NXP – Low-power voice activation possible with dual-core MCU


The LPC54110 series of MCUs from NXP Semiconductors has a power-saving dual-core architecture and the option of dedicated support for a digital microphone sub-system, enabling the implementation of voice-activated features.

The MCUs include an ARM® Cortex®-M4 main processor core and an ARM Cortex-M0+ co-processor. The ARM Cortex-M0+ co-processor is an energy-efficient and easy-to-use 32-bit core which is code- and tool-compatible with the ARM Cortex-M4 core.

This combination of two cores enables the LPC5411x MCUs to offer both a high level of integration, with many valuable features implemented on-board the MCU, and power efficiency. The ARM Cortex-M4 core has a good active-mode current of 80μA/MHz. But the dual-core architecture means that the MCU can shut down the -M4 core and use the -M0+ core to perform less taxing tasks, at an even lower active-mode current of 60μA/MHz.

The optional on-chip digital microphone sub- system on the LPC54110 family also markedly reduces the power consumed in applications which require voice input and processing. This sub-system includes a dual-channel Pulse Density Modulation (PDM) microphone interface, flexible decimators, 16-entry FIFOs, optional DC locking, hardware voice-activity detection, and the option to stream the processed output data to an I2S interface.

The digital microphone support enables system designers to stay within the tight power budgets of battery-powered products while providing always-on voice activation.


  • Up to 256kbytes of Flash memory
  • Up to 192kbytes of SRAM
  • 20-channel DMA controller
  • 12-bit ADC operating at up to 5Msamples/sec
  • Programmable power-management unit
  • 128-bit unique serial number for identification
  • Operating-temperature range: -40°C to 105°C


  • Portable fitness health-monitoring equipment
  • Intelligent sensors
  • Home and building automation
  • Fleet management and asset tracking
  • Robots and drones
  • Gaming accessories


The LPC54114 Audio and Voice Recognition Kit provides everything required to develop an always-on low-power voice-triggering product. It includes an OM13089 LPC54114 board and a shield which includes a Knowles SPH0641LM4H digital microphone, a Cirrus Logic WM8904 audio codec and a 160px x 160px monochrome OLED display.

Orderable Part Number: OM13090