Flash microcontroller

STMicroelectronics has announced a family of 32 bit flash microcontrollers based on the ARM Cortex-M3 core - a core with features specifically designed for embedded applications requiring a combination of high performance (1.25 Dhrystone MIPS/MHz), low power and low cost.

The STM32 family benefits from the Cortex-M3's architectural enhancements including the thumb-2 instruction set to deliver improved performance combined with better code density and a tightly coupled nested vectored interrupt controller for faster response to interrupts, all combined with good power consumption.

The devices are offered in two ranges - the STM32F103 'Performance' with 72 MHz clock frequency, provides best-in-class 32 bit MCU performance, while the STM32F101 'Access', with 36 MHz clock frequency, offers users of 16 bit devices an increase in performance at the same 16 bit price levels.

Both offer from 32 to 128 K of embedded flash memory but differ in maximum SRAM size and peripheral combinations.

At 72 MHz, executing from flash, the STM32 consumes 36 mA, corresponding to 0.5 mA/MHz.

The Cortex-M3 core's enhanced integrated features include a nested vector-interrupt controller with down to six CPU cycles inter-interrupt latency, atomic bit manipulation allowing individual bits to be modified in a single write operation, branch speculation, single-cycle multiply, hardware divide and the thumb 2 instruction set.

The devices operate from a 2.0 to 3.6 V supply and a power consumption down to 2 µA in standby mode with reset circuitry active. Other power-saving features include an integrated RTC with dedicated pin for battery operation and a dedicated 32 kHz oscillator and four low power modes.

The family provides up to 30% faster processing than an equivalent ARM7TDMI-based product or, for the same processing power, STM32 devices require 75% less power. Similarly, the thumb-2 instruction set of the new core allows designers to reduce code size communication up to 45%, almost halving the amount of memory they need to hold their applications.