JP2007164511A - Communication apparatus and received data notification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus and a received data notification method by which a time needed for an interruption processing in the processing of the received data. <P>SOLUTION: The communication apparatus includes: a detection means for detecting a use capacity of a reception memory; and an interruption manager for comparing a pre-set threshold for the use capacity of the reception memory with the use capacity for the reception memory to notify that the data are received by an interruption signal when the threshold of the use capacity of the reception memory is larger; and a data write means for writing the received data to the reception memory on the basis of the interruption signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for data communication, and more particularly to a communication apparatus and a received data notification method for receiving data via a communication network.

  In the reception process of the communication device that performs communication via the communication network, if continuous data reception continues, the CPU processing capacity is reached and the received data cannot be processed. In particular, when a PC equipped with a high-performance CPU and an embedded device equipped with a CPU with low processing capability communicate with each other, the processing of received data is not in time on the embedded device side.

  In such a case, data that cannot be processed in time is discarded. Thereafter, the embedded device executes a retransmission request according to the network protocol.

  In order to reduce the load of reception processing, there is a method of transferring data from a network device to a reception memory area using DMA (for example, see Patent Document 1).

  This method of transferring data has the system configuration shown in FIG. Reference numeral 13 in FIG. 1 denotes a DMA control unit, which is configured as shown in FIG.

  Processing in this system will be described.

  Register the reception memory area of the host memory on the host system where the received data is DMA transferred in advance, and when the network device receives the data, start the DMA transfer of the received data to the reception memory area for which registration is valid When the DMA transfer ends, the network device notifies the host system of the end of the DMA transfer using an interrupt, and the host system executes processing corresponding to the interrupt based on the notified interrupt.

According to this system, it is possible to suppress the number of occurrences of interrupts when the received data is transferred to the memory on the host system using the DMA transfer method.
JP-A-2005-222281

  However, the background art described above has the following problems.

  In the system described above, the host memory buffer manager executes DMA transfer when the host memory is free and there is data received from the network.

  Thus, for example, even if the host system is not in time for processing received data, when the DMA transfer is performed and the DMA transfer ends, the network device notifies the host system of the completion of the DMA transfer using an interrupt. To do.

  Here, the processing when the interrupt processing is performed will be described with reference to FIG.

  In the CPU, normal processing is performed. When an interrupt occurs, the CPU performs interrupt processing, and resumes normal processing after the interrupt processing is completed.

  When the interruption is performed, the CPU saves the processing state in the normal processing (step S302).

  Next, the CPU prepares for execution of interrupt processing (step S304).

  Next, the CPU performs an interrupt process (step S306).

  Next, the CPU performs interrupt termination processing (step S308).

  Next, the process is restored to the stored processing state (step S310).

  The processing as described above is performed by interrupting the completion of the DMA transfer. For this reason, it becomes a cause which delays a process further.

  Further, since an interrupt is generated every time transfer by the DMA transfer method is completed, there is a problem that the time required for interrupt processing increases while the reception memory is empty.

  Further, since this technique is premised on the use of the DMA transfer method, it cannot be applied to a system that is not equipped with a device that performs DMA transfer.

  Accordingly, the present invention has been made to solve at least one of the above-described problems, and an object of the present invention is to provide a communication device and a reception device that can reduce the time required for interrupt processing in received data processing. The object is to provide a data notification method.

  In order to solve the above-described problem, a communication device according to the present invention includes a detecting unit that detects a used capacity of a receiving memory, a threshold value for the used capacity of the receiving memory, and a used capacity of the receiving memory. In comparison, when the threshold of the used capacity of the reception memory is larger, an interrupt manager for notifying that data has been received by an interrupt signal, and receiving the received data based on the interrupt signal One of the features is that it comprises a data writing means for writing to the main memory.

  With this configuration, when the threshold of the used capacity of the receiving memory is larger than the used capacity of the receiving memory, that is, when there is room in the processing of the CPU, the received data can be processed quickly by interruption. Can do.

