Background - PatternAgents/SitV GitHub Wiki

I started working with the MXMXMX Ornament and Crime Polymorhpic Eurorack module, and quickly realized that the (brilliant) firmware had pretty much maxed out all the (considerable) resources of the Teensy3.2 CPU like the Flash, RAM, EEPROM, etc. If I was going to be able to add anything more, then I would need a larger CPU model.

About the same time, Paul Stoffregen (PJRC) came out the enlarged Teensy 3.6 CPU modules, with four (4x) times the memory and many more pin resources. The Teensy Audio library was also upgraded to support the internal Stereo ADCs & DACs resources in the Teensy 3.6 module.

However, the Teensy Audio Codec subsystem needs to use many of the pins that the uO_C design also needs to use, so the question became - "Can uO_C and Teensy Audio co-exist in the same CPU?" "Spoken Into The Void" is designed to support both the Teensy Audio Shield (2 of them) as well as the Ornament and Crime socket resources, by reassigning the Original Teensy3.2 socket, to unused pins of the Teensy 3.6 and Teensy Audio System. The result adds from two(2) to six(6) audio input/output channels to the micro:Ornament and Crime architecture. By default these are "Line Level" signals, both for modularity reasons, and because of space/time limitations.

When using the Teensy Audio ADC Inputs (ADC, ADCS) the number of ADC channels drops to only two (2) channels, which are used for the two Line Input jacks. In that (firmware dependent) use case, the uO_C CV inputs would not be usable at all, which is not good. In order to allow for that firmware use case, a separate four (4) channel external ADC (ADS1115) device was added to the design to enable use cases with both Stereo Line In (12 bits x 2 channels x 44kHz), and the uO_C CV inputs (16 bits x 4 channels x 1kHz) both functioning as expected. This allows the firmware designer to trade off ADC channels vs speed & accuracy, as the external 16 bit ADCs are slower than the internal Teensy 12 bit ADCs, so more accurate, but at a reduced frequency range.

I'm also working on another board to convert the Line Level signals to/from Eurorack levels (codenamed AVCV), which brings the Eurorack level signals out to front panel jacks together with offset and gain controls. AVCV boards will also allow for easy VCV Rack Interfacing using the "Ornament and Crime" together with "Spoken Into The Void" modules!

Stay Tuned!