DSP (Digital Signal Processing) is a digital signal processing technology, and a DSP chip refers to a chip that can implement digital signal processing technology. The DSP chip uses a Harvard structure with separate programs and data. It has a dedicated hardware multiplier, is widely used in pipeline operations, and provides special DSP instructions that can be used to quickly implement various digital signal processing algorithms. The following will introduce its characteristics and classification methods:
According to the requirements of digital signal processing, DSP chips generally have the following main features:
(1) Multiple operations can be performed in parallel.
(2) Fast interrupt handling and hardware I/O support.
(3) Hardware support with low or no overhead loops and jumps.
(4) With multiple hardware address generators operating in a single cycle.
(5) One multiplication and one addition can be completed in one instruction cycle.
(6) The program and data space are separated, and instructions and data can be accessed at the same time.
(7) Support pipeline operation, so that operations such as instruction fetch, decoding and execution can be overlapped.
(8) There is fast RAM on-chip, which can usually be accessed simultaneously in two blocks through an independent data bus.
DSP chips can be classified in the following three ways.
(1) According to basic characteristics
This is classified according to the working clock and instruction type of the DSP chip. If at any clock frequency within a certain clock frequency range, the DSP chip can work normally, except for the change in the calculation speed, there is no performance degradation. This type of DSP chip is generally called a static DSP chip. For example, the DSP chip of OKI Electric Company of Japan and the TMS320C2XX series chip of TI Company fall into this category. If there are two or more DSP chips, their instruction set and corresponding machine code machine pin structure are compatible with each other, then this type of DSP chip is called a consistent DSP chip. For example, TMS320C54X of American TI Company belongs to this category.
(2) According to the data format
This is classified according to the data format of the DSP chip work. DSP chips whose data works in fixed-point format are called fixed-point DSP chips, such as TI's TMS320C1X/C2X, TMS320C2XX/C5X, TMS320C54X/C62XX series, and ADSP21XX series of AD. Working in floating-point format is called floating-point DSP chip, such as TI's TMS320C3X/C4X/C8X and AD's ADSP21XXX series.
Different floating-point DSP chips use different floating-point formats. Some DSP chips use custom floating-point formats, such as TMS320C3X, and some DSP chips use IEEE standard floating-point formats, such as Motorola’s MC96002. .
(3) According to usage
According to the purpose of DSP, it can be divided into general-purpose DSP chip and special-purpose DSP chip. General-purpose DSP chips are suitable for ordinary DSP applications. For example, TI's series of DSP chips are general-purpose DSP chips. Dedicated DSP chips are designed for specific DSP operations, and are more suitable for special operations, such as digital filtering, convolution, and FFT, such as Motorola's DSP56200, Zoran's ZR34881, Inmos's IMSA100, etc. are dedicated DSP chips. .