JP2002063150A - Microcomputer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load of software at fetching of a signal from an input port, and to reduce power consumption, based on waiting control for intermittently monitoring an input port in a sleep state to an absolute minimum. SOLUTION: When a CPU 10 is turned into a sleep state, in which its function is stopped, a timing-generating circuit 15 outputs a power supply signal P before outputting an operating clock switching signal C3 for switching an operating clock from a low-speed sub-clock to a high-speed main clock for starting the software, and supplies a power to a pull-up resistance Rp during the rising time, until the state of a signal line L is made electrically stable. Also, an input signal from an input terminal TI, to which the signal line L is connected, is latched by a latch circuit LT in a power supply signal ending timing and is outputted to an IO port 13. Thus, the CPU 10 whose software has started can immediately fetch a signal from the IO port 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcomputer having a processor for executing a process based on a state of a signal received through an input terminal to which a signal line connected to a pull-up resistor is connected.

[0002]

2. Description of the Related Art Conventionally, a microcomputer (hereinafter referred to as a "microcomputer") constituting an electronic control unit (ECU) for controlling a vehicle is provided with a state signal from a sensor or a switch indicating the state of the vehicle or a signal from another ECU. There are provided a number of input ports for inputting various signals, such as a control request, and various processes are executed based on signals taken in through these input ports.

[0003] The input ports to be monitored for such processing tend to increase as the functions of the vehicle control become more sophisticated. As a result, the pull-up resistors connected to the signal lines to the respective input ports are reduced. This is one of the causes for increasing the power consumption of the microcomputer. On the other hand, there is known a method of reducing the power consumption due to the pull-up resistor by energizing the pull-up resistor only when taking in a signal from an input port.

However, the state of the signal line immediately after the power supply to the pull-up resistor is started due to the influence of the capacitance and inductance of the signal line connected to the input port and the equipment supplying the signal to the signal line. Becomes electrically unstable. Therefore, before capturing a signal from the input port,
It is necessary to continuously supply current to the pull-up resistor during the time required for the signal line to stabilize electrically, for a time equal to or longer than the rise time.

Therefore, as shown in FIG. 4 (a), a timer is set to start energizing the pull-up resistor and generate an interrupt after the elapse of the rise time. After the timer has started, it will time out and wait for an interrupt to occur.If a timer interrupt occurs, during the interrupt processing, it will take a signal from the input port or stop energizing the pull-up resistor. I was

[0006]

However, in the interrupt processing, in addition to the processing to be originally executed (in this case, fetching of a signal from an input port), saving and restoring of a register, and setting and canceling of an interrupt mask are performed. For example, there is a problem that a large number of processes specific to the interrupt process must be performed, which increases the load on software.

[0007] In recent years, there has been a method of locking and unlocking the door of a vehicle wirelessly, and the like. Even if the engine is stopped, the ECU must respond to these control requests and changes in the vehicle state. No. For this reason, when the engine is stopped, as shown in FIG. 4 (b), the microcomputer constituting the ECU is put into a sleep state in which the function is stopped but the operation can be resumed immediately upon a start request, and is put on standby. Wake-up state that can be processed periodically from the sleep state, and causes the processor to execute a monitoring process of receiving a signal from an input port and monitoring for a control request or a change in the vehicle state, that is, a so-called standby control. ing. And
As a result of the monitoring processing, if a control request or a change in the vehicle state is not detected, the sleep state is immediately returned. If a control request or a change in the vehicle state is detected, the corresponding processing is executed.

Since such standby control is performed while the engine is stopped as described above, it is necessary to reduce power consumption as much as possible to prevent excessive consumption of the battery. Therefore, particularly in the sleep state, at least a timer for generating a timing for transitioning from the sleep state to the wake-up state, a memory for storing history information such as the state of the input port taken in at the time of the previous wake-up, and the like. Power is supplied only to necessary peripheral devices, and the generation of a high-speed main clock (for example, 16 MHz) is stopped, and a sub-clock (for example, 25 to 30 KH) slower than the main clock is generated.
The power consumption is suppressed by driving the above-described timer and the like using z).

On the other hand, when the computer wakes up from the sleep state to the wake-up state, a high-speed main clock is supplied to the microcomputer, so that a large operating current flows to the microcomputer and the dark current (current flowing when the engine is stopped) is increased. Therefore, it is necessary to shorten the period in which the microcomputer is in the wake-up state as short as possible.

