HC210 datasheet(211/228 Pages) ALTERA

211 / 228 page

Altera Corporation

8–23

September 2008

Preliminary

Stratix II and HardCopy II Companion Memory Blocks

Your HardCopy II design can use M4K memory blocks to implement

memory designs instead of M512 blocks. Quartus II megafunctions offer

various memory implementations that use M4K blocks. When using the

Quartus II MegaWizard® Plug-In Manager to configure the

megafunction, Altera recommends selecting the Auto option to allow the

Quartus II software to determine how the design is implemented in the

memory blocks (Figure 8–2). This allows the Quartus II software to

optimize memory selection based on memory size and placement

requirements into the available memory blocks of the selected

HardCopy II and Stratix II companion pair.

Figure 8–2. Quartus II MegaFunction RAM selection

You can select logic cells in the megafunction to implement

small-memory blocks in your design. This implements the memory

design in Stratix II ALMs or HardCopy II HCells. However, there may be

power and performance trade-offs when choosing between an M4K or

M-RAM block or using the ALMs (or HCells). HardCopy II devices

power down unused M4K blocks, M-RAM blocks, and HCells.

Implementing memory blocks using logic cells, as seen in

Figure 8–2, allows you to select a memory implementation

functionally equivalent to M512 blocks or a non-equivalent

option to save resources. Altera recommends setting the option

to a functionally equivalent version with the M512 blocks.

For very small memory implementations such as a 8 × 16 single port

RAM, the M4K or M-RAM blocks will be under-utilized, and may be less

power efficient than a small number of HCells. If you select the logic cell

option, only a fraction of ALMs are required in the Stratix II device, which

translates into a small number HCells used in the HardCopy II device.

However, when performance is a key factor, or your design requires

ALMs to implement other logic, it may be more efficient to use M4K

blocks. Altera recommends using the Quartus II software to analyze

performance trade-offs between the given options.

HC210 Datasheet(PDF) 211 Page - Altera Corporation