NXP Semiconductors KITMPR121EVM

Overview

KITMPR121EVM from NXP Semiconductors (formerly Freescale) is an evaluation module for the MPR121 proximity capacitive touch sensor controller IC. It enables rapid prototyping of 12-electrode touch interfaces with independent auto-calibration, I²C communication, and a dedicated 13th simulated electrode for near-proximity detection. Designed for low-power embedded systems, it supports 1.71V–3.6V operation and delivers 29 μA typical run current at 16 ms sampling.

For engineers reviewing the KITMPR121EVM datasheet, KITMPR121EVM pinout, KITMPR121EVM application, or KITMPR121EVM equivalent, this module provides hands-on validation of electrode configuration, baseline tracking, touch/release threshold tuning, IRQ-driven event handling, and proximity sensing integration - critical for consumer electronics, lighting controls, and portable device HMI development.

Technical Context

The KITMPR121EVM implements the MPR121 QFN-20 IC in a ready-to-use PCB layout with pre-mounted decoupling capacitors, REXT resistor, and test points for all 12 electrodes plus IRQ, SDA, SCL, ADDR, and power pins. It supports both 1.71–2.75V (bypassed regulator) and 2.0–3.6V (internal regulator active) supply configurations per Freescale AN3889 and AN3890.

Hardware features include configurable I²C address selection via ADDR pin (0x5A–0x5D), LED indicators for electrode activity, jumper-selectable pull-ups on SDA/SCL, and direct access to ELE0–ELE11 for custom sensor pad attachment. The board operates across –40°C to +85°C and integrates Freescale's second-generation capacitance detection engine with digital filtering, debounce, and independent electrode charge-current/charge-time autoconfiguration.

Key Specifications

Availability

KITMPR121EVM is available at Aetrix Electronics and suitable for touch interface development, proximity-sensing validation, and I²C-based HMI prototyping requiring stable component supply, full documentation access, and long-term evaluation board availability.

Supply support for KITMPR121EVM 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, IoT, and mobile applications.

The MPR121 product line was developed by Freescale (acquired by NXP in 2015) specifically for energy-efficient, high-immunity capacitive touch and near-proximity sensing in battery-powered and space-constrained devices.

FAQ

What is the primary function of the KITMPR121EVM?

The KITMPR121EVM is an evaluation module designed to demonstrate and accelerate development with the MPR121 capacitive touch sensor controller. It provides a complete hardware platform-including the MPR121QR2 IC, supporting passives, test points, and LED indicators-to validate electrode configuration, I²C communication, touch/release threshold tuning, and proximity sensing behavior without custom PCB design. Engineers use KITMPR121EVM to verify real-world performance before integrating the MPR121 into final products.

Does the KITMPR121EVM support multiple I²C addresses?

Yes, the KITMPR121EVM supports four configurable I²C addresses (0x5A–0x5D) via the ADDR pin on the onboard MPR121QR2 IC. Users can select the address by connecting ADDR to VSS, VDD, SDA, or SCL using jumpers or solder bridges-enabling multiple KITMPR121EVM units or MPR121-based subsystems on the same I²C bus without address conflict. This feature is fully implemented and tested on the KITMPR121EVM board per Freescale datasheet Rev. 4.

Can the KITMPR121EVM be used for proximity sensing as well as touch detection?

Yes, the KITMPR121EVM directly supports proximity sensing through the MPR121's dedicated 13th simulated electrode (ELEPROX), which sums all 12 physical electrodes to create a larger effective sensing area. When enabled, ELEPROX operates as an independent channel with its own baseline, thresholds, and filtering registers-allowing simultaneous touch button detection and near-field proximity wake-up. This capability is verified on the KITMPR121EVM using the included firmware examples and register map (0x1C–0x1D, 0x2A, 0x59–0x5A).

What power supply options does the KITMPR121EVM support?

The KITMPR121EVM supports two validated power configurations: (1) 1.71V–2.75V applied to both VDD and VREG (regulator bypassed), and (2) 2.0V–3.6V applied to VDD only, with VREG decoupled via 0.1 μF capacitor (regulator active). Both configurations are implemented on the board per Figures 1 and 2 in the MPR121 datasheet Rev. 4, enabling flexible testing across battery-powered (e.g., dual AA) and regulated supply environments for KITMPR121EVM evaluation.

Is the KITMPR121EVM compatible with standard Arduino or mbed platforms?

The KITMPR121EVM is not plug-and-play with Arduino or mbed but is fully interoperable via its exposed I²C interface (SDA, SCL, IRQ, VDD, VSS) and 0.1" header footprint. Engineers routinely connect KITMPR121EVM to Arduino Uno, STM32 Nucleo, or mbed-enabled boards using jumper wires and standard I²C libraries. Example code and register-level drivers for KITMPR121EVM are available in Freescale application notes AN3894 and AN3895, confirming functional compatibility when proper voltage translation (if needed) and timing constraints are observed.