JPH11194847A - Computer system and initialization controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption of a USB controller by controlling the supply of a reset signal to the USB controller. SOLUTION: A reset control circuit 25 is provided in the front stage of a reset signal input terminal (RESET) of the USB controller 16, and consequently, a system reset signal and a resume reset signal can be supplied selectively to the reset signal input terminal of the USB controller 16. Therefore, power- down control over the USB controller 16 by host software using the suspend state prescribed in the USB specifications and power-down control over the USB controller 16 using the ON/OFF operation of the power source can be both used by selective switching at need at the time of the transition of the operation state of the system by controlling the reset signal selecting operation of the reset control circuit 25 with USB reset control information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a computer system and an initialization controller, and more particularly, to a computer system improved so that power consumption of a USB controller can be reduced and an initialization controller of a USB controller used in the system.

[0002]

2. Description of the Related Art In recent years, in personal computers and the like, in order to increase the degree of freedom of expandability of peripheral devices, U.S. Pat.
Support for SB (Universal Serial Bus) has begun. USB is a serial interface standard that can be commonly used for communication with various USB-compatible devices such as a keyboard, a mouse, a camera, a printer, and a modem. By using this USB, the connector prepared for each peripheral device can be
It can be integrated into a connector, which makes it possible to reduce the price of a personal computer and increase the degree of freedom of expandability.

In particular, in portable personal computers such as notebook type and sub-note type,
The use of a USB connector is very effective for miniaturization because there is a restriction on the mounting space of the connector.

[0004] The USB is a bus interface whose functions are separated into a device side and a host side, and has a mechanism in which the host manages devices. The host includes hardware called a host controller (HC) and software called host software (or a host control driver or USB driver).

The USB is a bus having a star network structure, and uses a connection function called a HUB to connect devices. The one at the top of the HUB is Ro
ot_HUB. This is often arranged in a place close to the host controller, and when the host controller is implemented as an LSI, the host controller and Ro
ot_HUB is built in the same LSI. This LSI is called a USB controller.

OHCI (Open Host Cont)
According to a USB specification such as a "roller interface", a suspend mode is defined in the USB controller to reduce its power consumption. In this suspend mode, the operation of most parts other than the part that detects the insertion and removal of the USB device from the USB connector is stopped. A software reset is used to return from the suspend mode to the normal operation mode. This software reset is performed by a USB status write operation in which the host software writes a status to a register of the USB controller. For example, when the USB controller detects that a USB device has been mounted during the suspend mode, It is executed when it is necessary to return from the suspend mode, such as when the device needs to be initialized.

In this software reset, no hardware reset is performed. Therefore, the internal state of the USB controller such as the information in the register can maintain the value immediately before the software reset.

The USB controller also has a reset signal input terminal to which an external reset signal is input for hardware reset. When a reset signal is input to this reset signal input terminal, US
All the internal states of the B controller are cleared, and their initialization can be performed.

As described above, in addition to the normal hardware reset function, the USB controller must support the software reset function used for returning from the suspend mode and initializing the USB device. It is specified by the USB specification.

In a portable personal computer such as a notebook type or a sub-note type, various power save modes for saving power of the computer system are provided in order to extend the time during which the battery can be driven. . The suspend mode is one of the power save modes that consumes the least power. That is, when the computer system is in the suspend mode, most other devices in the system are powered down except for the main memory in which system data necessary for restart such as the operating system and user programs are stored.

The system data saved in the main memory is the status of the CPU and the status of various peripheral LSIs immediately before the computer system is set to the suspend mode. The main memory also stores the execution state of the operating system and application programs and user data created by the application programs.

The system data is saved in the system BI
It is executed by a suspend routine incorporated in an OS (basic input / output program). The system BIOS is for controlling hardware in the system according to a request from the operating system, and includes a device driver group for controlling various hardware devices in the system. The suspend routine of the system BIOS is started when the system power is turned off, and is executed by the CPU.
After saving the registers and the status of various peripheral LSIs in the memory, the system is powered off.

The power supply to the main memory is maintained by the battery throughout the period when the system is powered off. Therefore, the system can be returned to the work state before the suspension without losing the status and user data of the system.

