STMicroelectronics has launched its STM32 F3 series of microcontrollers, an important new line in ST’s product family featuring the ARM® Cortex™-M core embedded.
STM32 F3 microcontrollers are system-on-chip devices based on the Cortex-M4 core with FPU, and are optimised for efficient handling and processing of mixed signals in circuits such as three-phase motor controls, biometrics and industrial sensor outputs or audio filters. They will help simplify design, cut power consumption and reduce pc-board size in consumer, medical, portable fitness, system monitoring and metering applications. The new F3 series extends the scope of ST’s STM32 family by allowing designers to tackle mixed-signal control applications.
 
Featuring versatile analog circuitry and the ARM Cortex-M4 with FPU, the STM32 F3 series provides low to medium memory sizes at competitive cost. The Cortex-M4 with FPU core augments the proven Cortex-M3 CPU with additional Digital Signal Processing (DSP) capability, optimised single-cycle and saturating arithmetic instructions, and Floating-Point Unit (FPU), to boost performance over ST’s STM32 F1 Cortex-M3 devices. It positions the new series between the successful STM32 F1 and the best-in-performance-class STM32 F4, which features the Cortex-M4 with FPU core and large memory capacity combined with high-speed 168MHz maximum CPU frequency for complex applications.
 
With the new F3 microcontrollers, ST’s STM32 family now offers more than 350 variants addressing applications from entry-level, price-sensitive designs through to those demanding high performance and rich on-chip features. The new F3 series enables ST to deliver the advantages of its STM32 devices and ecosystem to applications that have formerly required both high-performance analog and an entry-level digital signal controller, such as high-performance motor control or embedded digital audio.
 
“The new F3 series boosts our ARM Cortex-M4 portfolio to more than 70 devices, and will help our customers design even more powerful products leveraging the advantages of the STM32 family,” said Michel Buffa, microcontroller division general manager, STMicroelectronics. “Its advanced processor, high-quality advanced analog peripherals and mid-density memory present a strong combination unmatched by competing Cortex-based or proprietary devices.” 

STM32 F3 series devices also incorporate ST’s latest improvements to digital peripherals for its STM32 family, which Michel Buffa explains is a further advantage of the extensive compatibility between all ST’s ARM Cortex-M microcontrollers.

Further technical information:

The STM32 F3 family featuring the ARM Cortex-M4 with FPU comprises four product lines, differentiated according to on-chip memory density and integrated peripherals. The peripherals deliver extreme analog integration, offering best-in-class performance through functions such a 12-bit Analog-to-Digital Converter (ADC) offering 5Msamples per second performance. Extreme analog integration maximises flexibility for designers to implement advanced system features and functions without adding extra components on the pc-board.
 
STM32 F30x devices have seven fast comparators with 50ns response time, four programmable gain amplifiers supporting four different gain settings with 1% accuracy, two 12-bit digital-to-analog converters (DACs), and four 12-bit 5Msps analog-to-digital converters (ADCs). This is the fastest ADC performance in any ARM Cortex-M microcontroller, achieving up to 18Msps in interleaved mode. The devices also have two advanced motor-control timers running at up to 144MHz. These allow one microcontroller to manage two motors plus power factor correction (PFC) via its on-chip analog peripherals, in equipment such as home appliances. Among other capabilities of the advanced timers, timing resolution better than 7ns allows new applications such as digital power supplies in telecom infrastructure or data servers, micro-inverters in solar installation and LED lighting to benefit from the scalability, low power consumption and cost-effective performance of the STM32 family.

To help developers optimise code execution time, the STM32 F30x devices have 8Kbytes of SRAM mapped to the instruction bus as Core Coupled Memory (CCM-SRAM). Critical routines loaded in the 8KB CCM at startup can be completed at full speed with zero wait states, achieving 94 Dhrystone MIPS at 72MHz. This compares with 62 DMIPS when executing from Flash or SRAM; equivalent to a 52% performance increase for critical routines. The STM32 F30x series also has up to 40Kbytes of SRAM mapped on the data bus. The 8K CCM-SRAM can also be used for data storage with no performance trade-off. Devices are pin compatible with the STM32 F1 series, and also share the same API, which simplifies migration to higher performing devices.
 
The STM32 F37x devices deliver a different blend of peripheral functions. They are the first microcontrollers from ST to integrate a 16-bit Sigma-Delta ADC on-chip, allowing the STM32 family to solve a wider range of precision-sensing applications and providing a single-chip solution capable of replacing a discrete general-purpose processor and separate ADC. Up to three 16-bit Sigma-Delta ADCs are integrated on-chip, with separate analog supply from 2.2V to 3.6V, up to 21 single or 11 differential channels, and seven programmable gains per channel. 

Other STM32 F37x analog peripherals include two fast comparators, three 12-bit DACs, and one 12-bit 1Msps ADC. There is also an enhanced CEC (Consumer Electronics Control) unit, making these devices ideal for consumer multimedia products. Compared to the STM32 F1 series, STM32 F37x devices provide a system-on-chip solution enabling developers to reduce bill-of-materials cost and simplify board designs.

Key common features of STM32 F30x/F37x:

• SRAM and CCM-SRAM with parity bit for secure software data and code execution;
• Memory Protection Unit (MPU);
• Capacitive touch-sense capability (24 keys);
• Support for both USB and CAN connectivity;
• Communication peripherals: SPI 18Mbps, I²C 1MHz (fast mode plus), USART 9Mbps;
• Sub-ppm trimable RTC with HW calendar
• Four low-power modes with 5µA STOP mode having waking-up capability from communication peripherals with fast start-up time;
• 2µA standby mode with RTC running; below 1µA in Vbat mode (battery backup)
• Debug mode: serial wire debug (SWD), JTAG interfaces, Cortex-M4 ETM
• Power supplies: 2.0V to 3.6V or 1.8V+/-8% (dedicated sales types)

Both series are scheduled to enter full production in Q3 2012.