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density and reduced program memory requirements. The Cortex
®
-M7 instruction set
provides the exceptional performance expected of a modern 32-bit architecture, with the
high code density of 8-bit and 16-bit microcontrollers.
The Cortex
®
-M7 processor closely integrates a configurable NVIC, to deliver industry-
leading interrupt performance. The NVIC includes a Non Maskable Interrupt (NMI), and
provides up to 256 interrupt priority levels. The tight integration of the processor core and
NVIC provides fast execution of interrupt service routines (ISRs), dramatically reducing the
interrupt latency. This is achieved through the hardware stacking of registers, and the ability
to suspend load-multiple and store-multiple operations. Interrupt handlers do not require
wrapping in assembler code, removing any code overhead from the ISRs. A tail-chain
optimization also significantly reduces the overhead when switching from one ISR to
another.
To optimize low-power designs, the NVIC integrates with the sleep modes, that include a
deep sleep function that enables the entire device to be rapidly powered down while still
retaining program state.
The reliability is increased with automatic fault detection and handling built-in. The
Cortex
®
-M7 processor uses ECC and SECDED on accesses to memory and has Memory
Build-in Self Test (MBIST) capability. The Cortex
®
-M7 processor is dual-redundant, which
means it can operate in lock-step. The MCU vendor determines the reliability features
configuration and therefore this can differ across different devices and families.
To increase instruction throughput, the Cortex
®
-M7 processor can execute certain pairs of
instructions simultaneously. This is called dual issue.
1.3.1 System level interface
The Cortex
®
-M7 processor provides multiple interfaces using AMBA
®
technology to provide
high speed, low latency memory accesses. It supports unaligned data accesses.
The Cortex
®
-M7 processor has an MPU that provides fine grain memory control, enabling
applications to utilize multiple privilege levels, separating and protecting code, data and
stack on a task-by-task basis. Such requirements are becoming critical in many embedded
applications such as automotive.
1.3.2 Integrated configurable debug
The Cortex
®
-M7 processor implements a complete hardware debug solution. This provides
high system visibility of the processor and memory through either a traditional JTAG port or
a 2-pin Serial Wire Debug (SWD) port that is ideal for microcontrollers and other small
package devices. The MCU vendor determines the debug feature configuration and
therefore this can differ across different devices and families.
For system trace the processor integrates an Instrumentation Trace Macrocell (ITM)
together with data watchpoints and a profiling unit. To enable simple and cost-effective
profiling of the system events these generate, a Serial Wire Viewer (SWV) can export a
stream of software-generated messages, data trace, and profiling information through a
single pin.
The optional CoreSight technology components, Embedded Trace Macrocell
™
(ETM),
delivers unrivalled instruction trace and data trace capture in an area far smaller than
traditional trace units, enabling many low cost MCUs to implement full instruction trace for
the first time.