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ST adopts Cortex-M3 in new ARM-MCU line

ST Microelectronics has introduced a 32-bit flash microcontroller family, the STM32, based on ARM’s Cortex-M3 processor core. Key parameters of the design are a performance of 1.25 Dhrystone MIPS/MHz, for a power demand of 0.5 mA/ MHz. As a Cortex-M3 design, the chips use the Thumb-2 instruction set for minimum code size, and exploit the M3’s nested-vectored-interrupt controller for fast response to interrupts. ST will offer two lines: the STM32F103 is the high-performance variant that runs at 72 MHz, while the STM32F101—termed the “Access” line—runs at half that speed and claims to offer 16-bit-machine users a performanceupgrade while retaining 16-bit pricing. In both, you canselect from 32 to 128 kbytesof flash memory, with a varietyof SRAM and peripheralmixes. The chips will run from2.0 to 3.6V for direct batteryoperation, and standby modesextend to a 2-µA minimumpower consumption, at whichlevel the reset circuitry is stillactive. An on-board real-timeclock has its own dedicatedbattery pin. ST has providedmultiple levels of keep-aliveand recovery options: there ispower-on reset, power-downreset and a voltage supervisor.An embedded factory-trimmedand accurate 8-MHz RCoscillator operates as a referencefrequency for extendedperiods, automatically backingup the embedded 4- to16-MHz external crystal oscillator. Further recovery optionsinclude dual watchdogs. TheRC oscillator is trimmed toto 1% at 25°C, and 3% overtemperature.Among otherperipherals, you can have upto three 16-bit timers and adedicated 6-way PWM timerwith embedded dead timesfor vector motor-control drives.Forthcoming variants will takethe flash-memory size upto 512 kbytes; first devicesreleased are in 48- to 100-pinpackages. Development supportcomes from a rangeof third-party suppliers, withtoolchain support from Hitex,IAR, Keil, Raisonance andRowley. Pricing for the firstrelease of parts, from thesmallest “Access” chip to the128-kbyte-flash “Performance”part, spans $1.80 to $3.60(10,000).

STMicroelectronics,www.st.com.