====== VGA6448, A Text-based Monochrome VGA display ======

===== Introduction =====

VGA6448 is initially discussed on 6502.org forum [[http://forum.6502.org/viewtopic.php?f=10&t=6502|here]]: It is a simple design suitable as a piggy-back board for system RAM to add VGA capability.

[[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=d3d488&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/vga6448_banner.jpg|{{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/vga6448_banner.jpg?direct&600x333|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_crc65_vga64_vga6448_banner.jpg}}]]

[[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=56e301&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/dsc_64730222.jpg|{{https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/dsc_64730222.jpg?direct&500x352|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_crc65_vga64_dsc_64730222.jpg}}]]

===== Features =====

  * EPM7064S or ATF1504AS CPLD
  * 4K dual port RAM
  * 25.175MHz clock

===== Theory of Operation =====

===== Design Files =====

Schematic

CPLD design

==== Software ====

{{:builderpages:plasmo:crc65:vga64:matrix_working.zip|Matrix screen saver}}.  The program starts at $a000