However, in the input port monitoring process executed in the wake-up state, as described above, after the power supply to the pull-up resistor is started, a period from when the timer interrupt occurs, that is, when the signal line is disconnected. Until the start-up time required for the state to be electrically stable elapses, there is a waiting time during which no processing is performed. As a result, there is a problem that the dark current is unnecessarily increased and the consumption of the battery cannot be sufficiently suppressed.

The present invention has been made in order to solve the above problems.
A first object of the present invention is to reduce a load of software when a signal is taken in from an input port, and further, to minimize power consumption based on standby control for intermittently monitoring an input port in a sleep state. This is a second object.

[0012]

According to a first aspect of the present invention, there is provided a microcomputer according to the invention, wherein an energization command generated by an energization command generation means is connected to a pull-up terminal connected to a signal line to an input terminal. In order to energize the up resistor only during a preset energizing period, the up resistor is supplied to the outside via an output terminal and also supplied to a latch means.

The latch means latches the input signal from the input terminal at the end timing of the energization command and supplies the input signal to the input port, and the processor performs processing based on the state of the signal fetched from the input port. Execute. In addition, since the energization command generation unit generates the energization command periodically, the signal latched by the latch unit, that is, the signal taken in from the input port is updated periodically.

As described above, according to the present invention, since the power supply to the pull-up resistor is terminated at the same time as the input signal from the input terminal is latched, the power consumption of the pull-up resistor can be suppressed to the minimum necessary. Moreover, according to the present invention, the energization period from the start of energization in accordance with the energization command to the latching by the latch means is an electrical period between the start of energization to the pull-up resistor and the state of the signal line. The input signal to the input port can always be latched in a stable state because it is set to be longer than the rise time required for stable operation, improving the reliability of the signal read from the input port. Can be done.

Further, according to the present invention, the input signal from the input terminal is latched by hardware other than the processor and supplied to the input port, and when an external signal is required, it is immediately sent to the input port. Since signals can be captured from the input port, not only is it easy to create a program to be executed by the processor, but also there is no need to use interrupt processing to secure the startup time as in the conventional device. The load during operation can also be reduced.

By the way, the power supply to the input signal to the input port is interrupted immediately after the energization command is terminated due to the influence of the time constant based on the inductance and capacitance of the signal line and the resistance of the pull-up resistor. I won't.
For this reason, the latch means can normally latch the input signal from the input terminal in a stable state using the end timing of the energization command. However, if there is a possibility that transmission of the end timing of the energization command to the latch means may be delayed due to the circuit configuration,
It is desirable to provide a delay unit that delays the energization command supplied to the output terminal from that supplied to the latch unit.

When the input signal from the input terminal needs to be detected in real time, a latch inhibiting means for inhibiting the signal from being latched by the latch means is provided. Is desirably allowed to pass through the latch means.

As the energization command generating means, specifically, for example, when a specified time is set by a command from the processor, a predetermined period is set after the specified time elapses. A timer that outputs a time-out signal that only becomes active level only once can be used. In this case, the time-out signal may be used as the end of the energization command.

Further, a timer for repeatedly generating a PWM signal in accordance with a preset condition according to a command from the processor may be used. In this case, if the PWM signal is used as an energization command, Good. In particular, in the former case (claim 4), if some of the processes executed by the processor are activated at regular intervals, the specified time of the timer is set in the process. The signal read from the input port will be updated periodically. In the latter case (claim 5), if the condition is set once in the initialization processing or the like,
The signal read from the input port is updated every period of the set PWM signal.

Next, in the microcomputer according to the sixth aspect, the periodic activation means periodically generates the activation command, so that the processor can process the microcomputer from the sleep state in which the function of the processor is stopped. Is made to transition to a possible wake-up state.

When the microcomputer transits to the wake-up state, the processor executes processing based on the state of the signal fetched from the input port, and outputs a stop command when there is no processing to be executed and the function stops. I do. Then, in response to a stop command from this processor, the microcomputer shifts to a sleep state in which power consumption is low.

In addition, the pull-up resistor connected to the signal line to the input terminal generates the start command in response to an energization command generated prior to the start command by the periodic start means and supplied to the outside via the output terminal. Before the start, the power is supplied for a time equal to or longer than the start-up time so that the state of the signal line to the input terminal becomes electrically stable.

