The Cortex-M3 implements the ARMv7-M architecture supporting Thumb-1 and Thumb-2 instructions with a 3-stage in-order pipeline, with hardware Divide and Multiply, and an additional nonprivileged mode (User Thread). It supports Bit-banding in the lowest 1MB of the SRAM and Peripheral memory allowing individual bits to be toggled without performing a read-modify-write.

The Nested Vector Interrupt Controller (NVIC) supports up to 240 interrupt inputs from peripherals with programmable priority levels from 8 to 256 levels. 

The bus mechanism implements the 3x AHB-lite protocol interfaces. 

Optional Instruction (Embedded Trace Macrocell), Data Trace (DWT), and Instrumentation Trace (ITM), JTAG and Serial Wire Debug ports. Up to 8 breakpoints and 4 watchpoints.