  In addition, the received data notification method according to the present invention includes a threshold setting step for setting a threshold for the used capacity of the receiving memory, a used capacity detecting step for detecting the used capacity of the receiving memory, and a used capacity of the receiving memory. A comparison step for comparing the threshold value of the received memory with the used capacity of the reception memory, and an interrupt step for notifying that data has been received by an interrupt signal when the threshold value of the used capacity of the receiving memory is larger And a data writing step of writing the received data into the reception memory based on the interrupt signal.

  In this way, when the threshold of the used capacity of the receiving memory is larger than the used capacity of the receiving memory, that is, when there is a margin in the processing of the CPU, the received data can be processed quickly by interruption. it can.

  According to the embodiment of the present invention, it is possible to realize a communication device and a received data notification method that can reduce the time required for interrupt processing in received data processing.

  Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings.

  In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

  A communication apparatus according to an embodiment of the present invention will be described with reference to FIG.

  The communication apparatus 100 according to the present embodiment is mounted on, for example, an embedded device. The communication apparatus 100 outputs a network device 102 to which data is input from the network, an interrupt controller 114 to which an interrupt signal is input from the network device 102, a storage unit 116 connected to the network device 102, and the network device 102. A receiving memory 110 to which received data is input, and a CPU 112 as a detecting means and a data writing means to which an interrupt signal output from the interrupt controller 114 is input. The CPU 112 inputs / outputs data to / from the reception memory 110. The CPU 112 is connected to the storage unit 116.

  The network device 102 receives a signal converter 104 to which data from the network is input, a device buffer 108 to which data output from the signal converter 104 is input, and a reception notification signal output from the signal converter 104. The interrupt manager 106 is provided. The device buffer 108 outputs data to the reception memory 110. Further, the interrupt manager 106 outputs an interrupt signal to the interrupt controller 114 and stores information indicating the status in the storage unit 116.

  Data transmitted from the network is input to the signal converter 104 and signal conversion is performed. The signal converter 104 inputs data to the device buffer 108. The signal converter 104 also notifies the interrupt manager 106 that data has been received (reception notification).

  The CPU 112 stores a threshold value of the used capacity of the reception memory 110 for switching the reception data notification method in the storage unit 116 in advance. For example, the CPU 112 sets the used capacity as a threshold of the used capacity of the reception memory 110 when other data, such as received data processing, is not in time when notified that data has been received by interruption.

  Further, the CPU 112 detects the used capacity of the reception memory 110 and stores the used capacity in the storage unit 116.

  The interrupt manager 106 refers to the used capacity threshold of the receiving memory 110 and the used capacity of the receiving memory 110 stored in the storage unit 116, and determines the used capacity of the receiving memory 110 and the used capacity threshold. Compare.

  The interrupt manager 106 inputs an interrupt signal to the interrupt controller 114 when the used capacity of the receiving memory 110 is equal to or less than the used capacity threshold of the receiving memory 110. The interrupt controller 114 interrupts the CPU 112 according to the input interrupt signal. The CPU writes the data written in the device buffer 108 into the reception memory 110 in accordance with the interrupt from the interrupt controller 114. When the CPU finishes writing to the receiving memory 110, the CPU detects the used capacity of the receiving memory 110 and writes the used capacity to the storage unit 116.

  On the other hand, when the usage capacity of the reception memory 110 is equal to or greater than the threshold value of the usage capacity of the reception memory 110, the interrupt manager 106 writes a status indicating that reception data has been received in the storage unit 116.

  The CPU 112 refers to the status written in the storage unit 116 after the processing of the received data, for example, the processing of the network protocol is completed. When the status indicating that there is received data is written in the storage unit 116, the CPU clears the status and writes the data written in the device buffer 108 into the receiving memory 110. When the CPU finishes writing to the receiving memory 110, the CPU detects the used capacity of the receiving memory 110 and writes the used capacity to the storage unit 116.

