JP2000187578A - Interface device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save power in a sleep mode and to actualize secure automatic recovery to a standby mode by resending a start instruction with a necessary interval after the power recovery and when there is not response within the specific time. SOLUTION: When a shift to an energy-saving mode is instructed by the input of a signal from a control CPU 11 for the whole multifunction peripheral(MFP) 10, the power supply signal from a power circuit (PSU) 30 is cut off and power is supplied even in the respective energy-saving modes of an interface 100 to a host computer H connected by a parallel port, an operation part 27, and a scanner part 22. Signals from some detecting circuits are inputted to detect access from a user and the host computer H and the recovery from the energy-saving modes are controlled. If there is no answer from a device within the specific time after a host-side driver asserts a STROBE signal, operation for asserting the STROBE signal again the specific time later is performed more than once.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interface device, and more particularly, to an interface circuit and a driver for a host PC and a peripheral device connected by an LPT parallel interface.

[0002]

2. Description of the Related Art In order to save energy, it is common to set a sleep mode in order to minimize power consumption during standby. Conventionally, in the case of printers and scanners, control has been performed to cut off power supply to a recording unit and a reading unit, which are main power consumption units, according to a sleep mode command from a host PC. However, even in this case, the control system for monitoring the reception of the command from the host PC needs to be operated, which has been a barrier to the reduction of the standby power consumption.

[0003] Recently, a multifunction machine has appeared, in which facsimile, copy, and the like are combined with scanner functions such as a printer and a scanner. In these devices, it is necessary for the device to perform the transition to the sleep mode and the recovery to the standby mode regardless of the connection to the host and the ON / OFF of the host power supply. The transition to the sleep mode is generally based on the measurement of the elapsed time after the operation, and the return to the standby mode requires the presence or absence of an incoming call, user operation (button push, document insertion,
In general, the detection is performed by detecting access from a host and detecting a human body).

[0004] From the above two requirements: In the sleep mode, the power of the control unit (CPU or the like) is also shut off to reduce power consumption in the sleep mode. 2. A circuit for detecting access from the surroundings and outputting a detection signal and a power supply circuit specially prepared for supplying power to the circuit are prepared, and a trigger for restoring power supply is generated.

[0005] The foregoing has been actively attempted.

[0006]

However, there is no method for reliably detecting an access from the host PC without operating the control unit and not causing an erroneous detection.
The functions of sleep mode transition and automatic return when connected to the device are not realized. Accordingly, an object of the present invention is to realize a reduction in power consumption in a sleep mode and a reliable automatic return to a standby mode by enabling access detection from the host with a simple circuit.

[0007]

According to the first aspect of the present invention,
In order to solve the above problem, a peripheral device having means for reducing standby power consumption by turning off a power supply of a control circuit in a sleep mode, and a host device controlling the peripheral device are interposed between the peripheral device and the host device. In an interface device for transferring a data signal, a command signal, and a status signal transmitted and received between the host device and the host device by transmitting a command start from the host device to the peripheral device for a predetermined time, The present invention is characterized in that there is provided a means for transmitting a command start again after a lapse of a required time for power supply return / rise of the peripheral device.

According to a second aspect of the present invention, there is provided an interface device according to the first aspect, wherein:
In the sleep mode, there is provided means for maintaining power supply only to a circuit for monitoring a specific command signal, and the monitored command signal is at a high level in a standby state. According to a third aspect of the present invention, in order to solve the above-described problem, in the interface device according to the first aspect, when starting a communication job with the peripheral device, the communication device starts from a single continuous operation mode. Is what you do.

According to a fourth aspect of the present invention, there is provided an interface device according to the first or second aspect, wherein an exclusive logic of a command signal to be monitored and another command signal having the same polarity characteristic is provided. The sum is used as a start signal from the sleep mode.
According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the interface device according to the first or second aspect, a specific signal among status signals output from the peripheral device is set to a normal standby time in a sleep mode. The present invention is characterized in that there are provided means for holding the polarity in reverse, and means for stopping frequent peripheral device status check operations depending on the polarity of the status signal.

According to a sixth aspect of the present invention, in order to solve the above problem, in the interface device according to the first or second aspect, while the peripheral device returns from a sleep mode to a normal state, a status input is cut off. And means for maintaining the status output to the host device in a specific state.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the configuration of a multifunction peripheral (hereinafter abbreviated as MFP) shown in this embodiment. The output of the power supply circuit (PSU) 30 that supplies power to each unit is divided and wired into a power supply system that is cut off in the energy saving mode and a system that is not shut off in the energy saving mode, and the former system is powered by the latter. Controlled by an energy saving mode control circuit.

In this control circuit, when a signal is input from the control CPU 11 of the entire MFP 10 and a command to shift to the energy saving mode is issued, the power supply signal from the PSU 30 is cut off and connected by the parallel port. The interface 100 with the host computer H, the operation unit 27, and the scanner unit 22 each receive a signal from some of the detection circuits to which power is supplied even during the energy saving mode to detect access from the user or the host computer H. And control the return from the energy saving mode.

