Altera Cyclone IV - Single-Port Mode

3–8 Chapter 3: Memory Blocks in Cyclone IV Devices
Memory Modes
Cyclone IV Device Handbook, November 2011 Altera Corporation
Volume 1
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. Figure 3–6 shows the single-port memory configuration for Cyclone IV
devices M9K memory blocks.
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 “Read-During-Write
Operations” on page 3–15.
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
Figure 3–6. Single-Port Memory
(1)
,
(2)
Notes to Figure 3–6:
(1) You can implement two single-port memory blocks in a single M9K block.
(2) For more information, refer to “Packed Mode Support” on page 3–4.
data[ ]
address[ ]
wren
byteena[]
addressstall
inclock
inclocken
rden
aclr
outclock
q[]
outclocken