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Thread: 8501 replacement for C16 Plus4: work in progress...

  1. #11
    MCes's Avatar
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    I found a demo that use the krill's loader and illegal opcodes,
    the illegal opcode can't be compatible,
    but I want to try to make my project compatible with krill loader....
    Last edited by MCes; 23rd August 2019 at 07:49.

  2. #12
    MCes's Avatar
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    Now I have in my hand the jiffydos for PAL, and it work with my project.

    A "krill's loader" programmer was so kindle to make a little modify to eliminate 1 illegal opcode (ONE!!!)
    and to give me a version of V166 demo with no illegal opcodes: it work!

    Now I can suppose that CPLD design (that perform also the I/O port emulation) has no problem:
    the only limit knowed (and not superable) is the not possibility to execute the illegal opcodes.

    I just have to test it again with the new PCB I got and make it (finally) available.
    Last edited by MCes; 1st September 2019 at 20:43.

  3. #13
    MCes's Avatar
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    ok,
    now I have to prepare the announcement for the sale, the price of my 85MC01 will be:

    29€+untracked shipping cost: PPal "FOR FRIENDS" (I can't be responsible for untracked shipping)
    29€+tracked shipping cost + PPal fees: PPal "COMMERCIAL"
    Last edited by MCes; 8th December 2019 at 14:22.

  4. #14
    Inactive Member bmamo's Avatar
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    So I am in need of a CPU for my c16, and found your thread here. What exactly are you selling? PCB only or full package?

  5. #15
    MCes's Avatar
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    Last edited by MCes; 25th April 2020 at 12:27.

  6. #16
    MCes's Avatar
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    Some people want that own CPU could manage the illegal opcode for the best compatibility....
    OK!

    from the "85MC01" experience...... the "CPU4C16"!
    a CPU replacement (specific for the C16 shape) that use a selected 6502 N-MOS core: it manage the illegal opcodes
    Click image for larger version. 

Name:	cpuC16.JPG 
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ID:	157675

    Features:
    A) normal sw N-MOS 6502 behaviour (as 8501, illegal opcode included)
    B) The I/O bits are at right places: the self-turbo routines (loaders) will work
    C) R/W line is put on 3state and HOLD as 8501 timings spec
    D) TBC (Time Base Corrector) technique applied to help the CPU, also into the "worst case", for matching the correct bus timings
    E) each 6502 that I use on it are selected for 2 specs: 1) it has to be an N-Mos, 2) it has to match to the specifics timings (more than 2MHz)

    Remember that N-MOS 6502 chips are discontinued, often on market the sold chips are refurbished and relabelled with a label different to the old one:
    chips marked as "6502" may not be N-Mos as it have to be, and vice versa (C-MOS, so no execution of the illegal opcode).
    I found a chip labelled as "W65C02S" (10MHz C-MOS) that is a 1MHz N-MOS!!!!!

    http://www.amibay.com/showthread.php...-C16-(CPU4C16)

    My personal C16:
    Click image for larger version. 

Name:	new2C16.JPG 
Views:	14 
Size:	133.2 KB 
ID:	157676

    https://plus4world.powweb.com/forum/38827?fbclid=IwAR0_CVyOO4KjHJRIpl89QJsIw7c-uujlfePKxoI6PXv7ehp2pC7tgC41Le8


    Click image for larger version. 

Name:	P_20200608_104916.jpg 
Views:	11 
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ID:	157744
    Last edited by MCes; 10th June 2020 at 07:23.

  7. #17
    MCes's Avatar
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    Why a CPU4C16 and not a CPU4PLUS4?

    It's arriving!

    Click image for larger version. 

Name:	CPU4PLUS4-a.jpg 
Views:	3 
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ID:	162312
    CPU4PLUS4

    http://www.amibay.com/showthread.php...S4-(CPU4PLUS4)
    Last edited by MCes; 19th November 2020 at 12:05.

  8. #18
    SukkoPera's Avatar
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    (Please delete)
    Last edited by SukkoPera; 19th November 2020 at 10:49.

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