Altera Internal Memory (RAM and ROM) IP Core Bedienungsanleitung PDF herunterladen (Seite 24)

memory block being used, provided you do not assign block type when you instantiate the memory

block.

Power-Up Conditions and Memory Initialization

Power-up conditions depend on the type of embedded memory blocks in use and whether or not the

output port is registered.

Table 3-10: Power-Up Conditions for Various Embedded Memory Blocks

This table lists the power-up conditions in the various types of embedded memory blocks.

Embedded Memory Blocks Power-Up Conditions

M512 Outputs cleared

M4K Outputs cleared

M-RAM Outputs cleared if registered, otherwise unknown

MLAB Outputs cleared if registered, otherwise reads memory

contents

M9K Outputs cleared

M144K Outputs cleared

M10K Outputs cleared

M20K Outputs cleared

The outputs of M512, M4K, M9K, M144K, M10K, and M20K blocks always power-up to zero, regardless

of whether the output registers are used or bypassed. Even if a memory initialization file is used to pre-

load the contents of the memory block, the output is still cleared.

MLAB and M-RAM blocks power-up to zero only if output registers are used. If output registers are not

used, MLAB blocks power-up to read the memory contents while M-RAM blocks power-up to an

unknown state.

Note:

When the memory block type is set to Auto in the parameter editor, the compiler is free to choose

any memory block type, in which the power-up value depends on the chosen memory block type.

To identify the type of memory block the software selects to implement your memory, refer to the

fitter report after compilation.

All memory blocks (excluding M-RAM) support memory initialization via the Memory Initialization File

(.mif) or Hexadecimal (Intel-format) file (.hex). You can include the files using the parameter editor when

you configure and build your RAM. For RAM, besides using the .mif file or the .hex file, you can initialize

the memory to zero or ‘X’. To initialize the memory to zero, select No, leave it blank. To initialize the

content to ‘X’, turn on Initialize memory content data to XX..X on power-up in simulation. Turning on

this option does not change the power-up behavior of the RAM but initializes the content to ‘X’. For

example, if your target memory block is M4K, the output is cleared during power-up (based on Table 4–

8). The content that is initialized to ‘X’ is shown only when you perform the read operation.

Note:

The Quartus II software searches for the altsyncram init_file in the project directory, the project db

directory, user libraries, and the current source file location.

3-14

Power-Up Conditions and Memory Initialization

UG-01068

2014.12.17

Altera Corporation

Embedded Memory Functional Description

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