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[/] [z80soc/] [branches/] [RonivonCosta/] [rtl/] [VHDL/] [CHAR_ROM.VHD] - Rev 2
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library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.STD_LOGIC_ARITH.all;
use IEEE.STD_LOGIC_UNSIGNED.all;
LIBRARY lpm;
USE lpm.lpm_components.ALL;
ENTITY Char_ROM IS
PORT( clock : IN STD_LOGIC;
character_address : IN STD_LOGIC_VECTOR(5 DOWNTO 0);
font_row, font_col : IN STD_LOGIC_VECTOR(2 DOWNTO 0);
rom_mux_output : OUT STD_LOGIC);
END Char_ROM;
ARCHITECTURE a OF Char_ROM IS
SIGNAL rom_data: STD_LOGIC_VECTOR(7 DOWNTO 0);
SIGNAL rom_address: STD_LOGIC_VECTOR(8 DOWNTO 0);
BEGIN
-- Small 8 by 8 Character Generator ROM for Video Display
-- Each character is 8 8-bits words of pixel data
char_gen_rom: lpm_rom
GENERIC MAP ( lpm_widthad => 9,
lpm_numwords => 512,
lpm_outdata => "UNREGISTERED",
lpm_address_control => "REGISTERED",
-- Reads in mif file for character generator font data
lpm_file => "..\ROM\tcgrom.mif",
lpm_width => 8)
PORT MAP ( inclock => clock, address => rom_address, q => rom_data);
rom_address <= character_address & font_row;
-- Mux to pick off correct rom data bit from 8-bit word
-- for on screen character generation
rom_mux_output <= rom_data ( (CONV_INTEGER(NOT font_col(2 downto 0))));
END a;
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