DSP
Overview
DSP (Digital Signal Processor) is a calculator designed for applications that perform a large number of complex operations in a short period of time. Specific applications include speech processing, image processing, signal modulation/demodulation, fast Fourier transform and digital filters. Microcomputers also have products that can perform high-speed processing, but they are general-purpose products after all, so if you want to process complex calculations at high speed, DSP is very convenient.
For example, (16-bit data × 16-bit data) ± (16-bit data × 16-bit data) + 64-bit data = 64-bit data calculation, the microcomputer must use multiple instructions to process, but DSP can use one instruction And 1 cycle to execute. Having said that, if there is a DSP, there is no need for a microcomputer. For example, home appliances, etc. do not require high-speed computing power like DSP, and a microcomputer is sufficient. In the sense of versatility and ease of use, microcomputers are superior to DSPs. However, recently, like ARM's Cortex-M4 and M7, general-purpose microcomputers have also appeared to support the same operations as DSP microcomputers.
Defensive range of microcomputer and DSP
DSP can quickly process complex operations. For example, you can perform the following calculations with one instruction and execute them in one cycle.
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) = 32-bit data
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) + 32-bit data = 32-bit data
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) + 64-bit data = 64-bit data
These complex high-speed operations require speech processing, image processing, signal modulation/demodulation, fast Fourier transform and digital filters. If a microcomputer executes the same processing, it must execute multiple instructions at a very fast speed. This is not impossible, but you need a microcomputer with super high-speed computing capabilities. In this case, it can be said that it is more convenient to use DSP. Having said that, ordinary household appliances do not require such complicated high-speed calculations. Rather, it requires versatility, not fast processing. There are more types of microcomputers than DSPs, so users can easily choose a microcomputer that suits the products they want to make.
The advantages of microcomputers
Compared with DSP, the biggest feature of microcomputer is good versatility and easy to use. Originally, microcomputers were born as ICs for calculators. Later, they grew up as control ICs for household appliances and industrial equipment. Therefore, it has been widely used in fields ranging from household appliances to industrial equipment, medical equipment, health equipment, sporting goods, and game equipment. Microcomputers with simple functions include remote controls for TVs and air conditioners, clock functions for household appliances, and dimming functions for lighting. The complicated microcomputer is the motor control of air conditioner and refrigerator compressor.
Recently, microcomputers have also been used in touch detection functions used in tablet computers and car navigation systems. The microcomputer compactly integrates the functions of various applications and can be used in various products. In addition, novices can easily start using microcomputers by using the starter kits and free integrated development tools provided by each microcomputer manufacturer. No advanced professional knowledge is required, and middle and high school students can also use it proficiently.
Advantages of DSP
In short, complex calculations are fast. For example, when a microcomputer is used to perform the following calculations, a microcomputer with ultra-high-speed computing capability is required.
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) = 32-bit data
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) + 32-bit data = 32-bit data
(16-bit data × 16-bit data) ± (16-bit data × 16-bit data) + 64-bit data = 64-bit data
32-bit data ± (32-bit data × 32-bit data) = 32-bit data
(32-bit data × 32 Bit data) + 64 bit data = 64 bit data
If it is a DSP, such instructions can be executed in one cycle of one instruction. DSP is very useful when complex calculations require faster speed.
Microcomputer with DSP function
Recently, although it is a microcomputer, a microcomputer with high-speed computing capability with DSP characteristics has appeared. Cortex-M4 and Cortex-M7 of ARM Company. The M of the Cortex-M series is the initial letter of Microcontroller. As the name suggests, as a microcomputer for the first time, the Cortex-M4 series began to support DSP instructions and can also be used as a DSP. DSP instructions are newly added to the instruction set of the microcomputer of the existing product Cortex-M3. Cortex-M4 and Cortex-M7 can be used as both microcomputers and DSPs.