CN101853147B - Circuit and detection method for detecting external display device in laptop - Google Patents
Circuit and detection method for detecting external display device in laptop Download PDFInfo
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- CN101853147B CN101853147B CN200910130565.0A CN200910130565A CN101853147B CN 101853147 B CN101853147 B CN 101853147B CN 200910130565 A CN200910130565 A CN 200910130565A CN 101853147 B CN101853147 B CN 101853147B
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Abstract
The invention relates to a circuit and a detection method for detecting an external display device in a laptop. The laptop is provided with an image connection port capable of outputting a vertical synchronous signal, a horizontal synchronous signal, a red signal, a green signal and a blue signal to an external display device to display an image. The laptop comprises a screen device, an embedded controller and a detection circuit, wherein the screen device is internally arranged in the laptop, the embedded controller is capable of outputting an enable signal, and the detection circuit is used for receiving a first signal, a second signal and the enable signal, the first signal is the vertical synchronous signal or the horizontal synchronous signal, and the second signal is the red signal, the green signal or the blue signal. When the external display device is pulled out from the image connection port, the detection circuit can judge the second signal in the blank space of the first signal according to the behavior of the enable signal to generate an interrupt request signal, and automatically switch the image to the screen device of the laptop.
Description
Technical field
The present invention is about a kind of circuit and detection method that detects external display device, and particularly about a kind of, applies on notebook computer in order to detect testing circuit and the detection method of external display device.
Background technology
As everyone knows, notebook computer except appended LCD screen (LCD monitor) itself, an additional image connectivity port that all can be extra.This image connectivity port normally utilizes a D-SUB connector (D-subconnector) to be connected with an external connection display apparatus, and user can utilize external connection display apparatus to carry out bulletin or speech.In general, external connection display apparatus can be projector (projector), LCD screen (LCD monitor) or conventional screen (CRT monitor).
Conventionally, notebook computer can carry out the automatic switchover of image by the hot key on keyboard (hot key).That is, optionally by image display in appended LCD screen itself, can by image display in external connection display apparatus or simultaneously by image display in appended LCD screen and external connection display apparatus itself.That is to say, when user is connected to the D-SUB connector of external connection display apparatus after notebook computer, by the hot key of pressing on keyboard, can carry out the switching of image.When user's bulletin or give a lecture complete after, user can utilize hot key on keyboard that image is switched to appended LCD screen itself again, afterwards, the D-SUB connector of external connection display apparatus can be pulled out.
Moreover whether the D-SUB connector of the detection external-connection displayer that at present notebook computer of particular form can be is initiatively pulled out, and automatically image is switched to appended LCD screen itself, and user need not utilize the hot key on keyboard to switch.
Whether known detection mode is all utilized the program of software to detect external connection display apparatus and is pulled out.(Inter-Integrated Circuit, hereinafter to be referred as I as interior integrated circuit in pin position (pin) due to D-SUB connector, to include 2 pin positions
2c circuit) use, therefore, between notebook computer and external display device, can pass through I
2c circuit carries out the transmission of order or parameter.
That is to say, when external display device utilizes D-SUB connector to be connected to notebook computer, the central processing unit of notebook computer can periodically be carried out an interrogator (for example carrying out an interrogator for every 0.5 second), and utilizes I
2c circuit and external display device carry out the transmission of order or parameter.Therefore,, when external display device can be responded order or parameter, central processing unit can learn that the D-SUB connector of external display device is still connected with notebook computer; Otherwise, when external display device cannot be responded order or parameter, central processing unit can learn that the D-SUB connector of external display device is pulled out, now, notebook computer can be automatically by automatic video switching to appended LCD screen itself, and the hot key that user need not recycle on keyboard switches.
Yet, when the D-SUB of external display device connector is connected with notebook computer, the central processing unit of notebook computer must periodically be carried out interrogator just can learn the connection state of external display device, and therefore the efficiency (performance) of whole notebook computer can reduce.
