STMicroelectronics STEVAL-MKI117V1

Overview

STEVAL-MKI117V1 from STMicroelectronics is a USB-powered MEMS microphone demonstration board featuring the MP34DT01 bottom-port digital microphone and STM32F107RC microcontroller. It functions as a plug-and-play PC audio device, performing real-time PDM-to-PCM decoding and streaming 16-bit/48 kHz stereo audio over USB.

For engineers reviewing the STEVAL-MKI117V1 datasheet, STEVAL-MKI117V1 pinout, STEVAL-MKI117V1 application, or STEVAL-MKI117V1 equivalent, this board serves as a validated reference for digital microphone interface design, USB audio class 1.0 implementation, and embedded PDM signal processing in voice-enabled edge devices.

Technical Context

The board implements a complete digital audio acquisition chain: MP34DT01 microphones output 1-bit PDM streams at 1–3.25 MHz; the STM32F107RC executes firmware-based decimation filtering (e.g., cascaded integrator-comb + FIR) to convert PDM to PCM, then formats and transmits stereo PCM via USB full-speed (12 Mbps) using CDC ACM class descriptors.

No external clock source is required-the STM32 uses its internal PLL and USB SOF timing for synchronization. Audio path routing supports dual-microphone beamforming evaluation, with configurable gain and sample rate (default 48 kHz) via host-side control requests.

Key Specifications

Availability

STEVAL-MKI117V1 is available at Aetrix Electronics and suitable for voice interface prototyping, acoustic beamforming validation, and USB audio subsystem development requiring stable component supply and production-ready firmware examples.

Supply support for STEVAL-MKI117V1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL (ST Evaluation) series-engineered to accelerate customer adoption of ST sensors and MCUs through hardware-validated, firmware-supported reference designs targeting audio, motion, and environmental sensing applications.

FAQ

Does STEVAL-MKI117V1 require custom drivers on Windows or macOS?

No. The board implements USB Audio Class 1.0 (UAC1) descriptors and enumerates as a standard "USB Audio Device" without proprietary drivers. Windows 10/11 and macOS 12+ recognize it immediately as a stereo input device using built-in class drivers-no INF or kext installation needed.

Can the PDM sampling rate be changed from the default 3.25 MHz?

Yes. The MP34DT01 supports PDM clock frequencies from 1 MHz to 3.25 MHz. Firmware on the STM32F107RC allows reconfiguration of the timer input capture frequency and decimation filter coefficients to accommodate alternate PDM rates, enabling trade-offs between bandwidth and processing load.

Is the board capable of mono or stereo recording?

It supports both. By default, the two MP34DT01 microphones feed independent PDM channels into the STM32, producing true stereo 16-bit/48 kHz PCM. Firmware can be modified to sum channels for mono operation or route one microphone to left/right channel only.

What firmware resources are provided by ST for this board?

ST provides complete, open-source firmware (C code) including PDM decimation libraries, USB audio descriptor tables, and host-side configuration utilities. All source files, Keil/IAR/TrueSTUDIO project files, and application notes (AN3984, AN4327) are available on st.com under document ID 023000.