Building and Uploading the Rockit Firmware on Mac OS X

Like the Meeblip synth, the supported tool for Rockit development is AVR Studio which can only be used with Windows. It’s possible to build the Rockit code from the Mac OS X command line using the avr-gcc compiler and a new Makefile. The avr-gcc compiler is available for installation on Mac OS X through¬†MacPorts. You’ll also need to install avrdude which is also available from MacPorts.

I’ve adapted this Makefile to build the Rockit code. This Makefile may also work with Linux, although I’ve not tried it.¬†Simply place it in the directory with the Rockit source (make sure it’s named Makefile, not Makefile.txt) and type:

make
to build the source, then:
make hex
to create the Rockit.hex file for downloading. I’ve setup the Makefile to support the Sparkfun Pocket AVR programmer using avrdude so typing:
make install
will also upload the generated Rockit.hex file to the Rockit. If you’re using a different programmer, you’ll need to edit the writeflash target in the Makefile (line 199).
Alternatively, the avrdude command to upload the firmware is for the Sparkfun Pocket AVR programmer is:
avrdude -c usbtiny -p m644p -U flash:w:Rockit.hex

The avrdude options above can be modified to use your programmer.

The Rockit kit doesn’t ship with an AVR programming header, so you’ll need to solder your own header on the board. Here’s the correct way to connect the Sparkfun Pocket AVR programmer to the AVR header on the Rockit board:

Hackme Rockit with Sparkfun Pocket AVR programmer connected

Hackme Rockit with Sparkfun Pocket AVR programmer connected to the AVR programmer header. Note the orientation of the connector, with the wires facing toward the top of the board.

The header must be put on the top of the board so that the header pinout lines up with the AVR programmer connector. With a standard header on the board this looks like it will make it fairly tight against the case, although I’ve yet to try assembling a Rockit case.

 

Rockit Kit Build

After a few sessions of building, the Rockit is finished and working!
Rockit synth kit by HackMe Electronics

The Rockit has 2 digital oscillators, a 2-pole analog filter with low-pass, band-pass and high-pass modes, and 2 LFOs that can be routed to different control inputs of the oscillators and filter. From first impressions of playing the Rockit, the analog filter sounds nice. The band-pass mode of the filter is especially good, and offers something different from standard low-pass filtering, which can give the Rockit a nice ‘vocal’ sound when played in this mode.