Next, an example in which a signal for returning to the normal mode to be input to the energy saving mode control circuit by the signal access from the host computer H is generated will be described. The connection between the host computer H and the MFP 10 is generally performed by a parallel interface. Furthermore, it is common in recent years for this interface to conform to the IEEE 1284 standard. The correspondence between each signal and the connector in this standard is shown in the list of FIG. FIG. 3 shows a hardware input / output interface of each control signal line, and FIG. 4 shows a bidirectional data input / output interface. However, in many host computers, a pull-up resistor is often attached to an output pin of a signal line.

The access from the host computer H is started from the sequence shown in FIGS. 5 and 6 in IEEE1284. In FIG. 5, D
After the ATA signal is set, “nSTROBE” goes low.
This is a case in which the MFP side is notified of data transfer by going to the low level. When the forward data transfer (data transfer from the host PC to the MFP) is started from the standby mode, the sequence starts here.

FIG. 6 shows an example in which the MFP uses the IEEE as a peripheral device.
In this case, the sequence is started from an operation of confirming whether or not the terminal supports “1Select 1284”.
"In" to High and "nAutofeed" to Low
The sequence is started by indicating the start of negotiation, and instructing the MFP as a peripheral to respond to IEEE1284 (in FIG. 6, responding to IEEE1284 by inverting the hatched signal). You.

As described above, in the case of FIG. 5, "nSTROB"
E ”is detected to be at the Low level, and a return signal from the energy saving mode is generated. In the case of FIG.
ctIn ”is Low level and“ nAutofee ”
By detecting that d ″ is at the High level and generating a return signal from the energy saving mode, automatic return from the energy saving mode becomes possible.

However, even after returning from the energy saving mode, the time required for the peripheral device to respond in a normal response is defined as follows, and a normal response is not achieved because the recovery speed exceeds this. . In the case of FIG. 5... Within 500 ns, the device sets the BUSY signal to High level and returns a response.

In the case of FIG. 6, the device returns the above response within 35 msec. Next, the configuration and operation of the present invention will be described. In order to solve this problem, the host-side driver asserts the STROBE signal and then at least once performs an operation of re-asserting the STROBE signal after a predetermined time if there is no response from the device within the predetermined time. Is what you do.

FIG. 7 shows the sequence in the case of FIG. 5 as an example. First, the driver checks the BUSY status signal from the device and confirms that it is at the low level. Generally, this status signal is output when the device is working and cannot receive a command. Next, by setting the STROBE signal to Low, the device is urged to receive a transfer command (or data). If there is no BUSY response within a predetermined time, the strobe is transmitted again after a predetermined time. Note that the transmission strobe is generally defined as having a pulse width of 500 ns or less, but in this case, the transmission strobe may have an arbitrary length.

In this case, a response between the host and the device is established by setting the retransmission interval of the strobe to be longer than the time required for the device to return from the sleep mode to the normal standby mode. Next, the configuration and operation of the second aspect of the invention will be described. Access from the host is performed by monitoring the levels of the four command signal lines.
Detected on the device side. If all of these signals are monitored in the sleep mode, it becomes necessary to maintain all the pull-up power supplies of the four command signal lines at 5V.
At this time, when the signal at the low level is monitored during the normal standby, a current flows into the driver on the host side through the pull-up resistor.

According to the second aspect, in order to prevent the current consumption, only the signal at the high level in the normal standby mode is monitored. FIG. 8 shows the input interface of the embodiment, in which only the STROBE signal and the Autofeed signal are monitored, and the host access in each of FIGS. 5 and 6 is detected. In FIG. 8, detection is made possible by monitoring the logical sum of both (because both are low active signals).

In the sleep mode, each of the input elements S does not transmit an input signal to an internal circuit other than the monitoring section.
It is controlled by one signal. Next, a third aspect of the present invention will be described. By starting all jobs in the host driver from the data transfer operation shown in FIG. 5, the device-side interface circuit can have a simpler configuration as shown in FIG. is there.

Next, the configuration and operation of the invention will be described. When the host is powered off,
As described below, all command signals are unpredictable from the device side depending on the interface circuit of the PC.・ When current flow is protected ・ ・
-High level is detected.

A current flows into the output protection diode of the driver. A low level is detected. When current flows into the pull-up resistor in the drive section
Indeterminate Therefore, when this command indicates a low level, the circuit shown in FIGS. 8 and 9 may erroneously output an access detection signal from the host.

In order to solve this problem, a host access is monitored using a circuit as shown in FIG. In this case, in a case where the INIT signal goes low at the same time as STROBE, generation of a start trigger is automatically prevented. Next, the configuration and operation of the invention according to claim 5 will be described.

The device is an MFP, for example, a PC-F
When the host has a function such as AX, it is necessary for the host to periodically monitor the status of the device in order to check whether there is an incoming call. However, when the host issues a data transmission request indicating the status while the device is in the sleep mode, the device must return from the sleep mode each time, and the device cannot substantially shift to the sleep mode.

