KR19980040076A - Communication channel automatic inspection device for monitor - Google Patents

Abstract

The present invention relates to a communication channel automatic inspection device that is capable of automatically inspecting a communication channel for communicating with a main body of a computer in a monitor.

To this end, the apparatus of the present invention receives an RGB image signal, a vertical and horizontal synchronization signal from a computer, exchanges data with the computer, and combines the output of the on-screen display integrated circuit device 240 with the amplified RGB image signal. A monitor configured to enable on-screen display, comprising: a DDC1 test switch (SW1) for starting a test of a DDC1 communication channel; A DDC2 test switch SW2 for starting a test of the DDC2 communication channel; And when the DDC1 test switch SW1 is pressed, reads and checks EDID data stored on its own pyrom, and outputs the result to the on-screen display IC 240 to display it on a monitor screen. When the switch SW2 is pressed, the microcomputer 200 reads and checks EDID data and outputs the result to the on-screen display IC 240 to display it on the screen.

Therefore, the communication channel inspection apparatus according to the present invention can easily determine whether there is an abnormality of the communication channel by testing the EDID data used for the communication between the monitor and the computer meets the regulations defined in the protocol, and on-screen display the results. .

Description

An apparatus of automatically checking communication channel in a monitor

The present invention relates to a communication channel for communicating with a main body of a computer in a monitor, and more particularly, to a communication channel automatic inspection device which is capable of automatically checking whether a communication channel is abnormal.

In addition to the recent trend of larger monitors, the 'PLUG PLAY' method for increasing user convenience has been implemented in monitors. Here, 'plug and play' literally means that when you attach a new board or peripheral to your computer, you simply plug in cables, and when you power up, the computer automatically reconfigures your environment and makes it ready for immediate use. It means.

For this purpose, the conventional general monitor simply receives and displays the signal provided by the computer, whereas the plug and play monitor is a product that can exchange information with the computer, and the monitor provides information on the optimal available modes and adjustments to the computer. Must be able to provide Therefore, plug and play on a monitor should connect the signal cable to the computer and operate the monitor to automatically select the best mode for the computer to use and provide the user with the best adjusted screen.

In order to apply the plug and play function to the monitor, a protocol for storing its own information on the monitor and transmitting it to a computer must be preceded. Therefore, the Video Electronic Standards Association (VESA), a non-profit corporation established among US computer and peripheral companies, has established a standard for the display data channel (DDC) transmission method for plug and play monitors.

Here, the DDC transmission method defines a communication channel between the computer and the monitor, and refers to a protocol for transmitting the monitor information stored in the monitor to the computer or changing the monitor information using a keyboard mouse.

In other words, the existing monitor is only displayed by the one-way signal of the video card, but by using the DDC, the information and capabilities of the display can be communicated with the computer, and the integrated communication of the computer, monitor, keyboard, and mouse is possible. Done. This DDC monitor is convenient because it can be used immediately without connecting the display resolution setting process even if there is no manual of each product at the time of purchase.

On the other hand, the DDC monitor has a one-way to provide the monitor information to the computer and bi-directional to provide information to the monitor in the computer.

For example, 'DDC1' is a one-way transmission method that provides monitor information to a computer as the most basic communication method, and the computer cannot control the information transmission. When this monitor is connected to a computer and the monitor is powered on, the monitor provides information to the computer using the vertical frequency as the transmission clock, and the computer provides the optimal signal for the monitor to display in a mode that matches the information obtained from the monitor. to provide.

In addition, 'DDC2B' is a bi-directional transmission method that enables a monitor and a computer to communicate with each other and is based on the I ² C protocol.

'DDC2AB' is a full bidirectional transmission method, which frees the exchange of information between the monitor and the computer, and uses the ACCESS bus to modify the monitor information. Therefore, the DDC2AB monitor can directly connect a peripheral device, a keyboard, and a mouse, which are conventionally connected to a computer.

The communication channel connections are summarized in the table below compared with the existing VGA connection.

