做 FPGA 设计时经常要调用芯片内存。特别对于 ROM ,内存的初始化就显得比较重要。当然你完全可以手工在 QUARTUS II 打开 mif 文件的表格里或是在 EXCEL 中逐个输入,几十项(字)或是近百项(字)你还可以接受,如果上千项或是更多呢?估计能累的人吐血!
一般内存的初始化数据都是有规律的,符合一定的函数,我们完全可以用 MATLAB 来完成 ( 如果没规律只能逐项手工输入了 ) 。
首先,我们应该知道 *.mif 文件的格式。它是文本格式。随便打开一个 mif 文件,你会发现它具有如下的格式:
-- Copyright (C) 1991-2007 Altera Corporation
-- Your use of Altera Corporation's design tools, logic functions
-- and other software and tools, and its AMPP partner logic
-- functions, and any output files from any of the foregoing
-- (including device programming or simulation files), and any
-- associated documentation or information are expressly subject
-- to the terms and conditions of the Altera Program ******
-- Subscription Agreement, Altera MegaCore Function ******
-- Agreement, or other applicable ****** agreement, including,
-- without limitation, that your use is for the sole purpose of
-- programming logic devices manufactured by Altera and sold by
-- Altera or its authorized distributors. Please refer to the
-- applicable agreement for further details.
-- Quartus II generated Memory Initialization File (.mif)
WIDTH=8;
DEPTH=256;
ADDRESS_RADIX=UNS;
DATA_RADIX=UNS;
CONTENT BEGIN
0:127;
1:126;
2:126;
……
……
253:126;
254:126;
255:127;
END;
格式很简单吧。首先根据需要设置每个字的位宽 WIDTH 和总字数 DEPTH 。然后设置地址和数据的进制基数 ADDRESS_RADIX 、 DATA_RADIX ,建议大家不要修改,就使用无符号数( UNS )。然后用 MATLAB 生成需要的数据(按上边的格式,注意中间“:”,最后“ ; ”),往 CONTENT BEGIN 和 END 中间一贴就行了。 |