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Architecture RTL of work.vdu8

Implements a text based Colour Video Display Unit for System09

Defined in VHDL/vdu8.vhd

Authors: Bert Cuzeau and John E. Kent
Version: 0.4 from 2010-07-03


Detailed description

Supports 2KByte Text buffer and 2KByte Attribute memory. Displays 80 characters across by 25 character rows. Characters are 8 pixels across x 16 lines down. Character attribute bits for foreground and backgrond colour. 1 bit for each Blue Green and Red signal. Supports 2 x 8 chunky graphics character mode. Uses Generic arguments for setting the video synchronization timing.

Instantiated in...

work.my_system09 (rtl)

Libraries and global use clauses

library IEEE
use IEEE.numeric_std.all
use IEEE.std_logic_1164.all

Constants

HOR_DISP_CHR integer := VGA_HOR_CHARS
HOR_DISP_END integer := (HOR_DISP_CHR * VGA_HOR_CHAR_PIXELS) - 1
HOR_SYNC_BEG integer := HOR_DISP_END + VGA_HOR_FRONT_PORCH
HOR_SYNC_END integer := HOR_SYNC_BEG + VGA_HOR_SYNC
HOR_SCAN_END integer := HOR_SYNC_END + VGA_HOR_BACK_PORCH
VER_DISP_CHR integer := VGA_VER_CHARS
VER_DISP_END integer := (VER_DISP_CHR * VGA_VER_CHAR_LINES) - 1
VER_SYNC_BEG integer := VER_DISP_END + VGA_VER_FRONT_PORCH
VER_SYNC_END integer := VER_SYNC_BEG + VGA_VER_SYNC
VER_SCAN_END integer := VER_SYNC_END + VGA_VER_BACK_PORCH

Component declarations

char_rom
Block Ram Character gen
Default binding: work.char_rom
ram_2k
Default binding: work.ram_2k

Processes

vga_cpu_write (vdu_clk, vdu_rst)
CPU Write interface
vga_cpu_read (vdu_addr, vdu_cs, reg_character, reg_colour, reg_hcursor, reg_vcursor, reg_voffset)
CPU Read interface
vga_addr_proc (vga_clk, vdu_rst)
Video memory access
vga_shift_proc ( vga_clk, vdu_rst)
Video shift register
vga_sync (vga_clk)
Sync generator & timing process Generate Horizontal and Vertical Timing Signals for Video Signal

Instantiations

vdu_char_rom : char_rom
Binding: work.char_rom (rtl)
char_buff_ram : ram_2k
Character buffer RAM
Binding: work.ram_2k (rtl)
attr_buff_ram : ram_2k
Attribute buffer RAM
Binding: work.ram_2k (rtl)

Generated on 1 Jan 2018 19:48:42 with VHDocL V0.2.6