ARM Cortex-M3
EFM32 features the 32-bit ARM Cortex-M3

EFM32 includes the industry leading 32-bit ARM Cortex-M3

Cortex-M3 is ARM's flagship Cortex-M class processor

ARM®'s 32-bit Cortex™-M3 processor offers superior efficiency and flexibility and was specifically developed for response and power sensitive applications. EFM32 uses the Cortex-M3's low power and high performance abilities in combination with unique low power peripherals to create the best low power embedded systems platform ever.
Download the Cortex-M3 datasheet (PDF, 4 pages) and download the Cortex-M3 White Paper here (PDF, 17 pages). The ARM Cortex-M3 is a low power, efficient 32-bit processor


  • Low Power
    • 32-bit Cortex-M3 designed for low power operation
    • High power efficiency with Thumb-2 instruction set
    • Small core footprint with integrated power mode support
  • High Performance
    • Cortex-M3 delivering 1.25 DMIPS/MHz
    • Separate data- and instruction bus
    • High code density and performance with Thumb-2 instruction set
    • Excellent clock per instruction ratio
    • Nested Vectored Interrupt Controller for outstanding interrupt handling
    • Superior Math Capability

Thumb-2 Instruction Set Architecture (ISA)

Cortex-M3 supports 16- and 32-bit instructions available in the Thumb-2 instruction set. Both can be mixed without extra complexity and without reducing the Cortex-M3 performance. Hardware divide instructions and a number of multiply instructions give EFM32 users  high data-crunching throughput.

Harvard Architecture and 3-stage pipeline

The ARM Cortex-M3 3-stage pipeline includes instruction fetch, instruction decode, and instruction execution. Cortex-M3 also has separate buses for instructions and data. The Harvard architecture reduces bottlenecks common to shared data- and instruction buses.

Quickly servicing critical tasks and interrupts

From the low energy modes EFM32's Cortex-M3 is active within 2 μs and delivers 1.25 DMIPS/MHz on the Dhrystone 2.1 Benchmark. The Nested Vectored Interrupt Controller (NVIC) is an integral part of the Cortex-M3 processor and ensures outstanding interrupt handling abilities. It is possible configure up to 240 physical interrupts with 1-256 levels of priority, and Non-Maskable Interrupts further increase interrupt handling. For embedded systems this enhanced determinism makes it possible to handle critical tasks in a known number of cycles.

Reducing the 32-bit footprint

The Cortex-M3 has a small footprint which reduces system cost. High 32-bit performance reduces an application's active periods, the periods where the CPU is handling data. Reducing the active periods increases the application's battery lifetime significantly, and the EFM32 can spend most of the time in the efficient low energy modes.

EFM32 microcontrollers and Cortex-M3 = lowest energy!

ARM's processors have become the de facto 32-bit industry standard microcontroller, and EFM32 with Cortex-M3 is the best choice when new and legacy 8-, 16-, and 32-bit solutions need an easy low energy migration path. With EFM32 you get a microcontroller where you can be sure that every building block improves the performance with the lowest possible energy consumption!