What is bit-banding in Cortex-M3?

Bit-banding is a term that ARM uses to describe a feature that is available on the Cortex M3 and M4 CPU cores. Basically, the device takes a region of memory (the Bit-band region) and maps each bit in that region to an entire word in a second memory region (the Bit-band Alias Region).

Where can I use bit-banding?

Of course, as we’ve seen, bit-banding can be used on any register bit in the peripheral address space, so dedicated macros can be used to not only clear an interrupt flag but also to enable or disable individual interrupts or any peripheral feature controlled by a single bit.

Why Cortex-M3 is a 32 bit microprocessor?

The Cortex-M3 supports the Thumb-2 instruction set. This is one of the most important features of the Cortex-M3 processor because it allows 32-bit instructions and 16-bit instructions to be used together for high code density and high efficiency. It is flexible and powerful yet easy to use.

Where is ARM Cortex-M3 used?

The Cortex-M3 processor is specifically developed for high-performance, low-cost platforms for a broad range of devices including microcontrollers, automotive body systems, industrial control systems and wireless networking and sensors.

What is ARM bit?

An ARM processor is one of a family of CPUs based on the RISC (reduced instruction set computer) architecture developed by Advanced RISC Machines (ARM). ARM makes 32-bit and 64-bit RISC multi-core processors. An orthogonal instruction set. Mostly single-cycle execution. Enhanced power-saving design.

What is bit-band alias address?

BITBAND_PERI_BASE is the base address of bit-band alias region for peripherals. These are the base addresses for the related registers to set the pin high/low from portE (one register to set the pin and one to clear it) and to read a pin value from the portB.

How much power does a Cortex M3 use?

Dynamic power consumption from 10 to 150µW/MHz The dynamic power of the core ranges from 10 to 150µW/MHz depending on the technology used.

Is ARM Cortex M3 Little Endian?

Another feature of the memory system in the Cortex-M3 is the bit-band support. This provides atomic operations to bit data in memory or peripherals. In most cases, Cortex-M3-based microcontrollers are little endian. In the Cortex-M3, the endian mode is set when the processor exits reset.

What are the features of ARM Cortex M3?

Key features of Arm® Cortex®-M3 core

• Armv7-M architecture.
• Bus interface 3x AMBA AHB-lite interface (Harvard bus architecture) AMBA ATB interface for CoreSight debug components.
• Thumb/Thumb-2 subset instruction support.
• 3-stage pipeline.
• Nested Vectored Interrupt Controller (NVIC)

What are the two modes used in ARM Cortex M3?

The processor supports two modes of operation, Thread mode and Handler mode:

• The processor enters Thread mode on Reset, or as a result of an exception return. Privileged and Unprivileged code can run in Thread mode.
• The processor enters Handler mode as a result of an exception. All code is privileged in Handler mode.

Is ARM better than x86?

ARM is faster/more efficient (if it is), because it’s a RISC CPU, while x86 is CISC. The original Atom (Bonnell, Moorestown, Saltwell) is the only Intel or AMD chip in the past 20 years to execute native x86 instructions.

How big is Bit band in ARM Cortex-M3?

ARM Cortex-M3 Memory Map: The bit-band region starts with 0x20000000 address and the alias starts with 0x22000000. Adapted from: Cortex-M3 Technical Reference Manual To map each bit in bit-band region you need 1 word in the alias region. Apparently, the size of bit-band alias will be 32-MB.

Is the Cortex M3 processor compatible with arm?

The Cortex-M3 processor is usually incorporated into a SoC using a broad range of Arm technology including System IP and Physical IP. It is fully supported by Arm development tools.

What’s the price of the Cortex-M3 SoC?

Cortex-M3 is available to access for $0 upfront for prototyping and commercializing a custom SoC with Arm DesignStart.

How to map each bit in bit band region?

To map each bit in bit-band region you need 1 word in the alias region. Apparently, the size of bit-band alias will be 32-MB. As a condensed explanation, to set the value of a bit from bit-band region you need to change the value of the LSB in the alias address.