IDBG - any suggestions ?

Werner Almesberger werner at
Thu Jul 15 07:44:02 EDT 2010

I'm about to start making a new revision of the Internal Debug Board
(IDBG) for the Ben and I'm looking for suggestions for improvements.

IDBG ...

- is a small add-on board that goes inside the Ben,
- connects to USB through its own Micro-USB receptacle,
- provides a serial console with both TX and RX,
- can switch USB boot on and off, as commanded by the host,
- lets the host command a hardware reset,
- has a dual USB stack that allows the regular firmware (Open Source,
  of course) to be updated via DFU.

I made IDBG originally for the Openmoko phones. You can find
descriptions and photos here:

The git repository with firmware sources and design files is here:

This is what the IDBG looks like (before adding connections to
the Ben's main PCB):

This is what a Ben looks like from the outside with IDBG installed:

What I plan to change in the next hardware revision is:

- consider simplifying the "Ben is powered up" detection,
- make the board a bit larger to accommodate the changes below,
- add a separate pad for RESETP_N. Right now, RESETP_N comes from
  P3_0, which means that one has to run the cable around the board in
  a U shape, which isn't nice.
- rearrange the pads such that the wires don't get into each other's
- maybe add an explicit ground pad,
- maybe add an explicit VBUS or VDD pad (for in-circuit programming),

All this should make it easier to install it in a Ben. Speaking of
which, is anyone considering to actually build it ?

By the way, do we have data sheets of the Ben's speaker somewhere ?

- Werner

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