3–8
Chapter 3: Memory Blocks in the Cyclone III Device Family
Memory Modes
1
Violating the setup or hold time on the M9K memory block input registers may
corrupt memory contents. This applies to both read and write operations.
Single-Port Mode
Single-port mode supports non-simultaneous read and write operations from a single
address.
shows the single-port memory configuration for Cyclone III
device family M9K memory blocks.
Figure 3–7. Single-Port Memory
data[ ]
address[ ]
wren
byteena[]
addressstall
inclock
inclocken
rden
aclr
q[]
outclock
outclocken
Notes to
(1) You can implement two single-port memory blocks in a single M9K block.
(2) For more information, refer to
During a write operation, the behavior of the RAM outputs is configurable. If you
activate
rden
during a write operation, the RAM outputs show either the new data
being written or the old data at that address. If you perform a write operation with
rden
deactivated, the RAM outputs retain the values they held during the most recent
active
rden
signal.
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 read-during-write mode, refer to
The port width configurations for M9K blocks in single-port mode are as follow:
■
■
■
■
■
■
■
■
■
8192 × 1
4096 × 2
2048 × 4
1024 × 8
1024 × 9
512 × 16
512 × 18
256 × 32
256 × 36
Cyclone III Device Handbook
Volume 1
December 2011 Altera Corporation
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