The first production STM32 microcontrollers leveraging ST’s 90nm embedded Flash technology, which is already proven in smart card and automotive ICs, deliver faster operation, increased peripheral integration, lower power consumption, and increased on-chip memory densities. ST announced it was sampling these devices in 2009.
The proprietary ART memory accelerator balances the inherent performance advantage of the ARM Cortex-M3 over Flash memory technologies, which normally requires the processor to wait for the Flash at higher operating frequencies. The CPU can now operate up to 120MHz without waiting, thereby increasing overall system speed and efficiency.
To release the processor’s full 150 DMIPS performance at this frequency the accelerator implements an instruction pre-fetch queue and branch cache, enabling program execution from Flash at up to 120MHz with zero wait states. Competing Cortex-M3 MCUs can now only outperform the STM32 by operating at frequencies above 120MHz, which will increase power consumption and heat dissipation.
With this performance now available, developers can host extra elements of a system on the microcontroller, saving the need to use a more expensive microcontroller or a companion DSP. An example is in multimedia applications, where customers will be able to implement an audio codec, video processing functions, data encryption, digital filtering, and a multi-protocol gateway, with sufficient remaining resources to manage other tasks.
The latest STM32 variants benefiting from the 90nm process and the ART memory accelerator have been verified according to CoreMark™ tests created by the Embedded Microprocessor Benchmark Consortium. CoreMark results verify the STM32 executes 8% faster than Cortex-M competitors at 100MHz clock speed. The performance advantage is greater still at 120MHz. CoreMark analysis also confirms dynamic power consumption of only 188µA/MHz (98µA/CoreMark). This is equivalent to drawing 22.5mA at 120MHz (executing from Flash memory, with ART accelerator enabled and all peripherals off).
The new 90nm devices featuring the ART memory accelerator are sampling at lead customers. Product details will be announced later this year.