JP2000112586A - Data communication equipment, its method and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress data omission at the time of restoration from a power saving mode to a normal mode as much as possible and to attain power saving by transiting a data processing means to the power saving mode when a measured non-communication time exceeds a prescribed time. SOLUTION: When a data input/output is not generated (S3 No), current time is compared with a reference time and whether fixed time has elapsed or not is discriminated (S6). When the previously determined fixed time has not elapsed (S6 No), operation is returned to preceeding processing (S2). At the time of judging that the fixed time has elapsed (S6 Yes), a CPU is transmitted to the power saving mode (S7). During the operation of the CPU in the power saving mode, whether a data input interruption or a CPU data output request is generated from a serial port control module or not is discriminated (S8). When the data input interruption or the like is not generated (S8 No), reprocessing is repeated (S8), and when the data input interruption or the like is generated, the CPU is turned to the normal mode (S9).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data communication device,
A method and a storage medium.

[0002]

2. Description of the Related Art (A) Conventionally, in a battery-driven information processing apparatus, power saving has been a major problem. Some processors have a power saving mode to save power. In the power saving mode, the power consumption of the processor is kept low.

However, in an information processing apparatus that performs communication using a serial port, it is not possible to predict when data will be input due to the nature of the information processing apparatus. When operating the processor in the normal mode or shifting the processor to the power saving mode, it is necessary to terminate the communication through the serial port.

(B) Conventionally, in an information processing apparatus for performing communication using a serial port, when there is an input from the serial port, an interrupt from the serial port control device to the processor occurs every time one byte is input. However, the processor that has detected the interrupt performs input data input processing.

Here, if the next byte arrives at the serial port before the processor completes the input data input processing, an overrun error occurs and data is missed. . The interval at which the next one byte arrives after the interrupt from the serial port control device depends on the communication speed of the serial port.

Some serial port controllers have a buffer of several bytes, and there is a margin of several bytes in the interval between the data input processing of the processor and the occurrence of an interrupt from the serial port controller.

On the other hand, in a battery-driven information processing apparatus,
As mentioned above, power saving was a major problem. Further, there is a processor having a power saving mode for saving power. In the power saving mode, the power consumption of the processor is suppressed to be low.
However, it takes some time for the processor to return from the power saving mode to the normal mode, during which time the processor cannot process.

In other words, when power saving is performed by a device that performs data communication through a serial port, after the processor performs reception processing on the serial port, the processor returns from the power saving mode to the normal mode and waits until the next reception processing. When the input process for is completed, without losing any data,
Communication can be performed.

On the other hand, if the processor returns from the power saving mode to the normal mode and does not complete the data input process between the time when the next one byte arrives at the serial port after the occurrence of the interrupt from the serial port, A run error occurs and data is missed. In this case, the processor must be designed so as not to transition to the power saving mode between the reception processing of the serial port and the next reception processing.

(C) Further, conventionally, C having a power saving function
When there is no effective processing operation in the PU, when the CPU explicitly executes an instruction to make a transition to the power saving mode, the CPU stops execution of the instruction and partially stops supply of clock and power.

When a factor such as an interrupt occurs, the CPU returns to the normal mode. By effectively utilizing the power saving mode, it is possible to suppress the power consumption of the data communication device.

FIG. 12 is a flowchart showing a conventional communication processing procedure. The event is set by an interrupt of hardware or the like. It is determined whether or not there is an event (step S1001). If there is an event, processing such as transmission and reception is executed according to the type of the event (steps S1002, S1003,...), And step S100
It returns to the process of 1001. On the other hand, if no event has occurred, a tight loop occurs without any processing. In the case of a title loop, the CPU is wasted, so it is appropriate to shift the CPU to the power saving mode. As a trigger for shifting to the power saving mode, there may be a case where there is no event, an idle state for a certain time or a certain time.

[0013]

However, in the conventional example shown in (A), there is a time when there is no data to be transmitted and received temporarily even during communication, and in such a situation, sufficient power saving is required. Could not do.

Further, in the conventional example shown in (B), the interval between interrupts from the serial port depends on the communication speed of the serial port, and may change every connection with the communication partner. Further, the interrupt interval also changes depending on whether or not the serial port control device has a buffer. The time required for the processor to recover from the power saving mode to the normal mode also depends on performance such as the operating frequency of the processor.

If the information processing apparatus is designed such that the processor transits to the power saving mode during the input processing of the serial port, data is frequently lost when the communication speed is high. Further, if the processor is designed not to transition to the power saving mode during the input processing of the serial port, power consumption is wasted when the communication speed is low.

