JP2006048106A - Peripheral equipment device system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect an abnormal state of a USB interface signal and immediately inform a user of occurrence of any communication abnormality when the communication abnormality is caused during data communication from a host. <P>SOLUTION: This peripheral equipment device having a USB interface means and a means for controlling the USB interface means is provided with a means for monitoring VBUS, D+ and D- signals, a means for notifying USB control software of a monitor result, a time measuring means for recognizing a monitor period, a display means and a display control means for controlling the display means. When a USB interface signal is put in a suspend state or in the non-start state of a bus reset sequence by the D+ signal monitor means and D- signal monitor means regardless of the detection of the voltage of a VBUS, it is decided that the USB communication is invalid after the lapse of the time measuring means, and a user is notified of the USB communication abnormal state by a display device mounted on the device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a USB device connected to a host computer such as a personal computer via a USB cable. Furthermore, the present invention relates to a USB device that communicates required data via the USB cable.

  There is a universal serial bus standard (hereinafter abbreviated as USB) as an interface for connecting peripheral device devices to personal computers (hereinafter abbreviated as PCs) and the like, and it is becoming widespread due to the ease of handling.

  This method connects a PC and a plurality of peripheral devices via serial communication. Plug and play (a function that automatically recognizes a connection when a new peripheral device is connected or deleted), hot insertion (A function that can be connected and disconnected while the power is on) and a power supply function are provided so that the user does not have to worry about setting addresses and the like when connecting.

  For USB connection, it is stipulated that a total of four wires of a combination of two signals of 5V power source and GND called VBUS and D + and D− are attached and detached with a dedicated connector. There is a limit to the current value that can be supplied by this power supply, and the current is limited to 100 mA to 500 mA according to the USB standard. In USB, it is defined that a peripheral device must be in a suspended state by a command from a host. In this state, current consumption from VBUS must be reduced to 500 μA. There is a resume command for returning from the suspended state.

Patent Document 1 listed below describes a USB device initialization and power-off state.
JP 2001-337752 A

  However, when a communication error occurs during data communication from the host for some reason, for example, when the host PC fails to suspend, the user has conventionally had no way of knowing what situation has occurred. It was only expected that the work expected by the user failed because the operation on the device side was extremely slow.

  The present invention has been made to solve the above-described problems, and the present invention is intended to promptly inform the user that a communication error has occurred when a communication error occurs during data communication from the host for some reason. It is an object to improve the convenience of the user by informing and prompting a response to the abnormal state.

In order to solve the above problems, a first invention according to the present invention provides a USB interface unit and a peripheral device device having a control unit for the USB interface unit.
Means for monitoring VBUS, means for notifying USB control software of monitoring results, means for monitoring D + signal, means for notifying USB control software of monitoring results, means for monitoring D-signal, and monitoring results to USB control software Means for notifying, and having time measuring means for knowing the monitoring period,
Furthermore, it has a display control means for controlling the display means and the display means,
If the USB interface signal is suspended or does not start the bus reset sequence by the D + signal monitoring means and the D− signal monitoring means even though the voltage of VBUS is detected, the time measuring means has elapsed. Later, it is determined that USB communication is impossible, and a USB communication abnormal state is notified by a display device mounted on the device.

  According to the first aspect of the present invention, the D + signal monitoring circuit and the D + signal state are notified to the USB control software, and the D− signal monitoring circuit and the D− signal state are notified to the USB control software. As a result, even when the USB interface 120 is in an abnormal state in which the start of the bus reset sequence is abnormally long, the USB interface signal and the abnormal state of the USB communication are promptly notified to the user, and a response to the abnormal state is promoted. It becomes possible, and the convenience of the user can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Hereinafter, with reference to FIG. 1, the whole peripheral device which shows embodiment of this invention is demonstrated.

  FIG. 1 is a block diagram illustrating a schematic configuration of a peripheral device 110 and a host PC 150 to which the peripheral device is connected according to the first embodiment of this invention. Reference numerals 110 and 150 each have a USB interface 120 for a device and a USB interface for a host, and are connected by a USB cable 180.

  The operation of the USB HighSpeed device will be described below as an example.

