizard Plug-In
Manager in the Quartus II software. For more information about this behavior, refer to
“Read-During-Write Operations” on page 3–15
.
Figure 3–10. Cyclone IV Devices True Dual-Port Memory
:
(1) True dual-port memory supports input or output clock mode in addition to the independent clock mode shown.
data_a[ ]
address_a[ ]
w
ren_a
b
yteena_a[]
addressstall_a
clock_a
clocken_a
rden_a
aclr_a
q_a[]
data_
b
[ ]
address_
b
[]
w
ren_
b
b
yteena_
b
[]
addressstall_
b
clock_
b
clocken_
b
rden_
b
aclr_
b
q_
b
[]
Table 3–4. Cyclone IV Devices M9K Block Mixed-Width Configurations (True Dual-Port Mode)
Read Port
Write Port
8192
×
1
4096
×
2
2048
×
4
1024
×
8
512
×
16
1024
×
9
512
×
18
8192
×
1
v
v
v
v
v
—
—
4096
×
2
v
v
v
v
v
—
—
2048
×
4
v
v
v
v
v
—
—
1024
×
8
v
v
v
v
v
—
—
512
×
16
v
v
v
v
v
—
—
1024
×
9
—
—
—
—
—
v
v
512
×
18
—
—
—
—
—
v
v
Summary of Contents for Cyclone IV
Page 10: ...x Chapter Revision Dates Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 14: ...I 2 Section I Device Core Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 274: ...vi Contents Cyclone IV Device Handbook February 2015 Altera Corporation Volume 2...
Page 440: ...iv Contents Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 442: ...vi Chapter Revision Dates Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 446: ......