JP2005130019A - Audio apparatus and communication control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio apparatus for precluding the possibility of noise production when a communication control bus such as the IEEE 1394 connected to the audio apparatus in operation is reset. <P>SOLUTION: The audio apparatus is included in a system wherein a plurality of electric devices 2 to 7 including audio signal output devices 3 to 6 interconnected by the communication control bus 1 make communication and when the communication control bus 1 is reset, the connection state of the electric devices 2 to 7 is updated, and the audio apparatus stores a figure related to the number of the electric devices 2 to 7 connected to the communication control bus 1 after the communication control bus 1 is reset, and is provided with an inhibit means for inhibiting an output of an audio signal when the communication control bus 1 is reset. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is included in a system in which a plurality of electrical devices connected via a communication control bus such as IEEE 1394 perform communication and the connection state of the electrical device is updated when the control bus is reset. The present invention relates to an audio device that receives a digital audio signal output from an audio signal output device such as a CD player and a radio, converts the digital audio signal into an analog signal, and outputs the analog audio signal, and a communication control system including the audio device.

  The IEEE 1394 standard is a serial bus standard for electrical equipment to exchange digital data, and is defined in terms of connector physical and electrical standards and basic signal exchange. Each electrical device is connected to a serial bus through one or more nodes which are communication units in IEEE1394. Each node is assigned an address (node ID), and communication in a time division packet switching system is performed at a transfer rate of 100, 200, or 400 Mbps.

  In IEEE 1394, there are two types of communication methods, isochronous transmission for real-time transmission and asynchronous transmission for normal (asynchronous) data transmission. Isochronous transmission can be used for real-time data such as moving picture and audio, and asynchronous transmission can be used for asynchronous data such as control commands and still images. IEEE 1394 allows data transmission between a plurality of devices such as a personal computer and an AV (Audio Visual) device. However, a network can be constructed using only home appliances such as an AV device without including a personal computer. Can be used for one-to-one connections.

  Node ID assignment is reset (bus reset) when a change occurs in the topology (node connection state), such as when a new node is connected to or removed from the serial bus. Is called. Node ID assignment is automatically performed by communication between nodes according to whether the other nodes connected to each node are one (leaf) or multiple (branches) (tree identification; tree-identify). One node selected in (1) is used as a root (Root), and other nodes are identified so as to identify a route connected to the branch.

  In the case of a device having a display, the type of electrical device sent from each node to which the node ID is assigned and the code for each type can be displayed on the display. The user can select an electric device based on the displayed type and the code for each type, and can control the selected electric device.

  The ID of the electrical equipment manufacturer is registered with the IEEE 1394 registration organization upon application (Company ID). The electrical equipment type is the node unique ID of each electrical equipment, and each electrical equipment has text data. . The number for each type of electrical equipment is set by the user using a dip switch.

  When the tree identification is completed, each node selects a physical-ID to be used in the address, and creates management information related to the bus connection for constructing a low-level output management and system topology (self-identification; self- identify). When the tree identification is completed, the counter (self-ID-count) for determining the node ID of each node is zero. In the self-identification, the route grants transmission permission to the port having the smallest number among the port (connection terminal) numbers allocated in advance, and sets all other ports to the reception state.

  The node of the port to which transmission permission is given transmits the self-ID packet shown in FIG. 4 to the root and all other ports by setting the current counter value 0 as its own node ID. When a node that has been granted transmission permission has a lower port (child port), the same operation as described above is performed, and the self-ID packet of the lower port node is sent to the root and all other ports. Send. The nodes of the root and all other ports count the received self-ID packets with a counter.

