/* Imported from Wayback Machine
   Original URL : https://retrobrewcomputers.org/doku.php?id=builderpages:plasmo:crc65:vga6448r2
   Snapshot date: 2025-11-17
   Generator    : wayback-archiver
*/

==== Table of Contents ====

[[#vga6448_a_text-based_monochrome_vga_display_rev2|VGA6448, A Text-based Monochrome VGA display, Rev2]]

[[#introduction|Introduction]]

[[#features|Features]]

[[#design_information|Design Information]]

[[#software|Software]]

====== VGA6448, A Text-based Monochrome VGA display, Rev2 ======

===== Introduction =====

VGA6448 is initially discussed on 6502.org forum [[http://forum.6502.org/viewtopic.php?f=10&t=6502|here]]: It is designed as a video expansion board for RC6502 based computer.

This is link to [[builderpages:plasmo:crc65:vga6448|prototype VGA6448]]

[[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=20b590&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/dsc_66441026.jpg|{{https://retrobrewcomputers.org/lib/exe/fetch.php?w=600&h=355&tok=4a1677&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fcrc65%2Fvga64%2Fdsc_66441026.jpg?600x355|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_crc65_vga64_dsc_66441026.jpg}}]]

===== Features =====

Two EPM7064S or ATF1504AS CPLD

4K dual port RAM

25.175MHz clock

RC6502 expansion bus

[[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=39b6b4&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/crc65/vga64/dsc_66411026.jpg|{{https://retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=307&tok=f4705e&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fcrc65%2Fvga64%2Fdsc_66411026.jpg?500x307|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_crc65_vga64_dsc_66411026.jpg}}]]

===== Design Information =====

[[https://retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:crc65:vga64:vga6448r2_scm.pdf|Schematic]]

[[https://retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:crc65:vga64:vga6448_gerber_rev2.zip|Gerber photoplot]]

Bill of Materials

Engineering changes

CPLD design files

CPLD design file for U1, [[https://retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:crc65:vga64:vga_generator_cpld_vga6448r2.zip|VGA generator]]

CPLD design file for U3, [[https://retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:crc65:vga64:ps2kbd_cpld_vga6448r2.zip|PS2 Keyboard state machine]]

==== Software ====

Interim release of [[https://retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:crc65:vga64:crcmon_0_9b_interim_release.zip|CRCMon v0.9b]]. Commands can be entered either via terminal emulator or PS2 keyboard. Data displayed are sent to both VGA monitor as well as terminal emulator.