JPH06291802A - Multiplexer - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the generation of unnecessary transmission requests in response to fluctuations in external input signals. When the state change of the input signal from the switch 20 is detected by the detection circuit 15, the generation circuit 16 causes the multiplex communication I
Output a wake-up (WU) instruction signal to C13,
When the transition to the WU state is promoted and the operation mode is transitioned to the WU state, the detection circuit fixes the state fluctuation immediately after the input of the input signal based on the latch signals from the output circuit 17 and the latch circuit 18, and chatters. Prevention, multiplex communication IC
The 13 transmission requests are fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex transmission device for shifting an operation mode from a power saving operation state to a normal operation state.

[0002]

2. Description of the Related Art Conventionally, this type of multiplex transmission device has a wake-up / sleep control function in order to save power, and this device is waked up from a sleep (power-saving operation) state (normally As a trigger for transitioning to the (operation) state, there was a requirement that external input fluctuation was a requirement. For example, as shown in FIG. 4, the multiplex transmission device 10 is connected to a ground-grounded switch 20 that generates a plurality of input signals, and each input signal (representatively represented) generated when the switch is turned on. Fig. 5 (a) shows one input signal whose state has changed.)
The input signal and the chattering removal circuit 12 are taken in through the diode 11 and a predetermined chattering process is performed to determine the input signal. The multiplex communication control circuit (hereinafter, referred to as “multiplex communication IC”) 13 periodically monitors the input signal, generates a multiplex transmission request when a change occurs, and multiplexes the changed input signal. . When the input signal from the switch 20 is chattered and then the multiplex transmission device is woken up, the rise delay of the device becomes large, and thus the transmission delay of the input signal becomes large. In order to improve this, it is necessary to provide a detection circuit 15 for detecting the input signal (chattering signal) via the diode 14 and wake up the device in real time with respect to the fluctuation of the input signal. Since the detection circuit 15 may be connected to the input port of the multiplex communication IC 13 that also serves as the wakeup signal, a detection signal (see FIG. 5B) corresponding to the input signal is generated, and the multiplex communication IC 13 is generated. Had sampled this detection signal with the sampling clock shown in FIG. 5 (d) to generate the transmission request signal shown in FIG. 5 (c).

[0003]

However, the above-mentioned device has a problem that a transmission request is generated according to a change in the input signal, and a transmission which is not necessary in terms of the system occurs. The present invention has been made in view of the above problems, and an object of the present invention is to provide a multiplex transmission device capable of preventing the generation of a transmission request corresponding to a change in an input signal from the outside.

[0004]

In order to achieve the above object, the present invention has operation modes of a power saving operation state and a normal operation state, and takes in an input signal from a switch which is a connected signal generating means. An input circuit that is an input unit and a detection circuit that is a monitoring unit that monitors a change in the input signal that has been taken in. When the detection circuit detects a change in the input signal, the power saving operation state is changed to the normal operation state. In a multiplex transmission device that makes a transition and transmits multiplex data corresponding to the input signal to a connected transmission path, a transition instruction unit that outputs a transition instruction of the operation mode in accordance with a change in the detected input signal. And a multiplex communication IC which is a state transition means for transitioning the operation mode from the power saving operation state to the normal operation state in response to the transition instruction.
When the operation mode transitions, an output circuit and a latch circuit, which are state fixing means for fixing the state fluctuation immediately after the input of the input signal, and a transmission request that corresponds to the input signal whose state is fixed. Multiplex communication IC as request means
There is provided a multiplex transmission device comprising:

[0005]

When the state change of the input signal is detected, the multiplex communication IC is prompted to change the operation mode. When the operation mode is changed, the state change of the input signal is fixed to prevent chattering. Makes a transmission request corresponding to a fixed input signal. Therefore, the fluctuation of the input signal due to chattering can be prevented, and the transmission request by the multiplex communication IC can be generated without fluctuation.

