What is an Embedded Microprocessor?
An embedded microprocessor is a computer hardware system that runs dedicated software for performing specific tasks. Unlike general-purpose processors, embedded processors have low power consumption, small size and rugged operating ranges.
Embedded processors can crunch data in real time, so they are suitable for embedded systems such as those that monitor and control automotive systems. To develop an embedded microprocessor, a designer starts with a basic core from companies such as U.K.-based ARM Holdings PLC or Mountain View, Calif.-based Mips Technologies Inc.
Memory
Embedded microprocessors are designed to perform specific tasks in a small size and low cost. They can be found in everyday devices, such as microwave ovens and digital watches, as well as in more exotic machines, such as hybrid cars and avionics. The microprocessors used in these systems are typically based on either microcontrollers or ordinary microprocessors with integrated memory and peripheral interface circuits.
An embedded microprocessor’s memory is a storage space that holds a program, data, and instructions. It can be stored in a number of different types of memory, including ROM and RAM. The microprocessor also has a cache memory, which stores a copy of the program while it is running and speeds up its operation.
The microprocessor’s memory is connected to other components in the system through a bus, which is a communication pathway. The system bus sends information from the microprocessor’s memory to other parts of the system, such as the microprocessor’s on-chip peripherals and data cache. It also transmits address information to the microprocessor, allowing it to access memory locations.
The microprocessor’s clock speed determines how quickly it can execute instructions. Its instruction set determines the types of operations that it can perform. Its performance can be further improved by using pipelined logic, which allows the microprocessor to execute multiple commands simultaneously.
Bus
Embedded microprocessors use an embedded system bus, which allows the processor to communicate with memory and other peripheral devices. The bus also supports I/O ports that connect to external hardware such as keyboards and displays. The bus also includes a memory cache, which holds recently used data to speed up processing.
Typical microprocessors have a single bus linear voltage regulator circuit that transfers data between the central processor unit and all other components in the computer. The bus has several lines that carry specific types of information. These include addresses, control and data lines. The number of bus lines determines the bandwidth of the bus, which in turn relates to its performance capability.
An embedded system uses a simple interconnect that includes either a soft backplane (ribbon cable and female headers) or a hard backplane. These systems are designed to efficiently implement modern semiconductor technology and can be configured with a wide range of I/O functions. They can also be built with a variety of CPUs, including Intel® and ARM® chips.
Most embedded microprocessors do not run a popular PC operating system, although some may support Windows CE or Linux. Many designers start by licensing a core processor design from a company such as U.K-based ARM Holdings PLC or Mountain View, Calif.-based Mips Technologies Inc., then add features based on the product’s application. For example, a digital-camera processor might include a charge-coupled device controller chip; a vehicle microprocessor might contain an ethernet port.
Registers
Registers are a central part of any microprocessor. They store data on a temporary basis and are used to implement instructions. They can also be referred to as buffers or memory locations. The information stored in them is often related to the current CPU instruction, but can also be an address that points to data stored in main memory.
The accumulator register, or A, is the primary data storage location for all arithmetic operations. This register is backed up by the “R” (auxiliary) registers. This makes it easy for the computer to roll back to the previous instruction if it encounters an error.
In addition to the accumulator, the 6502 had eight 18-bit “A” registers (A0-A7) that could be coupled together with the corresponding X registers to store and load data from memory in one operation. These registers were also used as the other operand in arithmetic instructions and as the target of some address-register operations.
Embedded systems are usually found in machines that must run continuously for years and cannot be shut down for repairs. Typically, these systems include aerospace systems, railway signals, power plants, and safety-critical chemical factory controls. Unlike personal computers, these devices have limited hardware resources and are built to perform specific tasks. Therefore, their software must be written more carefully to prevent errors and to handle failures gracefully.
Processor
The processor of an embedded microprocessor handles the logical operations of a computer. It reads the instructions from memory, stores and retrieves data, and sends the results to other parts of the device. Clock Buffers component It is a vital component of any device that uses computers. Embedded microprocessors are used in a variety of devices, including automotive systems, medical devices, and communication and home automation systems.
A microprocessor’s central processing unit (CPU) contains logic and arithmetic units. The logic units perform logical operations, such as AND, OR and NOT. The arithmetic units are responsible for mathematical calculations. The microprocessor’s CPU also has a special type of fast memory, known as cache memory. This memory holds copies of the instructions and data it is executing, speeding up operation.
Different types of microprocessors are designed to suit specific tasks. For example, the Cell processor was designed specifically to handle the intensive mathematical calculations needed for virtual reality simulation engines in electronic games. It can also execute multiple instructions simultaneously and supports pipelining. CISC microprocessors have a simpler instruction set and can be cheaper to design.
Single-purpose embedded microprocessors are often highly reliable, as they are typically used in mission-critical applications where downtime is not an option. They can also be designed to have low power consumption, which is useful for battery-powered or energy-sensitive applications. These microprocessors usually have a word length of 8 or 16 bits, and they may use either the Harvard or RISC architecture.