New STMicro STM32G4 MCUs target cost-effective motor control systems with up to 512KB flash

STMicro introduced the STM32G4 family of mixed-signal microcontrollers in May 2019 for e-mobility (e.g. e-bikes), digital power supplies, advanced motor controls, lighting, and building-automation products.

The Arm Cortex-M4 based microcontrollers clock up to 170 MHz, and include new hardware mathematical accelerators to boost processing of applications using Cordic (Coordinate Rotation Digital Computer) and Filtering functions to support increased performance and energy efficiency. This enables faster and more efficient calculations for energy-saving motor controls and frees up the core to receive more sensor data and control additional user functions.

STM32G4 family
STM32G4 against other STM32 motor control MCUs

The STM32G4 Series of mixed-signal microcontrollers have three lines of products:

  • The STM32G4x1 Access line – general-purpose microcontrollers with an entry-level set of analog peripherals
  • The STM32G4x3 Performance line – general-purpose microcontrollers with the maximum number of analog peripherals
  • The STM32G4x4 Hi-resolution line with high-resolution timer and complex waveform builder plus event handler (HRTIM) for digital power conversion, such as digital switched-mode power supplies, lighting, welding, solar and wireless charging

At launch, STMicro offered the chip in various packages, LQPF32/48/64/80/100/128, UFBGA64/100/121, WLCSP48/64/81, UQFN32/48, and devices had 32 up to 512 Kbytes of Flash memory. However, the Access line was limited to 128 KB flash.

STM32G4 product matrix STM32G491

New STM32G4 MCUs for low-cost motor control systems

But to meet the need of engineers looking to use the STM32G4 in more cost-effective motor control systems, STMicro has now added STM32G491 parts with 256KB or 512KB flash, along with its STM32G4A1 equivalent adding AES-256 cryptography.

STM32G491/STM32G4A1 highlights:

  • Arm Cortex-M4 at 170Mhz (213DMIPS)
  • Math accelerator (CORDIC for trigonometric functions and Filter Mathematical ACcelerator or FMAC)
  • Up to 512 KB single-bank flash
  • 3x fast 12-bit ADC (4 Msps)
  • 4x DAC channels (15 Msps)
  • 4x operational amplifiers
  • 4x ultra-fast comparators (17 nanoseconds)
  • Does NOT include the “184 picoseconds high-resolution timers” needed for digital power systems, since the new parts focus on motor control
  • 2x CAN-FD and 1x USB-C PD controller
  • Motor control and digital power ecosystem support
STM32G4 access line family matrix
STM32G4 Access Line family only with 15 new part with more flash storage

NUCLEO-G491RE board

While it should be possible to develop firmware for the new part on NUCLEO-G474RE High-resolution line Nucleo board, STMicro also released the new NUCLEO-G491RE board specifically for the evaluation of the new microcontrollers.

NUCLEO-G491RE board

NUCLEO-G491RE key features and specifications:

  • MCU – STM32G491RE Cortex-M4 microcontroller with 512KB flash, 112KB SRAM in LQFP64 package
  • Expansion
    • ARDUINO Uno V3 expansion connector
    • ST morpho extension pin headers for full access to all STM32 I/Os
  • Debugging
    • On-board ST-LINK debugger/programmer with USB re-enumeration capability: mass storage, Virtual COM port and debug port
    • Micro USB connector for ST-LINK MIPI debug connector
  • Misc – User LED shared with Arduino, user and reset push-buttons, 32.768 kHz crystal oscillator, 24 MHz HSE
  • Power Supply
    • ST-LINK, USB VBUS, or external sources
    • External SMPS to generate Vcore logic supply, and reduce power consumption in run mode

STMicro offers software libraries and examples available via the STM32Cube MCU Package, and a wide choice of Integrated Development Environments (IDEs) are available including IAR Embedded Workbench, MDK-ARM, and STM32CubeIDE. The board is also part of the “Arm Mbed Enabled” program.

Pricing and availability

The entry-level STM32G491KC SKU is currently listed for $2.3203 per unit for 10k orders, but unavailable from any distributors nor on STMicro own eStore.  But the Nucleo board can be purchased now for just $15 the eStore or through distributors like Mouser (worldwide) or Farnell Element14 (EU). More details can be found on the product page and announcement post.

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