Further, in the conventional example shown in the above (C),
In general, when the CPU returns from the power saving mode to the normal mode, a delay occurs at the rise due to hardware setup. Therefore, there is a possibility that the interrupt processing after the occurrence of the interrupt is delayed. In the data communication device, when data arrives from the network, an interrupt is generated and the data is taken in. However, in the power saving mode, the data is missed. Also,
In packet communication for transferring data in a certain unit, 1
Missed bytes lead to missed one packet, leading to a decrease in communication efficiency.

Therefore, according to the present invention, the processor shifts to the power saving mode when there is no data input / output for a predetermined time during communication through the serial port, and returns to the normal mode when data is input / output again. An object of the present invention is to provide a data communication device, a method, and a storage medium capable of performing effective power saving without terminating communication by continuing communication.

Further, the present invention measures the frequency of overrun of the serial port, and determines at the time of communication whether or not to shift to the power saving mode during the input processing of the serial port based on the frequency. , A data communication device that can realize effective power saving within a range in which data is not lost without depending on the performance and communication speed of a processor,
It is another object to provide a method and a storage medium.

Further, the present invention provides a data communication device capable of realizing power saving while avoiding an unnecessary transition to a power saving mode and minimizing data loss in returning from the power saving mode to the normal mode. It is another object to provide a method and a storage medium.

[0020]

In order to achieve the above object, a data communication apparatus according to a first aspect of the present invention has a power saving mode, and has a data processing means for processing data transferred by communication. A time measuring means for measuring the non-communication time during which the communication is not performed; and a time determining means for determining whether the measured non-communication time exceeds a predetermined time. When the time exceeds a predetermined time, the data processing means transitions to the power saving mode.

According to a second aspect of the present invention, there is provided the data communication apparatus according to the first aspect, further comprising communication control means for controlling a communication port, wherein data is input from the communication port during the power saving mode. In this case, the data processing means returns to the normal mode.

According to a third aspect of the present invention, there is provided a data communication device which is capable of transitioning to a communication control means for controlling a communication port, and to a power saving mode for returning to a normal mode by interruption from the communication control means. A data processing unit for processing the power saving mode, a frequency measuring unit for measuring a frequency of an overrun error of data input to the communication port, and prohibiting a transition to the power saving mode when the measured frequency is a predetermined value or more. And a transition prohibiting unit that performs the transition prohibition.

According to a fourth aspect of the present invention, there is provided the data communication apparatus according to the third aspect, wherein the transition prohibiting means is prohibited during communication.

According to a fifth aspect of the present invention, in the data communication apparatus according to the third or fourth aspect, when the communication is completed, a transition to the power saving mode is permitted.

According to a sixth aspect of the present invention, in the data communication apparatus according to the second or third aspect,
The communication port is a serial port.

According to a seventh aspect of the present invention, in the data communication apparatus for performing data communication with a communication partner, a communication state detecting means for detecting the state of the communication, and based on the detected state of the communication, When it is determined that data is not transmitted from the communication partner, a mode control unit that shifts to a power saving mode in a state where the communication is maintained is provided.

[0027] In the data communication apparatus according to claim 8, in the data communication apparatus according to claim 7, the communication state detecting means detects a state in which a response from the communication partner has timed out. And

According to a ninth aspect of the present invention, in the data communication apparatus according to the seventh aspect, the communication state detecting means detects a state in which a transmission interruption request is received from the communication partner. And

[0029] In the data communication device according to the tenth aspect,
8. The data communication apparatus according to claim 7, wherein the mode control means transitions to the power saving mode by a logical product of a plurality of connected states.

[0030] In the data communication device according to the eleventh aspect,
8. The data communication apparatus according to claim 7, wherein the mode control means executes a transition to the power saving mode via a control line.

[0031] In the data communication device according to the twelfth aspect,
The data communication device according to claim 7, wherein at least a part of the central processing unit and the peripheral circuits transition to the power saving mode.

In the data communication method according to the thirteenth aspect, a step of measuring a non-communication time during which communication is not performed, a step of determining whether or not the measured non-communication time exceeds a predetermined time, When the measured non-communication time exceeds a predetermined time, the data processing means for processing data transferred by the communication is shifted to a power saving mode.

According to a fourteenth aspect of the present invention, in the data communication method, a step of measuring a frequency of an overrun error of data input to a communication port and a step of determining whether or not the measured frequency is equal to or more than a predetermined value And a step of prohibiting the data processing means from transitioning to the power saving mode when the measured frequency is determined to be equal to or greater than a predetermined value.

In a data communication method according to a fifteenth aspect, when data is communicated with a communication partner, a step of detecting a state of the communication, and data is transmitted from the communication partner based on the detected communication state. Transiting to the power saving mode in a state where the communication is maintained if it is determined that the communication is not transmitted.

