EP4SE360F35I4 Datasheet, PDF (79/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

Chapter 3: TriMatrix Embedded Memory Blocks in Stratix IV Devices
Design Considerations
3–23
Figure 3–22 shows a sample functional waveform of mixed-port read-during-write
behavior for don’t care mode in M9K and M144K blocks.
Figure 3–22. M9K and M144K Blocks Mixed-Port Read-During Write: Don’t Care Mode
clk_a&b
wrena
address_a
data_a
bytenna
rdenb
address_b
q_b_(asyn)
AAAA
11
A0
BBBB
01
CCCC
10
DDDD
A1
EEEE
11
FFFF
A0
A1
XXXX (unknown data)
Mixed-port read-during-write is not supported when two different clocks are used in
a dual-port RAM. The output value is unknown during a dual-clock mixed-port
read-during-write operation.
Power-Up Conditions and Memory Initialization
M9K memory cells are initialized to all zeros through a default .mif file in the
Quartus II software. However, you may specify your own initialization of the
memory cells through a defined .mif file. M144K memory cells are not initialized and;
therefore, come up in an undefined state. This is to prevent the programming file from
being too large. Again, you may specify your own initialization of the memory cells
through a defined .mif file.
MLABs power up to zero if output registers are used and power up reading the
memory contents if output registers are not used. You must take this into
consideration when designing logic that might evaluate the initial power-up values of
the MLAB memory block. For Stratix IV devices, the Quartus II software initializes
the RAM cells to zero unless there is a .mif file specified.
As mentioned, all memory blocks support initialization using a .mif file. You can
create .mif files in the Quartus II software and specify their use with the RAM
MegaWizard Plug-In Manager when instantiating a memory in your design. Even if a
memory is pre-initialized (for example, using a .mif file), it still powers up with its
outputs cleared.
f For more information about .mif files, refer to the Internal Memory (RAM and ROM)
User Guide and the Quartus II Handbook.
December 2011 Altera Corporation
Stratix IV Device Handbook
Volume 1