JPH057631Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an automatic protection circuit in a computer device including a built-in microprocessor, such as a portable measuring instrument.

<Prior art> Power is supplied to a measurement circuit from a battery power supply via a switch, the switch is controlled on/off by a keyboard switch on the surface of the device, and measurement data given from the measurement circuit is sent to a microprocessor and In a computer device that performs calculations using memory and outputs and displays the calculation results,
When the processor went out of control, the clear key was pressed to reset the processor.
However, in the case of small devices such as portable measuring instruments, the space on the keyboard is limited, making it difficult to provide additional keys.

<Problems to be Solved by the Invention> A technical problem to be solved by the invention is to make it possible to reset the runaway of the processor without adding any special keys to the keyboard.

<Means for solving the problem> Power is supplied to the measuring circuit 1 from the battery power supply 2 via the switch 3, and the switch 3 is controlled on/off by the keyboard switch 6 on the surface of the device. Calculations are performed on the measured data using a microprocessor 4 and memory 5 that are constantly connected to a battery power source 2.
In a computer device that outputs and displays calculation results, a. When the keyboard switch 6 is pressed, a control signal that turns on the switch 3 in one stable state, and a control signal that turns off the switch 3 in the other stable state. a flip-flop circuit that generates a flip-flop circuit; b. when the keyboard switch 6 is pressed and the output of the flip-flop circuit is inverted when the output of the flip-flop circuit is in an output state that turns on the switch 3; generates a reset signal that resets the microprocessor 4 after a certain period of time _Td has passed after the flip-flop is inverted, and when the keyboard switch 6 is pressed while the output of the flip-flop is in an output state that turns off the switch 3, the reset signal is immediately activated. c) means for generating an interrupt signal to the microprocessor 4 when the keyboard switch 6 is pressed; 4 goes out of control, press the keyboard switch 6 to invert the output of the flip-flop circuit, turn off the switch 3, stop the power supply to the measuring circuit 1, and when the interrupt signal is given to the microprocessor 4. , the microprocessor 4 checks the output state of the flip-flop circuit, evacuates the memory 5 by a certain period of time _Td , enters the hibernation state after the reset signal is applied, and turns off the switch 3. When the processor 4 goes out of control in a non-measuring state, press the keyboard switch 6 and immediately give a reset signal to the microprocessor 4. When the reset signal is given, the microprocessor 4 stops supplying power to the measurement circuit 1. Then, the output of the flip-flop circuit was inverted and switch 3 was turned on.

<Operation> The above technical means operates as follows. That is,
The computer device is provided with a switch for turning on and off the supply of power to the measuring circuit, and a key for controlling this switch is provided on the keyboard. In the present invention, this key is also used to reset the processor when it goes out of control.

In this case, the way to perform the reset operation differs depending on whether the switch is on or off. In the off state, pressing the key immediately generates a reset signal, which resets the processor. On the other hand, when the key is pressed in the on state, the processor is reset after a certain period of time has elapsed after the key operation, and the memory is evacuated during this period.

<Examples> Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the schematic structure of an embodiment of the present invention. In the figure, reference numeral 1 denotes a measuring circuit, which receives power from a battery power supply 2 via a switch 3. Reference numeral 4 denotes a one-chip microprocessor, which is connected to the measurement circuit 1 and memory 5 via a bus BUS. 6 turns switch 3 on/off/
It is a keyboard switch for control. Reference numeral 7 denotes an automatic protection circuit that generates an identification signal DS and a reset signal RS in connection with the operation of the keyboard switch 6 and the replacement operation of the power supply 2.

FIG. 2 is a circuit diagram of the automatic protection circuit 7. In the figure, the same elements as those in FIG. 1 are given the same reference numerals. One contact of the keyboard switch 6 is connected to the positive side of the battery power supply 2 through a resistor _R1 , and the other contact is connected to the negative side of the power supply 2 through a delay circuit _T1 . The voltage at the connection point between the resistor _R1 and the switch 6 is applied to the inverter _In1 , and the output of the inverter _In1 is applied to the clear terminal CL of the flip-flop _FF1 . The Q terminal output of the flip-flop FF ₁ is used as a drive signal for the switch 3, while being applied as an identification signal to the first port P ₁ of the microprocessor 4, the inverter In ₂ and the delay circuit T ₂ . The output of inverter In ₂ passes through the delay circuit T ₃ to the NOR circuit.
is added to one input of _G1 . Noah circuit G ₁
The _other input of
The Q terminal output of flop FF ₁ is added.

G ₂ is a NOR circuit in which the output of inverter In ₁ is added to one input via inverter In ₃ , and the output of delay circuit T ₂ is added to the other input, and G ₃ is a NOR circuit that has NOR circuit G ₁ and NOR circuit G. The NOR circuit _G4 to which the output of NOR circuit _G2 is added is a NOR circuit to which the output of NOR circuit _G3 is added to one input via the inverter _In4 .
The output of the NOR circuit _G4 is applied to the reset terminal RESET of the microprocessor 4 via an inverter _In5 .

G ₅ is a hysteresis gate with one input connected directly to the positive side of power supply 2 and the other input connected to the positive side of power supply 2 via delay circuit T ₄ ; G ₆ is a hysteresis gate with one input connected directly to the positive side of power supply 2; is a hysteresis gate connected to the positive side of the power supply 2, the other input of which is connected to the positive side of the power supply 2 via a delay circuit _T5 .

_G7 is an exclusive OR gate to which the outputs of hysteresis gates _G5 and _G6 are added, and this output is applied to the other input of NOR circuit _G4 , while the preset terminal of flip-flop _FF1
given to PR.

