JPH10221112A - Initialization circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an initialization circuit which uses an I/O port at a controller used to connect a high-impedance load, which can initialize the controller at the early stage of the connection of a power supply and which can obtain the degree of usage freedom of the I/O port by means of an extremely simple circuit constitution. SOLUTION: An initialization circuit is provided with a controller 1 which comprises a plurality of I/O ports 1 to 4 and which is composed of a microcomputer capable of controlling a high-impedance load 2 connected to outputs of the I/O ports. Pull-up resistances RU1, RU3 and pull-down resistances RD3, RD4 are connected respectively to the outputs of the I/O ports at the controller 1 and to connecting lines of the load 2. The controller 1 judges a binary number which is set by the pull-up resistances RU1, RU3 and the pull-down resistances RD3, RD4 while the I/O ports are used as inputs in an initial operation by connecting a power supply, and the execution function of the controller is initialized on the basis of the binary number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a controller provided with a plurality of execution functions so as to drive and control an electric component load such as a display device, and to select the driving condition according to the load specification. The present invention relates to an initial setting circuit for an execution function.

[0002]

2. Description of the Related Art Conventionally, a plurality of execution functions are prepared so that drive characteristics and drive conditions of a load of an electric component such as a display device can be selected according to a load specification, and a predetermined execution function is selected for each product specification. In some cases, a controller that enables the determination is used.

For example, taking an automobile speedometer as an example, when an electronic instrument main body such as a cross-coil instrument is used as an electrical component load, the indicating characteristic of a drive signal of the instrument main body itself depends on the destination of the automobile. In order to make it possible to change, instruction characteristic data or conversion constants for each destination are stored in a controller represented by a microcomputer, and external input conditions are set to input ports prepared for setting such execution functions. By setting according to the ground, an adapted execution function is determined.

That is, as shown in FIG. 3, a controller 1, which is a microcomputer, is provided with five input ports IN1 to IN5 for setting execution functions, and each input port IN is connected to a pull-up resistor RU1 to RU5. By pulling up, a binary code can be represented by 2 to the fifth power, that is, 32 different identification expressions depending on the presence or absence of a jumper wire connected to the ground, and the corresponding execution function of the controller 1 is initialized by this code setting. Is done.

[0005]

However, such an initial setting circuit occupies a large number of input ports for initial setting when there are a large number of function types of electrical component loads, and has other main functions such as a plurality of input ports. The number of ports required for setting calculation conditions for processing the measurement input is limited.

If a controller having a large number of ports is used, such a port assignment becomes Kano-Y. However, the controller itself becomes expensive, and as a result, a combination of parts suitable for the required functions of the entire apparatus can be made. Will be gone.

The present invention makes use of an I / O port of a controller to which a high-impedance load is connected, enables initial setting of the controller at the initial stage of power supply connection, and obtains a degree of freedom in port use with an extremely simple circuit configuration. The purpose of the present invention is to provide an initialization circuit that can be used.

[0008]

A controller having a plurality of I / O ports and capable of controlling a high impedance load connected to an output of the I / O port, wherein at least one of the I / O ports of the controller is provided. A pull-up resistor or a pull-down resistor is connected to a connection line between the two outputs and the load, and the controller is set by the pull-up resistor and the pull-down resistor using the I / O port as an input during an initial operation by power supply connection. A binary number is determined, and the execution function of the controller is initialized based on the binary number.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of I / O ports I / O1 to I / O
A controller 1 comprising a microcomputer having a / O4 and capable of controlling a high-impedance load 2 connected to the output of the I / O port, and a connection line between the I / O port output of the controller 1 and the load 2 RU1, RU3 and pull-down resistor R
D2 and RD4, and the controller 1
Determines the binary number set by the pull-up resistor RU and the pull-down resistor RD using the I / O port as an input at the time of initial operation by power supply connection, and initializes the execution function of the controller based on the binary number. Make up.

Thus, when the power supply is connected to the controller 1, the voltage of each connection line is detected by inputting the I / O port by the initial operation, and the combination of the voltage of each connection line is initialized to a binary number. Judge as data.

