JPH05242386A - Apparatus using one-chip microcomputer - Google Patents

Abstract

PURPOSE:To secure safeness by surely detecting the generation of an event like short-circuiting between input terminals including A/D converters and informing of the detected result, or executing the inhibition or the like of load control in an apparatus for controlling load by using an one-chip microcomputer. CONSTITUTION:Voltage dividing circuits respectively consisting of sensors 4, 5 and resistors 6, 7 prepared so that voltage values inputted to respective input terminals do not coincide with each other are connected to adjacent terminals I0, I1 respectively, including A/D conversion parts and a buzzer device 2 for generating an alarm. When the absolute value of a difference between digital data respectively obtained from the terminals I0, I1 does not exceed a tolerance T, load control is stopped and alarm based upon the buzzer device 2 is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to A / D (analog /
The present invention relates to a device using a one-chip microcomputer provided with a plurality of input terminals each having a built-in (digital) converter.

[0002]

2. Description of the Related Art Conventionally, as a device using this type of one-chip microcomputer, there is, for example, a vaporization type heating device. That is, in the vaporization type heating device, the divided output of the series voltage dividing circuit of the thermistor for detecting the room temperature is input to one of the two input terminals having the built-in A / D converter, and the other of the vaporizers for vaporizing kerosene is input. Input the partial pressure output of the temperature dividing thermistor that detects the temperature and the resistor, and when the carburetor temperature rises to a temperature suitable for starting combustion, supply kerosene from the tank to the carburetor to generate vaporized gas. The burner is ignited to start the combustion operation. During the combustion operation, the combustion operation is controlled so that the room temperature becomes the set temperature.

In such a heating device, when input chips forming the input terminals of the one-chip microcomputer are accidentally pinched with scraps of a conductive material such as a solder ball, the input pins are short-circuited. There is a problem that the input levels of the respective input terminals become substantially the same. Even if such a problem does not occur in the inspection at the manufacturing stage,
In some cases, scraps of the conductive material may be caught between the input pins due to heat cycles caused by vibrations during the transportation process of the product, operation or stop of the equipment.

[0004]

By the way, in the above heating device, the series division voltage of the thermistor and the resistor for detecting the room temperature and the series division voltage of the thermistor and the resistor for detecting the temperature of the carburetor, and the range of the divided output level of the voltage division output circuit of the series voltage dividing circuit of the thermistor and the resistor. If the level of the divided voltage output of the circuit changes and the input level of each input terminal becomes almost the same due to the inclusion of conductive waste between the input pins, the carburetor temperature will not be sufficiently heated. Problems such as kerosene being supplied to the room and room temperature control becoming impossible occur. Further, in other devices, load control may not be performed normally, which may cause a considerable risk.

Therefore, according to the present invention, load control is performed by using a one-chip microcomputer provided with a plurality of input terminals each having a built-in A / D converter.
To provide a device using a one-chip microcomputer capable of ensuring safety such as a detection of a situation where a short circuit occurs between input terminals having a built-in converter and notification of the situation or prohibition of load control. With the goal.

[0006]

The present invention is an analog / digital
In a device that controls a load using a one-chip microcomputer that has multiple input terminals with built-in digital converters, the voltage input to two adjacent input terminals with different input level ranges A judgment means for judging whether or not the difference between the digital values of the signals is equal to or larger than a preset value, and a warning notification and a load when the judgment means judges that the difference between the digital values is not equal to or larger than the preset value. A control means for performing at least one of prohibition of control is provided.

[0007]

In the present invention having such a structure, analog /
Different voltages are normally input to two adjacent input terminals having different input level ranges and having a built-in digital converter. Therefore, the difference between the digital values obtained by analog-to-digital conversion of those voltage values is equal to or greater than the preset value.

If adjacent input terminals are brought into conduction by, for example, sandwiching a solder ball between the input terminals adjacent to each other, the voltages input to the input terminals become the same, and therefore, the analog voltage is applied. / The difference between the digital values that have been digitally converted does not exceed a preset value.

Then, the judgment means judges that the difference between the digital values of the two adjacent input terminals is not more than a preset value, and the control means carries out at least one of the warning notification and the load control prohibition. Be seen.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a one-chip microcomputer, which is a CPU (central processing unit) which constitutes the main body of the control unit, and a ROM (in which program data of processing performed by the one-chip microcomputer 1 (that is, CPU) is stored. It is composed of a read only memory), a RAM (random access memory) in which areas of various memories are formed, and the like. Furthermore, the I0 terminal 1a of the adjacent input terminals of the one-chip microcomputer 1
A / D converter is built in each of the I1 terminal 1b and the I1 terminal 1b. Further, the power supply Vcc is supplied to the Vcc terminal 1c,
A ground (0V) is connected to the ss terminal 1d. Further, a buzzer device (BZ) 2 is connected to the O0 terminal 1e of the output terminal of the one-chip microcomputer 1,
Loads 3 such as a heater, a motor and a solenoid are connected to the other Ox terminals 1f via semiconductor elements such as relays and transistors.

