JPH07175785A - Wake-up device of microcomputer - Google Patents

Abstract

PURPOSE:To use an interruption terminal to be one port jointly with the interruptions of plural purposes by having a constitution that each interruption is inputted in the one interruption terminal of a microcomputer in an interruption discriminating circuit. CONSTITUTION:When a wake-up object input is inputted in an interruption discriminating circuit 2A via an input interface 1 in a sleep state, an interruption is inputted in an interruption terminal and a microcomputer 5A is entered into a wake-up mode. When interruption information is entered from an external local control unit 3 via a LAN communication IC 4 in the same sleep mode, an interruption decision circuit 2A outputs the interruption to the interruption terminal, the microcomputer is raised to the wake-up mode. At the time, when a battery power source is deviated from a negative, the interruption is inputted in the interruption terminal and the saving of data to a memory is made to be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wake-up device for a microcomputer for starting a microcomputer used in a vehicle-mounted local area network system (hereinafter referred to as LAN) from a sleep mode to a wake-up.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional wake-up device for a microcomputer. In FIG. 3, reference numeral 1 is an input interface for inputting a wake-up target, and 2 is an external local control via the input interface 1 and a LAN communication IC 4. Receives signals from the unit 3 and one interrupt terminal (IRQ) of the microcomputer 5.
An interrupt determination circuit 6 for interrupting the battery, 6 detects a decrease in the battery voltage, and detects the other 1 of the microcomputer 5.
It is a low voltage detection circuit that interrupts two interrupt terminals (NMI).

Further, 7 is a constant voltage power source connected to a battery, 8 is a power cut circuit for cutting the power in the sleep mode of the microcomputer 5, and 9 is an output circuit for outputting the output signal of the microcomputer 5 to an external circuit. is there.

Next, the operation will be described. Since the in-vehicle LAN as described above operates using a battery as a power source,
Under conditions where the engine is not running and the system is not operating, it is necessary to reduce power consumption in order to prevent the battery from going up. Therefore, when the ignition switch and the ACC switch are all off and all the loads (including the timer) are not operating for 30 seconds, the microcomputer 5 is set to the sleep mode as the low power consumption state. On the other hand, if the battery is removed for some reason, the microcomputer 5 is interrupted, the data in the memory is retained, the microcomputer 5 is reset, and then the power is turned off. .

Here, in order to operate the network system as a load again, for example, when the ignition switch is turned on, the microcomputer 5 is turned on.
Is switched from the sleep mode to the wake-up mode, and the control processing is enabled. When the ignition switch is turned on, the interrupt terminal (IRQ) different from the interrupt terminal (NMI) that has interrupted the microcomputer 5 is interrupted to perform the wakeup. These interrupts are
Since not only the switch input directly input to the BCM but also the information generated from the local control unit 3 is sent by communication, the OR determination is performed by the interrupt determination circuit 2.

That is, in this conventional example, as shown in the timing chart of FIG. 4, when the battery voltage is instantaneously cut off in the sleep state, the low voltage detection circuit 6 detects the low voltage and the microcomputer 5 of the microcomputer 5 detects the low voltage. If an interrupt is issued to the interrupt terminal (NMI) and the hardware standby mode is set, the wake-up does not occur even if an interrupt occurs.

On the other hand, when the wakeup target input is input to the input interface 1, the interrupt determination circuit 2 causes the interrupt terminal (IRQ) of the microcomputer 5.
Input an interrupt signal to. Therefore, the microcomputer 5 is in the wake-up mode. Then, in the wake-up mode, if there is a wake-up target input or if there is an interrupt from the external local control unit 3 through the LAN communication IC 4, the interrupt terminal (IRQ) of the microcomputer 5
Interrupts are interrupted by software, these interrupts are ignored by the software. When the LAN communication IC 4 receives an interrupt when the sleep mode is entered again, the microcomputer 5 enters the wake-up mode. In this wake-up mode, when the battery is unloaded from the load, low voltage detection is performed. The circuit 6 detects the decrease in the power supply voltage, interrupts the interrupt terminal (NMI) of the microcomputer 5, and saves the data from the RAM.

[0008]

However, such a conventional wakeup device for a microcomputer copes with the case where the battery is removed and the case where there is an input from the wakeup target or an interrupt from the LAN communication IC 4. Since the interrupt terminals (IRQ) and (NMI) for inputting interrupt signals are separately provided in the microcomputer 5 so that the number of input / output increases, the number of ports of the microcomputer 5 becomes insufficient and There was a problem such as the need to expand.

The present invention has been made in order to solve the above-mentioned conventional problems, and one port can be used for a plurality of interrupts at the same time, whereby a cost increase due to the expansion of ports can be avoided in advance. The purpose is to obtain a wake-up device.