  As described above, in the communication apparatus 100 according to the present embodiment, the interrupt manager 106 sends an interrupt signal to the interrupt controller 114 at the normal time, for example, when the usage amount of the reception memory 110 is equal to or less than a certain value (threshold). input. The interrupt controller 114 inputs an interrupt signal to the CPU 112. That is, during normal times, the CPU 112 is notified that there is received data by an interrupt signal.

  On the other hand, in a case other than the normal time, for example, when the usage amount of the reception memory 110 is a certain value or more, the interrupt manager 106 writes the status in the storage unit 116. For example, the interrupt manager 106 writes information indicating that there is received data in the storage unit 116. The CPU 112 refers to the status stored in the storage unit 116 and determines whether there is received data. Since the storage unit 116 is arranged in the shared area, it can be accessed from the CPU 112 and the interrupt manager 106. That is, in a case other than the normal time, the status is written in the storage unit 116 to notify that there is received data.

  After that, when returning to normal time, for example, when the usage amount of the reception memory 110 becomes a certain value or less, the interrupt manager 106 notifies the presence of received data by inputting an interrupt signal to the interrupt controller 114. To do. The interrupt controller 114 interrupts the CPU 112 according to the input interrupt signal. The CPU 112 writes the data written in the device buffer 108 into the reception memory 110 in accordance with the interrupt from the interrupt controller 114.

  An increase in the amount of use of the reception memory 110 means that processing on the received data of the CPU 112, for example, processing related to a network protocol or the like is not in time. In such a situation, when an interrupt is performed, the interrupt processing itself becomes a heavy load, causing the CPU 112 to delay processing.

  In the communication apparatus 100 according to the present embodiment, the interrupt process itself is omitted. That is, a threshold is provided for the usage amount of the reception memory 110, and when the memory usage amount exceeds the threshold value, interruption is prohibited and the status notification is switched. By doing so, it is possible to avoid as much as possible that the amount of use of the reception memory 110 becomes full and data cannot be received.

  Next, processing in the CPU 112 of the communication apparatus 100 according to the present embodiment will be described with reference to FIGS.

  Here, the processing of the CPU 112 will be described separately for initialization processing, writing processing, and reading processing.

  First, the initialization process will be described with reference to FIG.

  For example, when the power of the communication apparatus 100 is turned on, the CPU 112 sets, in the storage unit 116, a threshold value for the used capacity of the reception memory 110 that switches from notification by interruption to notification by status (step S502).

  Next, the writing process will be described with reference to FIG.

  The CPU 112 determines whether or not an interrupt signal has been input from the interrupt controller 114, that is, whether or not an interrupt has been performed (step S602).

  If no interrupt signal is input, that is, if no interrupt is made (step S602: NO), the process returns to step S602.

  On the other hand, when an interrupt signal is input, that is, when an interrupt is performed (step S602: YES), the CPU 112 stores the data stored in the device buffer 108 in the reception memory 110 (step S604).

  Next, the CPU 112 detects the used capacity of the reception memory 110 and writes the used capacity in the storage unit 116 (step S606). Thereafter, the process returns to step S602.

  Next, the reading process will be described with reference to FIG.

  The CPU 112 reads data stored in the reception memory 110 (step S702).

  Next, the CPU 112 detects the used capacity of the reception memory 110 and writes the used capacity in the storage unit 116 (step S704).

  Next, the CPU 112 determines whether a status indicating that there is received data is written in the storage unit 116 (step S706). Here, the CPU 112 clears the referred status.

  When a status indicating that there is received data is written (step S706: YES), the CPU 112 refers to the used capacity of the receiving memory written in the storage unit 116 and can store it in the receiving memory 110. It is determined whether or not (step S708).

  When the data can be stored in the reception memory 110 (step S708: YES), the CPU 112 stores the data stored in the device buffer 108 in the reception memory 110.

  Next, the CPU 112 detects the used capacity of the reception memory 110 and writes the used amount in the storage unit 116 (step S712). Thereafter, the process returns to step S706.

  On the other hand, when there is no reception data (step S706: NO) and when the data cannot be stored in the reception memory 110 (step S708: NO), the process ends.

