Bubble Development Board – first prototypes received

A couple of days ago I received the first examples of the Bubble Development Board and started testing them.


Much to my joy, the board fits neatly into a low-cost plastic case from Farnell, part number 1526699. With front and rear panels suitably cut out, it should be well protected and easy to connect things to.


But does it work? Well, yes, largely. Here are the results so far.

  • Power: the LEDs (green for +5V input, orange for VDD_IO from the Bubble) come on and the Bubble board starts up reliably.
  • Reset button: does what it says on the tin.
  • Serial port: console works.
  • USB host: tested to work with a memory stick and a USB-to-Ethernet adapter.
  • USB slave: working. USB networking connection successfully established to a desktop PC as documented at http://www.balloonboard.org/balloonwiki/USBNetworking.
  • Audio: output works, straight into a pair of headphones, and quality seems good with no unpleasant background noises. Haven’t tried input yet.
  • HDMI: the Bubble board I was using was set up to drive an LCD panel, but by installing fbset and fiddling around with the settings (making them roughly 800×600, 60Hz) I managed to get a display on a monitor connected to the HDMI port. However, the image tends to disappear every few seconds and then come back again with some flickering, so something’s not quite right. I tried another monitor via an HDMI-DVI cable with the same result.
  • Micro SD socket: not working yet. The kernel reports an error during boot and /dev/mmc* devices don’t appear. I’ve noticed that other implementations of the SD card socket from Bubble have pullup resistors on all the data and clock lines which I neglected to put on this board. This might be an easy fix because the wiring looks right.
  • JTAG, Samosa, Raspberry Pi header, Ethernet: not tested yet.

Here’s another picture with the Bubble board turned over so you can see what’s on it.


1 thought on “Bubble Development Board – first prototypes received

  1. Pingback: Bubble Development Board – progress | martinjonestechnology

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