Altera RAM Initializer - Manual (Page 27)

Altera Corporation Confidential—Internal Use Only 2–15
May 2008 RAM Initializer (ALTMEM_INIT) Megafunction User Guide
Getting Started
Figure 2–11. Design Example 1: RAM Initialization at Completion
At 257,500 ps, the ALTMEM_INIT megafunction initiates the last write
cycle to the RAM. The init_busy signal is deasserted during the next
rising edge of the clock at 262,500 ps to indicate the end of initialization.
Design
Example 2:
Memory
Initialization
with External
ROM This design example uses the ALTMEM_INIT megafunction in the
MegaWizard Plug-In Manager to initialize the RAM of a HardCopy II
device with an external on-chip ROM.
Design Files
The design files for this example are configured for the external-ROM
initialization mode and the latency is fixed with the ROM_READ_LATENCY
parameter. The RAM of the target HardCopy II device is initialized with
the content of an on-chip ROM, located in the device itself.
A top-level design file, DE2_top_externalROM.v, instantiates the on-chip
ROM, the ALTMEM_INIT megafunction, and the RAM of the
HardCopy II device.
Figure 2–12 shows the content of the on-chip ROM. In this design
example, the ROM has 16 words, with each word having a data width of
8 bits. The number of words and data width in the ROM are the same as
the corresponding parameter values in the megafunction.
Figure 2–12. Content of the On-Chip ROM