Recently, a new suspend mode (hibernation mode) has been proposed in which, when the system power is turned off, the system status and the contents of the main memory are saved on a hard disk, and then almost all devices in the system including the memory are turned off. ) Are also used.

In a computer system having such a power management function, two types of reset signals, a system reset signal and a resume reset signal, are usually used. The system reset signal is used to initialize each device in the system, and is generated when the computer system is powered on. on the other hand,
The resume reset signal is used when the computer system initializes a device that has been powered off during the suspend mode, is generated when the computer system returns from the suspend mode to the operation mode, and is used during the suspend mode. Is supplied only to the device that was powered off.

FIG. 7 shows a system for supplying a reset signal to the USB controller in a conventional computer system. Power control unit 200
Responds to a power-on signal (Power On) generated from a power supply circuit when the power is turned on, and responds to a system reset signal (System Reset) when the system starts.
t) is generated for all devices in the system, and when returning from the suspend mode, a resume reset signal (ResumeReset) is generated.

A reset signal for the above-described hardware reset and a state write (USB Stat) from the host software are sent to the USB controller 100.
Two types of reset are input, i.e., a software reset by eWrite), and a hardware reset signal is input to a reset signal input terminal (RESET) by a system reset signal (System Reset).
t) only, and the resume reset signal (Resum
e Reset) is not entered. Conventionally, when the system is suspended, the USB controller 100 simply sets the USB controller 100 to a suspend mode defined by the USB specification.
This is because the power supply of 0 is not turned off. In this case, when the system returns from the suspend mode, the USB
As for the controller 100, a software reset is performed.

[0018]

As described above, conventionally, power is continuously supplied to the USB controller 100 even during a system suspend period.
There is a problem that power consumption increases during the suspension period of the system.

The control of the USB controller 100 to enter the suspend mode and the return from the suspend mode by software reset is performed by dedicated host software.
Depending on the S environment or the host software, the USB controller 100 may not be set to the suspend mode in conjunction with the transition to the suspend mode of the system.
In this case, the power consumption during the suspension period of the system further increases.

Further, both the system reset signal (System Reset) and the resume reset signal (Resume Reset) are fixedly connected to the reset signal input terminal (RESET) of the USB controller 100, and the USB is suspended during the system suspend period. It is also conceivable to power off the controller 100. However, with such a hardware design, this time, when the system returns from the suspend mode, the USB
Since the controller 100 is always reset by hardware and its internal state is lost, the suspend control and the software reset of the USB controller 100 by the host software cannot be used. There is also a danger of occurring.

The present invention has been made in view of the above-mentioned circumstances, and when transitioning between operating states of a system, power down control of a USB controller by host software using a suspend state defined by the USB specification, Both power-down control of the USB controller using on / on can be selectively switched and used as needed, and low power consumption and highly flexible power management according to the OS environment and host software to be used It is an object of the present invention to provide a computer system capable of performing the above, and an initialization control device of a USB controller used in this system.

[0022]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a computer system capable of turning off power to some or all devices in a system and transitioning a system state from an operation mode to a suspend mode. Generating a system reset signal for initializing each device in the system when power is turned on, and initializing a device that has been powered off during the suspend mode when returning from the suspend mode to the operation mode. A reset signal generating means for generating a resume reset signal for resetting a USB device, and a USB controller for controlling a USB device, the USB controller being used for returning from a suspended state in which a part of operations of an internal circuit of the USB controller are stopped. Software reset function and the reset signal input terminal A USB controller having a hardware reset function for initializing an internal circuit by an external hardware reset signal, and a system reset signal and a resume reset signal from the reset signal generating means, and resetting them based on control information Reset control means for selecting one of the signals and supplying the selected signal to a reset signal input terminal of the USB controller.

In this computer system, U
A reset control unit is provided at a stage preceding the reset signal input terminal of the SB controller, whereby the system reset signal and the resume reset signal can be selectively supplied to the reset signal input terminal of the USB controller based on the control information. .

