Previously, we discussed how a microprocessor works and its various parts. There are many different types of microprocessors, each with advantages and disadvantages. No one type is better than another but may be more suited to specific applications. Let’s look at the five main types of microprocessors.
CISC – Complex Instruction Set Microprocessors
CISC microprocessors contain complex instruction sets, reducing the number of instructions needed per program. Fewer instructions cost less RAM memory and require fewer general purpose registers. However, because the instruction sets are so long, they take extra cycles to process, potentially slowing down the electronic device. CISC was one of the first designs of microprocessors and focuses mainly on hardware capabilities. CISC microprocessors are commonly used in computers.
RISC – Reduced Instruction Set Microprocessors
RISC microprocessors contain simple instruction sets and use a pipelining technique to execute multiple parts of instructions at once. This reduces the time it takes to process instructions, but more instructions are needed per program than CISC. RISC microprocessors have more registers, allowing less interaction with memory for processing. However, more RAM is required for storing assembly-level instructions. More work is also put on the compiler to break down high level programs into simple instructions. RISC processors were designed to overcome the disadvantages of CISC and focus on software capabilities. Smart phones and tablets often utilize RISC microprocessors.
ASIC – Application Specific Integrated Circuit Processors
ASIC microprocessors are used for specific applications, such as automotive emissions control and the computers of personal digital assistants. ASIC microprocessors are smaller than others. They use less power and process at high speeds. However, as customized chips, they are designed from the ground up and cost more than standardized microprocessors. Semi-custom ASIC microprocessors exist where the basics are already built, but they are less powerful.
Superscalar microprocessors can process multiple instructions at once through pipelining, like RISC. In fact, superscalar processors are sometimes referred to as “next generation RISC.” However, they are not standalone processors. They are frequently used as co-processors for arithmetic processing and as multipliers to speed up computing.
DSP – Digital Signal Processors
DSP microprocessors encode and decode real world inputs, like video, audio, temperature and pressure from analog signals to digital and vice versa through mathematical functions. Like Superscalar microprocessors DSPs are small, fast and low in power consumption. They are used in RADAR, home theaters, SONAR, TV set-top boxes and mobile phones.