psxjpma

  • 21 days ago
  • Joined Jan 29, 2018
  • 4 discussions
  • 10 posts
  • In Crackle box + Bela?

    well ... the output may be too hot, but if you divide it down with a a couple of resistors if should be safe enough ...
    you probably don't want to mess around with getting the line out from the UA709, as that may affect the feedback behaviour of the instrument ...

    Try something like this:

     C5
-||----+---------------+
       |               |
       |               z  2k2
       |_/|            z
        _ |  LS1       +--------Bela audio in
       | \|            |
       |               z 1k
       |               z
       |               |
J5-----+---------------+-----Bela GND
  • In Exceptions to using the external 5V power supply with digital pins

    What you should never do is plug 5V into any of the Bela P8/P9 pins. There are always 5V available on P9.07/P9.08. There is also 5V signal on the cape's analog out header, though this has a 100ohm resistor in series for legacy reasons and it's hardly usable for anything. If you send signals higher than 0.66 through any of the analog outs, these will also output a signal larger than 3.3V *.

    Additionally, when powered via the barrel jack, the 5V line coming in on the jack itself is also available on P9.05/P9.06.

    As long as you don't plug any of these signals into the other pins on P8 and P9 (either directly or via breadboard/switch or any external device), you are fine. In other words, if you do not take any signals from the P9 pins mentioned above or the analog out sockets, then you will be safe, _regardless of how you powered the device.

    * for completeness, I should mention that the signals on the analog out header are actually current-limited by a series resistor, so they are not guaranteed to destroy your device if you plug them into arbitrary P8/P9 pins, but do not try that (especially with the 5V pin).

  • In Neopixels (ws2811b RGB LEDs)

    You mean using SPI to bitbang a wS2812-compatible signal? Yes, it does work. However, only on BelaMini there is a spare SPI to use for this purpose. On Bela (not Mini), you can only access a data line from an unused SPI bus if you either:

    • disable audio input
    • disable analog I/O