Therefore, by controlling the reset signal selecting operation of the reset control means according to the control information,
At the time of the transition of the operation state of the system, the U by the host software using the suspend state specified by the USB specification.
Power down control of SB controller and power on / off
Both of the power-down control of the USB controller using ON can be selectively switched and used as needed.

That is, if the power of the USB controller is turned off during the suspend period of the system, the system BIOS is restored when the system returns from the suspend mode.
By controlling the reset control means by, for example, switching the selected reset signal from the system reset signal to the resume reset signal, the USB controller may be initialized, and the power supply of the USB controller is not turned off during the suspend period of the system. In such a case, the reset signal is not switched by the reset control means, and only the system reset signal may be fixedly input to the USB controller.

As described above, by providing a hardware configuration in which the reset signal input to the USB controller is switched by software, low power consumption and highly flexible power management can be performed in accordance with the OS environment and host software to be used. It is possible to do.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a computer system according to an embodiment of the present invention. This computer system is a notebook-type or sub-notebook-type personal computer that can be driven by a battery, and includes a computer main body and an LCD panel unit that is openably and closably attached to the computer main body. This computer has a built-in battery 22 and is configured to be operable with electric power from the built-in battery 22.

Further, power can be supplied from an external power supply such as an AC commercial power supply via the AC adapter 23. When power is supplied from an external power source, the power from the external power source is used as an operating power source for the computer system. At this time, charging of the built-in battery 22 is automatically performed by the power from the external power supply. When the AC adapter 23 is removed or the breaker of the AC commercial power supply is turned off, the power from the built-in battery 22 is used as the operation power supply of the computer system.

On the system board of this computer system, three types of buses, that is, a host bus 1, a PCI bus 2, and an ISA bus 3, are provided as shown in the figure. Also, on the system board, a CPU 11, a host-PCI bridge device 12, a main memory 13, a VGA
Controller 14, video RAM (VRAM) 15, U
SB controller 16, PCI-ISA bridge device 1
7, BIOS-ROM 18, HDD 19, embedded controller (EC; Embedded Control)
er) 20, a power controller 21, a power control circuit 24, a reset control circuit 25, and the like.

The CPU 11 executes a program loaded in the main memory 13 to execute operation control and data processing of the entire system. The main memory 13 is a memory device that stores an operating system, a device driver, an application program to be executed, processing data, and the like, and includes a plurality of DRAMs. The main memory 13 is connected to the host-PCI bridge device 12 via a dedicated memory bus having a 32-bit or 64-bit data bus.

The host-PCI bridge device 12 is a bridge LSI connecting the host bus (CPU bus) 1 and the PCI bus 2 and functions as one of the bus masters of the PCI bus 2. This host-PCI bridge device 12
Has a function of bidirectionally converting a bus cycle including data and addresses between the host bus 1 and the PCI bus 2 and a function of controlling access to the main memory 13 via the memory bus.

The VGA controller 14 is one of the PCI devices, and controls the LCD and the external CRT to control the VRAM.
The display data drawn in 15 is displayed on them. US
The B controller 16 is also realized as one of the PCI devices, and controls a USB device 35 connected to a USB port (USB connector) 34 provided in the computer main body. The USB controller 16 is realized by a one-chip LSI, and includes a host controller (HC) 31, a Root_HUB 32, and an I / O
The buffer 33 is built in. The USB controller 16, two serial bus (D ^+, D ^-) and exchanges data with the USB device 35 by transmitting a differential signal on.

The USB controller 16 has an OHCI
(Open Host Controller Int
The device conforms to the specifications of the device and has a suspend mode for reducing the power consumption. As described above, in this suspend mode, the US
Most of the functions other than the function of the Root_HUB 32 of detecting insertion / removal of the USB device 35 to / from the B connector 34 are stopped. A software reset is used to return from the suspend mode to the normal operation mode.

This software reset is performed by a USB status write operation in which the host software writes a status in a register of the USB controller 16.
6 is executed when it is necessary to return from the suspend mode, such as when attachment of a USB device is detected during the suspend mode, or when the USB device needs to be initialized.

In this software reset, no hardware reset is performed. Therefore, the internal state of the USB controller 16 such as the information in the register can keep the value immediately before the software reset.

