메시지

ST Cortex-A7 chip makes it easy for MCU designers to adopt Linux

The chip, called STM32MP1, gets its own open-source Linux distribution – OpenSTLinux – which contains Linux BSP, kernel, drivers, boot chain, and secure OS (OP-TEE: trusted execution environment).

“OpenSTLinux has already been reviewed and accepted by Linux Foundation, Yocto project and Linaro. The distribution contains all the essential building blocks for running software on the application-processor cores,” said the firm, continuing: “STM32MP1 extends the STM32 family to address customer requirements for real-time, power-constrained applications. With this combination of MPU and software, ST has assembled all the pieces to match the requirements of many industrial and professional applications.”

In view of the industrial target market, STM32MP1 is included in ST’s rolling 10-year longevity programme.

With heterogeneous cores, power can be saved, for example, by stopping Cortex-A7 execution and running only from the M4 – reducing power to 25%. “From this mode, going to stand-by further cuts power by 2,500 times, while still supporting the resumption of Linux execution in 1 to 3s, depending on the application,” said the firm.

For industrial control panels, there is an on-die 3D GPU with OpenGL ES 2.0 interface and native support for Linux and application frameworks including Android Qt. 24-bit parallel RGB displays are supported up to WXGA at 60fps and MIPI DSI with 2 data lanes running at 1Gbit/s.

External memory interfaces support DDR3, DDR3L, LPDDR2, LPDDR3 (32/16-bit at 533MHz), and flash including eMMC, SD card, SLC NAND, SPI NAND and Quad-SPI NOR.

Hardware security features include Arm TrustZone, cryptography, hash, secure boot, anti-tamper pins, and a real-time clock.

Peripherals, many familiar to the STM32 family, can be allocated to either Cortex-A (Linux) processing or Cortex-M (real-time) processing.

Interfaces include: 2x 16bit ADC, 2x 12bit DAC, on-chip LDOs, 29x timers, 3x watchdogs, 3x USB2.0 (including 2x High-Speed), Gigabit Ethernet GMAC, 2x CAN FD, I²C, UARTs, SPI and, depending on package, up to 176 GPIOs.

Packages are BGA, with options on 10 x 10mm, 12 x 12mm or 18 x 18mm.

Development-wise, there are two evaluation boards (STM32MP157A-EV1 and STM32MP157C-EV1) and two Discovery kits (STM32MP157A-DK1 and STM32MP157C-DK2) – boards available through distributors in April.

The STM32Cube tool package for Cortex-M has been extended to include the Cortex-A processors. STM32CubeMX facilitates software and hardware configuration of both the Cortex-A7 and Cortex-M4 cores. It handles C-code generation for the M4 core, DDR SDRAM interface configuration, and tuning tool. It can also generate Linux Device trees.

Three developer software packages will be available:

Starter package (STM32MP1Starter) – quickly easily start
Developer package (STM32MP1Dev) – add customer developments on top of the STM32MP1 embedded Software distribution
Distribution package (STM32MP1Distrib) – create customer Linux distribution, customer Starter, and customer Developer packages
ST has collaborated with Witekio for porting Android to STM32MP1.

Dedicated power support chip
STPMIC1 is a dedicated power supply chip (PMIC) for STM32MP1 that integrates four dc-dc buck converters, six LDOs, and a dc-dc boost converter. On top of this it has power switches for USB VBUS and general-purpose use.