In this way, the initial setting for selecting a preset execution function according to the binary number determined by the I / O port is performed, and after the completion of the initial setting, the I / O port is initialized as an output. Execute load control based on the executed function.

[0012]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
FIG. 2 is a circuit operation explanatory diagram for explaining the operation. In the figure, a controller 1 comprising a microcomputer
Has a plurality of I / O ports I / O1 to I / O4, and executes a predetermined execution function based on, for example, an external input signal, and
The high impedance load 2 connected to the / O port is controlled.

The connection line between the I / O port of the controller 1 and the load 2 is connected to pull-up resistors RU1 and RU3 connected to a predetermined voltage and pull-down resistors RD2 and RD4 connected to the ground level.
A combination of input voltages to the I / O port set by U and RD can be determined as a 4-bit binary number.

The connection between the pull-up resistor RU and the pull-down resistor RD is selected in accordance with the execution function stored in the controller 1 in advance in accordance with the required operating characteristics of the load 2; 1,0,1,0) 2
The radix data is set as the initial setting data. In this case, 16 kinds of execution functions can be set with 4 bits by selecting the connection resistance.

The controller 1 inputs an I / O port at the time of initial operation by power supply connection, determines a 4-bit binary number set by the pull-up resistor RU and the pull-down resistor RD as initial setting data, and determines the initial setting data. The execution function of the controller 1 is initialized based on the data, and the subsequent load driving is controlled based on the initialized execution function.

As a result, when a power supply is connected to the controller 1 by a power-on switch (not shown), the I / O ports I / O1 to I / O1
The initial setting data is determined from the voltage combination of the connection line input to / O4, and the load 2 is controlled based on the execution function selected by the initial setting.

Therefore, a pull-up resistor RU or a pull-down resistor RD is selectively connected to each I / O port connection line of the controller 1 in accordance with the operation specifications of the load 2 so that a binary number corresponding to a desired execution function is generated. By performing a simple mounting design, it is possible to perform an initial setting in which an execution function is determined at the time of an initial operation after power-on, and it is not necessary to allocate a dedicated input port for selecting an execution function as in the related art. Port number restrictions can be relaxed.

The selective connection of the pull-up resistor RU and the pull-down resistor RD is initially set so that the resistor can be mounted and connected to an electric circuit pattern corresponding to a connection line to the load 2 on a printed circuit board on which the controller 1 is mounted. By providing a unit, selection and setting can be easily performed.

In the embodiment shown in FIG. 1, all four connection lines of I / O ports I / O1 to I / O4 prepared in the controller 1 are used, and four bits and 16 execution function settings are set. However, the configuration may be such that at least two connection lines are used and the execution function setting is limited to two bits and four types of execution functions. It can be set freely according to one other port availability status.

[0021]

As described above, according to the initial setting circuit of the present invention, the controller is set by the pull-up resistors and the pull-down resistors input to the plurality of I / O ports at the time of the initial operation by the power connection. Since the execution function of the controller is initialized based on the binary data, the voltage is input to the voltage combination I / O port corresponding to the binary number set by the pull-up resistor and the pull-down resistor. Since the initial setting to select the execution function according to the binary data is made, the pull-up resistor or pull-down resistor is selectively connected according to the operation specifications of the load such as electrical components, and the voltage of the connection line is determined. Then, an initial setting in which the execution function is determined at the time of the initial operation after the power is turned on can be performed.

Therefore, it is not necessary to allocate a dedicated input port for selecting an execution function as in the related art, so that the number of ports of the controller can be relaxed and many ports can be allocated to other main functions.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the initial setting circuit of the present invention.

FIG. 3

[Explanation of symbols]

 1 Controller 2 High impedance load I / O1 to I / O4 I / O port RU Pull-up resistor RD Pull-down resistor

Claims (1)

[Claims] An I / O port having a plurality of I / O ports.
A controller capable of controlling a high impedance load connected to the output of the port is provided.
A pull-up resistor or a pull-down resistor is connected to at least two outputs of the / O port and the connection line of the load, and the controller receives the I / O port as an input and performs the pull-up resistor and the pull-down during an initial operation by power supply connection. An initial setting circuit configured to determine a binary number set by a resistor, and to initially set an execution function of the controller based on the binary number.