📄 synthesisable sine wave generator.htm
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3c.org/TR/1999/REC-html401-19991224/loose.dtd">
<!-- saved from url=(0078)http://www.doulos.com/knowhow/vhdl_designers_guide/models/sine_wave_generator/ -->
<HTML><HEAD><TITLE>Synthesisable Sine Wave Generator</TITLE>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="VHDL, models, tck, tk, perl, sine, wave" name=keywords>
<META content="Synthesisable Sine Wave Generator" name=description><!-- IE 5.x not detected, using proper stylesheets ()-->
<STYLE type=text/css media=screen>@import url( /layout.css );
</STYLE>
<STYLE type=text/css>@import url( /format.css );
</STYLE>
<STYLE type=text/css media=print>@import url( /print.css );
</STYLE>
<!--[if IE 5]>
<style>
@media print {
#content, #knowhow { margin-left: 50px; }
}
</style>
<![endif]-->
<SCRIPT language=javascript
src="Synthesisable Sine Wave Generator.files/cookies.js"
type=text/javascript></SCRIPT>
<SCRIPT language=javascript
src="Synthesisable Sine Wave Generator.files/search.js"
type=text/javascript></SCRIPT>
<SCRIPT language=JavaScript
src="Synthesisable Sine Wave Generator.files/DatePicker.js"
type=text/javascript></SCRIPT>
<SCRIPT language=JavaScript
src="Synthesisable Sine Wave Generator.files/validate.js"
type=text/javascript></SCRIPT>
<SCRIPT language=javascript
src="Synthesisable Sine Wave Generator.files/fixheight.js"
type=text/javascript></SCRIPT>
<META content="MSHTML 6.00.2900.3059" name=GENERATOR></HEAD>
<BODY onload="getDivs(); fixHeight(); ">
<DIV id=container><A id=top></A>
<DIV class=layerBackground id=DatePicker
style="VISIBILITY: hidden; POSITION: absolute; zIndex: 10">
<SCRIPT language=JavaScript type=text/javascript>
var currentDate = new Date() ;
arrayDays = new Array("Mo", "Tu", "We", "Th", "Fr", "Sa", "So") ;
arrayMonth = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec") ;
drawCalendar(currentDate.getFullYear(), currentDate.getMonth()) ;
document.write(docHTML) ;
callOnClose = "filterList()";
</SCRIPT>
</DIV>
<DIV id=header>
<DIV><A id=logo href="http://www.doulos.com/"></A></DIV>
<DIV id=bar1>
<FORM id=search name=search action=javascript:doSearch();><A
href="http://www.doulos.com/">Home <IMG alt=">"
src="Synthesisable Sine Wave Generator.files/arrow.gif"></A> <A
href="http://search.doulos.com/">Site Map <IMG alt=">"
src="Synthesisable Sine Wave Generator.files/arrow.gif"></A> <A
href="mailto:info@doulos.com">Contact <IMG alt=">"
src="Synthesisable Sine Wave Generator.files/arrow.gif"></A> <INPUT
class=field onfocus="if(this.value=='search') this.value=''" value=search
name=search><IMG class=searchButton alt=">"
src="Synthesisable Sine Wave Generator.files/spacer.gif" width=5><A
onclick="doSearch(); return false"
href="http://www.doulos.com/knowhow/vhdl_designers_guide/models/sine_wave_generator/#"><IMG
alt=search
src="Synthesisable Sine Wave Generator.files/search.gif"></A></FORM></DIV>
<DIV id=bar2></DIV>
<DIV id=navbar1><!-- Actual navigation links -->
<TABLE class=topnav cellSpacing=0 cellPadding=0>
<TBODY>
<TR>
<TD class=topnav><A
href="http://www.doulos.com/content/company.php">Company</A></TD>
<TD><IMG alt=|
src="Synthesisable Sine Wave Generator.files/nav-space.jpg"></TD>
<TD class=topnav><A
href="http://www.doulos.com/content/training.php">Training</A></TD>
<TD><IMG alt=|
src="Synthesisable Sine Wave Generator.files/nav-space.jpg"></TD>
<TD class=topnav><A
href="http://www.doulos.com/content/news.php">News</A></TD>
<TD><IMG alt=|
src="Synthesisable Sine Wave Generator.files/nav-space.jpg"></TD>
<TD class=topnav><A class=topnavLive
href="http://www.doulos.com/knowhow/">KnowHow</A></TD>
<TD><IMG alt=|
src="Synthesisable Sine Wave Generator.files/nav-space.jpg"></TD>
<TD class=topnav><A
href="http://www.doulos.com/content/products.php">Products</A></TD></TR></TBODY></TABLE></DIV>
<DIV id=crumb><A href="http://www.doulos.com/">Home</A> > <A
href="http://www.doulos.com/knowhow/">Knowhow</A> > <A
href="http://www.doulos.com/knowhow/vhdl_designers_guide/">Vhdl_designers_guide</A>
> <A
href="http://www.doulos.com/knowhow/vhdl_designers_guide/models/">Models</A>
> <A
href="http://www.doulos.com/knowhow/vhdl_designers_guide/models/sine_wave_generator/">Sine_wave_generator</A>
</DIV></DIV><!-- End of header area --><!-- Main central area, contains left nav bar, content and right pane.-->
<DIV id=central><!--This is the left hand navigation section -->
<DIV id=navbar2>
<UL>
<LI><A class=leftmenu
href="http://www.doulos.com/knowhow/vhdl_designers_guide/">VHDL</A> </LI>
<LI><A class=leftmenu
href="http://www.doulos.com/knowhow/verilog_designers_guide/">Verilog</A>
</LI>
<LI><A class=leftmenu
href="http://www.doulos.com/knowhow/systemc/">SystemC</A> </LI>
