/* Imported from Wayback Machine Original URL : https://www.retrobrewcomputers.org/doku.php?id=builderpages%3Aplasmo%3Avgarc Snapshot date: 2026-03-03 Generator : wayback-archiver */ ==== Table of Contents ==== [[#text-based_vga_display_for_rc2014|Text-based VGA Display for RC2014]] [[#introduction|Introduction]] [[#features|Features]] [[#theory_of_operation|Theory of Operation]] [[#design_information|Design Information]] [[#software|Software]] [[#adding_ps2_keyboard|Adding PS2 Keyboard]] [[#vgarc_prototype|VGARC Prototype]] [[#features1|Features]] [[#theory_of_operation1|Theory of Operation]] [[#design_information1|Design Information]] ====== Text-based VGA Display for RC2014 ====== ===== Introduction ===== VGARC is a text-based VGA display for RC2014. It is based on 8K of dual port RAM to communicate between RC2014 and video display. **Note: This page describes VGARC rev0.1 and prior prototype version. VGARC rev0.1 is now obsolete, replaced with [[builderpages:plasmo:vgarc1:vgarc1home|VGARC rev1]]** [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=0a5dcf&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_54191126.jpg|{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=600&h=338&tok=2291fa&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fvgarc%2Fdsc_54191126.jpg?600x338|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_54191126.jpg}}]] ===== Features ===== 8K bytes of dual port RAM to simplify communication between Z80 and video display logic State machine in Altera EPM7128S CPLD generates the video timings 8×8 pixel font Font lookup table resides in the dual port RAM and is user programmable Display 56 lines, 80 characters per line ===== Theory of Operation ===== ===== Design Information ===== [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_scm_r01.pdf|Schematic]] PC board [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_r01.zip|gerber photoplots]] EPM7128SQC100 [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:released_56x80_2xdpram.zip|CPLD equations]] ==== Software ==== [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:tinytype_font.zip|TinyType Font]], 8×8 font table Conway Game of Life demonstration, [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:glider_gun_56x80.zip|Glider Gun]] on 56 x 80 screen [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:banner56x80.zip|56 lines and 80 column text]] explaining the features of VGARC ===== Adding PS2 Keyboard ===== This section describes the modification to VGARC rev0.1 to add a PS2 keyboard. [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=03797f&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_61661129.jpg|{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=333&tok=98708f&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fvgarc%2Fdsc_61661129.jpg?500x333|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_61661129.jpg}}]] CPLD equation for [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vga56x80_ps2_keyboard.zip|VGARC with PS2 keyboard]] [[builderpages:plasmo:vgarc:ps2ec|Engineering change]] for adding PS2 keyboard Test software ---- ---- ===== VGARC Prototype ===== This prototype is based on RC2014 Rev 2 Prototype board which already has a EPM7128SQC100 connected to RC2014 bus with a number of user programmable test points. A 4Kx8 dual port RAM, IDT 71342, is breadboarded in the prototype area and connected to the EPM7128S. The CPLD outputs drive a HD15 connector's red and blue signals as well as the horizontal and vertical syncs. [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=a587d5&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_47901015.jpg|{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=373&tok=ea1ec1&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fvgarc%2Fdsc_47901015.jpg?500x373|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_47901015.jpg}}]] [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?tok=9debe2&media=https://www.retrobrewcomputers.org/lib/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_47911015.jpg|{{https://www.retrobrewcomputers.org/lib/exe/fetch.php?w=500&h=463&tok=874477&media=https%3A%2F%2Fwww.retrobrewcomputers.org%2Flib%2Fplugins%2Fckgedit%2Ffckeditor%2Fuserfiles%2Fimage%2Fbuilderpages%2Fplasmo%2Fvgarc%2Fdsc_47911015.jpg?500x463|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_47911015.jpg}}]] ==== Features ==== 4K x 8 dual port RAM, IDT71342 State machine in EPM7128SQC100 generates video timing 640 x 480 display area, only 640 X 192 contains data due to RAM size limitation 8×8 pixel font 1K x 8 font table resides in the dual port RAM, user programmable ==== Theory of Operation ==== ==== Design Information ==== [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_proto:vgarc_scm_preliminary.pdf|Schematic]] EPM7128SQC100 [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_proto:vga_proto_24lines_released.zip|CPLD equations]] === Software === Conway's game of life