Data Transmission Circuit for Digital Signal Processor Chip and Method Therefor

The present invention relates to digital signal processor chips, and more particularly to a data transmission circuit for a digital signal processor chip and method for transmitting data.

Recently, digital signal processor chips have become widely used as a result of the rapid development of integrated circuit technology. In particular, because of the low cost of digital signal processor chips due to large scale integration, highspeed, and improvement in the efficiency and availability of memory devices and logic devices, digital signal processor chips have been used in military, industrial, and consumer applications.

One of the most important functions of the digital signal processor chip is to process data in real time. Real time data processing requires many computation operations. The digital signal processor chip receives data, performs operations of multiplication and accumulation and outputs data as fast as possible. Digital signal processing can be performed more rapidly than analog signal processing using techniques such as high-precision and stability processing, pipeline control, and parallel processing.

The digital signal processor chip generally includes a memory device, arithmetic logic device, multiplier, register, controller, and a bus for transmitting data between the respective components. The bus includes local buses and a global bus configured so that the global bus is used for transmitting data between local buses and the local buses are used for transmitting data between associated components and the global bus.

Also, the digital signal processor chip may be capable of high-speed operation by parallel-processing the input signal using a plurality of interconnected digital signal processing chips.

In such a configuration, the bus inevitably has a complicated structure in order to appropriately connect the plurality of digital signal processor chips.

During data writing and reading operations, data may be transmitted to or output from all components via the bus. When data transmission is performed using a global bus, data is prevented from being transmitted into undesired components. In other words, the digital signal processor chip has switches for transmitting data or intercepting transmitted data. The switches prevent writing or reading data to or from undesired components during data transmission. Each switch, which is connected between the input and output terminals of the respective component and a local bus, functions as a gate which selectively forms a data transmission path.

However, in the conventional digital signal processor chip, although data transfer does not occur between components disconnected from the data transmission path, data is transmitted to both local and global buses connected to the respective components. Where data is transmitted over a short distance, this results in the unnecessary consumption of electricity.

An object of the present invention is to provide a data transmission circuit for a digital signal processor chip which connects only components relevant to data transmission.

Another object of the present invention is to provide a data transmission method for a digital signal processor chip which reduces unnecessary electricity consumption.

To accomplish the first and other objects, the present invention provides for a data transmission circuit for use in a digital signal processor chip having an internal bus, a plurality of function blocks, a plurality of local buses connected to the respective function blocks transmitting data between the function blocks, and a plurality of global buses for connecting the local buses for data transmission between the plurality of function blocks.

The data transmission circuit includes first switching means for selectively connecting the plurality of local buses and the plurality of global buses, and second switching means for selectively connecting the plurality of global buses.

To accomplish the second and other objects, the data transmission method for a digital signal processor chip according to the present invention connects only the buses necessary for data transmission, when data is transmitted between the plurality of function blocks.

In other words, according to the present invention, the buses are functionally separated for performing data transmission between the respective blocks and the separate bus sections are selectively connected by control switches.

The switches operate so that the separate bus sections between the blocks relevant to data transmission are connected during data transmission and unnecessary bus sections are disconnected from the used bus sections.

The above objects and other advantages of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings in which:

FIG.1 is a block diagram of a conventional digital signal processor chip;

FIG.2 is a detailed block diagram of a data transmission circuit for a digital signal processor chip according to the present invention; and

FIG.3 is a timing diagram of the clock pulse.

In FIG.1, the conventional digital signal processor chip includes a memory 10 for storing information or control data, a register 50 for temporarily storing data, a multiplier 30 for performing multiplication of input variables, an arithmetic logic operator 40 for executing arithmetic and logical operations according to an operand of instruction words, a controller 20 for controlling all the blocks inside the digital signal processor chip, a global bus 60 for transmitting data between the respective blocks, and local buses 61, 62, 63, 64 and 65 for transmitting data between the respective blocks and the global bus 60.

The buses have parallel data lines corresponding to the number of data bits. The global bus 60 is capable of enabling signal transmission between the internal components of the digital signal processor chip or between multiple digital signal processor chips. The local buses 61, 62, 63, 64 and 65 have switches (not shown) for controlling data transfer between the input and output terminals of the respective blocks.

