Altera RAM Initializer - Manual (Page 17)

Altera Corporation Confidential—Internal Use Only 2–5
May 2008 RAM Initializer (ALTMEM_INIT) Megafunction User Guide
Getting Started
Table 2–1 shows the options available on page 3 of the RAM Initializer
MegaWizard Plug-In Manager.
On page 4 of the RAM Initializer MegaWizard Plug-In Manager, you can
choose to generate a netlist for your third-party EDA synthesis tool to
estimate the timing and resource usage of the megafunction (
Figure 2–4 ).
Table 2–1. RAM Initializer MegaWizard Plug-In Manager [page 3] Options
Configuration Setting Description
Currently selected device family Select the device family you want to use.
Which RAM initialization mode should be used? If you want to initialize the RAM to all 0’s, select To zero.
If you want to initialize the RAM with the INIT_FILE
parameter, select From init data file and specify the file
name.
If you want to initialize the RAM in the external-ROM mode,
select From external ROM.
Turn on Use ROM data ready port if you want to control
the initialization process through the
rom_data_ready
input port. Turn on Use rom_rden port if the external ROM
supports the read-enable port.
Turn off Use ROM data ready port if you want to automate
the initialization process by specifying the read latency in
clock cycles. After initiating a read from the ROM, the
ALTMEM_INIT megafunction waits for the specified
number of delay cycles before sampling data from the
ROM at the subsequent cycle.
(1)
What is the number of words? Specify the number of words (memory depth) for the ROM
and the RAM.
(2)
What is the data width? Specify the data width for the ROM and the RAM.
Create a clken port Turn on this option to create the input port clken , which
is used as the clock-enable signal for the megafunction.
Notes to Table 2–1 :
(1) Set the read latency to match the latency, in clock cycles, of the ROM. Set the read latency to 1 clock cycle if only
the input port of the ROM is registered. Set the read latency to 2 clock cycles if both the input and output ports of
the ROM are registered.
(2) The number of words for the ALTMEM_INIT megafunction to initialize from the ROM to the RAM.