The USB controller 16 also has a reset signal input terminal (RESET) to which an external reset signal is input for hardware reset. When a reset signal is input to the reset signal input terminal (RESET), the USB controller 16
Are all cleared and the initialization is performed.

The PCI-ISA bridge device 17 is a PC
This is a bridge LSI that connects the I bus 2 and the ISA bus 3. The ISA bus 3 has a BIOS-ROM 18, an HD
D19 and EC20 are connected.

The BIOS-ROM 18 stores the system BIOS.
This is for storing S (Basic I / O System), and is constituted by a flash memory so that a program can be rewritten. System BI
The OS is a systematized function execution routine for accessing various hardware in the system.

The system BIOS includes an IRT routine executed when the system is powered on, and a group of BIOS drivers for controlling various hardware. Each BIOS driver includes a plurality of function execution routine groups corresponding to the functions for providing a plurality of functions for hardware control to an operating system or an application program.

The BIOS-ROM 18 also stores a system management program such as a suspend / resume routine. When the system is powered off, the suspend / resume routine saves the system status such as the status of the CPU registers and peripheral LSIs in the main memory 13 and powers off most other devices except the main memory 13 or the system. A suspend process such as saving the status and the contents of the main memory in the HDD 19 and turning off the system power is performed. Thereafter, when the system power is turned on, the suspend / resume routine is executed by the main memory 13 or the HDD 1.
9, the system state is restored.

The EC 20 is a controller for controlling the additional functions of the system. The EC 20 has a heat control function for controlling the rotation of the cooling fan according to the temperature around the CPU and the like. It has an LED / beep sound control function for notifying the user with a beep sound, a power supply sequence control function for controlling on / off of the system power supply in cooperation with the power supply controller 21, and the like.

The power supply controller 21 controls a power supply circuit to supply power to each unit in the system, and has a built-in one-chip microcomputer. The power supply controller 21 controls power supply / interruption in response to an on / off operation of a power switch (P-SW), an LCD panel opening / closing operation, and the like.

Even in the suspended state, these EC2
0 and the power controller 21 are supplied with operating power. The power control unit 24 controls a power-on signal (Power) generated from the power controller 21 when the power is turned on.
er On), a system reset signal (System Reset) is generated in all devices in the system at the time of system start, and a resume reset signal (Resu) is output at the time of returning from the suspend mode.
me Reset). The Power control unit 24 can be realized as a part of the power supply controller 21.

The system reset signal (System R)
(set) is a hardware reset signal used for a so-called power-on reset, which resets the entire system. USB controller 1
6, the system reset signal (System
When (Reset) is input, all the registers of the internal circuit are reset and transit to a state of waiting for initialization from software.

On the other hand, the resume reset signal (Resu)
me Reset) is also a hardware reset signal, but a system reset signal (System Reset)
Unlike t), it does not propagate to the whole system, but only to the device that was suspended, that is, the device that was powered off during the unsuspended suspend period.

The reset control circuit 25 applies a US signal to the reset signal input terminal (RESET) of the USB controller 16.
The hardware reset signal input as the B reset signal (USB RESET) is selectively switched between a system reset signal (System Reset) and a resume reset signal (Resume Reset), and the switching operation is reset. It is controlled by a select signal (Reset Select). The value of the reset select signal is determined by USB reset control information set in a predetermined register in the system.

As described above, in this embodiment, the USB
Reset signal input terminal (RESET
A reset control circuit 25 is provided at a stage preceding T), whereby a system reset signal and a resume reset signal are selectively supplied to a reset signal input terminal of the USB controller 16. Therefore, by controlling the reset signal selection operation of the reset control circuit 25 by the USB reset control information, when the operation state of the system transitions, the power down of the USB controller 16 by the host software using the suspend state specified by the USB specification is performed. Both the control and the power-down control of the USB controller 16 using the power on / on can be selectively switched and used as needed.