A storage medium according to claim 16 is a storage medium storing a program to be executed by a CPU in a data communication apparatus, wherein the program measures a non-communication time during which communication is not performed. A procedure for determining whether the measured non-communication time exceeds a predetermined time; and a data processing means for processing data transferred by the communication when the measured non-communication time exceeds the predetermined time. To a power saving mode.

A storage medium according to claim 17, wherein a program executed by a CPU in a data communication device is stored, wherein the program measures a frequency of an overrun error of data input to a communication port. And a step of determining whether the measured frequency is greater than or equal to a predetermined value. If it is determined that the measured frequency is greater than or equal to a predetermined value, the data processing unit enters the power saving mode. And a procedure for prohibiting the transition.

The storage medium according to claim 18 is a storage medium which is executed by a CPU in a data communication apparatus and stores a program for performing data communication with a communication partner, wherein the program detects the state of the communication. And, if it is determined based on the detected state of the communication that data is not transmitted from the communication partner, a step of transitioning to the power saving mode with the communication held. .

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a data communication device, a method and a storage medium according to the present invention will be described.

[First Embodiment] The data communication apparatus according to the first embodiment is applied to an information processing apparatus to which a modem is connected. FIG. 1 is a block diagram illustrating the configuration of the information processing apparatus according to the first embodiment. In the figure, reference numeral 1 denotes a serial port control module for controlling a serial port to which a modem is connected, and causes the CPU 3 to generate an interrupt when an input is made from the end of the serial port.

Reference numeral 2 denotes a timer module for periodically generating an interrupt for the CPU 3. Reference numeral 3 denotes a CPU that controls the entire apparatus, has a power saving mode and a normal mode, and returns to the normal mode when an interrupt occurs during the power saving mode. Reference numeral 4 denotes a modem connected to a serial port, which is connected to an external communication line (not shown).

The operation of the information processing apparatus having the above configuration will be described. FIG. 2 is a flowchart showing the communication mode control processing procedure. This processing program is executed by the CPU 3
And is executed by the CPU 3.

First, when the present apparatus starts using the modem 4, that is, when the communication is started, the reference time is set to the current time (step 1). The CPU 3 has a data input interrupt from the serial port control module 1, an interrupt from the timer module 2, and a data output request to the serial port requested by the CPU 3 itself (Step S).
2). If any of these three events has occurred, the process moves to step S3.

It is determined whether a data input from the serial port control module 1 or a data output request from the CPU 3 has occurred (step S3). If data input / output has occurred, input / output processing is performed (step S4). Then, the reference time is reset to the current time (step S
5), the process returns to step S2.

On the other hand, if no data input / output has occurred in step S3, the current time is compared with the reference time to determine whether or not a predetermined time has elapsed (step S6). If the predetermined time has not elapsed, step S
It returns to the process of 2. On the other hand, when it is determined that the certain time has elapsed, the CPU 3 shifts to the power saving mode (step S7).

During the operation in the power saving mode, the data input interrupt from the serial port control module 1 or the CPU 3
It is determined whether or not the data output request has been issued (step S8). If not, the process of step S8 is repeated, and if a data input interrupt from the serial port control module 1 or a data output request of the CPU 3 occurs, the CPU 3 shifts to the normal mode (step S9). After that, the processing shifts to the processing of step S4.

As described above, during communication through the serial port,
Even if there is no data input / output temporarily, effective power saving measures can be realized without terminating communication.

[Second Embodiment] The data communication apparatus according to the second embodiment is applied to an information processing apparatus to which a modem is connected, as in the first embodiment.

FIG. 3 is a block diagram showing the configuration of the information processing apparatus according to the second embodiment. In the figure, reference numeral 11 denotes a serial port control module for controlling a serial port to which a modem is connected, and causes the CPU 12 to generate an interrupt when data is input from the end of the serial port.

Reference numeral 12 denotes a CPU for controlling the entire apparatus, which has a power saving mode and a normal mode, and returns to the normal mode when an interrupt occurs during the power saving mode. 13 is C
The memory is readable and writable by the PU 12. Memory 1
3, there are three areas named variables oc, ob, and sa. Reference numeral 14 denotes a modem connected to a serial port, which is connected to an external communication line (not shown).

The communication processing operation of the information processing apparatus having the above configuration will be described. FIG. 4 is a flowchart showing a communication processing procedure. This processing program is stored in a ROM (not shown) in the CPU 12 and is executed by the CPU 12. When this apparatus starts communication using a modem, it first establishes a connection with a communication partner.