  When the node has three or less ports, the node transmits a self-ID packet shown in FIG. 4A. When the number of the ports is four or more, the node sends two to four self-ID packets shown in FIG. Transmit according to the number of ports. In FIG. 4, phy_ID (physical_ID) indicates the physical ID of the target, L (link_active) indicates power-on of the link and transaction layer, gap_cnt (gap_count) indicates the PHY_configuration.gap_count value, sp (PHY_SPEED) indicates a supported speed.

  del (PHY_DELAY) indicates the longest delay of the repeater, c (CONTENDER) indicates the bus or isochronous resource manager candidate, pwr (POWER_CLASS) indicates the power state, and p0-p2 (NPORT) indicates the port And i (initiated_reset) indicates that a reset has been issued. m (more_packets) indicates that the packet continues, n indicates the number of the concatenated packet, r and rsv indicate reservations, and pa-ph is the connection status of the parent and child of the port (up to p26) Indicates.

  When the self-recognition of the node that granted the transmission permission is completed, the route grants transmission permission to the port having the next smallest number, and thereafter grants transmission permission to the port in the order of the smallest port number. The node counts the received self-ID packets with a counter. Finally, the root node transmits its self-ID packet to all other ports, and self-identification ends. Thereafter, the bus is in an idle state for a certain period (arbitration reset gap), so that normal arbitration (arbitration for acquiring the right to use the bus) and packet communication can be performed.

In AV / C (Audio / video Control), an audio / video application layer of the IEEE1394 standard, if a bus reset occurs during audio sound output, the audio output state before the bus reset is maintained and the connection is made within 1 second. It is specified when the state is restored.
“TA Document 1999032 Clarification and Implementation Guideline for Isochronous Connection Management of IEC61883-1” Sponsored by 1394 Trade Association, Accepted for Release by 1394 Trade Association Board of Directors "Introduction to handling of isochronous communications by 1394" provided by the 1394 Diffusion Association Board of Directors Guarantee) “Introduction IEEE 1394 Standard” May 25, 2000, 2nd edition, 1st edition, Motohiko Inada, Technical Review Inc. "Application to IEEE 1394 AV equipment" January 28, 2000, first edition, first edition, supervised by Shinji Takada, Nikkan Kogyo Shimbun

  AV / C is specified as described above. For example, a bus reset occurs even when a CD player is removed from the system. However, an audio device that receives an audio signal from an audio signal output device such as a CD player, amplifies the audio signal, and outputs the amplified audio signal to a speaker is designed to be in a mute state (silent state) even when the audio signal output device is removed. Absent. Therefore, if the audio signal output device that outputs the audio signal is removed while audio is being output, the audio device will continue to be able to output the audio signal, and noise may be generated for a while. There is a problem of having sex.

  The present invention has been made in view of the above-described circumstances, and an audio device that does not cause noise when a communication control bus such as IEEE1394 connected during operation is reset, and the audio device. An object is to provide a communication control system including an audio device.

  In the audio device according to the first aspect of the present invention, when a plurality of electric devices including an audio signal output device connected by a communication control bus communicate and the communication control bus is reset, the connection state of the electric device is updated. When the communication control bus is reset, the digital audio signal output from the audio signal output device is received, converted into an analog signal and output, and connected to the communication control bus after the reset. An audio device that stores a numerical value related to the number of electrical devices is provided with prohibiting means for prohibiting output of an audio signal when the communication control bus is reset.

  This audio device is included in a system in which a plurality of electrical devices including audio signal output devices connected via a communication control bus communicate and the connection state of the electrical device is updated when the communication control bus is reset. The digital audio signal output from the audio signal output device is received, converted into an analog signal, and output. When the communication control bus is reset, a numerical value related to the number of electrical devices connected to the communication control bus after the reset is stored. When the communication control bus is reset, the prohibiting unit prohibits the output of the audio signal.

  When the communication control bus is reset, the audio device according to the second aspect of the invention is a storage means for re-storing the numerical value stored before the reset, and a numerical value related to the number after the reset. And a means for determining the magnitude of the value stored again by the storage means, and when the means determines that the numerical value related to the number is not smaller, the prohibiting operation of the prohibiting means is canceled. It is characterized by being done.

  In this audio apparatus, when the communication control bus is reset, the storage unit stores again the numerical value related to the number of electrical devices connected to the communication control bus, which was stored before the reset. The determining means determines the magnitude of the numerical value related to the number of electrical devices connected to the communication control bus after being reset and the numerical value re-stored by the storage means. When the determining means determines that the numerical value related to the number after being reset is not smaller, the prohibiting operation of the prohibiting means is canceled.

