JP3604868B2 - System and error handling method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a system connected on a network and an error processing method.
[0002]
[Prior art]
As a method of forming a network, there is a method of forming a stair-shaped star topology 1 (hereinafter, referred to as STN1) as shown in FIG. When the STN 1 is formed, each signal line is connected between the host computer system (hereinafter referred to as a host) 2 and the hubs 3, 4, 7, 8 or the devices 5, 6, 9, 10, 11, 12, 13; Alternatively, it is connected to the host 2 and another hub or device. In this case, there is only one host 1 on STN1 for controlling STN1.
[0003]
The hubs 3, 4, 7, and 8 having a signal repeater function are indispensable functions for forming the STN1 because they are connection points for adding devices. Each of the devices 5, 6, 9, 10, 11, 12, and 13 may be a computer I / O such as a printer, a scanner, and a keyboard.
[0004]
Conventionally, as a means for detecting a connected device in such a network system, there is a method of detecting a state of a signal line used for connection to perform a connection / disconnection state. This is to create an arbitrary state by connecting a resistor to a signal line and applying a voltage.
[0005]
[Problems to be solved by the invention]
However, in this method, the following problem occurs.
[0006]
(1) When a system of a certain device causes an unrecoverable error in a state where a network is formed, a host that does not know the status of the device repeats retries, thereby causing a retry load of a host that collectively manages the entire network. Increase.
[0007]
(2) When a system of a certain device causes an unrecoverable error in a state where a network is formed, the entire network may be unstable.
[0008]
Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a system and an error processing method capable of preventing a system error caused by a device abnormality.
[0009]
[Means for Solving the Problems]
In order to achieve such an object, the invention according to claim 1 is a system having a host and a device connected to the host via a signal line, wherein the device detects a device error. And stopping the power supply to a pull-up resistor connected to the signal line when the detection means detects a device error, and connecting to the signal line when the detection means does not detect a device error. Means for supplying power to the pull-up resistor, wherein the host determines whether the disconnection state of the signal line continues for a predetermined time, and the disconnection state of the signal line is determined by the determination means. Disconnection processing means for performing disconnection processing of the device when it is determined that the operation has continued for a predetermined time.
[0010]
The invention according to claim 2 is a system having an information processing device and another information processing device connected to the information processing device via a signal line, wherein the information processing device detects an error of the information processing device. Detecting means for controlling the signal line to be disconnected when an error of the information processing device is detected by the detecting means, and controlling the signal line to be connected when the error of the information processing device is not detected by the detecting means The other information processing device has a determination unit that determines whether the disconnection state of the signal line continues for a predetermined time, and that the disconnection state of the signal line continues for a predetermined time by the determination unit. Disconnection processing means for performing disconnection processing of the information processing device when the determination is made.
[0011]
The invention according to claim 3 is an error processing method in a system having a host and a device connected to the host via a signal line, wherein a detecting step of detecting an error of the device, and an error of the device being performed by the detecting step. Is detected, the power supply to the pull-up resistor connected to the signal line is stopped, and if no error of the device is detected by the detection step, the power supply to the pull-up resistor connected to the signal line is stopped. Performing a disconnection state of the signal line, and determining whether or not the disconnection state of the signal line continues for a predetermined time. If the determination step determines that the disconnection state of the signal line has continued for a predetermined time, a disconnection process of the device is performed. And a cutting process step.
[0012]
The invention according to claim 4 is an error processing method in a system having an information processing device and another information processing device connected to the information processing device via a signal line,
A detection step of detecting an error of the information processing device, and when the error of the information processing device is detected by the detection step, the signal line is disconnected, and when the error of the information processing device is not detected by the detection step, A control step of controlling the signal line to be in a connected state, a determining step of determining whether the disconnected state of the signal line continues for a predetermined time, and determining that the disconnected state of the signal line has continued for a predetermined time by the determining step. And a disconnection process step of performing a disconnection process of the information processing device.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0021]
FIG. 2 shows a logical connection configuration of the STN 1 of the present invention.
[0022]
In FIG. 1, devices 5, 6, 9 to 13 are finally connected to a host 2 via a hub (not shown). The hubs 3, 4, 7, and 8 in FIG. 1 have signal lines in the upstream direction connected to the host 2 and in the downstream direction connected to the device. Disconnection and state detection can be performed, and such information can be returned to the host 2. Therefore, since the host 2 can manage the state of the devices connected via the hub, each device is logically directly connected to the host 2 in parallel as shown in FIG. Further, the host 2 can individually perform processing for each device by assigning a number to the device connected to the STN 1. The hub will be described with reference to FIG.