Then, it is determined whether the current communication is the first communication or whether there is a possibility that the communication speed has changed from the previous communication (step S11). If this is the first communication, or if there is a possibility that the communication speed has changed, a value 0 is set to a variable oc for measuring the number of overrun errors, and the number of bytes of normally input data is measured. The variable is initialized by substituting the value 1 for the variable bc for use (step S12).

The CPU 12 receives an input from a serial port,
That is, it waits for an input interrupt from the serial port control module 11 (step S13). Here, when there is no other task to be executed in the CPU 12, an idle state process described later is performed. On the other hand, in step S13, the modem 14
When there is data input from the CPU, the serial port control module 11 generates an interrupt to the CPU 12, and shifts to the processing of step S14. At this time, if the CPU 12 is in the power saving mode, the process proceeds to step S14 after the return to the normal mode is completed.

It is determined whether or not an overrun error has occurred, that is, whether or not the return from the power saving mode to the normal mode was in time for an input interrupt from the serial port control module 11 (step S14). When an overrun error has occurred, the variable oc is set to the value 1
Is added (step S15). Then, the equation (oc / b)
It is determined whether the value of c) is smaller than the constant LRATIO (step S16). Here, the constant LRATIO is a limit value of the ratio of the overrun error to the number of normal input bytes. If the rate of the overrun error is equal to or greater than this value, it is determined that it is inappropriate to make a transition to the power saving mode during an input interrupt from the serial port control module 11, and a constant NO is substituted for the variable sa (step S
17). On the other hand, if the ratio of the overrun error is smaller than the constant LRATIO in step S16, the process directly proceeds to step S18.

Then, error processing of an overrun error is performed (step S18). Thereafter, the process returns to step S13 and waits for the next input.

On the other hand, if no overrun error has occurred in step S14, that is, if the input processing has been normally performed, the value 1 is added to the variable bc for counting the number of normal input bytes (step S19), and the data is input. Processing is performed (step S20).

Further, as described above, if there is no other task to be executed in the input interrupt waiting process in step S13, the idle state process is performed. FIG. 5 is a flowchart showing the processing procedure in the idle state. First,
With reference to the value of the variable sa indicating whether or not the transition to the power saving mode is possible, it is determined whether or not the constant is YES (step S21).

If the answer is YES, the mode shifts to the power saving mode (step S22). On the other hand, if the value of the variable sa is other than the constant YES, the idle state is maintained in the normal mode without transition to the power saving mode (step S2).
3).

FIG. 6 is a flowchart showing a communication termination processing procedure. This processing program is executed by the RO in the CPU 12.
M (not shown) and is executed by the CPU 12. When terminating the communication, the communication is disconnected (step S31), a constant YES is substituted for the variable sa, and the transition to the power saving mode is permitted (step S32).

As described above, it is possible to perform appropriate power saving according to the communication speed and the performance of the processor by determining whether or not to shift to the power saving mode during communication through the serial port at the time of communication.

[Third Embodiment] The data communication apparatus according to the third embodiment makes a transition to a power saving mode using a timeout caused by packet communication. FIG. 7 is a block diagram illustrating a configuration of a data communication device according to the third embodiment. In the figure, 101 is a CPU, 102 is a ROM for storing programs and the like, 103 is a RAM, 104 is a communication device, 105 is a timer, 106 is an input device serving as an interface with a user, 107 is a bus, and 108 is a communication line. is there.

The RAM 103 has a reception buffer (RBuf) 111 for storing data received from the communication partner, and a transmission buffer (SB) for storing data to be transmitted to the communication partner.
uf) 112, a response time area (RT) 113 storing an average response time, and an active flag (AF)
114 are provided.

The communication device 104 performs a process of outputting data of the RAM 103 to the communication line 108 under the control of the CPU 101 or notifying the CPU 101 by generating an interrupt when data comes from a communication partner. here,
The communication device 104 may have a function of transferring data to the RAM 103 by itself, or the CPU 101
3 may be performed.

After the set time has elapsed, the timer 105
It comprises a down counter for generating an interrupt to the PU 101 and the like. When the CPU 101 has a built-in timer and can operate in the power saving mode, the built-in timer may be used instead of the timer 105.

FIG. 8 is a flowchart showing a communication processing procedure. This processing program is stored in the ROM 102 and is executed by the CPU 101. Step S
In the processing of 201 to S203, the event is checked, and this is a part corresponding to step S1001 in FIG. 12 described above. Here, for simplicity, data transmission (step S201) and data reception (step S20)
2), and three events of timeout (step S203) are handled.