  During normal data communication, as shown in FIG. 2A, SOF packets are transmitted from the host-side USB interface 152 at a specified time interval of 125 μS. When receiving the SOF packet, the USB interface 120 on the device side issues an interrupt signal to the USB control software 131. The USB control software 131 starts the SOF packet interrupt processing routine shown in FIG. 3 by this interrupt signal. In a normal communication state, since a packet of transmission / reception data is communicated following the SOF packet generated by the host-side USB interface signal, the USB control software performs transmission / reception processing step 1303 when detecting data to be transmitted / received. Thereafter, the processing proceeds by repeating the same processing.

  Next, an operation when the host PC enters the suspend process after normal data communication is completed will be described. When the host PC 150 instructs the USB control software 151 to suspend, the USB interface 152 stops sending the SOF packet and pulls up the D + signal. When the USB interface 120 on the device side detects the last SOF packet, it sends an interrupt signal to the USB control software 131, and the interrupt processing routine of FIG. 3 is started. The USB interface 120 pulls up the D + signal after a predetermined time T3 (3 mS to 3.125 mS in the case of High Speed) has elapsed. In this way, the USB interface is suspended.

  Next, the operation when the host PC enters the bus reset sequence after normal data communication is completed will be described. When the host PC 150 instructs the USB control software 151 to perform bus reset processing, the USB interface 152 stops sending SOF and pulls up the D + signal. Further, after the lapse of the specified time T3, the D-signal is once driven to start a bus speed sequence for the HighSpeed device called CHARP. In this way, the USB interface enters the bus reset sequence state.

  The above is the description when the USB interface operates normally.

  Next, the operation of the proposed peripheral device when the host side enters an abnormal state during USB data communication for some reason will be described.

  In this case, the SOF packet that should be regularly transmitted from the host-side USB interface 152 is interrupted. Possible causes include failure of the suspend processing and bus reset sequence processing of the USB control software 151 and USB interface 152 on the host PC side due to some failure, and failure of the suspend processing and bus reset sequence processing due to a cable failure.

  In such a state, when the device-side USB interface 120 detects the last SOF packet, it sends an interrupt signal to the USB control software 131, and the interrupt processing routine of FIG. 3 is started. After performing the confirmation step 1302 for the presence / absence of transmission / reception processing, the USB interface 120 pulls up the D + signal corresponding to the suspend processing or the bus reset sequence. Thereafter, the VBUS monitoring circuit 121 monitors the VBUS voltage to confirm that the cable is not disconnected, and the D + signal monitoring circuit 122 and the D− signal monitoring circuit 123 indicate that the USB interface signal is in the suspended state and the bus reset. Monitor whether the sequence has been entered. If it does not correspond to any of the cases, it is further monitored whether the bus reset sequence is started for T5 (50 mS assuming the host HUB). After the time T5 has elapsed, it is determined that the start of the bus reset sequence is abnormally long, and the USB control software 131 causes the display device 140 to display the abnormal state via the display control device 132.

  By this display, the user can quickly know the abnormal state, check the state of the host PC and the cable state, and cope with the abnormal state.

  In the first embodiment, the abnormality of the USB interface signal is detected and then displayed on the display device. However, if the peripheral device has a printing device such as a printer, the communication abnormal state is printed and notified to the user. It is good also as composition to do.

The block diagram which shows schematic structure of the peripheral device which concerns on embodiment of this invention Timing chart explaining signal operation of USB HighSpeed device The flowchart explaining the operation of the USB control software in FIG.

Explanation of symbols

110 peripheral device 120 USB interface 121 of peripheral device 121 VBUS monitoring circuit 122 D + signal monitoring circuit 123 D− signal monitoring circuit 131 USB control software 140 display device

Claims (2)

In a peripheral device device having USB interface means and control means for controlling the USB interface means,
Means for monitoring VBUS and first notification means for notifying the USB control software of the monitoring result;
Means for monitoring the D + signal and second notification means for notifying the USB control software of the monitoring result;
Means for monitoring the D-signal and third notification means for notifying the USB control software of the monitoring result;
It has time measuring means and display means to know the monitoring period,
Although the peripheral device device detects the voltage of VBUS,
When the USB interface signal is suspended or does not start the bus reset sequence by the D + signal monitoring unit and the D− signal monitoring unit, it is determined that USB communication is impossible after the monitoring period by the time measuring unit has elapsed. A peripheral device device that notifies the display means of a USB communication abnormal state. The peripheral device device according to claim 1,
A peripheral device device that has a printing unit and prints and notifies a USB communication abnormal state by the printing unit when it is determined that USB communication is impossible.

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