JP2004127188A - Information processing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processing system capable of enhancing operability. <P>SOLUTION: A printer 102 has a CPU which performs control so that it is transited from a sleep mode for power saving to a normal operation mode and an interruption controller which inputs a V<SB>BUS</SB>signal of a USB as an interruption signal and a digital camera 101 has V<SB>BUS</SB>wake up logic which generates pulses by driving the V<SB>BUS</SB>signal. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an information processing system configured by connecting a USB Host-side device and a USB Device-side device.
[0002]
[Prior art]
In the information processing system described above, the USB Host-side device detects an event generated by the USB Device-side device by interrupt transfer. This is an operation in which the USB Host-side device polls the USB Device-side device at a fixed cycle, and does not receive a truly asynchronous event as a request from the USB Device-side device.
[0003]
Further, the USB device side device drives the USB bus signal only when the USB Host side device permits, and cannot drive at an arbitrary timing.
[0004]
[Problems to be solved by the invention]
However, when the USB Host-side device enters a sleep mode for power saving and stops the logic operation of the USB Host-side device, it becomes impossible to detect any operation of the USB Device-side device, and returns to the normal operation mode again. For this purpose, it is necessary for the user to operate the hardware of the USB Host-side device, so that the operability is poor.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the related art, and a first object of the present invention is to provide an information processing system with improved operability.
[0006]
A second object of the present invention is to provide an information processing system which does not apply an electric stress to a drive circuit of a _VBUS signal used as an interrupt signal to a USB Host-side device.
[0007]
[Means for Solving the Problems]
In order to achieve the first object, the information processing system according to claim 1 of the present invention is an information processing system in which a USB Host-side device and a USB Device-side device are connected, wherein the USB Host-side device is A control unit for controlling a transition from a sleep mode for power saving to a normal operation mode, and an interrupt circuit for inputting a USB V _BUS signal as an interrupt signal. has a _V BUS Wake Stay up-circuit for generating a pulse to drive the _BUS signal, the _V BUS Wake Stay up-circuit detects the level of the _{V BUS} signal, the USB Host-side device is not driving the _{V BUS} signal If not, a pulse is generated. It stops the driving of the _BUS signal, the detected pulses of the V _BUS signal, and generates an interrupt corresponding, and controls so as to transition from the sleep mode to the normal operation mode.
[0008]
In order to achieve the first object, the information processing system according to claim 2 of the present invention, in the information processing system according to claim 1, wherein the USB device side device has a user interface unit. , when a user inputs an instruction to the USB Host-side device, the USB device side device by the _V BUS Wake Stay up-circuit determines whether or not to drive the _{V BUS signal,} not drive the _{V BUS} signal If it is determined that there is no such signal, a pulse is generated by the V _BUS wake up circuit, an interrupt is generated in the control means of the USB Host-side device, and a transition can be made from the sleep mode to the normal operation mode. And
[0009]
Further, in order to achieve the second object, the information processing system according to claim 3 of the present invention is the information processing system according to claim 1, wherein the V _BUS wake-up logic is connected to a V _BUS signal line. It is characterized by having a pull-down resistor connection switching means and a drive circuit disconnecting means for the V _BUS signal.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
FIG. 1 is a block diagram showing the configuration of an information processing system according to an embodiment of the present invention. In FIG. 1, reference numeral 101 denotes a digital camera, 102 denotes a printer, and 103 denotes a USB interface. And to connect. In such a configuration, the digital camera 101 is a device on the USB Device side, and the printer 102 is a device on the USB Host side. The user operates the digital camera 101 to cause the printer 102 to perform a printing operation.
[0012]
FIG. 2 is a block diagram illustrating a configuration example of an interface-related portion of the printer 102. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals.
[0013]
2, reference numeral 201 denotes a CPU (Central Processing Unit); 202, a CPU bus for connecting the CPU 201 to each circuit; 203, a ROM (Read Only Memory) for storing programs of the CPU 201; 204, a RAM (Random Access Memory) , 205 control an external interrupt and generate an interrupt signal to the CPU 201, 206 a USB Host logic (Logic) for controlling the USB interface 103 of FIG. 1, and 207 control a V _BUS signal of the USB interface 103. A USB power controller, 208 is a power supply circuit, 209 is a USB V _BUS signal, 210 is a USB D + signal, 211 is a USB D- signal, and 212 is a USB GND signal.
[0014]
FIG. 3 is a block diagram showing a configuration example of an interface-related portion of the digital camera 101. In FIG. 3, the same reference numerals are given to the same components as those in FIGS.
[0015]
3, reference numeral 301 denotes a CPU (Central Processing Unit); 302, a CPU bus connecting the CPU 301 to each circuit; 303, a ROM (Read Only Memory) for storing programs of the CPU 301; and 304, a RAM (Random Access Memory) , 305 USB Device logic that controls each signal _{USB (logic), V BUS Wake} up logic 306 for controlling the _{V BUS} signal from the digital camera 101 side of FIG. 1 (logic), 307 pull-down of the _{V BUS} signal 209 308, a power supply circuit; 310, a user interface operated by a user, including an LCD (liquid crystal display), an LED (light emitting diode), a key switch, a dial switch, etc. .
[0016]
Next, an operation of the information processing system according to the present embodiment having the above configuration will be described.
[0017]
The user performs photographing using the user interface 310 of the digital camera 101, communicates with the printer 102, and performs a printing operation. Normally, the printer 102 detects the state of the digital camera 101 using USB interrupt transfer, and when detecting a print instruction, reads a print data file from the digital camera 101 and performs print processing.
[0018]
When the printer 102 does not detect an instruction to the printer 102, such as a print instruction, for a predetermined time, the printer 102 enters a sleep mode to save power consumption. At this time, the USB Host logic 206 is in a stopped state, and accordingly, the USB power controller 207 stops supplying the _VBUS signal 209. Next, the interrupt mask of the _VBUS signal 209 of the interrupt controller 205 is released, the power supply to each unit is stopped, and the CPU 201 enters the sleep mode. However, in this state, the interrupt controller 205 remains operating.
[0019]
When printing, the user designates a print file via the user interface 310 of the digital camera 101 and issues a print instruction. The CPU 301 controls the V _BUS Wake up logic 306 in response to the print instruction, and detects the state of the printer 102. The state of the printer 102 is detected by connecting a pull-down resistor 307 via a switch 308 and detecting a signal level. The pull-down resistor 307 is connected to fix the level when the signal line is in a high impedance state. If the signal level is close to GND, the printer 102 determines that the printer 102 is not driving a signal and is in a sleep state. At this time, the V _BUS Wake up logic 308 connects the drive circuit with the pull-down resistor 307 connected, generates a pulse, and disconnects the pull-down resistor 307 and the drive circuit after a predetermined time.
[0020]
The printer 102 causes the CPU 201 to generate an interrupt because the interrupt controller 205 is operating as described above and the interrupt of the _VBUS signal 209 is unmasked. The CPU 201 is started by this interrupt, masks the interrupt of the _VBUS signal 209 of the interrupt controller 205, and restarts the power supply of each unit. Thereafter, the supply of the _VBUS signal 209 from the USB power controller 207 is resumed, the operation of the USB Host logic 208 is resumed, the digital camera 101 communicates with the digital camera 101 via the USB interface 103, and the printer 102 performs a printing operation.
[0021]
After generating a pulse in the _VBUS signal 209 as described above, the digital camera 101 waits for an operation of the USB interface 103 from the printer 102 for a predetermined time. If the supply of the _VBUS signal 209 is started during this time, it is determined that the printer 102 has started the operation normally, and the printing operation in the normal operation mode is continued. If the supply of the _VBUS signal 209 is not started, the printer 102 determines that the printer is not connected, notifies the user via the user interface 310 of the fact, and cancels the print request.
[0022]
Note that the power supply circuit 309 connects the V _BUS signal 209, but this is not essential and is used as an auxiliary. The digital camera 101 does not need to supply the V _BUS signal 209 as described above. It is assumed that the following operation is possible.
[0023]
In addition, the printer 102 may cause the interrupt controller 205 to receive an operation of the user interface 310 of the printer 102 instead of the _VBUS signal 209 and generate an interrupt, thereby returning the printer 102 to the normal operation mode.
[0024]
As described above, according to the information processing system according to the present embodiment, even when the printer 102, which is the USB Host-side device, enters the sleep mode and the USB operation is stopped, the device is still the USB Device-side device. The printer 102 can be returned to the normal operation mode by a user operation from the digital camera 101 to perform a printing operation.
[0025]
【The invention's effect】
As described above, according to the present invention, the USB Host-side device in the sleep state can be returned to the normal state from the USB Device-side device connected thereto, and the operation function of the system can be improved.
[0026]
Further, according to the present invention, the USB Host-side device in the sleep state can be returned to the normal operation mode by the user interface operation of the USB Device-side device, and the operability of the system can be improved.
[0027]
Further, according to the present invention, it is possible to detect the state of the USB Host-side device and issue a return instruction to the normal operation mode without applying an unnecessary load to the USB _VBUS signal drive circuit.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an information processing system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration example of an interface-related portion of a USB Host-side device in the information processing system according to the embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration example of an interface-related portion of a USB device-side device in the information processing system according to the embodiment of the present invention.
[Explanation of symbols]
101 Digital Camera (USB Device side device)
102 Printer (USB Host side device)
103 USB interface 201 CPU (central processing unit)
202 CPU bus 203 ROM (read only memory)
204 RAM (random access memory)
205 Interrupt controller 206 USB Host logic 207 USB power controller 208 Power supply circuit 209 USB V _BUS signal 210 USB D + signal 211 USB D- signal 212 USB GND signal 301 CPU (central processing unit)
302 CPU bus 303 ROM (read only memory)
304 RAM (random access memory)
305 USB Device Logic (Logic)
306 V _BUS Wake up logic (Logic)
307 pull-down resistor 308 switch 309 power supply circuit 310 user interface