[0010]

A wake-up device for a microcomputer according to the present invention causes a microcomputer to determine that the wake-up mode is entered when an interrupt is issued in the sleep mode, and when the interrupt is issued in the wake-up mode. The interrupt determination circuit inputs each of the interrupts to one interrupt terminal of the microcomputer so that the microcomputer can determine that the battery power is disconnected.

[0011]

In the wakeup device of the microcomputer according to the present invention, the interrupt discriminating circuit takes in a sleep state signal and does not issue an interrupt even if there is a wakeup target input in the wakeup mode. In the sleep mode, the interrupt terminal of the microcomputer is set to 1 when the low voltage detection signal is input from the low voltage detection circuit so that no interrupt is issued.
It can be shared by two.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an input interface for wakeup target input, 2A is this input interface 1
And an interrupt determination circuit which receives a signal from the external local control unit 3 via the LAN communication IC 4 and interrupts one of the interrupt terminals of the microcomputer 5A, and 6 detects a decrease in the battery voltage, and the microcomputer 5A The same interrupt terminal (N
This is a low voltage detection circuit for interrupting MI). Further, 7 is a constant voltage power supply connected to a battery, 8 is a power cut circuit for cutting the power in the sleep mode of the microcomputer 5, and 9 is an output circuit for outputting the output signal of the microcomputer 5A to an external circuit.

Next, the operation will be described. Since the data is already held in the memory while the microcomputer 5A is in the sleep state and there is no problem even if the power is turned off as it is, it is not necessary to further interrupt the low voltage detection during the sleep. On the other hand, in the normal operating state where the device is awake, it is not necessary to wake it up further. Therefore, the microcomputer 5A determines to wake up when the interrupt terminal (NMI) is interrupted in the sleep mode, and on the other hand, in the wakeup state, the interrupt terminal (NMI).
Is interrupted, it is sufficient to recognize that the battery power supply has been removed from the load.

Therefore, as the interrupt discrimination circuit 2A,
In the wake-up mode by capturing the sleep state signal, no interrupt is issued even if there is a wake-up target input.On the other hand, in the sleep mode, no interrupt is issued even if it is recognized as a low voltage by the low voltage detection. The logic configuration is such that one interrupt terminal (NM
I) can be shared. That is, in this embodiment, as shown in the timing chart of FIG. 2, when the battery voltage is momentarily cut off in the sleep state, the low voltage detection circuit 6 detects a voltage drop, but the interrupt is the interrupt of the microcomputer 5A. It is not input to the terminal (NMI).

However, in the sleep state, when the wakeup target input is input to the interrupt discriminating circuit 2A via the input interface 1, an interrupt is input to the interrupt terminal (NMI), which causes the microcomputer. 5A enters wake-up mode. In the wakeup mode, the interrupt determination circuit 2A interrupts the interrupt terminal (NMI) of the microcomputer 5A even if the wakeup target is input again or the interrupt information is input via the LAN communication IC 4. Never enter.

In the sleep mode again, the LA
When the interrupt information is input from the external local control unit 3 via the N communication IC 4, the interrupt determination circuit 2A outputs an interrupt to the interrupt terminal (NMI) to activate the microcomputer 5A in the wakeup mode. Then, in this wake-up mode, when the battery power source becomes negative, an interrupt is input to the interrupt terminal (NMI) to save the data in the memory.

[0017]

As described above, according to the present invention, when an interrupt is issued in the sleep mode, the microcomputer determines that the wake-up mode has been entered,
When interrupting in wake-up mode,
In order to allow the microcomputer to determine that the battery power is disconnected, the interrupt determination circuit is configured to input each of the interrupts to one interrupt terminal of the microcomputer. It can be used in combination with interrupts, and therefore, the number of ports of the microcomputer can be reduced, and the device can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a wake-up device for a microcomputer according to an embodiment of the present invention.

FIG. 2 is a timing chart showing signals of respective parts of the block in FIG.

FIG. 3 is a block diagram showing a conventional wake-up device for a microcomputer.

FIG. 4 is a timing chart showing signals of respective parts of the block in FIG.

[Explanation of Codes] 2A Interrupt Discrimination Circuit 5A Microcomputer

Claims (1)

[Claims] 1. When connected to a battery power supply and not operating as a system, the sleep mode is set, and when the battery power supply is disconnected, an interrupt is issued to retain the memory contents and then reset, and the power is turned off. ,
When the network system operates, the microcomputer 5A is set to the wake-up mode, and when the interrupt is issued in the sleep mode, the microcomputer is judged to have entered the wake-up mode, and the interrupt is issued in the wake-up mode. A wake-up device for a microcomputer, comprising: an interrupt determination circuit 2A for inputting each of the interrupts to one interrupt terminal of the microcomputer so that the microcomputer determines that the battery power supply is disconnected.