PIN number VGA DDC-1,2 Disp DDC-1 Host DDC2 Host One R R R R 2 G G G G 3 B B B B 4 ID bit 2 Optional ID bit 2 ID bit2 5 Test Return Return Return 6 R return R return R return R return 7 G return G return G return G return 8 B return B return B return B return 9 NC + 5V load + 5V supply + 5V supply 10 Sync return Sync return Sync return Sync return 11 ID bit 0 Optional ID bit 0 ID bit 0 12 ID bit 1 SDA Data SDA 13 H.sync H.sync H.sync H.sync 14 V.sync V.sync (VCLK) V.sync V.sync 15 ID bit 3 SCL ID bit3 SCL

As shown in Table 1, + 5V provided by the computer is connected through pin 9 in the case of DDC in the 15-pin desub connector, and pin 12 in DDC1 is synchronized with the vertical sync clock (V.sync) of pin 14. Data is transferred from the monitor to the computer via (SDA), and in DDC2, data can be transferred in both directions through pin 12 (SDA) and pin 15 (SCL).

In these DDCs, file formats and commands are respectively set according to three communication channels. This is slightly different.

The PC with 'DDC-1' function reads the DDC1 data sent from the monitor, and if there is no data, it is recognized as an old monitor and does not send + 5V power to pin 9, but the difference between the old monitor and the power is not turned on. I don't recognize it.

PC with 'DDC2B' function checks EDID (Extended Display IDentification) using DDC2B. If there is no response, it is regarded as an old monitor and gives up DDC2B function. Here, EDID is a 128-byte data format that includes a manufacturer and a product ID, and is defined by VESA as a standard.

A PC with the 'DDC2AB' function first contacts the ACCESS bus, finds the EDID if there is no response, and then considers the old monitor if there is no response.

1 is a circuit diagram illustrating a conventional communication channel system in a monitor. As shown in Table 1, pin 12 of the sub-connector 101 is the data channel (SDA), pin 14 is the vertical synchronous clock (V.sync) used in DDC1, and pin 15 is the clock used in DDC2. Line (SCL).

The vertical synchronization signal V.sync input through pin 14 of the sub connector 101 is driven to a size of 5V in the buffer 102 and then connected to the communication IC 103. The serial data and clock lines SDA and SCL of the de-sub connector 101 are connected to the communication IC 103. At this time, these signal lines are protected by the zener diodes ZD1 to ZD3 to protect the circuit from shocks such as static electricity. The SCL and SDA signal lines are pulled up to the Vcc power supply by the pull-up resistors R6 and R7, and the noise is removed through the capacitors C3 and C4. In this communication channel, the communication IC 103 performs a protocol according to DDC1 or DDC2 to process the communication function between the monitor and the computer.

However, in such a conventional communication channel, it is difficult to know where it occurred when a failure occurs on the communication channel, and it is difficult to know whether it is normally operated. In addition, there is a problem in that test man-hours increase because it requires connection with a computer main body during the manufacturing process to test the normality of the communication channel.

Accordingly, the present invention has been proposed to solve the above problems, it is to provide a communication channel automatic inspection device of the monitor that can determine the normal state by automatically displaying the state of the communication channel when the user presses the test key. There is this.

In order to achieve the above object, the device of the present invention receives RGB image signals, vertical and horizontal synchronization signals from a computer through a sub connector, exchanges data with the computer, and provides an on-screen display (OSD) integrated circuit device. A monitor configured to combine an output and the amplified RGB image signal to display on screen, comprising: a DDC1 test switch for starting a test of a DDC1 communication channel; A DDC2 test switch for starting a test of the DDC2 communication channel; And when the DDC1 test switch is pressed, it checks the EDID data according to the DDC1 protocol and outputs the result to the on-screen display IC to display it on the monitor screen.When the DDC2 test switch is pressed, the EDID data according to the DDC2 protocol is pressed. Check and output the result to the on-screen display IC to display it on the screen.

1 is a circuit diagram showing a conventional communication channel system in a monitor;

2 is a circuit diagram showing a communication channel system according to the present invention in a monitor;

FIG. 3 is a flowchart illustrating a flow of operations performed by the microcomputer shown in FIG. 2.

* Explanation of symbols for main parts of the drawings

101: deserve connector 102,201,202: buffer

103: communication IC200: micom

210: video preamplifier 220: video power amplifier

230: CRT240: On-Screen Display IC

SW1: DDC1 test switch SW2: DDC2 test switch

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the DDC1, DDC2, and EDID formats will be briefly described to facilitate understanding of the present invention.

DDC1 sends the data in EDID format to the computer continuously according to the vertical sync clock (V.sync). In DDC2, if the computer requests display data format by command, it is in EDID format or VDIF (Video Display Identification File) format. Deliver display information to the computer.

At this time, EDID is a data format having 128 bytes of information as shown in Table 2 below.