[0023]
FIG. 3 shows a form of a signal line for configuring a host and a device.
[0024]
FIG. 3 illustrates the configuration of the host 2 and the device (reference numeral 21 in FIG. 3) that are logically connected as shown in FIG. The network cable 28 connecting the host 2 and the device 21 is composed of two cables composed of signal lines data1 and data2. All ports downstream of the host 2 and hub have pull-down resistors 26 and 27 on the data1 and data2 signal lines. Accordingly, when the device 21 is not connected to the downstream port of the host 2 or the hub, or when power is not supplied to the pull-up resistor 33 of the connected device 21, the pull-down connected to the downstream side is Both data1 and data2 are pulled down to the ground level by the resistors 26 and 27. This is called a disconnected state.
[0025]
On the upstream side of all the devices 21, the signal line data1 is connected to the device power supply by a pull-up resistor 33, and when power is supplied to the device side and the signal line is at rest, the potential is raised to an arbitrary potential. And the idle device state is generated on the two signal lines, data1 having the pull-up resistor 33 is at or above a certain voltage, and data2 is substantially at the ground level. This is called a connection state.
[0026]
In the device 21, the data1 signal is connected to the FET 34 via the resistor 33. As a result, by controlling the FET 34 to be turned on / off, the state of the signal line data1 changes, and two kinds of cable states can be generated in a pseudo manner.
[0027]
The bus monitoring circuit 25 is a circuit that monitors the voltage level via both the data1 and data2 signals from the transmission / reception circuit 23. Further, the bus monitoring circuit 25 determines whether or not data transmission / reception is being performed by the device control circuit 22, and outputs an enable signal to the bus monitoring circuit 25 during a period in which there is no data transmission / reception. The timer 24 counts the standby time.
[0028]
The device 21 includes a transmission / reception circuit 29, a device control circuit 30 for performing main control, a watchdog timer circuit 31 (hereinafter, WDT circuit) for detecting runaway of the device control circuit 30, a timer 32 for counting standby time, and a pull-up resistor 33. , FET34.
[0029]
The device control circuit 30 performs main control of the device, and executes a reset routine for the WDT circuit 31 at regular time intervals to detect runaway of the device. When a runaway is detected by the WDT circuit 31, a stop signal for stopping the circuit is connected.
[0030]
The WDT circuit 31 controls a GateEn signal that controls the gate of the FET 34. When power is supplied to the normal device 21, the WDT circuit 31 supplies power to the pull-up resistor 33 by turning on the gate of the FET 34, and can connect to the upstream host 2 by making a connection state. Recognize
[0031]
FIG. 4 is a circuit diagram showing a configuration of the transmission / reception circuits 23 and 29 of FIG. The transmission / reception circuit 23 includes output buffers 35 and 36 with output enable terminals for transmitting data, and input buffers 37 and 38 for receiving data. The transmission / reception circuit 29 includes output buffers 39 and 40 with output enable terminals for transmitting data, and input buffers 41 and 42 for receiving data.
[0032]
The transmission / reception circuit 23 receives the transmission data SEND1 and SEND2 output from the device control circuit 22 and the input signal of the OUTEn signal for enabling the output, and the input / output signals data1 and data2 via the input buffers 37 and 38 to the RCV1 and RCV2. Output as a received signal. The RCV1 and RCV2 signals are connected to the device control circuit 22 and the bus monitoring circuit 25. The device circuit 22 switches transmission and reception according to each sequence, and exchanges data.
[0033]
The transmission / reception circuit 29 receives the input signals of the transmission data SEND1 and SEND2 output from the device control circuit 30 and the OUTEn signal for enabling the output, and the input / output signals data1 and data2 via the input buffers 41 and 42 to the RCV1 and RCV2. Output as a received signal. Both signals RCV1 and RCV2 are connected to the device control circuit 30.
[0034]
FIG. 5 shows the configuration of the hub. In FIG. 5, the hub 45 has a transmission / reception circuit 49 on the upstream side and transmission / reception circuits 52 and 54 on the downstream side, centering on a hub control circuit 51 for controlling the main control. The number of downstream transmitting / receiving circuits is equal to the number of downstream ports of the hub. The transmission / reception circuits 52 and 54 are connected to the bus monitoring circuit 53, and can detect the state of each signal line by switching the hub control circuit 51. The timer 50 counts a standby time. The hub control circuit 51 enables the transmission / reception circuit 52 or 54 to which the corresponding device designated by the host 2 is connected for data processing from the upstream. For data processing from the downstream, the data is returned to the upstream host 2 according to the command from the host 2. As a result, as shown in FIG. 2, the devices connected to the host 2 via the hub 45 (not shown) are logically connected one to one.
