Understanding Microprocessors, Advantages of 32-bit CPUs and DSPs
A microprocessor chip-- also known as a central processing unit (CPU) -- is a complete computation engine of computers, embedded systems or other electronic devices. A chip is also called an integrated circuit, which can contain millions of transistors.
A microprocessor executes a collection of machine instructions that tell the processor what to do. Based on the instructions, a microprocessor does three basic things:
More important than knowing how a microprocessor works is knowing about a microprocessor's power and speed.
The Microprocessor's Power
The power of a microprocessor is measured in bits. The more bits, the more information (data) the microprocessor is capable of bandying about and, therefore, the more powerful the microprocessor. Specifically, an 8-bit CPU can add/subtract/multiply/etc. two 8-bit numbers, while a 32-bit ALU can manipulate 32-bit numbers. An 8-bit arithmetic logic unit (ALU) would have to execute four instructions to add two 32-bit numbers, while a 32-bit ALU can do it in one instruction.
In a way, the number of bits can be compared to lanes on a freeway: If you have only two lanes, too many cars congest traffic, and things slow down. A six-lane freeway, however, has plenty of room for lots of cars, and traffic flows smoothly. With more bits, just as with more lanes on a freeway, the microprocessor can do more powerful programming, operations and processes.
Technically, microprocessor speed is measured in hertz, or cycles per second. Microprocessors are capable of doing billions of things in one second. Therefore, their speed is measured in gigahertz (GHz). A microprocessor that can do 1 billion things per second is rated at 1.0 GHz. A microprocessor that can do 3.66 billion things per second is rated at 3.66 GHz. This rate is much faster than 1.0 GHz. The higher the speed value, the faster the chip. And, naturally, the faster the chip, the more you can do in a given amount of time.
The trend in processor design has primarily been toward full 32-bit ALU with fast floating point processors built in and pipelined execution with multiple instruction streams.
The ARM architecture (previously, the Advanced RISC Machine) is a 32-bit RISC processor architecture developed by ARM Limited that is widely used in a number of embedded designs. Because of their power saving features, ARM CPUs are dominant in the electronics market where low power consumption is a critical design goal.
Today, the ARM family accounts for over 75% of all 32-bit embedded CPUs, making it one of the most prolific 32-bit architectures in the world.
Digital Signal Processor (DSP)
In many applications, general-purpose microprocessors (such as the 32-bit ARM) and a digital signal processor (DSP) have distinct roles. The microprocessor and memory take care of mathematical operations, housekeeping tasks for communications with host and interface with other peripherals. The DSP receives input signals and performs tasks that enhance the performance and quality of the system and data such as reflective phase analysis, filtering, noise reduction, modulation, demodulation, encryption, decoding and encoding.
A DSP is a specialized microprocessor designed specifically for digital signal processing, generally in real-time computing. These process signals are generally purpose-designed application-specific integrated circuits (ASICs). When flexibility and rapid development are important at high volume, DSP algorithms may also be implemented using field-programmable gate arrays (FPGAs).
Since many applications require rapid processing and feedback, engineers often choose DSPs for their speed. Relevant real-time applications that benefit from DSPs include weather forecasting, flood warning, digital image processing, digital communications, data acquisition, control and industrial processes.
Companies such as Intel, Motorola, IBM, ARM Limited, and Microchip Inc. have made significant advancements in data processing and control technology in developing microprocessors to optimize the speed and power of electronic devices to meet current and anticipated applications in the future. Stevens new DL3000 has been designed with these latest developments for a powerful data acquisition / control system.