Therefore, according to the present invention, the processor capable of executing the process in response to the start command can immediately read the signal from the input port without using an interrupt process or the like, and the processor becomes in the wake-up state. Can be greatly reduced. As a result, for example, when the microcomputer of the present invention is used to configure an electronic control device for vehicle control and standby control for intermittently monitoring an input port when the engine is stopped is performed, The dark current flowing to the computer can be suppressed to a necessary minimum, and the battery can be prevented from being excessively consumed.

By the way, the energization of the pull-up resistor may be stopped after reading the signal from the input port in the processing executed by the wake-up processor. A latch means for latching an input signal from an input terminal and supplying the input signal to an input port at a timing when the energization command is completed, so that the energization command is supplied to the pull-up resistor for more than a rising time; It may be set to have a start timing and an end timing such that the processor takes in the signal from the input port immediately after the means latches. In this case, power consumption by the pull-up resistor can be minimized.

When the latch means is provided as described above, the delay means according to the second aspect and the latch inhibition means according to the third aspect may be further provided. The same effects as those of the inventions according to the second and third aspects can be obtained. By the way, when putting a microcomputer to sleep state, in order to suppress power consumption,
It has been practiced to stop the high-speed main clock and switch to a lower-speed sub-clock to perform the necessary minimum operation. Therefore, when waking up from the sleep state to the wake-up state, the main clock oscillation is started,
It is necessary to operate the processor after the oscillation state is stabilized, and a waiting time occurs here as in the case where the power is supplied to the pull-up resistor.

Therefore, as described in claim 8, the clock generation means for generating the main clock, the generation of the main clock is stopped in accordance with a stop instruction from the processor, or the power supply instruction generated by the periodic start means is provided prior to the energization instruction. In the case where a clock control unit for starting the generation of the main clock is provided, it is desirable that the activation control unit terminates the energization command until the oscillation of the main clock is stabilized.

That is, the power supply to the pull-up resistor can be performed without any problem even if the main clock is unstable. If the power supply to the pull-up resistor is terminated during this time, the main clock becomes stable. Then, the processor can immediately execute the processing and take in the signal from the input port. As a result, the generation period of the main clock in the standby control can be minimized, so that the dark current can be further reduced.

[0028] Next, in the microcomputer according to the ninth aspect, the energization command generating means is configured to energize the pull-up resistor connected to the signal line to the input port only for a predetermined energization period. An instruction is periodically generated, and the operation switching unit is configured to enable one of the energization instruction generation unit and the periodic activation unit.

Therefore, according to the present invention, by enabling the cycle starting means in the sleep state and the energization command generating means in the wake-up state, the signal which is periodically updated in any state. Can be always taken in from the input port in a stable state.

It should be noted that the power supply command generating means may be, specifically, the one described in claim 4 or claim 5 described above.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an in-vehicle electronic control unit (ECU) configured by incorporating a microcomputer provided with the present invention.

As shown in FIG. 1, the ECU 2 is mainly composed of a microcomputer (microcomputer) 4 of the present embodiment, and a plurality of signal lines from various switches and sensors indicating the state of the vehicle are connected. Here, 32 connection terminals T (T0 to T31), signal lines L (L0 to L31) for guiding an input signal from each connection terminal T to the microcomputer 4, and each signal line L are pulled up by the battery voltage B. Resistor Rp (Rp0 to Rp31) for controlling the power supply to the pull-up resistor Rp in accordance with a current supply command from the microcomputer 4.

The energizing circuit 6 is turned on when an energizing command from the microcomputer 4 is at an active (high) level, and a transistor TR1 for energizing a voltage dividing circuit composed of resistors R1 and R2; A transistor TR2 that conducts electricity to the pull-up resistor Rp when turned on by being biased by the circuit.

Next, the microcomputer 4 comprises a CPU 10, a ROM
11, a well-known configuration comprising a RAM 12 and a CPU
Either a PWM mode in which a PWM signal is repeatedly output in accordance with a condition set by the CPU 10 in accordance with a command from the CPU 10, or an output compare mode in which a signal having a predetermined pulse width is output when a set time set by the CPU 10 elapses. , A timing generation circuit 15 which operates in accordance with a sub-clock SCK to be described later and generates various timing signals PS, C1 to C3, an output PM from the timer circuit 14, or a signal from the timing generation circuit 15. A selection circuit 16 for selecting one of the outputs PS and outputting the selected signal as a pull-up resistance energizing signal P (corresponding to the energizing command of the present invention); and a delay circuit 17 for delaying the pull-up resistance energizing signal P output from the selecting circuit 16 And the pull-up resistor energizing signal P output from the selection circuit 16 and the Although delayed by circuit 17 selects either, and a changeover switch 18 supplies the energizing circuit 6 via the output terminal TO.