That is, when the power of the USB controller 16 is turned off during the suspend period of the system, the system BI is restored when the system returns from the suspend state.
By controlling the reset control circuit 25 by the OS or the like, the selected reset signal may be switched from the system reset signal to the resume reset signal to initialize the USB controller 16, and the USB controller 16 may be reset during the system suspend period. If the power is not turned off, the reset control circuit 25 does not switch the reset signal, and only the system reset signal needs to be fixedly input to the USB controller 16.

As described above, by providing the hardware configuration in which the reset signal input to the USB controller is selectively switched by the system BIOS, low power consumption and flexibility can be achieved in accordance with the OS environment and host software to be used. High power management can be performed.

FIG. 2 shows an example of a specific configuration of the USB controller 16. USB controller 1
6 is implemented as a PCI device, the host controller (HC) 31 and the Root_HUB described above.
32, a PCI bus interface 41 and a configuration register (CONFIG_REG) 42 in addition to the I / O buffer 33. Also,
The host controller (HC) 31 has an operational register (OP) used for reading / writing various statuses from / to the host controller (HC) 31.
_REG) 51, a buffer 52, a serial interface engine (SIE) 53, and a list processor engine (LPE) 54 for controlling the buffer 52 and the serial interface engine (SIE) 53 for data transfer. The suspend control and software reset of the USB controller 16 are executed by a status write to the operational register (OP_REG) 51.

Detecting USB device insertion / removal is Root_H
This is performed by the UB 32, and when insertion / removal is detected,
An interrupt signal is generated from UB32. This interrupt signal is sent to the CPU 11 as an interrupt signal INTA via the OR circuit 55, whereby the insertion / removal of the USB device is notified to the host software.

Of these internal circuits in the USB controller 16, software reset by the above-mentioned state write (USB State Write) by the host software is a part of the operational register (OP_REG) 51 and the Root_HUB.
32, the USB controller 16 returns from the suspend mode by writing a status indicating return from the suspend state to the operational register (OP_REG) 51 after the software reset.

The hardware reset signal is USB
It is sent to all internal circuits in the controller 16 and all internal statuses are initialized. Next, referring to FIG.
An example of a specific configuration of the reset control circuit 25 will be described.

The reset control circuit 25, as shown in FIG.
System reset signal (System Reset) and resume reset signal (Resume Reset)
t), a two-input OR gate 61, an output of the OR gate 61, and a system reset signal (System).
Reset) and a resume reset signal (Resu)
me Reset), select one of them and send it to the USB reset signal (USB RESE
T). The selection operation of the selection circuit 62 is controlled by the above-described reset select signal (Reset Select).

FIG. 4 shows a reset select signal (Res)
5 shows a relationship between the hardware reset signal and a hardware reset signal selected as a USB reset signal (USB RESET).

That is, the reset select signal (Res)
et Select) is “00”, the system reset signal (System Reset) is selected as the USB reset signal (USB RESET), and “0” is set.
If it is 1 ", the resume reset signal (Resume
Reset) is the USB reset signal (USB RESE
T). Further, when the reset select signal (Reset Select) is “11”, OR
The output of the gate 61, that is, (System Rese
t) or (Resume Reset) is selected as a USB reset signal (USB RESET).

As described above, in the present embodiment, the following three selective initializations can be performed. 1) System Reset A System Reset occurs when the system is initially powered on. This is a signal for resetting the entire system as described above, and all components including the USB controller 16 are initialized. However,
The Power control circuit 24 is not subject to initialization. At this time, the control circuits, registers, etc. of all the functional blocks are reset. Also, the reset select signal (Res
The “Set Select” is set to “00” as a default value, and the reset control circuit 25 sets the System Reset to the USB RESET when the power is initially turned on.
Output as

2) Resume Reset This occurs when returning from the suspend mode. USB
There are two ways for the controller 16 to return from suspend. One is US when the system is suspended
This is a case where power is supplied to the B controller 16. In this case, the host software of the USB controller 16 issues a software reset (writing of a reset state) to the USB controller 16 at the time of recovery. The other is a return from the suspend state in which the power supply of the USB controller 16 is cut off. In this embodiment, Resum is controlled by the reset control circuit 25.
Since eReset can be output as USB RESET, in the latter case Resume Reset
Can be used to reset the USB controller 16 by hardware. At this time, the system BIOS
When the B controller 16 returns from the suspend, Re
Set select control, Resume Res
et is output as USB RESET.