The transmission event is generated, for example, based on a factor input by the user to the input device 106. And
The data in the transmission buffer (SBuf) 112 is packetized according to the communication protocol (step S204),
The timer 105 is set (Step S205). TC
In a protocol that requires an acknowledgment such as P / IP, a response packet for a transmitted packet is sent from the other party. However, in order to determine that the packet has not been sent, the timer 105 used. The timeout period is determined based on the response time, taking into account the number of retransmissions and the like. When the time-out period is determined, the response time from the communicating partner is always measured, and the average value is updated as needed. In this embodiment, the average response time is stored in the RT 113 of the RAM 103.
To be stored.

Then, the communication device 104 actually sends out the packet on the communication line 108 (step S206).
When further processing is required for packet transmission, for example, when data of the transmission buffer (SBuf) 112 is transmitted in a plurality of packets, a new event is generated (step S209), and the processing is continued.

In the reception event, when data arrives from the communication line 108, the communication device 104 sends an interrupt signal to the CPU 101. In the reception interrupt routine, after data from a register inside the communication device 104 is stored in the reception buffer (RBuf) 111, a reception event is generated.

When the reception event is confirmed (step S
202) First, the packet processing of the reception buffer (Rbuf) 111 is performed (step S207). For example, if the packet has data, the packet is re-formed so that the data portion remains in the buffer. If an acknowledgment is included, processing such as changing the communication state is performed. If the received packet is an acknowledgment for the transmitted packet, the timer 105 is released (step S208).
Then, for example, when data is received from the other party, a transmission event is newly generated to transmit an acknowledgment (step S209), and the process returns to step S201.

In the timeout event, step S2
When the timer set in 05 has timed out, the timer 105 generates an interrupt signal to the CPU 101. In the timeout interrupt process, a timeout event is generated.

When the timeout event is confirmed (step S203), the previously transmitted packet is retransmitted (step S210). The timer 105 is set for timeout of the acknowledgment of the packet retransmitted this time (step S211). Thereafter, a command for transitioning to the power saving mode is issued to the CPU 101, and the CPU 101
Is shifted to the power saving mode and stopped.

As described above, while the data transfer can be executed without delay, the CPU 101 is not set to the power saving mode, and the processing can be performed immediately even if a packet is received from a communication partner and an interrupt is applied at any time. On the other hand, if the timer 105 waiting for an acknowledgment times out and retransmits the packet, the packet is not likely to come from the communication partner for the time being, and there is a very high possibility that no interrupt will be issued. Therefore, the CPU 101 is switched to the power saving mode to save power.

[Fourth Embodiment] Depending on the communication protocol, if data is continuously transmitted and the receiving buffer of the communication partner becomes full, a packet indicating that data cannot be received from the communication partner is transmitted from the communication partner. There are protocols that are coming. TCP / IP and the like correspond to this. When such a packet is transmitted, the packet is not to be transmitted here for a certain period of time, and it is expected that no packet will come from a communication partner for a certain period. Therefore, in such a situation, it is advisable to set the CPU in the power saving mode, and a data communication device that performs such processing will be described as a fourth embodiment.

FIG. 9 is a flowchart showing a communication processing procedure according to the fourth embodiment. Compared to the third embodiment, a step process is newly added to the process at the time of the reception event in the flowchart of FIG. The same step numbers as in FIG. 8 denote the same step processes, and a description thereof will be omitted.

After processing the packet in step S207, it is determined whether or not the packet is a transmission interruption request packet (step S207A). If the packet is a transmission interruption request packet, the transmission mode is changed so that the temporary data packet is not transferred even if there is data to be transmitted (step S208A), the set timer 105 is released, and a new Is set to the timer 105 (step S208B). When the other party's processing advances and the buffer becomes available, a packet instructing to resume data transmission is to be sent. It is set according to the case not to do.

When the timer 105 times out, a packet is sent from this side so as to notify the status of the buffer of the communication partner. After setting the timer 105, the CPU 101 is changed to the power saving mode (step S208C), and the execution of the instruction is stopped. When a packet arrives from a communication partner or when the timer 105 times out, the CPU 101 returns to the normal mode.

[Fifth Embodiment] In the third and fourth embodiments, a one-to-one communication connection has been described. However, a communication partner of a different host computer or a communication partner of the same host computer is usually used. However, it is not unusual to make a plurality of connections and simultaneously transmit and receive independent data. The fifth embodiment shows a case where a plurality of connections are made.

In the active flag (AF) 114 in the RAM 103 shown in FIG. 7, each bit corresponds to the state of each connection being connected. At the time of device startup, all bits have the value 0. When a new connection is established with the communication partner, the corresponding bit is set from value 0 to value 1. Before receiving an event in the event loop and starting processing, the bit of the connection related to the event is set to a value of 1.