  Next, processing in the interrupt manager 106 of the communication apparatus 100 according to the present embodiment will be described with reference to FIG.

  The interrupt manager 106 determines whether or not a reception notification is input from the signal converter 104 (step S802).

  If no reception notification is input (step S802: NO), the process returns to step S802.

  On the other hand, when a reception notification is input (step S802: YES), the interrupt manager 106 refers to the used capacity of the receiving memory 110 written in the storage unit 116 and the threshold of the used capacity, and It is determined whether or not the used capacity is smaller than the used capacity threshold value, that is, whether or not the used amount of the receiving memory <the threshold value is satisfied (step S804).

  When the usage amount of the reception memory 110 is smaller than the threshold value, that is, when the usage amount of the reception memory is smaller than the threshold value (step S804: YES), the interrupt manager 106 inputs an interrupt signal to the interrupt controller 114 (step S806). . Thereafter, the process returns to step S802. As a result, an interrupt is performed from the interrupt controller 114 to the CPU 112.

  On the other hand, when the usage amount of the reception memory is larger than the threshold value, that is, when the usage amount of the reception memory> the threshold value (step S804: NO), the interrupt manager 106 indicates that the storage unit 116 has reception data. Is written (step S808). Thereafter, the process returns to step S802.

  According to the embodiment of the present invention, it is possible to save time for interrupt processing when processing of received data is not in time for newly received data. For this reason, it is possible to spend the maximum time for processing the received data.

  Further, when there is a margin in processing received data, the received data can be processed quickly by interrupting.

  The communication apparatus according to the present embodiment can be applied regardless of a communication medium, for example, a serial method, USB (registered trademark), Ethernet (registered trademark), or the like.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the specific embodiments described above, and various modifications and changes can be made within the scope described in the claims.

  The communication device and the received data notification method according to the present invention can be applied to an embedded device having a communication function.

It is a block diagram which shows the structure of a DMA transfer data receiving system. It is a block diagram which shows the structure of the DMA control part in the network device of a DMA transfer data receiving system. It is a flowchart which shows an interruption process. It is a block diagram which shows the communication process concerning one Example of this invention. It is a flowchart which shows operation | movement of the communication apparatus concerning one Example of this invention. It is a flowchart which shows operation | movement of the communication apparatus concerning one Example of this invention. It is a flowchart which shows operation | movement of the communication apparatus concerning one Example of this invention. It is a flowchart which shows operation | movement of the communication apparatus concerning one Example of this invention.

Explanation of symbols

100 Communication device

Claims (4)

Detection means for detecting the used capacity of the reception memory;
A comparison is made between a threshold value for the use capacity of the reception memory set in advance and the use capacity of the reception memory, and when the threshold value for the use capacity of the reception memory is larger, data is received by an interrupt signal. An interrupt manager to notify
A communication device comprising: data writing means for writing received data into the reception memory based on the interrupt signal. The communication device according to claim 1,
Storage means for storing a status indicating that data has been received;
The interrupt manager writes a status indicating that data is received to the storage means when the used capacity of the receiving memory is larger than the threshold of the used capacity of the receiving memory,
The data writing means refers to the storage means and writes the received data to the reception memory when a status indicating that data has been received is written. A threshold value setting step for setting a threshold value of the used capacity of the reception memory;
A used capacity detection step for detecting the used capacity of the receiving memory;
A comparison step of comparing a threshold value of the used capacity of the receiving memory with a used capacity of the receiving memory;
An interrupt step for notifying that data has been received by an interrupt signal when the threshold of the capacity used for the reception memory is larger;
A data writing step of writing received data to the reception memory based on the interrupt signal. The received data notification method according to claim 3,
A status writing step of writing a status indicating that the data has been received into a storage means for storing a status indicating that the data has been received when the use capacity of the reception memory is larger;
A received data notification method comprising: referring to the storage means and writing the received data to the reception memory when a status indicating that the data has been received is written.

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