3) (System Reset) or
(Resume Reset) This is used only for the suspend mode in which power is shut off. There is an advantage that the control by the BIOS is not required at the time of the Resume Reset. However, Reset Se
The power of a circuit (register or the like) that outputs “select” is supplied even in the suspend mode, and the condition is that the value is held.

<Suspend and Return> When the power supply is cut off, the internal state of the LSI constituting the USB controller 16 is reset. Therefore, the state is first saved in the HDD or the like before entering the suspend state. Res
After the Ume Reset, the data stored in the HDD is written back to the block of the USB controller 16 to return from the suspend mode.

Next, referring to the flowchart of FIG.
The procedure of the suspend / resume operation of the system with the power on / off of the USB controller 16 will be described. At the time of initial power-on, the system reset signal (Sy
The reset of all devices is performed by "system Reset", and their initialization is performed by the system BIOS (step S101).

Thereafter, when a suspend is requested by the user during the operation of the system by turning off the power switch or pressing the suspend button, the system BIOS saves the system status necessary for restoring the working state at that time. Is performed (step S102). Then, the power of most devices in the system including the USB controller 16 is turned off (step S10).
3).

Thereafter, when the user requests a resume by turning on a power switch or the like, the system BI
A reset select signal (Reset Se) is set by the OS.
select) is changed to “01” and U is changed by a resume reset signal (ResumeReset).
The powered-down devices including the SB controller 16 are reset (step S104). Then, the state of each device is restored by the system BIOS (step S105).

Next, referring to the flowchart of FIG.
The procedure of the suspend / resume operation of the system using the suspend function of the USB controller 16 will be described.

At the time of initial power-on, all devices are reset by a system reset signal (System Reset), and their initialization is performed by the system BIOS.
(Step S201). Thereafter, when the suspend is requested by the user during the operation of the system by turning off the power switch or pressing the suspend button, the system BIOS saves the system status necessary for restoring the working state at that time ( Step S202). At this time, the USB controller 16 is set to the suspend mode by the host software.

Then, most of the devices other than the USB controller 16 are turned off (step S).
203). Thereafter, when the user requests a resume by turning on the power switch or the like, the powered-down device is reset by a resume reset signal (Resume Reset) (step S204). At this time, U
The SB controller 16 is reset by software.
Then, the state of each device is restored by the system BIOS (step S205).

The feature of the present invention resides in that a hardware configuration in which the reset method of the USB controller 16 can be switched by software control is realized. Therefore, the procedure of the suspend / resume operation described in this embodiment is described. It is also possible to perform a suspend / resume operation of the system involving turning on / off the power of the USB controller 16 or a suspend / resume operation of the system using the suspend function of the USB controller 16 by using a procedure other than the above.

Further, not limited to the USB controller 16,
If the device has a software reset function and a hardware reset function, the initialization operation can be controlled by the same reset signal switching control.

[0069]

As described in detail above, according to the present invention,
At the time of the transition of the operation state of the system, the U by the host software using the suspend state specified by the USB specification.
Power down control of SB controller and power on / off
Both of the power-down control of the USB controller using ON can be selectively switched and used as needed, and in particular, by adopting a configuration of switching a reset signal input to the USB controller by software control, It is possible to perform power management with low power consumption and high flexibility according to the OS environment and host software to be used.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a computer system according to an embodiment of the present invention.

FIG. 2 is an exemplary view showing a configuration of a USB controller provided in the system of the embodiment.

FIG. 3 is an exemplary view showing an example of a specific configuration of a reset control circuit provided in the system of the embodiment.