Specifically, the value is set to 1 by packet generation in step S204, packet processing in step S207, and packet retransmission in step S210.

The connection being processed is the CPU 10
When it becomes possible to change 1 to the power saving mode, the bit of the connection is set to the value 0. Specifically, when the CPU 101 enters the sleep state in step S212 in FIG. 8, the CPU 101 in step S208C in FIG.
Is in the sleep state. In the present embodiment, whether or not to actually transition to the power saving mode depends on the value of the active flag (AF) 114.

That is, steps S212 and S208C
The reason that the CPU 101 can actually transition to the power saving mode is
Only when all the bits of the active flag 114 are 0. If any of the bits has the value 1, there is an active communication connection, so that the CPU 101 does not transition to the power saving mode and continues the processing.

As described above, even when communication is performed through a plurality of connections, it is possible to appropriately transition to the power saving mode.

[Sixth Embodiment] FIG. 10 is a block diagram showing a configuration of a data communication apparatus according to a sixth embodiment. In the present embodiment, the CPU 101 has a function of executing the change between the normal mode and the power saving mode by a control (control) line instead of the instruction of the CPU.

The communication device 403 differs from the communication device 403 of the third embodiment in that the communication device 403 itself has the ability to execute control of a higher-level communication protocol controlled by the CPU 101 by hardware. Has become. That is, it has a function using a timer for processing packets, retransmitting packets, stopping transmission, and the like shown in the flowcharts of FIGS. 8 and 9.

In FIG. 8, reference numeral 401 denotes a register for storing a communication state. In the register 401, when communication is normally performed, a timer for retransmission times out as shown in FIG. When it enters, as shown in FIG. 9, a bit pattern or the like for distinguishing a case where there is a transmission interruption request from a communication partner is stored.

Reference numeral 402 denotes a control line for controlling the power saving mode of the CPU 101.
, The CPU 101 switches whether to shift to the power saving mode.

When the communication device 403 starts executing communication, the communication device 403 changes the register 401 indicating the communication status according to the communication state. When the communication status becomes a retransmission state or a transmission interruption state, via the control line 402,
The CPU 101 is shifted to the power saving mode.

As described above, the control line 402 depends on the communication state.
Can be used to effectively change the CPU 101 to the power saving mode.

In the above embodiment, the change of the CPU to the power saving mode has been described. However, the present invention can be easily applied to a case where peripheral devices other than the CPU have similar functions. .

The present invention may be applied to a system constituted by a plurality of devices, or may be applied to an apparatus constituted by a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. In this case, by reading out a storage medium storing a program represented by software for achieving the present invention into a system or an apparatus, the system or the apparatus can enjoy the effects of the present invention.

FIG. 11 is a diagram showing a memory map of a ROM as a storage medium. The ROM shown in FIG.
The communication mode control processing module shown in the flowchart of FIG. 2 is stored. The ROM illustrated in FIG. 11B includes the communication processing module illustrated in the flowchart of FIG.
The processing module in the idle state shown in the flowchart of FIG. 5 and the communication termination processing module shown in the flowchart of FIG. 6 are stored. ROM 10 shown in FIG.
2, a communication processing module shown in the flowchart of FIG. 8, a communication processing module shown in the flowchart of FIG. 9, and the like are stored.

The storage medium is not limited to ROM, but may be, for example, a floppy disk, hard disk, optical disk,
A magneto-optical disk, a CD-ROM, a CD-R, a DVD, a magnetic tape, a nonvolatile memory card, or the like can be used.

[0092]

According to the data communication apparatus of the first aspect of the present invention, the non-communication time during which the communication is not performed is measured by the time measuring means, and the measured non-communication time is measured by the time determining means. It is determined whether or not exceeds a predetermined time, and if the measured no-communication time exceeds a predetermined time, the data processing means transitions to the power saving mode. When the processor is in the power saving mode when there is no data input / output, and when the data is input / output again, the processor goes into the normal mode and continues the communication, thereby performing effective power saving without terminating the communication. Can be. The same effect can be obtained in the data communication method according to the thirteenth aspect and the storage medium according to the sixteenth aspect.

[0093] According to the data communication apparatus of the second aspect, there is provided communication control means for controlling a communication port, and when data is input from the communication port during the power saving mode, the data processing means is normally operated. Since the mode is restored, data transmission / reception can be performed without hindering communication.

