Download Internal Memory (RAM and ROM) User Guide

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Memory Modes
Memory Modes
Altera provides the following memory modes that you can create using the
corresponding MegaWizard interfaces (listed in brackets):
■
Single-port RAM (RAM:1-Port)
■
Simple dual-port RAM (RAM: 2-Port)
■
True dual-port RAM (RAM:2-Port)
■
Tri-port RAM (RAM:3-Port)
■
Single-port ROM (ROM:1-Port)
■
Dual-port ROM (ROM:2-Port)
You can find these MegaWizard interfaces under the Memory Compiler category
when you launch the MegaWizard Plug-In Manager.
In general, the memory block contains two address port (port A and port B) with their
respective output data ports, and you can use them for read and write operations
depending on your memory modes. This section shows the different memory modes
with their input and output ports in a block diagram.
1
The input and output ports shown in the block diagrams are referring to the ports of
the wrapper that contains the memory megafunction instantiated in it. The port name
reflects the usage related to the memory features you created. For example, byteena
relates to the byte enable feature, addresstall relates to the address clock enable
features, and so on. You can find more details about the various memory features in
the following sections.
In a single-port RAM, the read and write operations share the same address at port A,
and the data is read from output port A.
Figure 1 shows a block diagram of a typical single-port RAM.
Figure 1. Single-Port RAM
data[]
address[]
wren
byteena[]
addressstall
inclock
q[]
outclock
clockena
rden
aclr
Internal Memory (RAM and ROM) User Guide
© November 2009 Altera Corporation