JPH0570045U - Multiplexer - Google Patents

Abstract

(57) [Summary] [Purpose] The serial signal output from the transmitter 1 is
In a multiplex communication device that detects a rising edge of a clock signal that is output at regular intervals, a serial signal that is detected when the clock signal is affected by noise is invalidated to prevent malfunction. [Structure] The transmitter 1 converts the signals of the sensor group 2 into a serial signal and outputs the serial signal to the receiver 3. The transmitter 1 further outputs to the receiver 3 a clock signal that is output at regular intervals and a strobe signal that is output when a predetermined number of this clock signal is output. The receiving device 3 has a counter 5 and counts the number of clock signals in one cycle of the strobe signal. At the time of abnormality, the predetermined number does not match the count value of the counter 5, and the data based on the serial signal input at this time is invalidated so that the device group 4 does not malfunction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention, in a multiplex communication device that detects serial data for each clock signal output at a constant cycle, when this clock signal is affected by noise during transmission and may cause a malfunction in the receiving device, The present invention relates to a multiplex communication device that detects this state and prevents a malfunction.

[0002]

[Prior Art]

 FIG. 2 illustrates a conventional example of the present invention. The first transmitting device is a device that converts an output signal from the sensor group 2 provided in a plurality of measured objects into a serial signal. The receiving device of No. 3 is a device which inputs this serial signal and converts it into a parallel signal. Reference numeral 4 denotes a device group that performs processing in accordance with this parallel signal. This serial signal is output to the receiving device 3 as a pulse signal, but the transmitting device 1 outputs a clock signal to the receiving device 3 at regular intervals, and the receiving device 3 outputs the serial signal at the rising edge of this clock signal. The condition of is detected.

[0003]

[Problems to be solved by the device]

 By the way, while the serial signal is being output, the clock signal may be affected by noise. At this time, the clock signal that has been output in a constant cycle is disturbed, and the detection timing of the serial signal shifts, making it impossible to convert it to an accurate parallel signal.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention is a multiplex communication device in which serial data output from a transmission device is detected by a reception device for each clock signal output at regular intervals. Each time a predetermined number of the clock signals are output, or a constant time elapses, a strobe signal is output, and the receiving device has a counter that counts the clock signal for each cycle of the strobe signal. Characterize.

[0005]

[Action]

 The strobe signal is output every time a predetermined number of clock signals are output. In a normal state, the count value of the clock signal output to the receiving device in one cycle of the strobe signal and counted by the counter is equal to the predetermined number. However, when an abnormality occurs in the clock signal, this count value becomes a value other than the predetermined number. The state at this time is detected, and the signal input in one cycle of this strobe signal is invalidated to prevent malfunction.

[0006]

【Example】

 FIG. 1 illustrates a preferred embodiment of the present invention. The same reference numerals are attached to the same or similar parts as in the conventional example, and the detailed description thereof is omitted. The transmitting device 1 is a device that converts an output signal from a sensor group 2 provided in a plurality of measured objects into a serial signal. The receiving device 3 is a device that inputs this serial signal and converts it into a parallel signal. Further, the receiving device 3 is internally provided with a counter 5 for counting the number of clock signals and a memory 6 for storing a count value of the counter 5 and a predetermined number described later. A device group 4 that performs processing according to the parallel signal is connected to the subsequent stage of the receiving device 3. The serial signal is output to the receiving device 3 as a pulse signal, but the transmitting device 1 outputs a clock signal to the receiving device 3 at regular intervals, and the receiving device 3 outputs the serial signal at the rising edge of this clock signal. The state of is detected and converted into a parallel signal. Further, the transmitting device 1 outputs a strobe signal each time a predetermined number of clock signals are output, and the receiving device 3 counts the clock signal output at each cycle of the strobe signal by the counter 5.

Under normal conditions, the count value counted by the counter 5 is equal to the value stored in the memory 6. However, when an abnormality occurs in the clock signal, the number of clock signals counted by the counter 5 in one cycle of the strobe signal is not equal to the value stored in the memory 6. This is because the extra signal generated by noise is superimposed on the clock signal during transmission. At this time, the receiving device 3 invalidates the serial signal input in one cycle of the strobe signal so as to prevent malfunction.

In the above embodiment, the strobe signal is output every time a predetermined number of clock signals are output. However, the output cycle of the strobe signal is output at regular time intervals regardless of the clock signal. However, there is no problem. Further, even if the strobe signal is affected by noise, a difference occurs between the number of clock signals and the stored value of the memory 6, so that the same malfunction can be prevented.

[0009]

[Effect of the device]

 Accordingly, the present invention is a multiplex communication device in which serial data output from a transmitting device is detected by a receiving device for each clock signal output at regular intervals, and the transmitting device outputs a predetermined number of the clock signals. The strobe signal is output each time a certain period of time elapses, or the receiving device has a counter that counts the clock signal in each strobe signal cycle.The strobe signal is output to the receiving device in one cycle and is counted by the counter. When the count value of the generated clock signal becomes a value other than the predetermined number, the signal input in one cycle of the strobe signal can be invalidated to prevent malfunction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a preferred embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example of the present invention.

[Explanation of symbols]

 1 transmitter 3 receiver 5 counter

Claims (1)

[Scope of utility model registration request] 1. A multiplex communication device in which serial data output from a transmission device is detected by a reception device for each clock signal output at regular intervals, and the transmission device outputs a predetermined number of the clock signals. A multiplex communication device, characterized in that it outputs a strobe signal every time or after a lapse of a fixed time, and the receiving device has a counter for counting the clock signal for each period of the strobe signal.