According to the data communication device of the third aspect, the frequency measuring means measures the frequency of an overrun error of the data input to the communication port, and when the measured frequency is equal to or more than a predetermined value, Since the transition to the power saving mode is prohibited by the transition prohibiting means, the frequency of the serial port overrun is measured, and based on the frequency, it is determined whether or not the transition to the power saving mode may be performed during the serial port input processing. By determining at the time of communication, appropriate power saving can be performed without depending on the performance and communication speed of the processor within a range where data is not lost. Claim 14
The same effect can be obtained with the data communication method described in the item (1) and the storage medium described in the item (17).

According to the data communication device of the present invention, since the transition prohibition unit prohibits at the time of communication, it is possible to perform power saving corresponding to the situation at the time of communication.

According to the data communication device of the fifth aspect, the transition to the power saving mode is permitted at the end of the communication, so that power saving other than during communication can be effectively performed.

According to the data communication apparatus of the present invention, since the communication port is a serial port, power can be saved when communication is performed using a modem connected to the serial port.

According to the data communication device of the present invention, the communication state detecting means detects the state of the communication,
When it is determined that data is not transmitted from the communication partner based on the detected communication state, the mode control unit transitions to the power saving mode in a state where the communication is held. A power saving can be realized while avoiding a transition and minimizing data loss in returning from the power saving mode to the normal mode.

This enables the mode to be switched in accordance with the actual use state of the CPU by changing the CPU to the power saving mode depending on the communication state. In the communication processing, it is possible to predict to some extent that a reception interrupt will not occur depending on the state. Therefore, when the communication is suspended, the CPU is shifted to the power saving mode. In particular, TCP
Since higher-level protocols such as / IP have various functions such as measurement of the response time with the other party and retransmission when the response time expires, there are elements that can determine whether the current communication is active or not. Yes, it is effective.

Also, despite the possibility that the CPU must operate immediately, the mode transits to the power saving mode, and the data is carelessly stored due to the rise delay when the processing of the reception interrupt returns to the normal mode. Loss can be avoided. When data transmission and reception are performed without interruption, it is guaranteed that the CPU does not transition to the power saving mode. Therefore, the CPU appropriately reflects at least the communication state in which the loss does not occur continuously.
Can be switched to the power saving mode, the adverse effects of the mode switching can be minimized, and effective power saving can be realized. The same effect can be obtained in the data communication method described in claim 15 and the storage medium described in claim 18.

According to the data communication apparatus of the present invention, since the communication state detecting means detects a state in which the response from the communication partner has timed out, the data transfer can be executed without delay. In the meantime, the CPU is not set to the power saving mode, and even if a packet from the communication partner comes at any time and an interrupt occurs, it can be processed immediately. In the event of a situation, it is very likely that no packet will come from the communication partner for the time being and no interrupt will be taken, so it is worthwhile putting the CPU to sleep,
The CPU can transition to the power saving mode to save power.

According to the data communication device of the ninth aspect, the communication state detecting means detects a state in which a transmission interruption request is received from the communication partner. Subsequently, there is a protocol in which when the reception buffer of the communication partner becomes full, a packet indicating that data from the communication partner cannot be received is transmitted from the partner. When a packet such as TCP / IP is transmitted, the packet is not transmitted from the packet for a certain period of time, and it is expected that the packet will not come from the communication partner for a certain period. Power saving can be performed during this period.

According to the tenth aspect of the present invention, the mode control means transitions to the power saving mode by a logical product of a plurality of connected states, so that communication through a plurality of connections is performed. Even when the power saving mode is set, the transition to the power saving mode can be appropriately realized.

According to the data communication device of the eleventh aspect, the mode control means executes the transition to the power saving mode via the control line, so that the CPU can effectively use the control line depending on the communication state. It is possible to change to the power saving mode.

According to the data communication device of the twelfth aspect, since at least a part of the central processing unit and the peripheral circuits transition to the power saving mode, the central processing unit (CPU)
The present invention is not limited to this, and a further power saving effect can be expected by applying to peripheral circuits.

According to the storage medium of the present invention, in the storage medium storing the program executed by the CPU in the data communication device, the program measures a non-communication time during which no communication is performed. A procedure for determining whether or not the measured no-communication time exceeds a predetermined time; and a data for processing data transferred by the communication when the measured no-communication time exceeds a predetermined time. Since the procedure includes a procedure for shifting the processing unit to the power saving mode, the expandability and versatility of the data communication device can be improved. The same effect can be obtained in the storage medium according to the seventeenth and eighteenth aspects.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an information processing apparatus according to a first embodiment.

FIG. 2 is a flowchart illustrating a communication mode control process procedure;

FIG. 3 is a block diagram illustrating a configuration of an information processing apparatus according to a second embodiment.

FIG. 4 is a flowchart illustrating a communication processing procedure.