[0035]
Further, the hub 45 can monitor the state of the signal line for each downstream device by the bus monitoring circuit 53. The hub 45 detects disconnection of the device by a flowchart process of FIG. 2 is notified of the information of the corresponding cutting device.
[0036]
FIG. 6 shows a WDT process for detecting a device error. 6, in a process 60, a device power-on process is performed. When the power is turned on, the WDT circuit 31 is reset by the device control circuit 30 in a process 61. In process 62, the WDT circuit 31 starts counting. In the determination process 63, it is determined whether the counter of the WDT circuit 31 is Full (count up). If the counter is not Full, it is determined in a determination process 64 whether a clear signal of the WDT circuit 31 is output from the device control circuit 30. If not, the process returns to the process 62 to continue counting. When the device circuit 30 is operating normally, the clear signal is detected before the counter becomes Full by the determination process 64, and the counter of the WDT circuit 31 is reset. When the operation is performed normally, the processes 61, 62, 63, and 64 are continuously performed.
[0037]
When an abnormality occurs in the device circuit 30, a clear signal is not normally generated to the WDT circuit 31. Therefore, the WDT counter becomes Full by the count-up in the process 62, and it is detected that the device circuit is abnormal. Then, in step 65, a device error occurs, and in step 66, the gate signal GateEn of the FET 34 is set high in order to stop power supply to the signal line.
[0038]
As a result of this processing, when the data line is not driven on the data1 signal line, data1 and data2 are pulled down to the ground level by the upstream pull-down resistors 26 and 27.
[0039]
FIG. 7 is a flowchart showing a standby time process between data transmission and reception. In FIG. 7, the host 2 and the device 21 need to track the elapsed time from when the transmission side completes data transmission to when the next data reception starts. This time is important for exchanging data in both directions and is necessary to avoid data collisions.
[0040]
Before the host 2 or other device attempts to communicate new data, the ongoing data communication must be terminated. If this is not observed, the bus of the network may collide, and up to two consecutive transfer data may be damaged.
[0041]
The host 2 and the device 21 are equipped with timers 24 and 32, respectively, and the tracking is controlled by the timer on the data transmission side. The timer starts counting from the point of transition to the idle state based on the data end waveform appearing at the end of the data, and continues counting until the data start state is detected from the next idle.
[0042]
In the process 70, the state of the signal is detected by the bus monitoring circuit 25 that monitors the state of the signal lines data1 and data2. Here, upon recognizing the data end state sent at the end of the transfer data, the data line is stopped by processing 71. By stopping the data line, the bus monitoring circuit 25 can check the state of the data line. At the same time, in the process 73, the standby time is counted. The timer is reset, and counting is started in process 74. The timer continues to count according to the clock, and in a determination process 75, it is determined whether the counter of the timer is Full. If the counter is not Full in the judgment processing 75, the state of the signal line is checked in the judgment processing 76.
[0043]
When data1 is at the high level and data2 is at the ground level, it is determined that the device is normally connected, and the process returns to the determination processing 75. Since the timer is counted by the clock, when the standby time elapses, the timer is stopped in step 77, and the data line is restarted in step 79 after step 78.
[0044]
When the disconnection state is detected by the determination processing 76 within the standby time, it is determined in the device disconnection detection processing 90 whether the disconnection state continues for a predetermined time or more or returns. If it is determined in the determination process 90 that the disconnection is not made, the process returns to the process 75 and the standby time process is performed again.
[0045]
When it is determined in the determination process 90 that the disconnection state has occurred, the disconnection process of the device corresponding to the host 2 is performed. By performing the disconnection process, the host 2 stops transmitting data to the corresponding device and disconnects from the STN 1.
[0046]
FIG. 8 is a flowchart illustrating the device disconnection detection process. When the signal lines data1 and data2 enter the disconnected state, the process 100 resets a timer for keeping the disconnected state. If the state of the signal line is the disconnected state in the determination processing of the processing 101, the timer is incremented. If the value of the timer is not Full in step 103, steps 101 to 103 are repeated. When the timer becomes Full in the process 103, the disconnection state is continued for a certain period of time, and the bus monitoring circuit in the process 104 is turned off. Thereafter, in a process 105, a device disconnection process is executed.