The global bus 60 includes three sections 60a, 60b and 60c. According to this construction, when data is transferred between blocks or computing operations are performed using data from two blocks, only the necessary bus sections are used. For example, when the information from the register 50 is moved to the memory 10, the information is moved from path 60a of the global bus 60 to path 60b. Here, path 60c is not part of the active signal path. Thus, the path 60c can be disconnected from paths 60a and 60b. Other information such as multiplier 30 and arithmetic logic operator 40 can be moved through path 60c.

FIG.2 is a block diagram of the bus structure according to the present invention. In FIG.2, the bus is constituted by blocks 100.sub.1, 100.sub.2, . . . 100.sub.n, input/output control switches 110.sub.1, 110.sub.2, . . . 110.sub.n for controlling data input and output, local buses 130.sub.1, 130.sub.2, . . . 130.sub.n connected to the input/output control switches 110.sub.1, 110.sub.2, . . . 110.sub.n, global buses 140.sub.1, 140.sub.2, . . . 140.sub.n, and bus control switches 120.sub.1, 120.sub.2, . . . 120.sub.n for controlling connection of the global buses 140.sub.1, 140.sub.2, . . . 140.sub.n.

The global buses 140.sub.1, 140.sub.2, . . . 140.sub.n are separated by the bus control switches 120.sub.1, 120.sub.2, . . . 120.sub.n. In other words, the respective blocks are connected or disconnected by the bus control switches. Thus, only the buses necessary for data transfer are connected.

The respective bus control switches 120, 120.sub.2 . . . 129.sub.n enable the data carried on the global bus lines to move between the blocks necessary for the operation. Path to blocks unnecessary for the operation are disconnected. The respective switches may be implemented using, by way of example, CMOS transistors or bidirectional gate buffers.

If CMOS transistors are used, a pair of transistors should be arranged symmetrically about a bus line. The transistors can thus perform the switching operation of connecting and disconnecting separate bus sections. Controller 20, shown in FIG. 1, can be used to control the gates of the transistors.

Referring to the timing diagram shown in FIG.3, the operation of the bus structure shown in FIG.2 will be described. If the instruction "move 100.sub.1, 100.sub.2 " is input, the data of block 100.sub.1 should be moved to block 100.sub.2. Typically, such an instruction word is decoded by an instruction word decoder (not shown) within the controller 20. When the instruction is executed, the controller 20 controls the data input/output control switches 110.sub.1 and 110.sub.2 of blocks 100.sub.1 and 100.sub.2 to turn on the respective switching transistors. Also, the respective switching transistors of bus control switches 120.sub.2 are all turned on. Therefore, only the paths between block 100.sub.1 and block 100.sub.2 are connected, thereby performing data transmission only between the relevant two blocks. In the same manner, when the instruction "move 100.sub.2, 100.sub.n " which means the data of block 100.sub.2 should be moved to the block 100.sub.n, is executed, the transistors of data input/output control switches 110.sub.2 as are 110.sub.n of the two blocks 100.sub.2 and 100.sub.n are turned on and the transistors of the data input/output control switches 120.sub.3, . . . 120.sub.n between block 100.sub.2 and block 100.sub.n are turned on, thereby providing a bus for data transmission between desired blocks. The control operation by such control switches is performed during a clock period T1 or T2 of one cycle generated in the controller 20.

In the above configuration, the electricity consumed in transmitting data between near blocks and far blocks may be different, but the adverse effects of excess consumption of electricity can be prevented in design of the digital signal processor layout by centering the blocks used most frequently.

Therefore, data transmission between unit blocks inside a digital signal processor chip is performed according to the present invention by using a minimized number of isolatable bus sections, thereby preventing the unnecessary consumption of electricity in the unnecessary bus sections.

While the foregoing description sets forth many specific details, these are intended to be merely illustrative of the present invention. It will be readily apparent to those of skill in the art that many modifications may be made to the above description without departing from the spirit and scope of the invention, as defined by the appended claims and their equivalents.