FIG. 5 is a flowchart showing a processing procedure in an idle state.

FIG. 6 is a flowchart illustrating a communication end processing procedure;

FIG. 7 is a block diagram illustrating a configuration of a data communication device according to a third embodiment.

FIG. 8 is a flowchart illustrating a communication processing procedure.

FIG. 9 is a flowchart illustrating a communication processing procedure according to a fourth embodiment.

FIG. 10 is a block diagram illustrating a configuration of a data communication device according to a sixth embodiment.

FIG. 11 is a diagram showing a memory map of a ROM as a storage medium.

FIG. 12 is a flowchart showing a conventional communication processing procedure.

[Explanation of symbols]

 1, 11 Serial port control module 2, 105 Timer (module) 3, 12, 101 CPU 4, 14 Modem 13 Memory 102 ROM 103 RAM 104, 403 Communication device 401 Register

Claims (18)

[Claims] 1. A data processing unit having a power saving mode for processing data transferred by communication, a time measuring unit for measuring a non-communication time during which the communication is not performed, and a measured non-communication time. Data communication means for determining whether or not a predetermined time has been exceeded, wherein the data processing means transitions to the power saving mode when the measured no-communication time exceeds a predetermined time. apparatus. 2. A communication control means for controlling a communication port, wherein, when data is input from the communication port during the power saving mode, the data processing means returns to a normal mode. 2. The data communication device according to 1. 3. A communication control means for controlling a communication port, a data processing means capable of transitioning to a power saving mode for returning to a normal mode by an interrupt from the communication control means and processing data received by communication, A frequency measuring unit for measuring a frequency of an overrun error of data input to the communication port; and a transition prohibiting unit for prohibiting a transition to the power saving mode when the measured frequency is a predetermined value or more. A data communication device characterized by the above-mentioned. 4. The data communication apparatus according to claim 3, wherein said transition prohibition means prohibits at the time of communication. 5. The data communication device according to claim 3, wherein a transition to the power saving mode is permitted when the communication ends. 6. The data communication device according to claim 2, wherein said communication port is a serial port. 7. A data communication apparatus for performing data communication with a communication partner, comprising: a communication state detection unit for detecting the communication state; and based on the detected communication state, if data is not transmitted from the communication partner. A data control device that, when determined, shifts to a power saving mode in a state where the communication is held. 8. The data communication apparatus according to claim 7, wherein said communication state detecting means detects a state in which a response from said communication partner has timed out. 9. The data communication apparatus according to claim 7, wherein said communication state detection means detects a state in which a transmission interruption request is received from said communication partner. 10. The data communication apparatus according to claim 7, wherein said mode control means transitions to said power saving mode by a logical product of a plurality of connected states. 11. The data communication apparatus according to claim 7, wherein said mode control means executes a transition to said power saving mode via a control line. 12. The data communication device according to claim 7, wherein at least a part of the central processing unit and peripheral circuits transition to a power saving mode. 13. A step of measuring a non-communication time during which communication is not performed; a step of determining whether or not the measured non-communication time exceeds a predetermined time; Transiting the data processing means for processing the data transferred by the communication to a power saving mode when the time is exceeded. 14. A step of measuring a frequency of an overrun error of data input to a communication port; a step of determining whether or not the measured frequency is equal to or more than a predetermined value; Prohibiting a transition of the data processing means to the power saving mode when it is determined that the value is equal to or greater than the value. 15. When performing data communication with a communication partner, detecting a state of the communication; and determining that data is not transmitted from the communication partner based on the detected communication state. Transiting to a power saving mode while communication is maintained. 16. A storage medium storing a program executed by a CPU in a data communication device, the program comprising: a procedure for measuring a non-communication time during which communication is not performed; A procedure for determining whether or not a predetermined time has elapsed; and a procedure for, when the measured non-communication time exceeds a predetermined time, transitioning a data processing unit that processes data transferred by the communication to a power saving mode. A storage medium characterized by including: 17. A storage medium storing a program executed by a CPU in a data communication device, the program comprising: a procedure for measuring a frequency of an overrun error of data input to a communication port; A procedure for determining whether or not the frequency is equal to or more than a predetermined value; and a procedure for prohibiting the data processing unit from transitioning to the power saving mode when the measured frequency is determined to be equal to or more than the predetermined value. A storage medium characterized by including. 18. A storage medium stored with a program executed by a CPU in a data communication device for communicating data with a communication partner, the program comprising: a procedure for detecting a state of the communication; When it is determined based on a communication state that data is not transmitted from the communication partner, a procedure of transitioning to a power saving mode while the communication is maintained.