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6800 to 6809 adapter needed

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  • Ruud
    replied
    I checked everything AFAIK but the EE3404 part contains the only documents regarding the 6809. One of the PDFs mentions a part list but no schematics. It also shows a picture of the Heathkit with module. The module contains two TTL ICs, a crystal and an EPROM, for example, parts not mentioned at all in the parts list. More than a bit confusing.

    My first idea was anyway to look for a direct replacement: just a 6809 plus maybe an IC (Kevin's design). But I'll give it another thought now.
    Last edited by Ruud; January 28, 2019, 05:00 AM.

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  • Ruud
    replied
    Hallo Gilbert,

    I joined the group and will see what is available. Thank you very much!

    Leave a comment:


  • gcoville
    replied
    Ruud,

    I'm so sorry I didn't see this post earlier.

    The Heathkit ET-3400 Microprocessor trainer was a 6800-based single board computer. There was a follow-on called the ET-3400A that used a 6802 or 6808 (It didn't use the on-chip RAM). There were several instructional courses that went with these machines. One of the optional courses was EE-3404, "6809 Microprocessors". The purpose of the course was to have the student become familiar with the 6809. The course came with an adapter board and which would plug directly into the CPU socket on the ET-3400 or ET-3400A. In the case of the ET-3400 (the earlier 6800-based version), you also had to replace the 6875 clock chip with a header that re-routed some signals.

    This is all documented in the EE-3404 manual.

    The information, courses, schematics are all available in the files section of the yahoo group ET-3400:
    https://groups.yahoo.com/neo/groups/ET-3400/info

    Gilbert

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  • daver2
    replied
    Thanks for sharing. Very interesting.

    Dave

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  • Ruud
    replied
    Thank you very much!

    Leave a comment:


  • Kevin C.
    replied
    I have posted my 6800 and 6802 to 6809 adapter circuits to my website. The URL for the page with links to schematics is 680x to 6809 adapters.

    Leave a comment:


  • Ruud
    replied
    Originally posted by Kevin C. View Post
    If any one is still interested in using a 6809 in place of either a 6800 or 6802 I could made the schematics available.
    I am interested!

    Leave a comment:


  • Kevin C.
    replied
    I used to have a Motorola D2 kit. It used a 6800 processor. I eventually modified it to use a 6809 processor and rewrote the monitor software to work with the 6809 and handle the extra registers it has. The board I designed and built to allow a 6809 to plug-in to the 6800 socket used only 2 diodes, 2 resistors, and a transistor. I no longer have my D2 kit but I remembered the diodes were an OR gate and the transistor was an inverter. I went over the datasheets for the 6800 and 6809 and have worked out what I had done before. I've drawn up a(n untested) schematic for it. I also looked at how to plug a 6809 in to a 6802 socket and worked up schematic for it as well. The only catch is that the simple 6802 to 6809 mod doesn't include memory. If any one is still interested in using a 6809 in place of either a 6800 or 6802 I could made the schematics available.

    Leave a comment:


  • Ruud
    replied
    Originally posted by ncherry View Post
    I just had a look at the Euro 1 and I now see how Frank comments relate. He is correct the 6809 has no RAM internally. So you'll need to add RAM and the decoding for it. Also the 6802 ROM code won't run on the 6809. So it's not a drop in replacement.
    But the Eurocom has 1 KB RAM of its own starting from $0000. The lower RAM isn't used because the 6802 will use its internal RAM. The PCB on the picture in the book is very small. IMHO it is just a 6809 plus maybe two IC under it, certainly no extra RAM.

    Leave a comment:


  • Ruud
    replied
    Hallo ncherry,

    I'm looking forward to the schematic!

    Leave a comment:


  • ncherry
    replied
    Oh, sorry forgot to add this. I seem to recall this design coming from an EE magazine. I recall seeing the article. I am finding it really odd the I can find that information in a search of the internet.

    Leave a comment:


  • Elminster
    replied
    This would be something I am interested in as well. Is anyone going to look at knocking out a designing based on above screenshots and putting it on somewhere like oshpark? Or is this something I will have to look at doing when I have a free slot in my todo list (somewhere in the next 10 years).

    Leave a comment:


  • ncherry
    replied
    Originally posted by ncherry View Post
    Frank you are correct, if the board for the 6802 has no ram then the 6809 will have some trouble running (it's possible to write code that doesn't use ram but I won't do it ).

    I've got pictures of the board and I'll upload them to my site and provide a link here. The pictures are large and I doubt I have permissions to post links yet (new user, less than 10 posts).
    I just had a look at the Euro 1 and I now see how Frank comments relate. He is correct the 6809 has no RAM internally. So you'll need to add RAM and the decoding for it. Also the 6802 ROM code won't run on the 6809. So it's not a drop in replacement.

    Leave a comment:


  • ncherry
    replied
    Hi Ruud, not a schematic yet but huge pictures:

    Component side:
    http://ushomeautomation.com/Projects...604_115916.jpg

    Copper side:
    http://ushomeautomation.com/Projects...604_115828.jpg

    This board dates back to the 80's and it's still clean, wow.

    Leave a comment:


  • ncherry
    replied
    Frank you are correct, if the board for the 6802 has no ram then the 6809 will have some trouble running (it's possible to write code that doesn't use ram but I won't do it ).

    I've got pictures of the board and I'll upload them to my site and provide a link here. The pictures are large and I doubt I have permissions to post links yet (new user, less than 10 posts).

    Leave a comment:

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