I’ve discovered to my shock that the type definition “prog_uchar” that I’ve been using to place data in SRAM has been deprecated in the latest version of the IDE (Arduino 1.6.0). It means that most of the firmware for the MB won’t compile in the latest IDE!
While I update the code, the work-around is to not use Arduino 1.6.0, but instead to use the version before – Arduino 1.0.6. I’m working on a fix as we speak.
Here’s a first video of the Bravo firmware for the MB. The Bravo you’ll recall is based on the Bleep Labs Bleep Drum – it turns the MB into a 4 voice, 8-bit drum machine. The user manual and complete feature list will be up soon.
UPDATE: the Bravo firmware can be downloaded here. The manual will soon be available in the same page.
While we wait for the enclosures to arrive, I’ve taken the time to implement a host of improvements to the multiboard PCB. And before our brave pioneers feel short-changed, the PCB is not functionally different in any way – rather the changes reflect sound design practice.
Here’s the new board.
For the following changes, I’m hugely indebted to Old Crow, a US-based synth builder with many years of experience (for a somewhat more involved DIY build than the Groovesizer, have a look at his crOwBX).
All power traces are now 32mils.
Lots of bypass capacitors – specifically on all of the multiplexer ICs.
The 7805 voltage regulator is now flat mounted.
The crystal and trim caps have been moved closer to the oscillator pins on the Atmega.
A ground plane now shields the various circuit elements from one another and from clock noise.
The serial input pin for 5th row 4021 is now terminated.
Thanks also to Mutable Instruments‘ Olivier Gillet for suggesting the use of a 6N137 optocoupler in the MIDI input circuit to replace the 4N35 I’ve been using.
Last but not least, thanks to Ewald Cress for insisting on the 1N4001 reverse polarity protection diode.
The first batch of black PCBs have arrived and they sure are purdy!
I’m building one to make sure they’re retail ready. I was tempted to offer them for sale a bit early, but I don’t think it’s the best of ideas – best to wait until the Alpha firmware is feature complete and bug free, and the enclosures are available too. Not long now though!
I’ve started building one already as you can see – 82 resistors later… I’m documenting my progress on this one for building instructions. I’m hoping this board will be identical to the production boards (except that the real ones will be black and not green).