JPH0546734B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an in-vehicle audio device, and more specifically, to a unit having a bidirectional data bus and an interface conforming to the bus. The present invention relates to an in-vehicle audio device that can be operated by being connected to a bus through a connector, and can automatically determine whether or not a source unit that is connected to the bus is connected.

[Technical Background of the Invention and Problems Thereof] A conventional device of this type is shown in FIG. 2.

In the figure, numeral 1 is an operation unit that is also used to operate source equipment such as a cassette deck, tuner, and compact disc player (CD), and 2 is an operation unit that is also used to display the status of the operating source equipment. A display unit 3 encodes key inputs input by operating the keys of the operation unit 1 and gives commands through a bidirectional data bus 4, and a source device connected to the bidirectional data bus 4. This is a system control unit that inputs display data etc. from the display unit through the bidirectional data bus 4 and causes the display unit 2 to perform a predetermined display.

5 is a system power supply that can be used with an in-vehicle battery, 6
7 is an accessory switch operated by the ignition key of the car, and 7 is a source device presence/absence determination circuit that determines whether or not a source device is connected. Depending on the rise of the voltage, it is determined via the bidirectional data bus 4 whether or not the source device is connected, and a code indicating whether or not the source device is connected is provided to the system control unit 3. This connection presence/absence code is used so that when the system control unit 3 executes a job according to a predetermined program, it skips the part related to the source device that is not connected and does not perform any extra work. This is used to ignore operations on the operation panel for source devices that are not connected.

8 is a deck control unit that controls the deck mechanism 9;
0 is a tuner control unit that controls the tuner unit 11;
Reference numeral 12 denotes a CD control unit that controls the CD mechanism, and these control units 8, 10, and 12 operate to input key command commands through a bidirectional data bus and to send out a display data bus, etc. 1 together with the controlled parts 9, 11, 13 controlled by
Each device is configured with two source devices. In addition,
14 is a power supply line that supplies power from the power supply 5 to each part.

In the above configuration, when power is supplied from the power supply 5 through the power supply line 14 while each source device is connected to the bidirectional data bus 4 and the power supply line 14, a judgment is made to determine whether or not the source device is connected. The circuit 7 operates in response to power up, and sends a command code for checking the connection of all connectable source devices in a predetermined sequence through the bidirectional data bus 4, and receives a confirmation command from each source device. have. When a confirmation command is received within a certain period of time, it is determined that the source device is connected. When the maximum number of connectable devices is checked and the determination is completed, a code corresponding to the connected source device is output to the system control section 3.

The system control unit 3 converts the input key code of the operation unit 1 into a command and issues the command through the bidirectional data bus 4 only to the connected source device. The source device extracts a corresponding command from the bidirectional data bus 4 and operates, and also sends display data to the system control section 3 through the bidirectional data bus 4 to cause the display section 2 to perform a predetermined display.

Note that once the power supply 5 is connected for purposes such as memory backup, it is not normally disconnected. Further, the device is turned on and off using an accessory switch 6. When changing the source device connected to the bidirectional data bus, it is necessary to disconnect the power supply 5.

[Problems with conventional technology]

As described above, in the conventional device, the determination circuit 7 operates only when the power supply 5 is connected to the power supply line 14. Therefore, the connector connection procedure when installing a car stereo etc. in a car becomes complicated, and it is necessary to disconnect and reconnect the power supply each time the source device is changed or expanded after installation. The problem was that the preset memory of the camera was erased.

There is also a method that does not include a circuit that automatically determines the presence or absence of a source, but instead uses an external switch to set the presence or absence of the source. However, if a malfunction occurs due to incorrect settings, it may cause damage to the circuit, etc. in the case of a bidirectional data bus method. I may invite you.

[Purpose of the invention]

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional ones, and the present invention has been made by detecting that a car accessory switch is turned on from an off state to trigger a determination circuit that determines whether a source device is connected. The purpose of the present invention is to provide an in-vehicle audio system that improves workability when installing it in a vehicle, and when adding or replacing source equipment.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of an in-vehicle audio device according to the present invention. In FIG. 1, the same components as those of the conventional device shown in FIG. 2 are given the same reference numerals. It is shown as follows.