Claims (3)

In an information processing system that connects a USB Host-side device and a USB Device-side device,
The USB Host-side device includes a control unit that controls a transition from a sleep mode for power saving to a normal operation mode, and an interrupt circuit that inputs a USB _VBUS signal as an interrupt signal.
The USB Device-side device has a _VBUS Wake up circuit that drives a _VBUS signal to generate a pulse,
The _V BUS Wake Stay up-circuit detects the level of the _{V BUS} signal, generates a pulse if the USB Host-side device is not driving the _{V BUS} signal,
The control means stops driving of the _VBUS signal at the time of transition from the normal operation mode to the sleep mode, detects a pulse of the _VBUS signal, generates a corresponding interrupt, and switches from the sleep mode to the normal operation mode. An information processing system characterized by performing control so as to make a transition. The USB Device-side device has a user interface unit, and when the user inputs an instruction to the USB Host-side device, whether the USB Device-side device drives a _VBUS signal by the _VBUS Wake up circuit. If it is determined that the V _BUS signal is not being driven, a pulse is generated by the V _BUS wake up circuit, an interrupt is generated in the control means of the USB Host-side device, and the sleep mode is normally set. The information processing system according to claim 1, wherein the information processing system is configured to be capable of transitioning to an operation mode. 2. The information processing system according to claim 1, wherein the V _BUS wake up logic includes a pull-down resistor connection switching unit to the V _BUS signal line and a driving circuit disconnection unit for the V _BUS signal.

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