CML Microcircuits Adds Advanced Voice Codec to Raspberry Pi

January 10, 2020 Brandon Lewis

CML Microcircuits has released the EV6550DHAT, a Hardware Attached on Top (HAT) for Raspberry Pi that integrates the low-power voice capabilities of the CMX655D codec. Designed for digital voice and sensor applications, the single-chip CMX655D codec covers the entire signal chain through:

  • Dual-Matched Digital MEMS Microphones
  • A 1 W Class D Speaker Driver with Decimation, Filtering, Signal Processing, and Digital Gain
  • An I2S/PCM Audio Interface
  • SPI Control Interface

The EV6550DHAT is compatible with the 40-pin extended GPIO connector, allowing ultra-low-power voice coding and decoding to be easily added to and powered by Raspberry Pi devices. The HAT also supports external power sources.

The systems is packaged with pre-recorded sample files, and able to record and playback .wav audio files at different sample rates and levels. Support for open source GUI software such as GTK3+ and GLADE allow users to interface with the CMX655D and quickly configure sample rates (8, 16, 32, or 48 ksamples per second), dB levels (-12 dB to +3 dB), or volume (-90 db to 0 dB).

Muting and smoothing functionality is also supported.

The EV6550DHAT is available now from Digi-Key and Mouser. For more information, visit www.cmlmicro.com/products/cmx655d-ultra-low-power-voice-codec/?s=CMX655D.

About the Author

Brandon Lewis

Brandon Lewis, Editor-in-Chief of Embedded Computing Design, is responsible for guiding the property's content strategy, editorial direction, and engineering community engagement, which includes IoT Design, Automotive Embedded Systems, the Power Page, Industrial AI & Machine Learning, and other publications. As an experienced technical journalist, editor, and reporter with an aptitude for identifying key technologies, products, and market trends in the embedded technology sector, he enjoys covering topics that range from development kits and tools to cyber security and technology business models. Brandon received a BA in English Literature from Arizona State University, where he graduated cum laude. He can be reached by email at brandon.lewis@opensysmedia.com.

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