In FIG. 1, a detection circuit 15 for detecting on/off of the accessory switch 6 is provided.
The switching from the OFF state to the ON state is detected by the rise of the voltage, a trigger pulse is generated, and this is applied to the determination circuit 7 to perform its determination operation.

In the above, when the accessory switch 6 of the car is turned on from off, the detection circuit 15 detects this and applies a trigger pulse to the determination circuit 7, causing the determination circuit 7 to perform an operation to determine whether or not the source device is connected. Let it start. Judgment circuit 7 is bidirectional data bus 4
The device sequentially outputs a code for determining the presence or absence of a source through the device, and checks the confirmation data sent from the corresponding source device through the bidirectional data bus 4. If confirmation data is received within a certain period of time after sending the determination code, it is determined that the source device is connected, and if confirmation data cannot be received even after waiting for a certain period of time, it is determined that the source device is not connected. Repeat this for all connectable source devices. When all checks are completed, the determination circuit 7 outputs data regarding the source device determined to be connected to the system control unit 3.

The system control unit 3 receives the data from the determination circuit 7 and puts the system into an operable state. Then, when the user presses a source selection button in the operation section 1, a desired source device is put into operation. At this time, the system control unit 3
determines whether or not the source device corresponding to the pressed source selection button is connected by comparing it with the data from the determination circuit 7, and when it is determined that it is not connected, the source device corresponding to the pressed button is connected. No processing is performed. If the selected source device is connected, an on command is sent to the selected source device via the bidirectional data bus 4 to cause it to operate. The source device that receives the ON command starts operating, sends data to the system control section 3 via the bidirectional data bus 4, and causes the display section 2 to display its own operating state.

In addition to the source selection button, the operation unit 1 is provided with keys that can be used for a plurality of source devices.
Similarly, the display device 2 is provided with all the display devices necessary to display the status of a plurality of source devices.

For example, a DR/BAND key is provided, which is used as a playback direction switching button when selecting a deck, and as a band switching button when selecting a tuner. When this key is pressed during deck operation, the system control section 3 sends a code corresponding to the DR/BAND key to the deck control section 8 via the bidirectional data bus 4. The deck control section 8, which has received this data, inverts the tape playback direction of the deck mechanism 9 and sends data to the system control section 3 through the bidirectional data bus 4 to cause the display section 2 to display the tape playback direction.

In the above-described embodiment, the determination circuit 7 is operated in response to the turning of the accessory switch 6 from OFF to ON, but there is an inconvenience that the determination cannot be made when the power source 5 is not connected at this time. In order to prevent this from happening, it is preferable that the determination circuit 7 is operated by the logical product of the connection of the power source 5 and the detection of the accessory switch 6 turning from off to on.

〔Effect of the invention〕

As described above, according to the present invention, when the car accessory switch is turned on from off, it is automatically determined whether or not a connectable source device is installed. This simplifies the connector connection procedure when installing the product in a car, and prevents failures due to mistakes in the connection procedure during installation.

In addition, when making changes after installation due to reasons such as adding more source devices to the system or upgrading the source device, the accessory switch can be changed without disconnecting the power connector, which is difficult to access in narrow vehicles. This can be done by simply turning off the switch, resulting in better workability. Furthermore, since there is no need to disconnect the power supply connector, the inconvenience of clearing the contents of the preset memory of a tuner or the like using a backup power supply can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a vehicle-mounted audio device according to the present invention, and FIG. 2 is a block diagram showing a conventional example. 3...System control unit, 4...Bidirectional data bus,
6...Accessory switch, 7...Judgment circuit, 8...
Detsuki control section, 9... Detsuki mechanism, 10... Tuner control section, 11... Tuner section, 12... CD control section,
13...CD mechanism.

Claims (1)

[Claims] 1. Data exchange between a source device connected to the bidirectional data bus and a system control unit via a bidirectional data bus to which a plurality of predetermined source devices can be connected. The in-vehicle audio device is operated by performing the following steps, and includes a detection means for detecting switching from off to on of a vehicle accessory switch, and a bidirectional data bus in response to detection by the detection means. The system control unit includes a determination means for determining a connected source device and a display means, and based on the determination result by the determination means, the system control unit recognizes the source device connected to the bidirectional data bus, and displays the source device accordingly. An in-vehicle audio device characterized in that said source device and said display means are controlled by said source device and said display means.