In the field of embedded MCUs, CoreMark is a well-known method for measuring MCU performance. The CoreMark score often becomes an important indicator for evaluating the performance of a particular MCU. Recently, STMicroelectronics launched the new generation STM32H7, which refreshed the Cortex-M general-purpose MCU score record with a CoreMark score of 3224, becoming the undisputed performance king among general-purpose MCUs based on the Cortex-M core.
Among STMicroelectronics’ powerful STM32 family, it includes multiple product series based on different Cortex-M cores, targeting different application positions, mainly including ultra-low power series, mainstream MCU series, high-performance series, wireless series, etc. In the high-performance series, the STM32H7 based on Cortex-M7, released by STMicroelectronics in 2016, has always been a representative of high-performance MCUs in the STM32 family.
The newly launched generation of STM32H7 is the dual-core version of STM32H7, adding a Cortex-M4 core on the basis of the original Cortex-M7. The new generation STM32H7 not only pushes the performance of Cortex-M general-purpose MCUs to a new peak but also brings great convenience to users with its new designs in safety and built-in peripherals, making it a perfect combination of strong performance and rich functionality.
Steady Growth of STM32 Processors
Mr. Cao Jindong, Marketing and Applications Director of STMicroelectronics’ Microcontroller Division in China, introduced the overall business development situation of STMicroelectronics in the MCU field. He stated that globally, STMicroelectronics’ performance in the MCU field in 2018 improved from third place in 2017 to second place in 2018. In the Chinese market, STMicroelectronics was ranked first in the Chinese MCU market in 2018.
Mr. Cao Jindong, Marketing and Applications Director of STMicroelectronics’ Microcontroller Division in China
Mr. Cao stated that for more than a decade, STMicroelectronics has maintained continuous growth in the MCU field, and it is “organic” growth—completely driven by its own business development rather than growth brought about by acquisitions, mergers, or consolidations.
Mr. Cao attributed STMicroelectronics’ success in the Chinese market to three development strategies that ST has actively pursued from the past to the present and into the future: first, actively expanding the ecosystem and partnerships; second, focusing on vertical applications; and third, providing broader support for small and medium-sized customers. Mr. Cao stated, “This matrix ensures that our business can develop healthily and sustainably over the long term, and this is a complementary result.”
Regarding the future planning of STM32, Mr. Cao mentioned that on the one hand, in terms of products, STMicroelectronics will launch more targeted product lines based on application needs, such as higher performance, lower power consumption, wireless connectivity, and more cost-competitive demands; on the other hand, it will focus on building a stronger software ecosystem, including development platforms, artificial intelligence, graphic design, and security services.
Dual-Core Creates the MCU Performance King
Renaud BOUZEREAU, Senior Marketing Manager of the STM32 High-Performance Product Line at STMicroelectronics, detailed the newly launched STM32H7.
Renaud BOUZEREAU, Senior Marketing Manager of the STM32 High-Performance Product Line at STMicroelectronics
The STM32H7 dual-core product includes two cores: one is a Cortex-M7 with a main frequency of 480 MHz, equipped with a double-precision floating-point unit, MPU, DSP, and Level 1 cache; the other is a Cortex-M4 core with a main frequency of 240 MHz, equipped with a single-precision FPU, DSP, MPU, and ST’s unique ART accelerator. The dual-core architecture enables the newly launched STM32H7 to exhibit powerful performance, with a CoreMark score exceeding 3200.
Renaud BOUZEREAU stated that the powerful cores of the STM32H7 are supported by a robust architecture, mainly including four aspects:
(1) In the display part, because the STM32H7 has a built-in Chrom-ART accelerator and MJPEG encoder, it can reduce the workload by 90% during image display.
(2) In the data transmission part, the main DMA built into the STM32H7 series can trigger event links and handle the most complex data transfer configurations between memory and peripherals, providing up to 16 channels, thereby reducing the CPU workload.
(3) The STM32H7 embeds a high-precision timer module that can generate complex PWM outputs, including all event types. This high-precision process is mainly aimed at digital power supplies or more complex event triggers, allowing the CPU to participate less in the event triggering process when the trigger mode is set.
(4) In the data encryption and decryption part, hardware encryption algorithms are embedded, including a hardware accelerator for hashing, allowing customers to shift from using software for encryption to utilizing internal hardware resources for encryption and decryption, which also reduces the CPU workload by 90%.
Which application scenarios are best suited for the dual-core design? Renaud BOUZEREAU provided two examples: First, the human-machine interface in industrial control, where the existence of dual cores allows customers to freely allocate tasks to the two cores for different tasks, such as processing the human-machine interface display control on the Cortex-M7, while real-time control parts, such as gateway communication, motor driving, and sensor data collection, are handled by the real-time processing core Cortex-M4. The second example is in home automation and security modules, where the Cortex-M7 can handle artificial intelligence neural networks, including applications like image display, voice recognition, and image recognition; the Cortex-M4 core handles real-time tasks, such as Wi-Fi communication and Ethernet real-time communication modules.
Regarding the advantages of the dual-core architecture, Renaud BOUZEREAU summarized four main aspects: increasing system performance, increasing system efficiency, shortening development cycles, and reducing system costs.
Firstly, the two cores can operate independently, allowing for two different tasks or executing one task while monitoring the operation of the other core to ensure its safety. In such an architecture, computation time and average power consumption in applications can be reduced.
In terms of power architecture, the STM32H7 dual-core product is divided into three power domains: the high-performance domain, managed by the Cortex-M7 for GUI, DSP, and safety control; the second, the Cortex-M4, mainly handles real-time connectivity and control, such as external connections, real-time operating systems, motor driving, and more control tasks. The third domain is known as the large data collection domain, where the other two domains automatically collect data from sensors, including external voltage and current, while in sleep mode. Once a certain quantity or threshold is reached, it can wake up the other two domains for processing. In the three domains, work timing can be freely allocated, allowing for the decision of when to turn on and off processes, achieving an overall dynamic power consumption balance.
Because the two cores of the STM32H7 work independently, tasks can be directly assigned to the dual cores. Therefore, during the development process, the configurations, including internal resources, can be arranged such that once properly allocated, two teams can develop based on their cores or allocated resources, avoiding interference with each other’s work and shortening the circuit board design and project evaluation time.
Fourthly, dual-core products can reduce the overall system cost. Because many peripheral resources are built into the STM32H7 dual-core product, in many cases, there is no need to add external ADCs, comparators, or amplifiers, thereby reducing the demand for external components. The dual-core setup allows the functionalities of two systems to be processed by one dual-core MCU.
