JPH02112046A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve the processing ability of a microprocessor (MPU) by providing a storage device which stores the address of a program the function of which is to be switched in a peripheral LSI and directly reading out data for setting function from a memory. CONSTITUTION:A peripheral LSI reads out an address, the function of which is to be switched during the execution of a program, from a designated area of a memory in addition to initial data for setting the function for executing the program and stores the data and address in a program address buffer 4. Then the LSI compares addresses continuously generated from an MPU with an address stored in the buffer 4 by means of an address comparator circuit 5 during the course of the execution of the program and, when the addresses coincide with each other, directly reads out data from the memory after acquiring memory accessing right from the MPU and switches the function by using a signal from a control signal generation circuit 1. Therefore, no memory space is occupied for the program and no influence is given to the process of the MPU when the function is set. Thus the processing ability of the MPU is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device surrounding a microprocessor.

[Conventional technology]

Figure 3 shows a conventional microprocessor (see below).

(hereinafter referred to as MPU) and semiconductor devices surrounding the MPU (hereinafter referred to as MPU).

1 is a block diagram showing the configuration of a microcomputer system (hereinafter abbreviated as system) using a peripheral LSI. In the figure, (6) is the MPU, (7) is the main storage device (hereinafter abbreviated as memory), (11-1) to (1
1-n) indicate peripheral LSIs connected to the MPU via a system bus (8).

Next, the operation will be explained. In a system using MPU+61, the peripheral LSI (11-1)
By changing the functions of ~(11-n), it is possible to build a system that can meet various demands.

In addition to its own initial settings at system start-up, the MPU (5) performs peripheral LSI (11-1) to (1
x-n) is read from the memory for initial setting, and the peripheral LSIs (11-1) to (11
-n) functions. When it becomes necessary to switch the functions of the peripheral LS I (11-1) to (11-n) while executing the program, the MPU (6) reads data from the memory address specified by the program in the memory. , respective peripheral LSIs (H-1) to (11-
By writing data to peripheral LSI (11-
1) Set the functions of ~(11~n).

[Problem to be solved by the invention]

In conventional systems, in order to set or change the function of a peripheral LSI, an instruction for the change is set in the program in advance, and the MPU reads the function of the peripheral LSI at the memory address specified by the instruction from memory. This was done by reading out the data that sets the peripheral LSI and then writing it to the peripheral LSI, so especially in systems where the functions of the peripheral LSI are frequently switched, the MPtJ often interrupts the program to switch the function of the peripheral LSI.

This resulted in a decrease in processing capacity. Further, since commands and data for switching functions exist in the memory where the program is stored, problems arise in that the memory area is occupied and the number of programs increases.

This invention was made to solve the above-mentioned problems, and includes a storage device for storing program addresses necessary for switching functions inside a peripheral LSI, and allows data for setting functions to be directly read from memory. Since it is read out,
The purpose of the present invention is to obtain a system in which an MPU does not need to read data for function setting from a memory and write it to a peripheral LSI.

[Means to solve the problem]

In this invention, the peripheral LSI is provided with a function of reading out data for function setting from an external storage device based on the program address generated by the MPU.

[For production]

The peripheral LSI in this invention stores internally a program address necessary to switch functions.

Data for function setting is read directly from memory by detecting a match with the program address output from the MPU.

〔Example〕

An embodiment of a semiconductor device according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a peripheral LSI. In the figure, (1) is a control signal generation circuit, (
2) is an external input/output circuit, (3) is a data signal, and (4 is
) indicates a program address buffer for switching functions, and (5) indicates an address comparison circuit that compares the address of this buffer with the address output from the MPU.

Next, the operation will be explained. When the system is started, the peripheral LSI according to the present invention saves initial data for function settings for program execution from a designated area of memory.
Addresses whose functions need to be switched during program execution are successively extracted and stored in the program address buffer 7 (4). Next, during program execution, the address generated by the MPU and the address stored in the program address buffer (4) are constantly compared by the address comparison circuit (5), and if they match, the right to access the memory is obtained from the MPU. Data is read directly from the memory, and functions are switched by signals from the control signal generation circuit (1).

In other words, the MPU does not perform any processing such as reading data from memory or writing data to the peripheral LSI for switching the function of the peripheral LSI. In addition.

In the above embodiment, a case has been described in which the program address buffer (4) stores the initial data of function settings for program execution and the address necessary to switch functions during program execution. Data for setting functions may also be stored. Furthermore, in the above embodiment, data for setting functions is read from the memory to the peripheral LSI, but the data is stored in a storage device independent of the memory, and a dedicated bus is provided for the peripheral LSI to read the data. It may be provided.

FIG. 2 is a block diagram showing the configuration of the system in this case. In the figure, (6) to (8) are the same as those shown in the conventional example of FIG. 3, so their explanation will be omitted. (9-1
) to (9-n) indicate peripheral LSIs according to the present invention, and (
10) indicates a function data memory that stores only function setting data, and a bus dedicated to function switching data.

The operation of the Teno peripheral LS I (9-x) to (9-n) in Figure 2 is based on the program address generated by the MPU (61) using a data-only bus αno different from the system bus (8). The data for function switching is directly read from the memory that stores it. Therefore, the MPU (51) can read the data for peripheral LSIs (9-1) to (9-n) without being hindered from performing processing operations using the system bus (8). (7) The function is switched.

〔Effect of the invention〕

As described above, according to the present invention, the MPU is freed from the operation of reading data from memory and writing data to the peripheral LSI for setting functions according to a program in the peripheral LSI. Furthermore, by storing data for setting a function corresponding to an address whose function needs to be switched inside the peripheral LSI, the time that one peripheral LSI occupies the bus is reduced. If data for function settings is stored in the function data memory and a dedicated data bus is provided, the memory space for the program will not be occupied, and the function settings will not affect MPU processing in any way. It's gone.

The direction of the processing capacity of the MPU can be obtained. Furthermore, since instructions related to rewriting peripheral LSIs can be deleted from the program, memory can be used more effectively.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a peripheral LSI according to an embodiment of the semiconductor device according to the present invention, and FIG. 2 is a block diagram showing the configuration of a system using the peripheral LSI according to another embodiment of the invention. FIG. 3 is a block diagram showing the configuration of a conventional system. In the figure, (1) is the control signal generation circuit, (2) is the input/output circuit, (3) is the data signal, (4) is the program address buffer 1, (5) is the address comparison circuit, and (6) is the MP
U, (71 is memory, (8) is system bus, (9-1
) to (9-n) are peripheral LSIs, (lω is a functional data memory, and (12) is a data-only bus. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A semiconductor device surrounding a microprocessor whose functions can be switched by a program has a storage device that stores the program address necessary to switch the function, and the program address output by the microprocessor and the address held in the storage device A semiconductor device surrounding a microprocessor, characterized in that it has a function of comparing data and reading data for function setting from an external main memory when they match.