The microcomputer 4 receives an input signal from an input terminal TI (TI0 to TI31) to which each signal line L is connected, and outputs a pull-up resistor energizing signal P
Latches LT (LT0 to LT31) that respectively latch at the end timing (falling edge) of the above, an IO port 13 for taking in the output of each latch circuit LT into the CPU 10, and each latch circuit in accordance with a command from the CPU 10. An operation setting register 19 for setting the operation mode (latch / through) of the LT and the operation of the selection circuit 16 and the changeover switch 18 is provided.

Normally, the latch circuit LT operates in an operation mode for latching a signal, and the selection circuit 16 selects the output PS from the timing generation circuit 15 and the changeover switch 18
Is the pull-up resistor energizing signal P output from the selection circuit 16
It is assumed that S is set to be supplied to the output terminal TO.

As shown in FIG. 2, the timing generation circuit 15 has a constant period tcy (75 ms in this embodiment).
A main clock operation start signal C1 is periodically output every time, a peripheral resource energization start signal C2 is output after a time tw1 (1 ms in the present embodiment) has elapsed, and a time tw2 (0.3 ms in the present embodiment). After the elapse, the operation clock switching signal C3 (corresponding to the start signal of the present invention) is output. At the same time, a configuration is made to output an energization signal PS that becomes active at the same time as the start timing of the peripheral resource energization start signal C2 or slightly later (about 100 μs), and becomes inactive at the start timing of the operation clock switching signal C3. Have been.

However, the time tw2 is set to be equal to or longer than the rise time necessary for the state of the signal line L to be electrically stabilized after the start of the current supply to the pull-up resistor Rp.
w1 is set to a length such that tw1 + tw2 is equal to or longer than the oscillation stabilization time necessary for stabilizing the oscillation state after the generation of the main clock MCK is started.

Further, the microcomputer 4 has a main clock MC.
K (16 MHz in this embodiment) and the sub clock SC
K (in this embodiment, 30 KHz), two kinds of operation clocks are generated, and the microcomputer 4 is shifted to a sleep state in accordance with a stop command SLP from the CPU 10, and according to outputs C1 to C3 from the timing generation circuit 15, A sleep control circuit 20 that causes the microcomputer 4 to transition from the sleep state to the wake-up state is provided.

The sleep control circuit 20 has a stop command S
When the LP is input, power supply to the ROM 11, the IO port 13, the timer circuit 14, and peripheral circuits other than those shown in FIG. 1 is stopped. At the same time, the generation of the main clock MCK is stopped, and the sub-clock SCK is supplied as the operation clock of the microcomputer 4, thereby causing the microcomputer 4 to transition to a sleep state in which the function of the CPU 10 is stopped.

Before outputting the stop command SLP, CP
U10 is set to an operation mode in which all the latch circuits LT latch the input signal from the input terminal TI at the end timing of the pull-up resistance energizing signal P.
The operation setting register 19 is set so that the output PS from the timing generation circuit 15 is selected as the pull-up resistance energizing signal P.

In the sleep state, when the main clock operation start signal C1 is input from the timing generation circuit 15, the generation of the main clock MCK is started. After that, when the peripheral resource energization start signal C2 is input, When transitioning to the sleep state, power supply to each unit whose power supply has been stopped is started, and the operation clock switching signal C
3 is input, the operation clock is set to the subclock SCK.
To the main clock MCK. When the operation clock is switched to the main clock MCK in this manner, C
The PU 10 starts executing a process according to the program stored in the ROM 11.

However, generation of these main clocks MCK, energization of peripheral resources, and switching of operation clocks are performed by C
All are stopped by a stop command SLP from the PU 10. Here, the processing executed by the CPU 10 when the microcomputer 4 is in the wake-up state will be described with reference to the flowchart shown in FIG. Note that, as described above, this processing is performed using the main clock MC as the operation clock.
It is activated when K is supplied.

As shown in FIG. 3, when this processing is started,
First, in S110, an initialization process for performing various settings required for execution of a program, such as setting of a program counter, a stack pointer, and an interrupt vector, is performed. S12
At 0, a signal is fetched from the IO port 13 and the subsequent S1
At 30, it is determined whether or not there is a change by comparing with the data taken in at the time of the previous activation.

