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| builderpages:plasmo:vgarc [2025/07/11 14:20] – Revision from 2025-07-11 | builderpages:plasmo:vgarc [2026/06/15 13:15] (current) – external edit 127.0.0.1 |
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| | /* Imported from Wayback Machine |
| | Original URL : https://www.retrobrewcomputers.org/doku.php?id=builderpages%3Aplasmo%3Avgarc |
| | Snapshot date: 2026-03-03 |
| | Generator : wayback-archiver |
| | */ |
| | |
| | ====== 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]]** |
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| | [[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/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_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 |
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| | State machine in Altera EPM7128S CPLD generates the video timings |
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| | 8×8 pixel font |
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| | Font lookup table resides in the dual port RAM and is user programmable |
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| | Display 56 lines, 80 characters per line |
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| | ===== Theory of Operation ===== |
| | |
| | ===== Design Information ===== |
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| | [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_scm_r01.pdf|Schematic]] |
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| | PC board [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:vgarc_r01.zip|gerber photoplots]] |
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| | EPM7128SQC100 [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:released_56x80_2xdpram.zip|CPLD equations]] |
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| | ==== Software ==== |
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| | [[https://www.retrobrewcomputers.org/lib/exe/fetch.php?media=builderpages:plasmo:vgarc:tinytype_font.zip|TinyType Font]], 8×8 font table |
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| | 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 |
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| | [[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. |
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| | [[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/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_61661129.jpg?500x333|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_61661129.jpg}}]] |
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| | 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 |
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| | 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. |
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| | [[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/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_47901015.jpg?500x373|www.retrobrewcomputers.org_lib_plugins_ckgedit_fckeditor_userfiles_image_builderpages_plasmo_vgarc_dsc_47901015.jpg}}]] |
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| | [[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/plugins/ckgedit/fckeditor/userfiles/image/builderpages/plasmo/vgarc/dsc_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 |
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| | 640 x 480 display area, only 640 X 192 contains data due to RAM size limitation |
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| | 8×8 pixel font |
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| | 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 |
| |