The I0 terminal 1 having a built-in A / D converter
The a and I1 terminals 1b are connected to the power source Vcc via variable resistance type sensors 4 and 5 such as thermistors, and are also connected to the ground via resistors 6 and 7, respectively. Therefore, the voltage divided between the power source Vcc and the ground by the sensor 4 and the resistor 6 is input to the I0 terminal 1a, and similarly, the voltage between the power source Vcc and the ground is divided by the sensor 5 and the resistor 7. The generated voltage is input to the I1 terminal 1b. Here, the characteristic specifications of the sensors 4 and 5 and the resistance values of the resistors 6 and 7 are as follows.
It is selectively set so that the voltages input to b do not match. FIG. 2 shows the flow of the continuity inspection process performed by the one-chip microcomputer 1.

The voltage inputted to the I0 terminal 1a is A / D converted, and the digital data obtained thereby is converted into an area "M" formed in the RAM in the one-chip microcomputer 1.
0 memory ”.

Next, the voltage input to the I1 terminal 1b is converted to A /
D conversion is performed, and the digital data obtained thereby is stored in an area "M1 memory" formed in the RAM in the one-chip microcomputer 1.

Therefore, the digital data stored in the "M1 memory" is subtracted from the digital data stored in the "M0 memory" to obtain an absolute value, and whether the absolute value of the difference between the digital data is the tolerance T or more. Whether or not it is judged (judgment means), if it is not the tolerance T or more, the load control is stopped, the buzzer device 2 is operated to give an alarm, and thereafter, energization to the load 3 is prohibited and error processing is performed. It becomes like this (control means).

The absolute value of the difference between the digital data obtained from the I0 terminal 1a and the I1 terminal 1b is the tolerance T.
If it is above, it will shift to normal load control processing, and this continuity inspection processing will be ended.

In the present embodiment having such a configuration, A
The I / D converter is built in and is provided adjacent to each other.
The sensors 4 and 5 and the resistors 6 and 7 are selected and set so that the voltages input to the terminals 1a and I1 terminals 1b do not match, and normally load control is performed.

For example, a solder ball or the like is connected to the I0 terminals 1a and I1.
When it is sandwiched between terminals 1b, I0 terminals 1a and I1
When the terminal 1b becomes conductive, the I0 terminal 1a
And the voltage input to the I1 terminal 1b has the same value.

Therefore, the digital data obtained by A / D converting the voltage values at the same place also match at least within the tolerance T. As a result, the load control is stopped, the buzzer device 2 is activated, and an alarm is generated. Also, load 3
The energization to is prohibited and the error processing is performed.

As described above, according to the present embodiment, the conduction state between the adjacent input terminals having the built-in A / D converter can be detected, whereby the load control can be stopped and the alarm can be issued. It is possible to prevent malfunction and accident due to conduction of the input terminal of the one-chip microcomputer of the device incorporating the chip microcomputer. Therefore, the reliability and safety of the device incorporating this one-chip microcomputer can be further improved.

[0021]

As described in detail above, according to the present invention,
When load control is performed using a one-chip microcomputer provided with a plurality of input terminals with built-in A / D converters, when a short circuit occurs between the input terminals with built-in A / D converters. It is possible to provide a device using a one-chip microcomputer capable of ensuring safety such as reliably detecting and notifying it or prohibiting load control.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a flow of main part processing of the embodiment.

[Explanation of symbols]

1 ... One-chip microcomputer, 1a ... I0 terminal, 1b ... I1 terminal, 2 ... Buzzer device, 3 ... Load, 4,
5 ... Sensor, 6, 7 ... Resistor.

Claims (1)

[Claims] 1. A device for controlling a load using a one-chip microcomputer provided with a plurality of input terminals each having a built-in analog / digital converter, wherein two adjacent input terminals having different input level ranges are provided. Determining means for determining whether or not the difference between the digital values of the voltage signals input to the two input terminals is equal to or greater than a preset value, and the determining means determines that the difference between the digital values is not equal to or greater than the preset value. A device using a one-chip microcomputer, which is provided with a control means for performing at least one of warning notification and prohibition of load control when judged.