  The audio device according to a third aspect of the invention is characterized in that when the digital audio signal output from the audio signal output device is received, the prohibiting operation of the prohibiting means is canceled.

  In this audio apparatus, when the digital audio signal output from the audio signal output device is received, the prohibiting operation of the prohibiting unit is canceled.

  A communication control system according to a fourth aspect of the present invention includes a communication control bus and an audio signal output device, and includes a plurality of electric devices connected to the communication control bus and performing communication through the communication control bus. In a communication control system in which a connection state of the electrical device is updated when reset, the audio device according to any one of claims 1 to 3 is provided.

  In this communication control system, when a plurality of electrical devices including audio signal output devices are connected to the communication control bus and communicate through the communication control bus, and the communication control bus is reset, the connection state of the electrical devices is updated. Is done. An audio device according to any one of claims 1 to 3 is provided.

  The audio device according to the first aspect of the present invention can realize an audio device that does not cause noise when a communication control bus such as IEEE1394 connected during operation is reset.

  According to the audio device of the second invention, there is no possibility of generating noise when the communication control bus such as IEEE1394 connected during operation is reset, and the bus reset is not caused by the removal of the device. In this case, an audio device that can be quickly restored can be realized.

  According to the audio device of the third aspect of the present invention, when a communication control bus such as IEEE1394 connected during operation is reset, there is no possibility of generating noise, and there is no possibility of generating noise. An audio device that can be restored to the above can be realized.

  According to the communication control system according to the fourth aspect of the present invention, it is possible to realize a communication control system in which there is no possibility that the audio device generates noise when a communication control bus such as IEEE1394 is reset.

  Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof. FIG. 1 is a block diagram showing a configuration of an in-vehicle LAN (Local Area Network) which is an embodiment of a communication control system according to the present invention. In this in-vehicle LAN, a controller 2, a CD player 3, an MD player 4, a cassette deck 5, a radio receiver 6, and an audio device 7 are connected to an IEEE 1394 serial bus 1 that is a communication control bus.

  The controller 2 is a root node and controls the entire in-vehicle LAN system through the serial bus 1. The audio device 7 receives the digital audio signal output from the CD player 3, the MD player 4, the cassette deck 5 or the radio receiver 6, which is an audio signal output device, through the serial bus 1, converts it into an analog signal, and amplifies it. To the speaker 8.

  FIG. 2 is a block diagram showing a configuration of an audio apparatus according to an embodiment of the present invention. The audio device 7 is connected to the IEEE 1394 serial bus 1 connected to an operation unit 16 having means for inputting keys and the like, a display unit 17 having a display screen, and other electrical devices in the network. And an IEEE 1394 controller 19 for controlling the bus 1.

  The audio device 7 also includes an output unit 12 that converts a digital audio signal received through the IEEE 1394 controller 19 into an analog signal, amplifies the signal, and outputs the amplified signal to the speaker 8, a memory 13 (storage means), and a processor 15. The output unit 12, the operation unit 16, the display unit 17, the IEEE 1394 controller 19, and other parts of the audio device 7 are connected to a 32-bit internal bus 18, and the internal bus 18 is connected to the memory 13 and the memory via the bridge circuit 14. It is connected to the processor 15.

  Hereinafter, the operations of the audio apparatus 7 and the in-vehicle LAN having such a configuration will be described with reference to the flowchart of FIG. When a topology (node connection state) changes, such as when a new electrical device (node) is connected to the IEEE 1394 serial bus 1 or an electrical device is disconnected from the serial bus 1, the serial bus 1 is reset (bus Reset), a bus reset signal is transmitted to all electrical devices connected to the serial bus 1.

