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  • Directly connecting the Raspberry Pi Pico to the Apple II slot bus

    From Oliver Schmidt@21:1/5 to All on Mon Aug 15 19:32:35 2022
    Hi,

    I wanted to let you know that it actually is feasible to directly
    connect the Raspberry Pi Pico to the Apple II slot bus. Today I
    published my Pico source code that makes this possible:

    https://github.com/a2retrosystems/A2retroNET

    Regards,
    Oliver

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  • From Anthony Ortiz@21:1/5 to Oliver Schmidt on Sun Aug 28 19:24:06 2022
    On Monday, August 15, 2022 at 3:32:37 PM UTC-4, Oliver Schmidt wrote:
    Hi,

    I wanted to let you know that it actually is feasible to directly
    connect the Raspberry Pi Pico to the Apple II slot bus. Today I
    published my Pico source code that makes this possible:

    https://github.com/a2retrosystems/A2retroNET

    Regards,
    Oliver

    Oliver, good stuff man! I've been on the comp.sys.apple2 group and didn't see this post. I never worked on the Pico but about 5 years ago I was fooling around with my PI 3 and made it so that I could read/write to the Apple II bus via GPIO bit-banging.
    Back then I only used 8 pins for the bus so I had to push the LO and HI address bytes as well as the data bytes separately into some flip-flops, but recently I've revisited the project and I'm in the middle of simplifying it to an FPGA, but I think I'm
    going to go with the Max V CPLD instead. What are your plans for the Pico?

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  • From Oliver Schmidt@21:1/5 to All on Mon Aug 29 10:21:26 2022
    Hi Anthony,

    Oliver, good stuff man!

    Thanks for the positive feedback :-)

    What are your plans for the Pico?

    One usecase is using the RPi Pico to connect an "ordinary" RPi to the
    A2. Instead of fiddling with RPi GPIO, you just use a USB cable. The
    simplest USB setup is to have the RPi Pico act as USB device
    implementing a virtual serial port (following the ACM CDC
    specification). The "ordinary" RPi acts as USB master, that
    automatically loads its ACM CDC driver offering a /dev/ttyACMn port.

    I've taken the two exsisting well-known "connect an RPi to the A2"
    projects and applied that approach to them:

    https://github.com/oliverschmidt/Apple2-IO-RPi https://github.com/oliverschmidt/apple2pi

    They now both work nicely with my Pico-based prototype card - incl.
    their firmware ROM being emulated by the Pico :-)

    There are of course many other usecases, either emulating other
    existing A2 cards or inventing totally new ones. We'll see ;-)

    Regards,
    Oliver

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