Monday, August 10, 2015

More USB and MIDI

Time goes fast, new and more powerful microprocessors are introduced, and the favourites of a year ago are fading and starts to collect dust in a draver filled with useful but not quite exciting boards. These days the Cortex M3 of the Maple board feels a bit old, the Teensy 3.1 is a great board and the Arduino type libraries and support is superb, but it has a bit limited memory and no hardware floating point.The boards I use mostly for audio generation at the moment are the Netduino plus 2, without the Netduino bootloader and .Net libraries, the STM32F4 Discovery and the XMC4500 Relax Kit Lite. All of these have Cortex-M4F processors, more than 128KB RAM and  1024KB of flash, they are all cheap and good value for money.

I need stable USB MIDI and after wrangling with the device libraries and development platforms, endless hierachies of folders and files that are usually targeted at Windows and often lacking USB MIDI, I decided to write yet another lightweight USB implementation. I know this might sound stupid and a waste of effort but having some time free due to vacation times and a bit of rainy summer I went ahead.

The code is written from scratch and uses only some MCU specific header files borrowed unchanged  from the manufaturer supplied code libraries. When time allows and I have done some more testing a few minimal example programs will be added.

I have uploaded the code to my Cortal Dendrites repository on Github:

https://github.com/mlu/cortal_dendrites/tree/master/cortex_m/usblib

Happy Coding :)

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