[0047]
If the disconnection state is not reached in the process 101, the process returns to the process 75 in FIG. 7, and the standby time process is continued again.
[0048]
FIG. 9 and FIG. 10 show the state of the signal lines downstream of the host 2 or the hub.
[0049]
FIG. 9 shows a connection state. When power is supplied to the pull-up resistor 33 of the device 21, the voltage of the data1 signal increases with connection, and reaches a voltage level Voh or more at which the connection can be detected by the bus monitoring circuit 25. When the state of reaching Voh continues for a certain period of time, the bus monitoring circuit recognizes and determines that the device is connected, and reports it to the host 2.
[0050]
FIG. 10 shows a cut state. When the power supplied to the pull-up resistor 33 of the device 21 is cut off by the FET, the voltage of the data1 signal falls, and reaches a voltage level Voh or less at which the connection can be detected by the bus monitoring circuit 25, and the data monitoring signal is cut off. After a certain period of time, the bus monitoring circuit recognizes and determines that the device has been disconnected, and reports it to the host 2.
[0051]
The following example can be implemented in addition to the above embodiment. In the tenth embodiment, a connector called a hub has been described as an example of a relay device for connecting the device 21 to the network signal line 28. However, a relay device for taking a branch from a network, such as a router or a gateway, may also be used as a relay device. Can be used.
[0052]
【The invention's effect】
As described above, in the present invention, an unrecoverable information processing device does not affect other information processing devices or networks.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a network structure.
FIG. 2 is a block diagram showing logical connections in the present embodiment.
FIG. 3 is a block diagram illustrating a connection mode between a host and a device according to the present embodiment.
FIG. 4 is a circuit diagram showing a configuration of a transceiver according to the present embodiment.
FIG. 5 is a block diagram showing a configuration of a hub in the present embodiment.
FIG. 6 is a flowchart illustrating a WDT error detection process according to the present embodiment.
FIG. 7 is a flowchart illustrating standby time processing according to the present embodiment.
FIG. 8 is a flowchart illustrating device disconnection detection processing according to the present embodiment.
FIG. 9 is a diagram showing a disconnection / detection state in the present embodiment.
FIG. 10 is a diagram showing a disconnection / detection state in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Star type topology 2 Host computer systems 3, 4, 7, 8 Hubs 5, 6, 9-13 Devices

Claims (4)

A system comprising a host and a device connected to the host via a signal line,
A detecting unit that detects an error of the device,
When the error of the device is detected by the detection unit, the power supply to the pull-up resistor connected to the signal line is stopped. When the error of the device is not detected by the detection unit, the device is connected to the signal line. Means for supplying power to the pull-up resistor,
A determination unit configured to determine whether the disconnection state of the signal line continues for a predetermined time;
A disconnection processing unit configured to perform a disconnection process of a device when the determination unit determines that the disconnection state of the signal line has continued for a certain period of time. A system having an information processing device and another information processing device connected to the information processing device via a signal line,
The information processing device, a detection unit that detects an error of the information processing device,
Control means for controlling the disconnection of the signal line when the error of the information processing device is detected by the detection means, and controlling the connection state of the signal line when the error of the information processing device is not detected by the detection means; Has,
The other information processing device, a determination unit that determines whether the disconnection state of the signal line continues for a predetermined time,
And a disconnection processing unit configured to perform a disconnection process of the information processing device when the determination unit determines that the disconnection state of the signal line has continued for a predetermined time. An error processing method in a system including a host and a device connected to the host via a signal line,
A detecting step of detecting an error of the device;
If an error of the device is detected by the detecting step, the power supply to the pull-up resistor connected to the signal line is stopped. If no error of the device is detected by the detecting step, the device is connected to the signal line. Supplying power to the pull-up resistor;
A determining step of determining whether the disconnection state of the signal line continues for a predetermined time;
An error processing method comprising: performing a device disconnection process when the disconnection state of the signal line is determined to have continued for a predetermined time in the determination step. An error processing method in a system having an information processing device and another information processing device connected to the information processing device via a signal line,
A detecting step of detecting an error of the information processing device;
When an error of the information processing device is detected by the detection step, the signal line is disconnected, and when an error of the information processing device is not detected by the detection step, a control step of controlling the signal line to a connection state; ,
A determining step of determining whether the disconnection state of the signal line continues for a predetermined time;
A disconnection processing step of performing a disconnection process of the information processing device when it is determined in the determination step that the disconnection state of the signal line has continued for a predetermined time.

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