Help with VIC-MIDI Software

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Schema
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Help with VIC-MIDI Software

Post by Schema »

As seen elsewhere on Denial, Retro Innovations has released the VIC-MIDI cartridge for the VIC-20!

I've been working on some code to implement the MIDI side of it. The MIDI In capability works very well (IMHO) but there are a couple of areas where I need some help:

1. MIDI Out capability. I added a very simple single-note output interface for testing the hardware, but what would be needed would be a table to track multiple keypresses and multiple notes, for Note On/Note Off. This would allow the VIC to be played like a keyboard, maybe with the Incredible Music Keyboard overlay.

2. I was never able to get viznut's waveforms to work reliably. They have to be applied at each note and I couldn't get the timing right.

3. The GUI is pretty plain, though I incorporated a font for it someone made a while back.

Here's the code and some preliminary documentation. Feel free to fork it! Alternately, I can give you access to the repo (PM me if you want to do this).

https://github.com/LeifBloomquist/VICMIDI
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Re: Help with VIC-MIDI Software

Post by pixel »

Schema wrote: 2. I was never able to get viznut's waveforms to work reliably. They have to be applied at each note and I couldn't get the timing right.
You have to switch the channels you want to viznut off for a couple of cycles until the shift registers get reset before. Cannot see it happening in that mess of illegal opcodes. :)

Code: Select all

    lda #$7e	; Turn off but set to highest frequency, so it's getting done as fast as it could.
    sta $900a
    sta $900b
    sta $900c
    sta $900d
    ldy #0
l:  dey
    bne -l
    ; ...now viznut them

A man without talent or ambition is most easily pleased. Others set his path and he is content.
https://github.com/SvenMichaelKlose
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