If there is no change, it is determined that there is no change in the control request or the vehicle state, and the flow shifts to S140. On the other hand, if it is determined in S130 that there is a change in the value taken in from the IO port 13, it is determined that a control request or a change in the vehicle state has occurred, and the process proceeds to S150. In the processing corresponding to, it is determined whether or not the processing amount is large. Specifically, the wake-up cycle tcy of the microcomputer 4
It is determined whether or not the wake-up state continues, and if the wake-up state has a duration shorter than the wake-up cycle tcy, the process shifts to S160 to execute a process corresponding to the request or change.

At S165, the corresponding process (S160)
It is checked whether or not a new IO port 13 has been changed during the execution of the process. If there is no change, it is determined that a new processing request has not been issued, and the routine goes to S140. Further, in S150, it is determined that the wake-up state duration is equal to or longer than the wake-up cycle tcy, or as a result of the check in S165, the IO port 13 has changed, and a new processing request is generated. If it is determined that there is, the process proceeds to S170.

In S170, the setting of the timer circuit 14 is performed, and the selection circuit 16 is switched to the setting in which the output PM from the timer circuit 14 is used as the pull-up resistance energizing signal P. Is executed. In the following S190, the corresponding process (S18)
It is checked whether there is a change in the new IO port 13 during the execution of (0). If there is a change, it is determined that a new processing request has occurred, and the process returns to S180 to execute the processing corresponding to the processing request. Execute. On the other hand, if there is no change as a result of the check, it is determined that a new processing request has not been generated, and the process proceeds to S200, where the selection circuit 16 is returned to the setting in which the output PS from the timing generation circuit 15 is set to the energization command. , To S140.

In step S140, a stop command SLP for causing the microcomputer 4 to transition to the sleep state is output, and the process ends. That is, when there is no process to be continuously executed, such as when the engine is stopped, the apparatus is normally in a sleep state, and performs standby control for intermittently waking up from this sleep state and monitoring the IO port 13. If there is no control request or change in the vehicle state, the system immediately returns to the sleep state and the standby control is continued. On the other hand, when the process is continuously performed due to the start of the engine or the like, the output PM from the timer circuit 14 is used as the pull-up resistance energizing signal P instead of the output PS of the timing generation circuit 15. As a result, the data taken in from the IO port 13 is updated at a cycle according to the setting of the timer circuit 14.

As described above, in the microcomputer 4 according to the present embodiment, before the software for monitoring the IO port 13 is operated, the energization of the pull-up resistor Rp is performed.
Since the state of the signal line L has been performed for a period of time equal to or longer than the rise time necessary for electrical stability, a signal can be immediately taken in from the IO port 13 when the software is operated.

Therefore, according to the present embodiment, it is not necessary to perform an interrupt process unlike the conventional device, so that the configuration of the software executed by the CPU 10 can be simplified and the load during the operation of the software is greatly reduced. Can be reduced. Further, in the present embodiment, since the interrupt processing is not performed,
Not only is the period during which the microcomputer 4 is in the wake-up state shortened, but also the latch circuit LT latches the input signal from the input terminal TI and at the same time terminates the energization of the pull-up resistor Rp. Is performed during the period until the oscillation state of the main clock MCK is stabilized, so that the period during which the pull-up resistor Rp is energized and the period during which the main clock MCK is generated during the standby control are both minimized. Can be suppressed.

As a result, according to the present embodiment, the dark current flowing through the microcomputer 4 when the engine is stopped is greatly reduced, so that it is possible to prevent the battery from being excessively consumed while the engine is stopped. Further, in the present embodiment, by setting the operation setting register 19, the latch by the latch circuit LT is prohibited, and the input signal from the input terminal TI can be supplied to the IO port 13 as it is.
This can cope with a case where an input signal from the input terminal TI needs to be detected in real time.

Further, in this embodiment, when the wake-up state of the microcomputer 4 continues for a long time, the output PM of the timer circuit 14 whose setting can be arbitrarily changed by the CPU 10 is used as the pull-up resistance energizing signal P. Therefore, the update period of the signal taken in from the IO port 13 can be set arbitrarily, and it is possible to flexibly cope with various processes.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in various modes. For example, in the above-described embodiment, the case where the microcomputer 4 is incorporated in the ECU 2 has been described. However, not limited to the ECU 2, a signal transmitted through a signal line to which a pull-up resistor is connected is captured via the IO port 13, The present invention may be applied to any device that performs various processes based on the captured signal.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle-mounted electronic control device in which a microcomputer of an embodiment is incorporated.

