Using Block Rams

[Stephen Coe]

Hi guys,

I have a circuit that I wish to implement on a virtex IIE. I need to
use the block rams for memory,
but don't know how to load information into the ram before execution.
Can someone give me an
idea??

Steve
Reply to (e-mail address removed)

 

[Barry Brown]

If you mean that you want to use it like ROM, then use generics for
simulation, and attributes for synthesis. Refer to the section titled
"Using Block SelectRam Memory" in the Virtex II User's Guide.

 

[Arnaud Dion]

Hi,

You can initialize your BRam in the UCF files with their instance names.

Here is an example for a VirtexII 18Kbit Bram with "U_RAM_COEFF"
instantiation name in the module "U_MEM_COEFF" under your top file



INST "U_MEM_COEFF/U_RAM_COEFF" INIT_00 =
674c674c674c684c684c684c684c684c684c694b694b694b694b694b694b694b;

INST "U_MEM_COEFF/U_RAM_COEFF" INIT_01 =
654e654d654d654d654d654d654d664d664d664d664d664d664d674c674c674c;

INST "U_MEM_COEFF/U_RAM_COEFF" INIT_02 =
634f634f634f634f634f644e644e644e644e644e644e654e654e654e654e654e;

.....

.....

.....

INST "U_MEM_COEFF/U_RAM_COEFF" INIT_3e =
00900090009000900090008f008f008f008f008f008f008f008f008f008f008f;

INST "U_MEM_COEFF/U_RAM_COEFF" INIT_3f =
0091009100910091009100910091009100910090009000900090009000900090;

The first data are in the rigth of the vector.

Arnaud.

 

[Mike Treseler]

I have a circuit that I wish to implement on a virtex IIE. I need to
use the block rams for memory,

If no process is writing, then it's a ROM.

related thread:
http://groups.google.com/groups?q=this_rom+small_rom+a_length

-- Mike Treseler