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Thread: Experience with the 8042 keyboard controller (or equivalent) in other systems?

  1. #1

    Default Experience with the 8042 keyboard controller (or equivalent) in other systems?

    I have a handful of 8042 keyboard controllers or equivalents like JetKey or the HT6542. I was wondering if there is anybody around who used one in another system equipped with for example a 6502 or Z80? If so, would he or she share their experience with us?

    I know how to connect an AT-keyboard directly to a C64 but I was wondering if things could be simplified by using this controller.
    Last edited by Ruud; September 13th, 2020 at 11:55 PM.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  2. #2
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    Aren't the 8042 PC controllers pretty much wedded to the PC-AT and later architecture?

    A small cheap MCU would be far easier to work with.

  3. #3

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    These controllers have one advantage: they are ready to be used and known how to be connected to a system. Any other MCU has to be programmed and I have not enough experience to do that myself. But any other solutions are always welcome of course!
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  4. #4

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    Quote Originally Posted by Ruud View Post
    These controllers have one advantage: they are ready to be used and known how to be connected to a system. Any other MCU has to be programmed and I have not enough experience to do that myself. But any other solutions are always welcome of course!
    The 8042 "exposes" to the system two ports, mapped at 0x60 and 0x64 on a PC. So, if you design a brand new 8 bit system, there's surely a lot to be gained by using a very well known controller.
    However, to connect a PS/2 type keyboard to say a C64 or a PET, we need to simulate a matrix row/column keypress, so the 8042 alone wouldn't be much useful (unless maybe if one could completely re-program an 8742 and have enough I/O pins to simulate the matrix).
    Another way would be re-writing part of the kernel to read keypresses from the 8042 interface, or adding a second MCU after the 8042 to simulate the key matrix (but then the 8042 is almost useless as you could "chat" directly with the keyboard).
    In other words I'm saying you take less time to design a new interface from scratch (I've had to do it).

    Frank IZ8DWF

  5. #5

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    First the idea is design a new system based on a 65816 including ISA slots on an ATX board. I'm going to use my ATX based XT clone as base. There are two further ideas: using an XT keyboard interface including 8255, 74LS322 and other parts plus an AT2XT converter or using an 8042 or equivalent keyboard controller. But I have no experience with using the 8042, therefore this thread.

    Anyway, the 8042 will be connected to 65816 as it was to the 80286. I'm going to use the schematic of IBM's AT as example. Of course the 8042 will be addressed somewhere in the 65816's memory range. So I have no idea why you mean an extra MCU is needed. Simulation of a matrix row/column keypress is not needed IMHO.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  6. #6

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    Quote Originally Posted by Ruud View Post
    First the idea is design a new system based on a 65816 including ISA slots on an ATX board. I'm going to use my ATX based XT clone as base. There are two further ideas: using an XT keyboard interface including 8255, 74LS322 and other parts plus an AT2XT converter or using an 8042 or equivalent keyboard controller. But I have no experience with using the 8042, therefore this thread.

    Anyway, the 8042 will be connected to 65816 as it was to the 80286. I'm going to use the schematic of IBM's AT as example. Of course the 8042 will be addressed somewhere in the 65816's memory range. So I have no idea why you mean an extra MCU is needed. Simulation of a matrix row/column keypress is not needed IMHO.

    Ok, as I said, for a newly developed system, it can make sense. You don't need much of anything else, just decoding and glue logic (but I know nothing about the system you're developing).
    Here's a good start for the 8042 keyboard controller:

    https://wiki.osdev.org/%228042%22_PS/2_Controller

    HTH
    Frank

  7. #7

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    Thank you!
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

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