• I was looking at the schematic for the digital control board and noticed that pin 17 of the ATMega is leading to something labeled SECRET_MIDI_OUT – JP1.

    On the PCB it seems to be a dead end just before the header.

    What is it? Anyone know?

  • It is the TX port of the second UART of the ATMega644p. During development it was used to pipe data out, first through a USB>serial dongle ; then through a second midi connector.

    Currently, its sole use is to send CV data in digital format to the digital filter board.

  • You won’t believe me, but that was my guess. I was really hoping that it was some sort of treasure map.

    I’ll keep looking…

  • But given it is a synth, having more MIDI outputs isn’t a lot of use :)

  • I grant you, it was more interesting when it was a secret…

  • Should have left well alone then ;-)

    Sometimes it’s better not to know.


  • The little secret pin no one should know about.
    Revealed veil of mystery never let you sleep in calm.
    This is the price for curiosity, this will never be unseen.

  • Maybe unexplained pins should be treated the same way as undocumented jumpers?

    As Dave Haynie (hardware engineer at defunct Commodore) used to say:
    NEVER EVER mess with a PCB jumper you don’t understand, even if it’s labelled “SEX AND FREE BEER”

  • Thats what i will include on my next PCB......

  • Schrab, I think that’s haiku?

  • @Titus
    Now that you mention that… maybe i should also try to solder sober?

  • Let’s take a vote: who thinks DMM solders sober? He produces the neatest builds ever known…

  • Titus, some kind of. I have not classified it yet.
    whispering: who is DMM?

  • He is the guy that built the programmer/xt in this thread.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

In this Discussion