JPH0456150A - Large scale integrated circuit - Google Patents

Abstract

PURPOSE:To minimize an increase in the number of input pins and to be adapted for many functions by connecting input terminals of a plurality of processing units to common input pins, and providing a selector S for selectively outputting the outputs of the units. CONSTITUTION:Input terminals of units P1, P2,..., Pn for processing input data are connected in parallel with input pins I1, I2,..., 101 of an LSI. On the other hand, a mode selection signal for determining the processing mode of the LSI is supplied to mode selection input pins A1,..., Ak of the LSI to conduct processing units for processing by selecting means as a coder unit such as a selector unit S2 inputting the output of the P2, and supplies the output of the unit P2 as the input of a common processing unit C. The unit C outputs processing output to the output pins O1, O2, Oq of the LIS.

Description

[Detailed Description of the Invention] [Industrial Application Field] A large-scale integrated circuit (hereinafter referred to as LSI) in which a plurality of units each having various functions are formed on a single semiconductor substrate.
related to).

3. Detailed Description of the Invention [Summary] This invention relates to a large-scale integrated circuit in which a plurality of units each having various functions are formed on a single semiconductor substrate. [Prior art] LSIs are widely used to miniaturize computer peripheral devices, but in order to add special functions to these peripheral devices, custom LSIs that can perform each function are individually created. This results in high-mix, low-volume production, resulting in a significant price increase.

To solve this problem, we constructed an LSI in which multiple processing units were generated on a semiconductor substrate, pulled out the input pins of each of these units, and operated the desired unit by selecting and inputting these input pins. let me,
It is known that this allows necessary processing to be performed.

[Problem to be solved by the invention]

However, the number of pins for external connections on an LSI, including input pins, is determined by standards or the size of the connector, so it is not possible to increase the number of input pins very much, so the method described above cannot It is only possible to obtain an LSI with many functions.

Therefore, an object of the present invention is to obtain an LSI that can be adapted to many functions while minimizing the increase in the number of input pins.

[Means to solve the problem]

As shown in the principle diagram of FIG. 1, a large number of processing units P,
In a large-scale integrated circuit in which S, C, and D are produced on a semiconductor substrate, the input terminals of a plurality of processing units P each having a function of processing input data are connected to a common input pin I.
I 2. -1 to I, and a selector S for selectively outputting the output of this processing unit in accordance with a mode selection signal corresponding to the processing mode was provided.

[Function] Unit P for processing input data, P29. P,
The respective input terminals of the LSI are input pins I, , 12 .
・---・1. The data input to this input pin is connected in parallel to the above units P,, P2,...-P.
, are processed simultaneously.

On the other hand, mode selection input pins A and -A of this LSI are supplied with a mode selection signal that determines the processing mode of this LSI, and the selection means shown as a decoder unit in FIG. 1 performs the required processing. The output of the processing unit P2, for example, the selector unit S2 to which the output of the processing unit P2 is inputted, is turned on, and the output of the processing unit P2 is supplied as the input of the common processing unit C.

This common processing unit C operates, for example, as an output interface, and outputs pins 0, 02 of the LSI...
0. The processing output is output to . If the selector unit S, for example, is brought into conduction instead of the selector unit S2, the processing unit P.

The processed result can be output to the above output pin.

〔Example〕

FIG. 2 shows an embodiment of the present invention. Components corresponding to those in FIG. 1 are given the same reference numerals. In this embodiment, two processing units P, However, one of the processing units P is shown by a dotted line to perform only transmission without processing, and it goes without saying that a simple transmission path is sufficient.

The selector units S, S2 are provided with one tri-state buffer for each transmission path, and become conductive when a negative logic signal is applied to their control terminals.

In this embodiment, since there are two processing units, Pl and P2, binary values are sufficient for selection of these processing units, so the mode selection signal applied to the mode selection input pin A is "H" and "L". This selection signal is sent from the decoder unit D directly to the control terminal of the tri-state buffer of the selector unit SI, and is inverted by the inverter of this decoder unit D to the control terminal of the tri-state buffer of the selector unit S2. Applied to the control terminal.

Therefore, during the period when the "L" logic signal is applied to the mode selection input pin A, the selector unit S remains conductive and supplies the data processed by the processing unit P to the common processing unit C; During the period when the "H" logic signal is applied to the mode selection input pin A, the selector unit S2 remains conductive and supplies the data processed by the processing unit P2 to the common processing unit C.

In this embodiment, a processing unit P is used as a processing unit having a function of processing input data, a processing unit P2 configured as a line for simple transmission, and a common processing unit C, but more processing units are used. What can be used is as explained with reference to FIG. It is sufficient to use a mode control signal consisting of digits and a decoder that decodes the signal.

A special effect is achieved in that a wide variety of products can be realized with one type of LSI.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention.

Claims (1)

[Claims] In a large-scale integrated circuit in which a large number of processing units P, S, C, and D are formed on a semiconductor substrate, the input terminals of the plurality of processing units P, each having a function of processing input data, are connected to common input pins I_1, I_2,・・・・・・・・・I
1. A large-scale integrated circuit characterized by comprising a selector S that is connected to the _n and selects and outputs the output of this processing unit in accordance with a mode selection signal corresponding to a processing mode.