Currently, the most popular 32-bit microcontrollers on the market primarily use ARM processor cores. These 32-bit microcontrollers are widely used in products such as mobile phones, PDAs, and others. With the introduction of new products using ARM-based 32-bit microcontrollers and a continuous decline in prices, opportunities are emerging for their applications to expand into lower-end markets.
In 2006, ARM introduced the Cortex-M3 processor core, specifically designed for embedded applications that are price-sensitive but require high performance. The Cortex-M3 processor incorporates multiple technologies that deliver industry-leading performance while helping to reduce costs. Its primary application areas include microcontrollers, automotive body systems, white goods, and networking equipment. It is important to note that ARM does not manufacture chips itself; rather, it sells its chip designs and licenses them to semiconductor companies.
The STM32 series of microcontrollers, developed by STMicroelectronics, are based on the Cortex-M3 processor and are paired with various peripherals to create a powerful microcontroller product family. The STM32 microcontrollers are widely used in applications such as programmable logic controllers (PLCs), inverters, three-phase motor control (Only applicable to STM32F103), appliance control systems, human-machine interfaces (HMI) for home appliances, and HVAC systems.
STMicroelectronics' STM32 series microcontroller is a milestone product because it is the first microcontroller from STMicroelectronics with a Cortex-M3 processor core. The benefits of the ARM processor core are low power consumption and high performance, and the same software is compatible across different cores. STMicroelectronics focuses its application on non-mobile markets, that is, markets other than mobile phones, such as intelligent control, network equipment, industrial control, etc.
The STM32 series consists of two product lines: basic and enhanced. Both the basic and enhanced series feature 5 serial ports, 2 SPIs, 2 I²C interfaces, an on-chip real-time clock, 2 independent watchdogs, power-on reset, and power-down reset. There are up to 11 DMA channels, and 80% of the pins on all chips are GPIO. The difference between the basic and enhanced series is that enhanced products have independent ADC channels with a conversion time of 1 microsecond. Enhanced STM32 products also include a USB 1.1 transmission interface and have the lowest power consumption in the 32-bit microcontroller field, equivalent to 0.5mA/MHz. The maximum operating clock speed of basic products is 36MHz, while the maximum for enhanced products is 72MHz.
In addition, for motor vector control, the STM32 series offers special advantages: 2 independent A/D sampling channels, timers capable of generating 6 PWM outputs, hardware multiplication and division instructions, and dead-zone control. In terms of pricing, the basic series is priced at US$1.80 (for 10K units), while the enhanced series is priced at US$3.60 (for 10K units). These prices are comparable to those of mid- and high-end 8-bit microprocessor products, highlighting the significant price advantage of STM32 microcontrollers.
For most design engineers, completing product design as quickly as possible and rapidly entering the market is crucial. To support this, STMicroelectronics provides completely free low-level peripheral driver libraries based on the STM32 series microcontrollers, simplifying system development. Furthermore, these driver libraries are written by STMicroelectronics staff and have undergone internal testing, giving engineers confidence in their use. These libraries cover all peripherals, including general-purpose IO, A/D converters, timers, serial ports, etc. Users can download them from the STMicroelectronics website. Additionally, STMicroelectronics offers specialized libraries for USB devices and motor control with Hall sensors for engineers to reference.