FIG. 2 is a timing chart illustrating the operation of each unit of the microcomputer.

FIG. 3 is a flowchart showing the contents of processing executed by a CPU 10 when the microcomputer is in a wake-up state.

FIG. 4 is an explanatory diagram showing a problem of the conventional device.

[Explanation of symbols]

2 electronic control unit (ECU) for vehicle, 4 microcomputer (microcomputer), 6 energizing circuit, 13 IO port, 14 timer circuit, 15 timing generation circuit,
16 selection circuit, 17 delay circuit, 18 changeover switch, 19 operation setting register, 20 sleep control circuit, L (L0 to L31) signal line, LT (LT0 to LT)
31) Latch circuit, Rp (Rp0 to Rp31) pull-up resistor, R1 to R3 resistor, T (T0 to T31)
Connection terminal, TI (TI0 to TI31) ... input terminal, TO
... output terminals, TR1, TR2 ... transistors

Claims (9)

[Claims] 1. An input terminal to which a signal line to which a pull-up resistor is connected is connected, an input port for receiving a signal supplied from outside via the input terminal, and a state of a signal received from the input port. A processor that executes processing based on: a microcomputer that includes: a power-up command generation unit that periodically generates a power-up command for supplying power to the pull-up resistor during a preset power-on period; An output terminal for supplying an energization command generated by the energization command generation means to the outside; and an input port for latching an input signal from the input terminal at an end timing of the energization command generated by the energization command generation means. And a latch means for supplying to the signal line, and during the current supply period, the state of the signal line is electrically stabilized after the current supply to the pull-up resistor is started. Microcomputer, characterized in that it is set to rise hours or longer required for the. 2. An energization command supplied to the output terminal,
2. The microcomputer according to claim 1, further comprising a delay unit for delaying a signal supplied to said latch unit. 3. The microcomputer according to claim 1, further comprising a latch inhibiting means for inhibiting a signal from being latched by said latch means. 4. When a designated time is set by a command from the processor, the energization command generating means outputs a timeout signal that becomes an active level only for a preset period after the designated time elapses, once. 4. The microcomputer according to claim 1, further comprising a timer, wherein the timeout signal is used as an end of the energization command. 5. The power supply command generating means according to claim 1, wherein said power supply command generation means generates a PWM according to a condition set in advance by a command from said processor.
4. The microcomputer according to claim 1, further comprising a timer for repeatedly generating a signal, wherein the PWM signal is used as the energization command. 6. An input terminal to which a signal line to which a pull-up resistor is connected is connected, an input port for receiving a signal supplied from outside via the input terminal, and a state of a signal received from the input port. And a processor that outputs a stop command when the function is stopped due to no processing to be executed, and a sleep state that consumes less power when the stop command is output from the processor. In the microcomputer, from the sleep state, the processor periodically generates a start command for transitioning to a wake-up state in which the processor can execute processing, and prior to the start command, connects to a signal line to the input terminal. A cycle starting means for generating an energizing command for energizing the connected pull-up resistor; And an output terminal for supplying the power supply signal, wherein the energization command is based on the start command, and is equal to or longer than a rise time required from the start of energization to the pull-up resistor until the state of the signal line is electrically stabilized. A microcomputer which is started at an early timing. 7. An energizing command generated by the periodic activation means is provided, wherein latch means for latching an input signal from the input terminal and supplying the input signal to the input port at an end timing of the energization instruction generated by the periodic activation means. The start timing and the end timing are set so that the energization of the pull-up resistor is performed for the start-up time or longer, and that the processor executes the capture of the signal from the input port after the latch unit performs the latch. The microcomputer according to claim 6, wherein the microcomputer is set. 8. A clock generating means for generating a main clock for operating the processor, stopping the generation of the main clock according to the stop command, and starting the generation of the main clock prior to the energization command. 8. A microcomputer according to claim 6, further comprising: clock control means for causing the power supply command to be terminated until oscillation of the main clock is stabilized. . 9. A power supply command that operates during the wake-up state and periodically generates a power supply command for supplying a pull-up resistor connected to a signal line to the input terminal only for a predetermined power supply period. The microcomputer according to any one of claims 6 to 8, further comprising: an energization command generation unit; and an operation switching unit that validates one of the energization command generation unit and the periodic activation unit.