# Prototyping a Midi to CV module with more functionality than existing offerings

**URL:** <https://lookmumnocomputer.discourse.group/t/prototyping-a-midi-to-cv-module-with-more-functionality-than-existing-offerings/3797>\
**Category:** KOSMO MODULES\
**Created:** [July 25, 2021, 8:57am UTC](https://lookmumnocomputer.discourse.group/t/prototyping-a-midi-to-cv-module-with-more-functionality-than-existing-offerings/3797 "2021-07-25T08:57:03Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\
**Post date:** [July 25, 2021, 12:35pm UTC](https://lookmumnocomputer.discourse.group/t/prototyping-a-midi-to-cv-module-with-more-functionality-than-existing-offerings/3797/2 "2021-07-25T12:35:22Z")

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To dispense with DACs you can use PWM pins and external filters. If you look at @HAGIWO’s [designs](https://lookmumnocomputer.discourse.group/t/fm-vco-with-arduino-hagiwo/3566/13) he uses two PWM pins for a single CV output, to get higher resolution, and a 2nd order passive filter. On the other hand the Kassutronics [Quantizer](https://kassu2000.blogspot.com/2019/10/quantizer.html) uses only a single pin because for semitone resolution that’s all you need, but it uses a 4th order buffered passive filter; see the [build docs](https://github.com/kassu/kassutronics/blob/master/documentation/Quantizer/Quantizer_Build_Docs_1.1A.pdf), page 15. I sort of suspect the former design is too simplistic for accurate MIDI to CV and the latter is too low resolution if you want sub semitone accuracy (for microtones etc.) but both are worth studying for ideas.

You can get up to 16 bits resolution on a single PWM pin with some more involved programming, see [Arduino & Advanced 16-bit PWM - Codrey Electronics](https://www.codrey.com/arduino-projects/arduino-advanced-16-bit-pwm/) and [arduino uno - Increase PWM bit resolution - Arduino Stack Exchange](https://arduino.stackexchange.com/questions/12718/increase-pwm-bit-resolution) . The 32 bit Teensys use a different microcontroller, though, so the details would be different.

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