OMLmic

All initialization routines for the codec, microcontroller, and memory - The codec is capable of multiple sample rates, and these can be easily changed to trade-off between audio quality and processing time. The codec also has an on-board headphone driver and microphone input which can be enabled, although the off-board hardware is much better. Both input and output filters can be modified, along with gain and internal signal path.
FTDI cable header - This will allow for connection to computers, and future bootloading capability. All of the necessary components are attached to mimic the Arduino bootloader.
Clip and level LEDs - The level LED comes on at approximately -35dB, and becomes brighter with more signal. The clip LED turns on, and stays on for 1 second, every time the signal goes above approximately -3dB. 0dB is when distortion begins.
Variable gain input stage - The front end presents an input impedance of 520k to AC signals, and has a variable gain of 0db to +34dB.
Socketed op-amps - Just in case you want to fiddle around with the sound. We suggest the TLC074 for good frequency response and output drive, but unless your listening on headphones at the output, you probably won't notice too much difference with the less expensive TLV274.
Optional jumpers - There are jumpers for installing a hard bypass switch between the input and output. There is also a jumper for installing a foot-switch in parallel with the rotary encoder push-button.

The current MICrODEC implementation is fun to use, but there are a number of things that would make it even better.

Internal USB - There is currently an FTDI cable header onboard, but it would be far more convenient if the case did not need to be removed to take advantage of it.
Bootloader - Once there is USB, there can be bootloader! This would allow for downloading and trading of MICrODEC programs by those who aren't interested in the details of AVR programming.
MIDI - An optional MIDI board would allow the MICrODEC to be controlled by external pedals, synths, and computer software. Sample MIDI code has been written and tested, so merely a break-out board is required. Currently, there is only one USART for both MIDI and USB, so a solution to allow for both is needed.
Arduino compatibility - Although this would seriously reduce the full power of the processor, it would also allow for a wider user base.
C code - The current assembler needs to be ported to C for those who are into such things.

Files: Version 1.0

Files: Datasheets

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