<LI><A class=leftmenu
href="http://www.doulos.com/knowhow/sysverilog/">SystemVerilog</A> </LI>
<LI><A class=leftmenu href="http://www.doulos.com/knowhow/psl/">PSL</A> </LI>
<LI><A class=leftmenu href="http://www.doulos.com/knowhow/perl/">Perl</A>
</LI>
<LI><A class=leftmenu href="http://www.doulos.com/knowhow/tcltk/">Tcl/Tk</A>
</LI></UL></DIV><!-- End of left hand navigation section -->
<DIV id=printHeader><IMG alt="(c) Doulos Ltd"
src="Synthesisable Sine Wave Generator.files/printlogo.jpg"></DIV>
<DIV id=knowhow><!-- This is the central content -->
<H1>Synthesisable Sine Wave Generator</H1>
<P>This page offers you a customisable sine wave generator. Below is a generic
VHDL description of a sine wave generator. It is parameterised by constants and
subtypes declared in <SPAN class=snippet>sine_package</SPAN>. </P>
<P>Further below is a HTML form for you to specify word and address sizes for a
lookup table to store the values of a sine wave. Submit the form and a short
Perl script runs on this server to generate a customised <SPAN
class=snippet>sine_package</SPAN> complete with lookup table for you. </P>
<P>This implementation is moderately memory efficient because it stores only the
first Pi/2 radians of sine values. The second Pi/2 radians is a mirror image of
the first in time and the second Pi radians is a mirror image in amplitude of
the first Pi radians. </P>
<P>Memory could be saved if the increments were recorded rather than each
absolute value. Fewer bits per value would be needed, however, extra hardware
would be needed for an adder. </P><PRE>-- Synthesisable design for a sine wave generator
-- Copyright Doulos Ltd
-- SD, 07 Aug 2003
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use work.sine_package.all;
entity sine_wave is
port( clock, reset, enable: in std_logic;
wave_out: out sine_vector_type);
end;
architecture arch1 of sine_wave is
type state_type is ( counting_up, change_down, counting_down, change_up );
signal state, next_state: state_type;
signal table_index: table_index_type;
signal positive_cycle: boolean;
begin
process( clock, reset )
begin
if reset = '1' then
state <= counting_up;
elsif rising_edge( clock ) then
if enable = '1' then
state <= next_state;
end if;
end if;
end process;
process( state, table_index )
begin
next_state <= state;
case state is
when counting_up =>
if table_index = max_table_index then
next_state <= change_down;
end if;
when change_down =>
next_state <= counting_down;
when counting_down =>
if table_index = 0 then
next_state <= change_up;
end if;
when others => -- change_up
next_state <= counting_up;
end case;
end process;
process( clock, reset )
begin
if reset = '1' then
table_index <= 0;
positive_cycle <= true;
elsif rising_edge( clock ) then
if enable = '1' then
case next_state is
when counting_up =>
table_index <= table_index + 1;
when counting_down =>
table_index <= table_index - 1;
when change_up =>
positive_cycle <= not positive_cycle;
when others =>
-- nothing to do
end case;
end if;
end if;
end process;
process( table_index, positive_cycle )
variable table_value: table_value_type;
begin
table_value := get_table_value( table_index );
if positive_cycle then
wave_out <= std_logic_vector(to_signed(table_value,sine_vector_type'length));
else
wave_out <= std_logic_vector(to_signed(-table_value,sine_vector_type'length));
end if;
end process;
end;
</PRE>
<H1>Lookup Table</H1>
<P>We will use a short Perl script to generate a lookup table in a package,
<SPAN class=snippet>sine_package</SPAN>. Specify a word size and address size
suitable for your application. Values of 8 and 7 will generate a ROM of size 256
bytes. </P>
<P>
<FORM
onsubmit="window.open('','testbench','width=800,height=600,scrollbars=yes,resizable=yes');return true"
action=/cgi-bin/knowhow/vhdl_sine_gen.pl method=post target=testbench><INPUT
size=4 value=7 name=word_size> Lookup table word size<BR><INPUT size=4 value=7
name=address_size> Lookup table address size<BR><BR><INPUT type=submit value="Generate sine_package Code"> </FORM></P>
<H1>Test Bench</H1>
<P>Download an example sine wave generator with a test bench: <A
href="http://www.doulos.com/knowhow/vhdl_designers_guide/models/sine_wave_generator/sine_testbench.zip">sine_testbench.zip</A>
</P>
<P>We have bundled a simple testbench to show how this code works. There's also
a Tcl script called <SPAN class=snippet>go.tcl</SPAN> to drive ModelSim for you.
Here's what the output looks like in ModelSim. </P>
<P><IMG alt="Doulos: Training and Consultancy for FPGA/SoC Designers"
src="Synthesisable Sine Wave Generator.files/wave.gif"> </P>
<H1>Synthesis</H1>
<P>Both Synplicity's Synplify⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -