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Thread: Commodore 128 - Switchless Jiffydos

  1. #1
    Join Date
    Apr 2018
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    Los Angeles, CA
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    Default Commodore 128 - Switchless Jiffydos

    Hi All,

    I recently built up a switchless jiffydos board that I thought I'd put into my C128. For now i'm just doing the C64 side of the 128, though I might make another board up for the 128, not sure. In any case, I can't seem to figure out where to connect the two wires. On a C64 it's the Restore and Reset lines, but it doesn't appear the C128 has a Restore line? I found an image on the net where someone seems to have connected a 128 DCR to the Reset line like on the C64 (pin 34 on CIA) and then the Cap lock line on the 8502 (pin 24). I tried that but it didn't work. maybe I don't know how that would switch (caps lock on or off seems to have no affect). Are there better lines to maybe attach this to? Has anyone else done this successfully with a 128? All documentation that I could find out there for the 128 is just the kind that uses a switch but there are references to a switchless one that people sell but no details on how to connect.

    Thanks!
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

  2. #2
    Join Date
    Jan 2013
    Location
    Washington State
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    14

    Default

    ...but it doesn't appear the C128 has a Restore line?
    Sure it does, pin 3 of the keyboard connector is RESTORE.
    Has anyone else done this successfully with a 128?
    I have, and it works fine.

  3. #3
    Join Date
    Apr 2018
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    Default

    Quote Originally Posted by buzbard View Post
    Sure it does, pin 3 of the keyboard connector is RESTORE.

    I have, and it works fine.
    Thanks, I actually got this working the other day and forgot about this thread. My problem was an issue with my reset line and not the restore line, so nothing was working. It was user error in the orientation of the CIA chip

    For anyone else reading this in the future:

    Reset Line: Pin 34 on either CIA (U4 or whatever the other one is) or pin 8 on U63.. obviously lots of reset lines, those are just a few.

    Restore Line: R9 Resistor (I also noticed one of the caps by pin 3, or likely pin 3 as you mentioned)
    Caps Lock: Pin 24 on 8502 (U6)

    I did the restore line, but I kinda get why people use the Caps Lock since it's a bit of a pain to hold the Commodore Key, Hit the Restore Key, and also turn on the power, if you wanted to boot straight into Jiffydos on C64 mode.
    -- Brian

    Systems: Amstad PCW 8256, Apple IIe/II+/GS/Mac+/Mac 512k, Atari 800/520STFM, Commodore 64/128/Amiga 3000/PET 4032/SX-64, IBM PS/1 2121-B82, Kaypro II, Osborne 1, Tandy 1000 SX, TI-99/4A, Timex Sinclair 1000, TRS-80 Color Computer 3/Model 4 GA

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