Delay circuit connected to keyboard switch 6
The output of T ₁ is applied to the interrupt terminal INT and the second port P ₂ of the microprocessor 4 via cascade-connected inverters In ₆ and In ₇ , and is also applied from the third port P ₃ of the microprocessor 4. A clock pulse is applied to the clock terminal CP of flip-flop _FF1 .

The operation of the apparatus according to the present invention having such a configuration will be explained with reference to timing charts shown in FIGS. 3 to 5. FIG. 3 is a waveform diagram when the processor runs out of control in the measurement state with switch 3 on, and FIGS. 3A to 3H represent waveforms at each point in FIG. When the processor goes out of control and keyboard switch 6 is pressed, the pulse shown in Figure A is generated, which clears flip-flop FF ₁ , and the Q terminal output becomes L (Figure B), which turns switch 3 off. be done.

On the other hand, the pulse in Figure A is inverted by inverter In ₃ (Figure F) and given to NOR circuit G ₂ , but the Q terminal output (Figure B) given through delay circuit T ₂ becomes H.
Therefore, even if the gate is applied to NOR circuit _G2 (Figure G) (Figure E), a reset pulse will not be generated.

In NOR circuit _G1 , the signal in figure B becomes L,
After a certain period of time _Td has elapsed, a signal shown in Figure H is generated.
Based on this, the reset signal shown in FIG. c is generated from the inverter In ₅ , and the microprocessor 4 is reset.

During this time, the interrupt signal shown in Figure D is sent to the microprocessor 4 by the operation of the keyboard switch 6.
given to. Given this signal, the port
Check the status of the identification signal in Figure B of _P1 , find out that the power is turned off from on, save the memory by time _td , and enter the HALT state after the reset signal is given.

Figure 4 is a waveform diagram when the processor runs out of control in a non-measuring state with switch 3 off.
~D, M, E~G represent waveforms at each point in FIG. Processor goes out of control and keyboard switch 6
When is pressed, flip-flop _FF1 is in a cleared state, and even if the pulse shown in Figure A is applied, the Q terminal output remains at L (Figure B).
As a result, in the NOR circuit _G2 , when a pulse that is an inversion of the pulse in Figure A shown in Figure F is given, it immediately generates the pulse in Figure G, and based on this, the inverter
The reset signal shown in Figure C is generated from In ₅ , and the microprocessor 4 is reset.

In microprocessor 4, check the state of the power flag, apply the clock pulse shown in Figure M to the clock terminal CP of flip-flop FF ₁ , set the Q terminal output to H level (Figure B), and turn on switch 3. . Note that the power flag is a flag that goes up when the voltage level rises when the power is turned on, and is used as a signal to indicate whether the power is on or not.

The device of this embodiment has a function that allows the memory to be automatically reset to the initial value without requiring the user to press the reset key when replacing the battery power supply. This function will be explained according to FIG. Figures I, J, K, L, C, and B represent waveforms at each point in Figure 2. Point I is the connection part with the battery 2, and when the battery 2 is replaced with a new one, the voltage increases as shown in Figure I. As a result, the signals shown in Figures J and K are generated at the outputs of gates _G5 and _G6 , and the signals shown in Figures L from gate _G7 are generated.
is given to the NOR circuit G ₄ and the inverter In ₅
After that, the reset signal shown in FIG. C is generated and resets the microprocessor 4.

Based on this, microprocessor 4 checks the status of the signal shown in Figure B of port _P1 , and if it is at H level, it knows that the battery needs to be replaced. , the signal in Figure B is L), and sets the contents of the memory to the initial value.

<Effects of the Invention> According to the present invention, the runaway of the processor can be reset using the existing power on/off keys without adding any special keys to the keyboard.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of the device according to the present invention, FIG. 2 is a circuit diagram of the device according to the present invention, and FIGS. 3 to 5 are explanatory diagrams of the operation of the device according to the present invention. be. 1...Measuring circuit, 2...Battery power supply, 3...
...Switch, 4...Microprocessor, 5...
Memory, 6...keyboard switch, 7...automatic protection circuit.

Claims (1)

[Claims for Utility Model Registration] Power is supplied to the measuring circuit 1 from the battery power supply 2 via the switch 3, and the switch 3 is controlled on/off by the keyboard switch 6 on the surface of the device, and the power is supplied from the measuring circuit 1. Calculations are performed on the measured data using a microprocessor 4 and memory 5 that are constantly connected to a battery power source 2.
In a computer device that outputs and displays calculation results, a. When the keyboard switch 6 is pressed, a control signal that turns on the switch 3 in one stable state, and a control signal that turns off the switch 3 in the other stable state. a flip-flop circuit that generates a flip-flop circuit; b. when the keyboard switch 6 is pressed and the output of the flip-flop circuit is inverted when the output of the flip-flop circuit is in an output state that turns on the switch 3; generates a reset signal that resets the microprocessor 4 after a certain period of time _Td has passed after the flip-flop is reversed, and when the keyboard switch 6 is pressed while the output of the flip-flop is in an output state that turns off the switch 3, the reset signal is immediately activated. c) means for generating an interrupt signal to the microprocessor 4 when the keyboard switch 6 is pressed; 4 goes out of control, press the keyboard switch 6 to invert the output of the flip-flop circuit, turn off the switch 3, stop the power supply to the measuring circuit 1, and when the interrupt signal is given to the microprocessor 4. , the microprocessor 4 checks the output state of the flip-flop circuit, evacuates the memory 5 by a certain period of time _Td , enters the hibernation state after the reset signal is applied, and turns off the switch 3. When the processor 4 goes out of control in a non-measuring state, press the keyboard switch 6 and immediately give a reset signal to the microprocessor 4. When the reset signal is given, the microprocessor 4 will stop supplying power to the measurement circuit 1. 1. An automatic protection circuit for a computer device, characterized in that the output of the flip-flop circuit is inverted, and a switch 3 is turned on.