HC230 ALTERA [Altera Corporation], HC230 Datasheet - Page 212

• Manufacturer Part Number: HC230
• Description: HardCopy II Device Family
• Manufacturer: ALTERA [Altera Corporation]

HardCopy Series Handbook, Volume 1
8–24
M4K Utilization
HardCopy II M4K block functionality is similar to Stratix II M4K blocks.
You cannot pre-load HardCopy II M4K blocks with a memory
initialization file (.mif) when used as RAM. Also, unlike Stratix II devices,
the HardCopy II M4K RAM contents and their output registers are
unknown after power up. However, if the HardCopy II M4K block is
designated as ROM, it powers up with the ROM contents. When
designing M4K blocks as RAM, Altera recommends writing to the block
before reading from it to avoid reading unknown initial power-up data
conditions. One advantage over Stratix II RAM blocks is unused M4K
blocks are disconnected from the power rails, optimizing overall power
consumption.
M-RAM Compatibility
HardCopy II M-RAM blocks share the same functionality as Stratix II
M-RAM blocks. One key feature with HardCopy II M-RAM blocks is
power optimization when the M-RAM block is not used. Unused M-RAM
blocks are disconnected from the power rails, optimizing overall power
consumption.
1
Some Stratix II devices (engineering sample devices and
Revision A production devices) have M-RAM functionality that
differs slightly from current Stratix II production devices.
HardCopy II M-RAM functionality only matches that of current
Stratix II devices. Hence, in order to maintain proper
compatibility, compiling only for current production Stratix II
devices is supported. More information on the Stratix II M-RAM
errata can be found in the Stratix II FPGA Family Errata Sheet
available on the Altera website (www.altera.com).
Altera Corporation
September 2008