Byte size division 8 bytes Header 10 bytes Manufacturer / Product Identifier 2 bytes EDID format version 15 bytes Basic Display Parameters / Features 19 bytes Extended / Standard Timing 72 bytes Timing and Monitor Details 1 byte Extension Flag 1 byte Whitsum Sum 128 bytes

The EDID includes manufacturer / product information, parameter information, timing information, and the like, as shown in Table 2, so that the computer can automatically set the mode.

Subsequently, as shown in FIG. 2, the automatic communication channel inspection apparatus according to the present invention includes the sub-connector 101, the microcomputer 200, the video preamplifier 210, the video power amplifier 220, and the CRT 230. , On-screen display IC 240, key switches (SW1, SW2) and the like.

Referring to FIG. 2, the signal line of the desub connector 101 is defined as shown in Table 1 above. The vertical synchronization signal V.sync input through pin 14 of the desub connector is buffer 201. ) Is driven into the size of 5V and is input to the microcomputer 200. The serial data line SDA and the clock line SCL of the desub connector 101 are directly connected to the microcomputer 200. At this time, the SCL and SDA signal lines are pulled up to the Vcc power supply by the pull-up resistors R11 and R12, and noise is removed by the capacitors C11 and C12. In this communication channel, the microcomputer 200 processes a communication function between the monitor and the computer by performing a protocol according to DDC1 or DDC2.

In addition, the microcomputer 200 transmits data to the on-screen display IC 240 through the SDA and SCL signal lines so that the on-screen display IC 240 generates a video signal for the on-screen display according to the corresponding data, thereby providing a video preamplifier ( Output to the output terminal of 210). At this time, the communication lines (SDA, SCL) between the microcomputer 200 and the on-screen display IC 240 are pulled up to Vcc by the pull-up resistors R13 and R14, and the noise is removed by the capacitors C13 and C14. have.

The video preamplifier 210 amplifies the image signals R, G, and B input through the de-connector 101 according to the contrast signal, and outputs the video signals to the video power amplifier 220. 220 amplifies the video signals R, G, and B input from the video preamplifier 210 and the on-screen display IC 240 with high gain to drive the CRT 230.

In addition, as shown in FIG. 3, when the DDC1 test key SW1 is pressed, the microcomputer 200 reads the data of the EDID data format according to the DDC1 protocol from the internal YPIROM and checks whether there is an error. The result is transferred to the on-screen display IC 240, and the on-screen display IC 240 allows the on-screen display of the test results of the microcomputer 200 in a form that is easy for the user to understand at an appropriate timing.

In addition, when the DDC2 test key SW2 is pressed, data of the EDID data format according to the DDC2 protocol is read from the internal EPIROM to check whether there is an error, and the result is transmitted to the on-screen display IC 240. The screen display IC 240 displays the test results of the microcomputer 200 at an appropriate timing in a form that is easy for the user to understand.

Referring to FIG. 3, if the test key is input, it is determined whether the test is a DDC1 test (301,302), and if the test is in the EDID format according to the DDC1 protocol (304). On screen display (306 307), if not normal, indicates that the EDID format is 'abnormal state' (308).

In addition, if the test key is a DDC2 test request, the EDID format is checked according to the DDC2B protocol to display on-screen display of abnormality (303, 305).

For example, since the total size of the EDID format is 128 bytes as shown in Table 2, it is determined whether the data is normally stored by checking the size of the data stored in the EPIROM or by checking the checksum value.

As described above, the communication channel inspection apparatus according to the present invention tests EDID data used for the communication between the monitor and the computer according to the protocol defined in the protocol, and then displays the result on-screen to check for abnormality of the communication channel. You can easily grasp.

Claims (1)

It receives the RGB image signal, the vertical and horizontal synchronization signals from the computer through the sub connector 101, exchanges data with the computer, and combines the output of the on-screen display integrated circuit device 240 with the amplified RGB image signal. For monitors that can be displayed on-screen, A DDC1 test switch SW1 for starting a test of the DDC1 communication channel; A DDC2 test switch SW2 for starting a test of the DDC2 communication channel; And When the DDC1 test switch SW1 is pressed, the EDID data stored on its own EPIROM is read and checked, and the result is output to the on-screen display IC 240 to be displayed on a monitor screen, and the DDC2 test When the switch SW2 is pressed, the communication channel automatic inspection apparatus in the monitor equipped with the microcomputer 200 to read and check the EDID data and output the result to the on-screen display IC 240 to display on the screen .