STMicroelectronics – Arm Cortex-M4-based MCUs support superior graphics effects and user interfaces


STMicroelectronics has extended its family of STM32L4+ low-power microcontrollers based on the high-performance Arm® Cortex®-M4 32-bit processor core.

The STM32L4R5xx, STM32L4R7xx and STM32L4R9xx devices, which operate at a core frequency of up to 120MHz, offer sophisticated graphics capabilities and large internal random-access memory provision.

Featuring 640kbytes of embedded SRAM, these MCUs support up to WQVGA standard displays or 400px x 400px round displays with no need for external RAM.

The STM32L4Rxxx devices also enable designers to produce superior graphics effects and fluid user interfaces thanks to the built-in Chrom-ART Accelerator™, a hardware acceleration engine for common graphics functions. The MCUs also include ST’s unique Chrom-GRC™ memory optimisation feature for circular displays.

The new STM32L4+ MCUs offer various interface options for large displays, including embedded MIPI-DSI, TFT LCD and parallel display controllers.

The Arm Cortex-M4 core features a single-precision floating-point unit, which supports all the Arm single-precision data-processing instructions and all the data types. The core also implements a full set of DSP instructions and a memory protection unit, which enhances the application’s security.

As well as the SRAM provision, the MCUs include 2Mbytes of Flash memory and a flexible external memory controller for static memories and two OctoSPI Flash interfaces. The embedded memories feature protection mechanisms including read-out protection, write protection, proprietary code read-out protection and a firewall.

The STM32L4Rxxx family is available in a choice of six packages, which have from 100 to 169 pins.


  • Up to 24 capacitive sensing channels
  • Four I2C interfaces
  • Three serial peripheral interfaces
  • Two serial audio interfaces
  • Camera interface
  • Two DAC channels
  • 12-bit ADC operating at up to 5Msamples/s


  • Industrial equipment
  • Consumer devices
  • Motor-control systems

The 32L4R9IDISCOVERY kit enables users to easily prototype applications that offer high energy efficiency, and provides stunning audio and graphics rendering with direct support for a 1.2″ round AMOLED LCD screen.

Orderable Part Number: STM32L4R9I-DISCO