AR# 1839

Foundation XVHDL: How to use Wide-Edge Decoders

描述

Keywords: foundation xvhdl edge decoders

Urgency: standard

General Description:
Below is an example of how to instantiate Wide-edge Decoders
in XC4000 Foundation XVHDL (Metamor) designs.

解决方案

1

Foundation F1.3/F1.4
====================

--Example of instantiating Wide Edge Decoders.

--The IEEE standard 1164 package, declares std_logic, rising_edge(), etc.
library IEEE;
use IEEE.std_logic_1164.all;

entity edge_decoder is
port (DATA3, DATA2, DATA1, DATA0: in std_logic;
CLK: in std_logic;
IN1: in std_logic;
RESET: in std_logic;
QOUT: out std_logic);
end edge_decoder;

architecture use_decode of edge_decoder is
component DECODE4
port ( A3, A2, A1, A0: in std_logic; O: out std_logic);
end component;

component PULLUP
port (O: out std_logic);
end component;

signal DECOUT: std_logic;

begin
U1: DECODE4
port map (A3 => DATA3, A2=>DATA2, A1=>DATA1, A0=>DATA0,
O=>DECOUT);
U2: PULLUP
port map (O=>DECOUT);

process (CLK, RESET)
begin
if RESET='1' then
QOUT <= '0';
elsif (CLK'event and CLK='1') then
if DECOUT = '1' then
QOUT <= IN1;
end if;
end if;
end process;

end use_decode;

2

Foundation 6.x
==============

--Example of instantiating Wide Edge Decoders.

--The IEEE standard 1164 package, declares std_logic, rising_edge(), etc.
library IEEE;
use IEEE.std_logic_1164.all;

entity edge_decoder is
port (DATA3, DATA2, DATA1, DATA0: in std_logic;
CLK: in std_logic;
IN1: in std_logic;
RESET: in std_logic;
QOUT: out std_logic);
end edge_decoder;

architecture use_decode of edge_decoder is
component DECODE4
port ( A3, A2, A1, A0: in std_logic; O: out std_logic);
end component;

component PULLUP
port (O: out std_logic);
end component;

signal DECOUT: std_logic;

begin
U1: DECODE4
port map (A3 => DATA3, A2=>DATA2, A1=>DATA1, A0=>DATA0,
O=>DECOUT);
U2: PULLUP
port map (O=>DECOUT);

process (CLK, RESET)
begin
if RESET='1' then
QOUT <= '0';
elsif (CLK'event and CLK='1') then
if DECOUT = '1' then
QOUT <= IN1;
end if;
end if;
end process;

end use_decode;

=============================================================

The following files must also be copied into the project
directory:

<ACTIVE>\VHDL\XLNX_LIB\XC4000\DECODE4.XNF
<ACTIVE>\VHDL\XLNX_LIB\XC4000\PULLUP.XNF

where <ACTIVE> is the install directory for the Foundation
Active-CAD software. (Typically C:\ACTIVE)
AR# 1839
日期 01/02/2000
状态 Archive
Type 综合文章