The status signal from the device in the sleep mode is undefined when viewed from the host, similarly to the command signal in the fourth embodiment. Therefore, a device side means for holding a specific signal of a status signal outputted from the device side in a polarity opposite to that of a normal standby state in a sleep mode, and a frequent device status check based on the polarity of the status signal By stopping the operation, the host can detect that the device is not in the normal standby state by a specific status signal. In the case where the device is not in the normal device standby state (that is, the sleep mode state), the above-described problem is solved by eliminating the periodic status check from the operation.

FIG. 11 shows an embodiment of a device-side status signal output circuit. By forcibly outputting the SLCT signal at the low level in the sleep mode, the host can detect that the device is not in a normal state even in the sleep mode when the SLCT is in the low level state. Next, FIG. 12 shows the configuration of the invention according to claim 6.

If BUSY is output from the internal circuit during the recovery of the device in response to the host access in FIG. 5, the host may erroneously recognize that the response is a device response to the access. In FIG. 12, BUS during sleep mode
Since the Y output forcibly keeps the Low level, such a problem can be solved.

[0030]

According to the first aspect of the present invention, when the start of a job is transmitted from the host to the device, the transmission is performed again after the power recovery / rise time of the device, so that the device can respond normally. Become. According to the second aspect of the present invention, since the command signal to be monitored is normally at the high level in the idle mode (standby state), it is possible to prevent current consumption from flowing to the host through the pull-up resistor in the receiving unit.

According to the third aspect of the present invention, since the operation is always started from a single operation mode, it is sufficient to monitor only a single command signal. According to the fourth aspect of the present invention, even if the command signal to be monitored when the host-side power supply is turned off is asserted, an exclusive OR operation with another command signal having the same polarity characteristic is performed to prevent access from the host. It becomes possible to identify and prevent erroneous detection in the sleep mode.

According to the fifth aspect of the present invention, frequent access from the host in the sleep mode can be stopped, so that the device can shift to the sleep mode. According to the invention described in claim 6, after the power supply is restored, the CP
Until initialization of U and peripheral circuits is completed, the specified status line is forcibly maintained at a predetermined polarity, preventing the host from erroneously detecting the response of the device when the device has not yet returned to the normal state. it can.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of a multifunction peripheral according to the present invention.

FIG. 2 is a list showing correspondence between signals and connectors according to the IEEE1284 standard.

FIG. 3 is a block diagram showing an input / output interface of a control signal line.

FIG. 4 is a block diagram showing a bidirectional data input / output interface.

FIG. 5 is a diagram showing each signal level.

FIG. 6 is a diagram showing each signal level.

FIG. 7 is a flowchart illustrating processing when a response from a device is not received within a predetermined time.

FIG. 8 is a block diagram showing an input interface for monitoring only a signal at a high level in a normal standby mode.

FIG. 9 is a block diagram illustrating a main circuit configuration of the interface device.

FIG. 10 is a block diagram illustrating a main circuit configuration of the interface device.

FIG. 11 is a block diagram showing an output circuit configuration of a device-side status signal.

FIG. 12 is a block diagram showing an output circuit configuration of a device-side status signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multifunction peripheral (MFP) 11 Control CPU 12 ROM 13 RAM 14 Energy saving mode control circuit 21 Scanner control unit 22 Scanner unit 23 Printer control unit 24 Printer unit 24a Discharge stack sensor 25 Communication control unit 26 Operation control unit 27 Operation unit 28 Image processing coding circuit 29 Nonvolatile storage element 30 PSU 100 Host I / F (interface device) H Host device

Claims (6)

[Claims] 1. A peripheral device having means for reducing standby power consumption by turning off a power supply of a control circuit in a sleep mode, and a host device for controlling the peripheral device, interposed between the peripheral device and the host device. Data signals, command signals,
In an interface device for transferring a status signal by a parallel interface function, when a command start from the host device is transmitted to the peripheral device and there is no response for a predetermined time, the time required for the peripheral device to return and rise in power supply. An interface device comprising means for transmitting a command start again after a lapse of time. 2. The interface device according to claim 1, further comprising means for maintaining a power supply only to a circuit for monitoring a specific command signal in a sleep mode, wherein said command signal to be monitored is in a standby state and is high. An interface device characterized by being a level. 3. The interface device according to claim 1, wherein a communication job with said peripheral device is started from a single operation mode. 4. The interface device according to claim 1, wherein an exclusive OR of a command signal to be monitored and another command signal having the same polarity characteristic is used as a start signal from the sleep mode. Interface device characterized. 5. The interface device according to claim 1, wherein a specific signal of a status signal output from the peripheral device has a polarity opposite to that of a normal signal in a sleep mode in a standby mode. Means for stopping a frequent peripheral device status check operation in accordance with the polarity of the status signal. 6. The interface device according to claim 1, wherein a status input is cut off and a status output to said host device is changed to a specific state while said peripheral device returns from a sleep mode to a normal state. An interface device comprising means for maintaining.