JPH03263185A - Lsi with any-time writable interface circuit - Google Patents

Abstract

PURPOSE:To reduce the size of the LSI by including the system-to-system interface circuit of an LSI-applied system in the LSI and constituting it as a programmable logic circuit. CONSTITUTION:The logical and electric interface circuit between systems or LSIs, etc., is included and constituted as the programmable logic circuit. Namely, a part corresponding to an external circuit is LSI-implemented on the LSI which has a certain function and constituted as a programmable logic circuit. Consequently, the interface circuit need not be provided outside, the system can be simplified, and the chip size is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention includes an inter-system interface circuit in an LSI application system inside an LSI.

This relates to a programmable logic circuit.

[Conventional technology]

Generally, the interface circuit that connects the microcontroller to the peripheral LSI (including memory) is formed using glue logic (TTL, etc.), and there are not many examples of it being incorporated into the LSI, but as far as I know, it is installed in the HL 6 and i80186 MPU. It is about the same as the chip select circuit that is used. The present invention makes the entire interface section programmable so as to be compatible with not only the chip select circuit but also various MPUs and peripheral LSIs.

[Problem to be solved by the invention]

- The present invention reduces the number of external logic circuits by incorporating interface circuits between various LSIs and systems into the LSI.

■ The corresponding part of the interface circuit is a programmable logic circuit (PROM, EPROM, E [EPROM
, G/A.

PAL, etc.), it is possible to interface multiple Targetera 1 systems with one type of hardware.

(2) As a result of the above, the LSI itself does not need to have a large number of interface circuits, and the LSI size can be reduced.

[Means to solve the problem]

In order to achieve the above object, a portion corresponding to an external circuit is integrated into an LSI having a certain function, and this is further made into a programmable logic circuit.

[Effect]

A predetermined logic that will be required by the user or remanufacturer at a later date will be integrated into the LSI.
It can be built after completion.

〔Example〕

The present invention will be explained in detail below.

As an embodiment of the present invention, FIG.
A logic circuit consisting of one or a combination of I components such as MPU, random logic, memory, etc., an interface circuit for logically and electrically connecting this logic circuit with external circuits, and external input/output. This figure shows an LSI that is composed of an interface circuit that can interface with circuits and an interface circuit that can also connect logic circuits inside the LSI. In this example, the parts corresponding to these interface circuits are FROM and EFROM.
.

EPROM, G/A, PAL @ Constructed of writable memory elements and registers, and by making it possible to write logic appropriate for the purpose, a desired circuit function can be obtained.

FIG. 2 shows a general form of a system normally constructed using LSI. Under the microcomputer MPU,
Memory circuits and peripheral circuits are arranged via a bus for passing address, data, and control signals, and an interface circuit is also arranged to logically and electrically interface these circuits. As an example of applying the present invention, M
Examples of incorporating an interface circuit into a basic circuit such as a PU circuit are shown in FIGS. 3 to 5.

According to this example, there is no need to externally attach an interface circuit, and the system can be simplified.

Figure 6 shows not only people on the system side but also people outside the system.
An example of configuring an input/output interface circuit for interfacing with an output circuit is shown.

According to this example, an external input/output interface circuit is not required, and the system can also be simplified.

FIG. 7 shows an example in which a programmable interface circuit is provided in a memory circuit. According to this example, the same memory can be adapted to different MPU systems by programmably matching the interface circuit.

Usage example 1: When having a programmable circuit for an external interface.

In the example shown in FIG. 7 that has both a memory circuit and a programmable interface circuit, one of (1) the corresponding host-side MPUI, 2.3 is selected (for example, the MPUI
UI).

(2) Write the interface software that corresponds to the selected MPU (depending on how the programmable circuit is made, this may be burnout rather than writing, PROM, G/A,
(The expression differs depending on each PLD method.)

(3) The IC written in the above manner becomes a memory having a dedicated MPUI interface circuit.

All that remains is to actually incorporate it into the system as a component of the MPUI system.

Programmable interface circuits may or may not have programming input/output pins. General programming (writing, burnout) if it has input/output pins
A case like G/A is a case where there is no difference between the two cases.

Usage Example 2 In the case of having a programmable circuit for internal interfaces FIG. 8 shows an example of having a plurality of CPU circuits, memory circuits, I10 circuits, and programmable interface circuits.

In this example, CPU2. Memory 2.
■Set 102 combinations.

〔Effect of the invention〕

According to the present invention, various interface circuits can be set arbitrarily. Furthermore, the chip size can be reduced compared to an LSI having a plurality of interface circuits.

Furthermore, there is no need to create an LSI corresponding to each interface, and the number of LSI types can be reduced.

[Brief explanation of drawings]

Figure 1 shows an LSI with a built-in programmable interface, Figure 2 shows a general system constructed using a normal LSI, and Figures 3 to 5 show interfaces to MPU circuits and other basic circuits. Figure 6 shows an example of an input/output interface circuit configured to interface with an input/output circuit external to the system, and Figure 7 shows an example of incorporating a programmable interface circuit into a memory circuit. FIG. 8 is a diagram illustrating a one-chip LSI having a composite circuit. Figure 2 Figure 3 Figure 5 District

Claims (1)

[Claims] 1) In a system that appropriately combines microcomputers, similar systems that perform passive and active logical operations, and peripheral LSIs that perform incidental operations dependent on these, the system used and the logical relationship between LSIs,
1. An LSI with an interface circuit that can be written at any time, characterized in that the interface circuit includes an electrical interface circuit, and the interface circuit is formed of a programmable logic circuit.