JPH0417050A - One-chip microcomputer - Google Patents

Abstract

PURPOSE:To make the testing time shorter so that trouble analysis can be performed easily by connecting a main data bus to a local data buses through a connection circuit. CONSTITUTION:A main data bus 1, local data bus 2, connection circuit 3 which connects the buses 1 and 2 to each other, CPU 4 connected to the bus 1, peripheral functions 5a and 5b respectively connected to the buses 1 and 2 are provided. Thus the connection circuit 3 which is able to transfer data in both directions is provided between the main data bus 1 and local data bus 2. Accordingly, data on the local bus 2 can be inputted to the CPU 4 through the main bus 1 and the CPU 4 can send data to the local bus 2 through the main bus. Therefore, the testing time is reduced and trouble analysis becomes easier.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a test method for a one-chip microcomputer.

[Conventional technology]

Figure 3 is a block diagram showing the configuration of a conventional one-chip microcomputer. In the figure, (1) is the main data bus, (2) is the local data bus, and (4) is connected to the main data bus (1). CPU, (F, a)
, (b) are transmitting/receiving devices respectively connected to the main data bus (1) and the local data bus (2).

Next, the operation will be explained. The data output from the CPU (4) is manually input to the transmitter/receiver (5a) (5b) via the main data bus (1), and
a) The data output from (5b) is manually input to the CPU (4) via the main data bus (1).

Further, the transmitting/receiving devices (5a) (5b) can directly transmit and receive data via the local data bus (2).

[Problem to be solved by the invention]

Conventional one-chip microcomputers were configured as described above, so when testing the function of directly transmitting and receiving data between transmitting and receiving devices via a single data bus, the CPU transmits data via the main data bus to the transmitting side. The sending-side sending-receiving device sends data to the receiving-side sending-receiving device via the local data bus, and the receiving-side sending-receiving device sends data to the CPU via the main data bus. Since the test is performed by comparing the data sent by the transmitting/receiving device on the transmitting side and the data sent from the transmitting/receiving device on the receiving side, each test takes time, and when a problem occurs, it is difficult to identify the part. Have difficulty. For example, there are problems in that it is unclear whether it is a malfunction in the peripheral function on the transmitting side or a malfunction in the peripheral function on the receiving side.

This invention was made to solve the above-mentioned problems, and aims to provide a one-chip microcomputer that can shorten test time and facilitate failure analysis.

[Means to solve the problem]

A one-chip microcomputer according to the present invention is provided with a connection circuit that can transfer data bidirectionally between a main data bus and a local data bus.

[Effect]

According to this invention, by providing a connection circuit between the main data bus and the local data bus, it is possible to input data on the local data bus to the CPU via the main data bus, and also to input data from the CPU to the CPU. can be placed on the local data bus via the main data bus.

(Example〕 An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (1) is the main data bus, (2) is the local data bus, and (3) is the main data bus (1).
and a connection circuit (4) connecting the local data bus (2) and the local data bus (2).
) is the CPU connected to the main data bus (1), (5
d) and (5b) are peripheral functions connected to the main data bus (1) and the local data bus (2), respectively.

FIG. 2 is a diagram showing the configuration of the connection circuit (3).

In the figure, (lla) (Ilb) are buffers with control signal terminals, (12) are local data buses (2)
Put the above data on the main data bus (1) (・1
) The read signal input terminal (13) is the control signal terminal of the buffer (lld), and the buffer (Ilb) carries the data on the main data bus (1) onto the local data bus.
) is a write signal input terminal which is a control signal terminal.

Next, the operation will be explained. The data output from the CPU (4) is inputted via the main data bus (1) to the transmitting/receiving devices (5a) (5b), and from the main data bus (1) to the connecting circuit (3) and the local Manual input to the transmitter/receiver devices (5a) (5b) is also possible via the data bus. Transmitting/receiving device (5a) (5b)
The data output from the main data bus (1) is input to the CPU (4). In addition, transmitting and receiving equipment (
5a) From (5b), local data bus (2),
C via the connection circuit (3) and the main data bus (1)
PU (4) can also be manually operated. In addition, peripheral functions (
5a) (5b) can directly send and receive data via the local data bus (2).

Next, the operation of the connection circuit (3) will be explained.

When inputting °H” to the read signal input terminal (12) of the buffer (Ha), the buffer (lla) is enabled and the data on the local data bus (2) is transferred to the main data bus (1) and transferred to the buffer (11b). ) Manually inputting “H” to the write signal input terminal (13) enables the buffer (llb) and connects the main data bus (
1) The above data gets on the local data bus (2). Therefore, from the local data bus (2) to the connection circuit (3)
), when inputting data to the CPU (3) via the main data bus (1), use the read signal input terminal (12).
When inputting data manually from the main data bus (1) to the transmitting/receiving device (5a) (5b) via the connection circuit (3) and local data bus (2), input the write signal. Input H'' to the terminal (13), and input L'' to the read signal input terminal (12) and write signal input terminal (13) for other cases than those mentioned above.

(Effects of the Invention) As described above, according to the present invention, since the main data bus and the local data bus are connected via the connection circuit,
When testing a function that directly sends and receives data via a local data bus between transmitting and receiving devices
Since data can be directly output from the CPU via the local data bus, the transmitter and receiver on the transmitter and the receiver can be tested separately. Not only does it save time, but when a problem occurs, it becomes easier to identify the part where the problem occurs, making it easier to analyze the problem.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a one-chip microcomputer according to an embodiment of the present invention, Fig. 2 is a block diagram showing a connection circuit of an embodiment of the invention, and Fig. 3 is a block diagram showing the configuration of a one-chip microcomputer according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of FIG. In the figure, (1) is the main data bus, (2) is the local data bus, (3) is the CPU, (4) is the connection circuit, (
5d) (5b) is a transmitting/receiving device, (lla) (
Ilb) is a buffer, (12) is a read signal input terminal, and (13) is a write signal input terminal. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In a one-chip microcomputer that has at least two types of data buses, one is a main data bus connected to a CPU, and the other is a local data bus connected between peripheral functions, the local data bus and A one-chip microcomputer characterized in that a connection circuit capable of bidirectionally transferring data is provided between the main data buses.