1. Introduction to ARM
ARM Ltd. designs the ARM (Advanced RISC Machine) series of low-cost, power-efficient, 32-bit microprocessors. More than 10 billion processors featuring an ARM core have been shipped, primarily for use in embedded systems. In fact, 98 percent of the world’s mobile phones contain at least one ARM processor. You can apply ARM architectures to almost any embedded application, from automotive communications protocols to security systems and medical devices.
However, ARM Ltd. does not manufacture or sell any physical chips. Instead, it provides other semiconductor companies with intellectual property (IP) solutions in the form of ARM architecture cores or systems on a chip (SOCs). The licensees of the ARM core can then optimize, customize, and manufacture the IP for their particular use cases or customer requirements. Variations of ARM cores include changing clock frequencies, adding on-chip RAM, or adding an on-chip peripheral such as analog-to-digital converters (ADCs). Examples of ARM licensees include Luminary Micro, NXP, STMicroelectronics, and Texas Instruments.
ARM Ltd. provides a wide range of processor designs depending on the system requirements. Typically ARM offerings are categorized into application-level microprocessors or embedded system microcontrollers.
2. Comparison of Embedded Processor Types
An application microprocessor (MPU) solution is typically used to create a system similar to a PC, mobile phone, or personal media player running a complex operating system. These processors focus mainly on providing the maximum performance amount and place a lower importance on minimizing power consumption and cost. Another major distinguishing feature of a microprocessor is that the chip itself consists only of a processing unit. The microprocessor must be programmed to communicate with peripherals, such as analog and digital I/O, external to the chip. Embedded hardware engineers must place the peripherals on their board designs to give their microprocessor the ability to communicate to the outside world, and embedded software engineers must develop software to interact with these external peripherals.
Microcontroller (or MCU) solutions are used in real-time systems in automotive, industrial, and networking applications. Microcontroller designs emphasize simplicity and lower processing capabilities in exchange for a low-power, inexpensive price point. The major distinguishing factor between a microcontroller and microprocessor is that many of the peripherals are located on-chip. Peripherals such as analog and digital I/O and networking capabilities are often located on the microcontroller, reducing the complexity of the board design and software communications for hardware and software engineers, respectively.
Another commonly used embedded component is a field-programmable gate array (FPGA). An FPGA is a reconfigurable semiconductor that engineers can use to create custom circuitry defined in software. FPGAs are incorporated in a variety of applications such as high-performance data processing and high-speed control. This performance capability is achieved through the inherently parallel nature of FPGA hardware. FPGAs in embedded systems are often paired with a microprocessor, such as in NI reconfigurable I/O (RIO) products.
3. ARM Microcontroller Families
ARM has several microcontroller families: ARM7, ARM9, and Cortex-M3. The NI LabVIEW Embedded Module for ARM Microcontrollers can program more than 300 microcontrollers, and National Instruments provides evaluation board options for ARM7 and Cortex-M3 architectures.
Figure 1. Target ARM hardware with LabVIEW graphical programming.
The ARM7 microcontrollers are the longest-serving ARM processors. The ARM7 family features a small microcontroller with very low power consumption. The microcontroller has been on the market for more than 10 years, but its implementation continues to improve with new technologies. It is the most widely used 32-bit embedded processor and is the choice of most microcontroller licensees.
The Cortex-M3 processor is one of the newest architectures in the ARM microcontroller family. It is designed to provide higher performance than ARM7 processors with comparable power consumption (up to 70 percent more efficient per megahertz versus ARM7 processors). Additionally, the Cortex-M3 is more memory-efficient, so silicon licensees can make less expensive designs.
4. LabVIEW Embedded Module for ARM Microcontrollers
Using the LabVIEW Embedded Module for ARM Microcontrollers, you can take advantage of low-cost, power-efficient ARM microcontrollers in your own embedded systems with LabVIEW graphical development. By providing high-level abstraction for program logic and access to on-chip peripherals, the LabVIEW Embedded Module for ARM Microcontrollers makes it easier to create an embedded system for applications such as medical devices, appliances, or industrial communications.
You can choose from several evaluation hardware boards to prototype your ARM application with the LabVIEW Embedded Module for ARM Microcontrollers before moving to custom ARM hardware. The Keil MCB2300 evaluation board features an NXP 2378 ARM7 processor, two serial interfaces, a speaker, analog input, two CAN interfaces, an LCD, and Ethernet. The Luminary Micro LM3S8962 evaluation board features a Luminary Micro Cortex-M3 with one CAN interface, OLED graphics display, Ethernet, analog input, and analog output.
Figure 2. Accelerate ARM-based embedded system designs with evaluation hardware.
With the LabVIEW Embedded Module for ARM Microcontrollers, engineers and scientists unfamiliar with embedded development can fully take advantage of the benefits ARM architectures provide. Experienced embedded developers can also use the LabVIEW Embedded Module for ARM Microcontrollers to accelerate development through high-level abstraction for I/O, communication protocols, and a wide array of analysis and signal processing.
Jamie Brettle is a product marketing engineer at National Instruments. He holds a Bachelor of Applied Science in computer engineering from the University of Waterloo.