FIG. 4 is a diagram for explaining a reset signal selecting operation of the reset control circuit of FIG. 3;

FIG. 5 is an exemplary flowchart illustrating a first example of a suspend / resume operation in the system according to the embodiment;

FIG. 6 is an exemplary flowchart illustrating a second example of a suspend / resume operation in the system according to the embodiment;

FIG. 7 is a diagram illustrating an initialization control operation of a USB controller in a conventional system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... CPU 13 ... Main memory 16 ... USB controller 18 ... BIOS-ROM 19 ... HDD 24 ... Power control circuit 25 ... Reset control circuit 61 ... OR circuit 62 ... Selection circuit

Claims (8)

[Claims] In a computer system capable of turning off power to some or all devices in the system and changing a system state from an operation mode to a suspend mode, when the power is turned on, each device in the system is initialized. Reset signal generating means for generating a system reset signal, and when returning from the suspend mode to the operation mode, generating a resume reset signal for initializing a device that has been powered off during the suspend mode. A USB controller for controlling a USB device, a software reset function used for returning from a suspended state in which a part of operations of an internal circuit is stopped, and an external controller input to a reset signal input terminal. Internal reset by hardware reset signal A USB controller and a hardware reset function to initialize the reset signal to enter the system reset signal and resume the reset signal from the generating means, the USB selects one of them reset signal based on the control information
A computer system comprising: reset control means for supplying a reset signal input terminal of a controller. 2. The USB controller according to claim 1, wherein said USB controller is turned off in said suspend mode, and said reset control means is controlled using said control information when said computer system returns from suspend mode to operation mode. 2. The computer system according to claim 1, wherein a reset signal supplied to a reset signal input terminal of the controller is switched from the system reset signal to a resume reset signal. 3. When the USB controller is set to a suspend state in the suspend mode and the software reset function is used when the computer system returns from the suspend mode to the operation mode, a resume reset signal to the USB controller is transmitted. 2. The computer system according to claim 1, wherein said control information causes said reset control means to fixedly select said reset signal in order to prevent input. 4. The system according to claim 1, further comprising a register configured to be accessible by a CPU of said computer system, wherein said control information is set, wherein a reset signal selecting operation of said reset control means is controlled by software. The computer system according to claim 1, wherein 5. The reset signal generating means selects a system reset signal and supplies it to a reset signal input terminal of the USB controller, and a reset signal of the USB controller by selecting a resume reset signal. A second mode for supplying a logical sum of the system reset signal and the resume reset signal to a reset signal input terminal of the USB controller; a first mode for supplying a logical sum of the system reset signal and the resume reset signal to the reset signal input terminal of the USB controller; 2. The computer system according to claim 1, wherein one of the third modes is selected. 6. In a computer system capable of turning off power to some or all of the devices in a system and changing a system state from an operation mode to a suspend mode, to initialize each device in the system when the power is turned on. Reset signal generating means for generating a system reset signal, and upon returning to the operation mode from the suspend mode, generating a resume reset signal for initializing a device that has been powered off during the suspend mode. , A software reset function used for returning from a suspended state in which a part of operation of an internal circuit is stopped,
A first device having a hardware reset function for initializing an internal circuit by an external hardware reset signal input to a reset signal input terminal; and a system reset signal and a resume reset signal from the reset signal generating means. And a reset control means for selecting one of the reset signals based on the control information and supplying the selected reset signal to a reset signal input terminal of the first device. 7. US for use in a computer system
An initialization control device for controlling initialization of a B controller, comprising: a system reset signal generated to initialize each device in the computer system when the power of the computer system is turned on; and an operation from a suspend mode of the computer system. Upon return to the mode, a resume reset signal generated to initialize a device that has been powered off during the suspend mode is input, and one of the reset signals is selected based on control information to select the reset signal. An initialization control device comprising means for supplying a reset signal input terminal of a USB controller. 8. A software reset function used for returning from a suspended state in which a part of the operation of the internal circuit is stopped, and an internal hardware reset signal input to a reset signal input terminal is used to reset the internal circuit. What is claimed is: 1. An initialization control device for controlling initialization of a first device having a hardware reset function for initializing, wherein each device in the computer system provided with the first device is turned on when a power supply is turned on. A system reset signal generated to initialize the computer system, and a resume generated to initialize a device that has been powered off during the suspend mode when the computer system returns from the suspend mode to the operation mode. A reset signal and input those reset signals based on the control information. Select one initialization control apparatus characterized by comprising means for supplying to the set signal input terminal of the first device.