[0006]

Embodiments of the present invention will be described with reference to the drawings of FIGS. FIG. 1 is a configuration block diagram showing a configuration of a multiplex transmission device according to the present invention. Note that, in FIG. 1, the same components as those in FIG.
The same code is used.

1 is different from FIG. 4 in that a generation circuit 16 for outputting a wake-up (hereinafter referred to as "WU") instruction signal according to a detection signal input from a detection circuit 15 and the WU instruction signal. And a latch circuit 18 that outputs a predetermined signal based on a trigger signal input from the multiplex communication IC 13, and a latch circuit 18 that outputs a latch signal to the detection circuit 15 according to the output signal from the output circuit 17. .

When any one of the switches 20 is turned on, the input signal (chattering signal) shown in FIG. 2A is generated at the input side of the multiplex transmission device 10. Note that this input signal has the same waveform as the input signal shown in FIG. At the same time when the input signal and the chattering removal circuit 12 start input, the input signal is also taken into the detection circuit 15, where the waveform is shaped in the same manner as the conventional example, and the detected signal shown in FIG. Is output. The waveform of the detection signal is the same as the waveform shown in FIG. 5B at the initial stage, and the detection signal is input to the generation circuit 16.

The generating circuit 16 uses the WU based on the detection signal.
A WU instruction signal that gives an instruction to transit to a state is generated and output. Unless otherwise processed by the generation circuit 16, the WU instruction signal has the same waveform as the detection signal, and the multiplex communication IC
13 and the output circuit 17. Multiplex communication IC13
Takes in the input signal from the input circuit and the removal circuit 12 and takes in the WU instruction signal from the generation circuit 16. Then, the multiplex communication IC 13 detects a transition instruction to the WU state based on the WU instruction signal, transitions the operation mode from the sleep state to the WU state, and outputs the trigger signal shown in FIG. 2 (c) for a predetermined time. Occur. The trigger signal is input to the output circuit 17.

When the trigger signal is input, the output circuit 17 outputs a high level signal based on the input state of the fetched WU instruction signal. The output signal is input to the latch circuit 18. Upon receiving the output signal, the latch circuit 18 outputs the latch signal shown in FIG. 2 (e) in order to latch the input signal from the switch 20 according to the output signal. The latch signal is input to the detection circuit 15.

With this latch signal, the detection circuit 15 fixes the waveform-shaped input signal at a high level and outputs it to the multiplex communication IC 13 via the generation circuit 16. As a result, in the multiplex communication IC 13, the WU instruction signal having the same waveform as this detection signal is sampled by the sampling clock shown in FIG. 2 (g), and the transmission request signal fixed to the high level shown in FIG. 2 (f) is generated. Can be made.

Therefore, in this embodiment, when the state change of the input signal is detected, the WU instruction signal fixed to the high level is output to the multiplex communication IC to prompt the transition to the WU state, and the operation mode becomes the WU state. When transitioned to
Since the transmission request is fixed and chattering is prevented, the variation of the input signal due to the chattering can be prevented, and the transmission request by the multiplex communication IC can be generated without variation.

FIG. 3 is a circuit diagram showing a specific structure of the multiplex transmission apparatus according to the present invention. In the multiplex transmission device 10 of FIG. 3, a monitoring transistor 15a that regularly monitors the input from the switch 20 and an input signal from the input circuit and the chattering removal circuit 12 from a pair wire or the like according to the change in the input. The multiplex communication IC 13 having the function of performing multiplex transmission via the multiplex bus 21, the WU input latch transistor 18a, the input circuit pullup power supply transistor 19a, and the pullup resistor 19b.

First, when any one of the switches 20 is turned on when the multiplex transmission device 10 is in the sleep state, chattering of the input signal occurs, and the monitoring transistor 15a is turned on / off according to the chattering. To be done. A chattering signal is input to the WU input port by the collector output according to the ON / OFF of the monitoring transistor 15a.

