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Bus accurate 1802 in a PIC lives! (Protect the antiques. Use a PIC)

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  • ted_rossin
    I want to add more features to my Elf but was torn between preserving the past and using up a limited supply of RCA 1802 processors for a new toy. So last
    Message 1 of 2 , Feb 12, 2010
      I want to add more features to my Elf but was torn between preserving the past and using up a limited supply of RCA 1802 processors for a new toy. So last December I started looking into the possibility of implementing an 1802 using a "modern" microcontroller.

      Last night I finally got reality (protoboard with chips) to match theory (simulation) and have a low cost full speed Elf clone running 1802 code that I loaded using DMA. The glue logic is identical to what would work with a real 1802 except for a single MUX chip (74LS157) as I was 2 pins short.

      Here is a link to some details which has simulation traces of the bus as well as hardware logic analyzer traces of some basic operations such as DMA, Interrups and load mode.

      http://www.tedrossin.x10hosting.com/Electronics/RCA/RCA.html

      I hope to have the 1861 emulator working by the end of the month but life might get in the way.

      Let me know what you think.
    • Andrew Wasson
      Congrats Ted, That is cool! Andrew ... Andrew Wasson Luna Design | www.lunadesign.org 1651 West 15th Street North Vancouver BC, V7P 1N3 [Non-text portions of
      Message 2 of 2 , Feb 12, 2010
        Congrats Ted,
        That is cool!

        Andrew


        On 2010-02-12, at 10:46 AM, ted_rossin wrote:

        > I want to add more features to my Elf but was torn between preserving the past and using up a limited supply of RCA 1802 processors for a new toy. So last December I started looking into the possibility of implementing an 1802 using a "modern" microcontroller.
        >
        > Last night I finally got reality (protoboard with chips) to match theory (simulation) and have a low cost full speed Elf clone running 1802 code that I loaded using DMA. The glue logic is identical to what would work with a real 1802 except for a single MUX chip (74LS157) as I was 2 pins short.
        >
        > Here is a link to some details which has simulation traces of the bus as well as hardware logic analyzer traces of some basic operations such as DMA, Interrups and load mode.
        >
        > http://www.tedrossin.x10hosting.com/Electronics/RCA/RCA.html
        >
        > I hope to have the 1861 emulator working by the end of the month but life might get in the way.
        >
        > Let me know what you think.
        >
        >

        Andrew Wasson
        Luna Design | www.lunadesign.org
        1651 West 15th Street
        North Vancouver BC, V7P 1N3





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