  When receiving the bus reset signal via the serial bus 1 (S2), the processor 15 of the audio device 7 stores the count value of the self-ID packet received at the previous bus reset stored in the IEEE 1394 controller 19 in the memory 13. Redo (S3). Next, the controller 19 deletes the stored topology information (information relating to node connection) (S4), and the processor 15 starts the mute state (silent state) in the output unit 12 (S6) (prohibiting means). . The processor 15 returns if it does not receive the bus reset signal (S2).

  Next, the controller 19 performs tree identification processing through communication with other electrical devices (nodes) (S8). Similarly, the other electric devices perform the tree identification process, and the path connecting the other electric devices (nodes) to the branches is identified using the controller 2 as the root (tree identification).

  Next, the controller 19 selects the physical-ID used by the audio device 7 (node) in the address, creates management information related to the bus connection, configures it into a self-ID packet, and configures other information through the serial bus 1. A self-identification process for transmitting to all electrical devices (ports (connection terminals)) is performed (S10). Moreover, the self-identification process which receives and counts the self-ID packet from another electric equipment is performed (S10). Note that the tree identification and self-identification are described in detail in the background art, and thus description thereof is omitted.

  When the self-identification process (S10) of the controller 19 is completed, the processor 15 counts the stored self-ID packet and stores the count value (S10) stored in the memory 13, and the count stored in the memory 13 again. The magnitude of the value (S3) is compared (S12). As a result, if the stored count value (S 10) is not smaller than the count value (S 3) stored again in the memory 13, the electrical device is not removed, and therefore an audio signal is given to the audio device 7. Since the audio signal output device is not removed, the mute state is canceled (S16), and the process returns.

  If the stored count value (S10) is smaller than the count value (S3) stored again in the memory 13 (S12), the processor 15 determines whether or not the controller 19 receives a digital audio signal (data). Determine (S14). As a result, if a digital audio signal is received, the audio signal output device providing the audio signal to the audio device 7 has not been removed, and the mute state is canceled (S16) and the process returns. If the digital audio signal is not received, the mute state is continued until the digital audio signal is received. If the power of the audio apparatus 7 is turned off during that time (S18), the process returns to perform the power off process.

It is a block diagram which shows the structure of the vehicle-mounted LAN which is embodiment of the communication control system which concerns on this invention. It is a block diagram which shows the structure of embodiment of the audio apparatus which concerns on this invention. It is a flowchart which shows the operation | movement of the audio apparatus which concerns on this invention, and vehicle-mounted LAN. It is explanatory drawing which shows the structure of a self-ID packet.

Explanation of symbols

1 (IEEE 1394) serial bus 2 controller 3 CD player (audio signal output device)
4 MD player (audio signal output device)
5 Cassette deck (audio signal output device)
6 Radio receiver (audio signal output device)
7 Audio device 8 Speaker 12 Output unit 13 Memory (storage means)
15 processor 19 (IEEE 1394) controller

Claims (4)

When a plurality of electric devices including an audio signal output device connected by a communication control bus communicate and the communication control bus is reset, the connection state of the electric device is included in a system that is updated, and the audio When the digital audio signal output by the signal output device is received, converted into an analog signal, and output, and the communication control bus is reset, it relates to the number of electric devices connected to the communication control bus after the reset. In an audio device that stores numerical values,
An audio apparatus comprising: prohibiting means for prohibiting output of an audio signal when the communication control bus is reset.   When the communication control bus is reset, the storage means for re-storing the numerical value stored before the reset, and the numerical value related to the number after the reset and the storage means have been stored again 2. The apparatus according to claim 1, further comprising means for determining the magnitude of the numerical value, and when the means determines that the numerical value related to the number is not smaller, the prohibiting operation of the prohibiting means is canceled. Audio equipment.   3. The audio apparatus according to claim 1, wherein when the digital audio signal output from the audio signal output device is received, the prohibiting operation of the prohibiting unit is canceled. A communication control bus and an audio signal output device, and a plurality of electric devices connected to the communication control bus and performing communication through the communication control bus, and when the communication control bus is reset, the electric device In the communication control system where the connection status of
A communication control system comprising the audio device according to any one of claims 1 to 3.

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