HardMPU with wavetable module support

This is a clone of ab0tj's HardMPU board. I wanted one with a "Wave Blaster" header, so... here it is! If you don't need to install a wavetable module on your HardMPU, rather use ab0tj's original board. In particular, to quote the HardMPU repo, the circuit design is free for non-commercial use. The presence of this implementation does not permit commercial exploitation. If you build this, you may do so only for your own personal use. All software is bound by the terms of the GPL.

The ATmega needs to be programmed before use. This can be done using any AVR programmer (AVRISP, STK500, USBtinyISP, USBasp etc) - I recommend the programmer from Pololu. Program the board loose (not plugged into a computer!) with the programmer configured to power the target at 5V. The required firmware can be found here, and AVRDUDE is used to install the firmware onto the ATmega. You will need to modify the program.bat to reflect your programmer and environment. For example, to use a Pololu programmer detected at COM4, change (per-line):

-c usbasp-clone

to

-c stk500v2 -P COM4

For Mac and Linux, change the BATch file to a shell script and adapt it accordingly (use /dev/ttyUSB0 instead of COM4 etc).

The optional User port (J2) allows adventurous builders to add features to the board, either internally or externally. It breaks out 4 GPIO pins, an I²C interface, the "Internal" serial interface (shared with the Wavetable header), and fused power and ground pins. Either regular or right-angled header (as pictured) can be installed in the J2 position; a hole will need to be cut in the bracket for external access. You will need to write your own code to use these interfaces - maybe add a status display using a common I²C LCD? The possibilities are not particularly limited!

The design permits "nicer" parts than necessary - for example, the audio jack footprint accepts both switched and unswitched sockets. Not all pads and holes in the board need to be filled. The OPA2134 can be substituted for other common dual opamps (like the NE5532). Some connectors are optional - J2 and J5 in particular are seldom-used.

Bill Of Materials and part references are below. The specified parts are just the ones I used, and can be substituted as needed - Mouser links provided for convenience and reference. You will need to drill a single hole in the specified bracket for the audio jack - refer to the PCB file for size and location.