JPS62155439A - Control device for gas instrument or the like - Google Patents

Abstract

PURPOSE:To obtain a plurality of functions with an inexpensive and small-sized microcomputer by a method wherein an input for an input port is read as a function selecting signal during a predetermined period of time and, thereafter, the input is switched into a control signal input circuit to effect the normal reading of data. CONSTITUTION:The output of a reset circuit 1 is switched into a high level after a predetermined period of time (t1) has elapsed and a microcomputer 9 beings the reading of a program while a timer circuit 2 is started simultaneously and the output thereof becomes a high level. Then, a switch 4 is turned ON, the switch 5 is turned OFF and the condition of a function selecting switch 7 is inputted into the input port 9a of the microcomputer 9 through an analog switch 4 while an input signal from a control signal input circuit 8 is cancelled. In the program of the microcomputer 9, the condition of the input port is read and a function after reading is selected. Further, the output of the timer circuit 2 is switched into a low value when the predetermined period of time has elapsed or at a time (t2), the switch 4 is turned OFF and the switch 5 is turned ON. As a result, only the control signal input circuit 8 transmits the signal to the input port 9a of the microcomputer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for gas appliances and the like that uses a microcomputer (hereinafter referred to as a microcomputer).

(Conventional technology and problems) In control devices for gas appliances such as water heaters and bathtubs that use microcomputers, it is difficult to provide multiple functions to a single chip, such as changing the signal processing method. A separate input port for function selection is provided, and reading starts immediately after reset.When the special microcontroller starts braking operation, the level of the input port for function selection is read into ?1j, and subsequent control functions are selected. h4 is constructed to do so.

Providing input ports for function selection in this way limits the number of inputs, so there are problems such as having to reduce the number of functions or using a microcontroller with many input ports (see Figure 3). Purpose of the Invention) Book 5.: 11 is intended to describe such a uif system as h'f?, and will be specifically explained below based on an example of the drawings.

In Figure 1, (1) is a reset circuit, (2) is a timer circuit, (3) is an inverter that inverts the output of timer 1 circuit (2), and (4) is a timer fill path (the February power of (5) is an analog switch that uses the output of the inverter (3) as a control signal;
(6) is a pull-up resistor, (7) is a function selection switch,
(8) is an il+t control signal input circuit, and (9) is a microphone.

In the above basic structure, when the power supply Vcc is supplied, the reset circuit (1) first operates, its output becomes a low value, and the microcomputer (9) is reset. At this point, the timer circuit (2) does not operate and its output becomes low level. After a predetermined time t1 has elapsed, the output of the reset circuit (1) switches to high level and starts reading the microcomputer L9Nf program, and at the same time the timer circuit (2) starts and its output goes high. Then, the analog switch (4) is turned on and the analog switch (5) is turned off. As a result, the state of the function selection switch (7) is changed to the input of the microcontroller +9J via the analog switch (4).
9a], and the input signal from the control signal input circuit (3) is canceled. In the program of the microcomputer (9), after initialization is performed immediately after the start of reading, the state of the input port is read, and subsequent functions are selected depending on whether the level is high or low. Further, at time t2 when a predetermined time has elapsed, the outputs of all the timer circuits (2) are switched to four values, the analog switch (4) is turned off, and the analog switch (5) is turned on. As a result, only the control signal input circuit (8) is sent to the input ports (9a) of the microcomputer (9). The microcomputer (9) may be programmed to accept the state of the input port after t2 as normal data.

(Effects of the Invention) As described above, the present invention connects the function selection means to a normal input port for a predetermined period of time after resetting the microcomputer, and reads the input to the input port as a function selection signal within this predetermined period of time. Since then, the input port has been switched to a control signal input circuit and normal data reading has been performed. .

Can provide control devices for gas appliances, etc.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing one embodiment of the present invention, FIG. 2 is an explanatory diagram of the same side, and FIG. 3 is an electric circuit diagram showing a conventional example. (1)...Reset circuit (7)...Function selection switch (8)...Control signal input circuit (9)...Microcomputer (9a)...Input port

Claims (1)

[Claims] A reset circuit that operates when power is supplied, an input port of a microcomputer is connected to a function selection means for a predetermined period of time after the reset circuit is activated, and the input port is switched to a control signal input circuit after a predetermined period of time. A control device for gas appliances, etc., characterized by: