MC6809-Based Arcade Game

Single Board Computer with Video Output

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Single board system w/16KB RAM uses cheap video techniques described in The Cheap Video Cookbook by Don Lancaster for output.

The board is designed to use either an MC6809 (on-chip clock generator) or MC6809E (external clock generator).  This works because I don't require any of the functionality that differs between the two versions (DMA~BUSY, MRDY~AVMA, TSC, LIC).  Switching between the two types requires configuring a jumper and including or eliminating one IC.

Display is 16 lines x 32 characters, using an 8 x 8 grid for each character.  Fonts are contained in a 2732A EPROM, so can be changed and custom characters added.

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View all 18 components

  • Making Progress

    Steve Toner04/03/2019 at 21:28 0 comments

    Buttons and coin acceptor now operating...

  • Video Output Schematic

    Steve Toner04/03/2019 at 20:09 0 comments

    This is the video output section, providing monochrome NTSC composite video:

    Based on the TVT 6 5/8 design presented in The Cheap Video Cookbook by Don Lancaster, but see notes for changes I made to make it work properly.

  • Memory Schematic

    Steve Toner03/02/2019 at 04:05 0 comments

    Schematic diagram of the arcade game memory.  Program memory is provided by a 27C512 EPROM, and RAM by a pair of CY7C162 static RAM chips (chosen because they have separate input/output lines, which makes implementing the "upstream tap" for the cheap video circuit easy).

  • Minor Catastrophe

    Steve Toner02/27/2019 at 05:09 0 comments

  • Memory Map

    Steve Toner02/19/2019 at 00:18 0 comments

    How the 64KB address space is allocated & decoded.

  • Designing for MC6809 or MC6809E

    Steve Toner02/18/2019 at 20:43 0 comments

    Here is the schematic of the CPU part of the design, which shows how to design for either a 6809 or 6809E processor.  Note that this depends on certain processor-specific functions (TSC, LIC, MRDY/AVMA, DMA/BUSY) not being used.  Note that I haven't actually tested this with a 6809E yet, so you're on your own if you decide to copy it...

  • Status VLOG

    Steve Toner02/07/2019 at 22:57 0 comments

    See YouTube Playlist for updates.

View all 7 project logs

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Steve Toner wrote 02/12/2019 at 17:33 point

I'll put everything up once it's finalized.  I'm not sure it'll have very wide appeal, as some of the parts (e.g., Cypress Semi memory chips) are rather obscure and hard to find.  As for PCB layout, well, I may not provide that as the current boards I've had made have some flaws (e.g., the sound chip is going to require a daughter board) but are usable for a one-off build.  If I update the PCB layout it'll be untested (unless I absolutely have to do a second run to make it work rather than just hacking the current boards).

  Are you sure? yes | no

fredmatic1 wrote 02/12/2019 at 08:36 point

Will you be releasing the board layout/software? I am interested in duplicating. I was a developer of SBC's back in the early 80's using the 6809E..... and nostalgia is pushing me to get re-interested in the 6809.

  Are you sure? yes | no

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