STMicroelectronics STEVAL-MKI126V2

Overview

STEVAL-MKI126V2 from STMicroelectronics is a MEMS microphone system evaluation board built around the STA321MPL digital audio processor and two MP34DB01 PDM microphones. It converts up to six PDM microphone inputs into three independent I²S streams and filtered PWM outputs, supporting biquad-based sound preconditioning, voice enhancement, and real-time audio analysis for embedded voice interfaces.

For engineers reviewing the STEVAL-MKI126V2 datasheet, STEVAL-MKI126V2 pinout, STEVAL-MKI126V2 application, or STEVAL-MKI126V2 equivalent, this board enables rapid validation of PDM-to-I²S/PWM conversion, multi-microphone array synchronization, and APWorkbench-driven filter configuration in voice-enabled edge devices.

Technical Context

The board implements a fully digital audio path: PDM signals from MEMS microphones are processed by the STA321MPL's 32-bit DSP core, which applies up to 10 user-programmable biquad filters per channel. The device supports configurable clock routing, I²S format selection (standard/LSB-justified), and PWM output filtering for analog headset playback.

It integrates dual MP34DB01 microphones (36 dB SNR, 65 dB dynamic range, ±1 dB sensitivity tolerance) and provides socketed headers for up to six additional PDM microphones. Configuration is performed via USB-connected APWorkbench software, enabling real-time parameter tuning without firmware reflash.

Key Specifications

Availability

STEVAL-MKI126V2 is available at Aetrix Electronics and suitable for voice interface development, multi-microphone array prototyping, and audio preprocessing validation requiring stable component supply and documented reference hardware.

Supply support for STEVAL-MKI126V2 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, Switzerland, designing and manufacturing microcontrollers, sensors, power ICs, and analog/mixed-signal products for industrial, automotive, and consumer applications.

The STEVAL-MKI126V2 belongs to ST's MEMS evaluation platform family, specifically engineered to accelerate development of high-fidelity voice capture systems using ST's PDM microphones and audio SoCs.

FAQ

Does STEVAL-MKI126V2 support more than two microphones?

Yes - it ships with two MP34DB01 microphones mounted, but includes four additional socketed positions and full signal routing to support up to six PDM microphones simultaneously. Schematic pages 4–5 confirm dedicated PDM_INx lines and array detection logic for all six channels.

What software is required to configure the STA321MPL on this board?

The board requires ST's APWorkbench software suite, a Windows-based GUI that communicates over USB to load biquad coefficients, select I²S format (standard/LSB-justified), adjust sample rate, and enable/disable PWM output filtering. No custom firmware or SDK is needed for basic operation.

Can STEVAL-MKI126V2 output analog audio directly?

Yes - the board generates a low-pass-filtered PWM signal that drives standard 3.5 mm headsets without external DACs. This analog-ready output is derived from the STA321MPL's integrated PWM modulator and RC filter stage shown in Figure 5 of the schematic.

Is the I²S output compatible with common audio ADCs or processors?

Yes - the three I²S outputs conform to standard left-justified and I²S formats at 32-bit/48 kHz, with configurable word length and frame sync polarity. Pinouts match industry-standard I²S timing, verified against the STA321MPL datasheet and schematic page 1 signal routing.