The multiplex communication IC 13 has the functions described above,
It also has the functions of the generation circuit and output circuit shown in FIG.
When the chattering signal indicating the change in the input state is input, the sleep state is transited to the WU state. Then, the multiplex communication IC 13 outputs a high level signal indicating the WU state from the low level signal indicating the sleep state to the pull-up power supply transistor 19a. At this time,
Since the power supply transistor 19a is off, the input circuit and the chattering removal circuit 12 are not supplied with power.

With the input of this high level signal, the power supply transistor 19a is turned on, and the monitoring transistor 1 is turned on / off by chattering.
5a is always turned on by the voltage supply from the power supply. This prevents fluctuation of the WU dual-purpose input port due to chattering immediately after the switch 20 is turned on. At the same time, by turning on the power supply transistor 19a, the input circuit and the chattering removal circuit 12 are turned on via the pull-up resistor 19b. The voltage from the power supply is supplied to the multiplex communication IC 13, and the multiplex communication IC 13 receives the input signal input from the input circuit and the chattering removal circuit 12 from the multiplex bus 21.
Can be sent to.

Therefore, in this embodiment, the operation mode is WU.
When transitioning to the state, the multiplex communication IC fixes the transmission request and prevents chattering, so that it is possible to prevent generation of an unnecessary transmission request due to chattering. In addition, in the present embodiment, by detecting the change in the state of the input signal, the multiplex communication IC can wait for the W state from the sleep state without any delay.
It is possible to transit to the U state and chattering immediately after the switch input is turned on is input to the WU dual-purpose input port. Therefore, the signal is sent out in a short time because the signal is sent out through the generation circuit and the output circuit. Can be suppressed.

[0018]

As described above, according to the present invention, there are the operation mode of the power saving operation state and the normal operation state, and the input means for receiving the input signal from the connected signal generating means, and the input thus taken in. A monitoring means for monitoring a change in the signal, and when the monitoring means detects a change in the input signal, the power saving operation state is transited to the normal operation state, and the multiplexed data corresponding to the input signal is connected. In a multiplex transmission apparatus for transmitting to a transmission line, transition instruction means for outputting a transition instruction of the operation mode in response to a change in the detected input signal, and an operation mode in response to the transition instruction from a power saving operation state State transition means for transitioning to a normal operation state, state fixing means for fixing the state variation immediately after the input of the input signal when the operation mode transitions, and input for fixing the state. Since a transmission request means for performing a transmission request in response to the signal, it is possible to prevent the occurrence of transmission requests corresponding to variation of the input signal from the outside.

[Brief description of drawings]

FIG. 1 is a configuration block diagram showing a configuration of a multiplex transmission device according to the present invention.

FIG. 2 is a time chart for explaining the embodiment shown in FIG.

FIG. 3 is a circuit diagram showing a specific configuration of a multiplex transmission device according to the present invention.

FIG. 4 is a configuration block diagram showing a configuration of a conventional multiplex transmission device.

FIG. 5 is a time chart for explaining a conventional example.

[Explanation of symbols]

 10 multiplex transmission device 12 input circuit and chattering removal circuit 13 multiplex communication control circuit (multiplexed communication IC) 15 detection circuit 16 generation circuit 17 output circuit 18 latch circuit

Claims (1)

[Claims] 1. An input device which has an operation mode of a power saving operation state and a normal operation state, and which takes in an input signal from a connected signal generating device, and a monitoring device which monitors a change in the taken input signal. When the monitoring means detects a change in the input signal, it transits from a power saving operation state to a normal operation state, and multiplex data corresponding to the input signal is transmitted in a multiplex transmission device connected to a transmission line, Transition instruction means for outputting a transition instruction of the operation mode according to the change of the detected input signal, and state transition means for transitioning the operation mode from the power saving operation state to the normal operation state in response to the transition instruction. When the operation mode transitions, a state fixing unit that fixes a state change immediately after the input of the input signal, and a transmission request that makes a transmission request corresponding to the input signal whose state is fixed A multiplex transmission apparatus comprising: requesting means.