Summary of the invention
The object of the invention is to propose a kind of testing circuit and detection method of external display device, when being pulled out between external display device and notebook computer, testing circuit can produce a look-at-me to central processing unit, and central processing unit is shown automatic video switching to appended LCD screen own.
The present invention proposes a kind of notebook computer, described notebook computer has an exportable vertical synchronizing signal in image connectivity port, a horizontal-drive signal, a danger signal, a green and blue signal to external connection display apparatus to show an image, comprise: a screen apparatus, is inside built in notebook computer; One embedded controller, an exportable enable signal; And a testing circuit, receive a first signal, a secondary signal and this enable signal, and first signal is vertical synchronizing signal or horizontal-drive signal, secondary signal is danger signal, green or blue signal; Wherein, when external connection display apparatus is pulled out by image connectivity port, testing circuit can judge that according to the action of enable signal secondary signal is in order to produce an interrupt request singal between a clear area of first signal, and automatic video switching is returned to the screen apparatus of notebook computer.
The present invention also proposes the connection detection method of display device in a kind of notebook computer, described notebook computer has an exportable vertical synchronizing signal in image connectivity port, a horizontal-drive signal, a danger signal, a green and a blue signal, described connection detection method comprises the following steps: to be connected to behind image connectivity port in an external connection display apparatus, receives a first signal, a secondary signal and an enable signal; In between a clear area of first signal, according to first signal and enable signal, provide a supply voltage to secondary signal; And, according to the magnitude of voltage in secondary signal, determine the annexation between external connection display apparatus and image connectivity port; Wherein, first signal is vertical synchronizing signal or horizontal-drive signal, and secondary signal is danger signal, green or blue signal.
Accompanying drawing explanation
For enabling further to have a clear understanding of feature of the present invention and technology contents, refer to the detailed description of following cooperation accompanying drawing to preferred embodiment of the present invention, yet accompanying drawing only provides reference and explanation, is not used for the present invention to be limited, wherein:
Figure 1A and 1B are depicted as the display schematic diagram on D-SUB connector.
Figure 2 shows that the circuit diagram of external connection display apparatus and display chip.
Figure 3 shows that notebook computer of the present invention and testing circuit schematic diagram thereof.
Figure 4 shows that the first embodiment of testing circuit of the present invention.
Embodiment
Please refer to Figure 1A and 1B, it is depicted as the display schematic diagram on general D-sub connector.The signal of 5 pin positions on D-SUB connector comprises: vertical synchronizing signal (Vsync), horizontal-drive signal (Hsync), danger signal (Red), green (Green) and blue signal (Blue).The display device of 640*480 resolution, refreshing frequency 60Hz of take is example, and Figure 1A is known, and the cycle of vertical synchronizing signal (Vsync) is 16.68ms.Wherein, the cycle of vertical synchronizing signal (Vsync) starts from low level generation, and low level width is 0.06ms; After low level finishes, during through 1.02ms, danger signal (Red), green (Green) must be exported 640*480 pixel data with blue signal (Blue), and the time of 640*480 pixel data of output is 15.25ms; Afterwards, after 0.35ms, start the cycle of next vertical synchronizing signal (Vsync).Moreover, in the cycle of each vertical synchronizing signal (Vsync), also comprise cycle of 480 horizontal-drive signals (Hsync).
From Figure 1B, the cycle of horizontal-drive signal (Hsync) is 31.77 μ s.Wherein, the low level width of horizontal-drive signal (Hsync) is 3.77 μ s; After low level finishes, during through 1.89 μ s, danger signal (Red), green (Green) must be exported 640 pixel datas with blue signal (Blue), and the time of 640 pixel datas of output is 25.17 μ s; Afterwards, after 0.94 μ s, start the cycle of next horizontal-drive signal (Hsync).
Clearly, from Figure 1A and 1B, when vertical synchronizing signal (Vsync) and horizontal-drive signal (Hsync) are low level, danger signal (Red), green (Green) and the neither exportable any pixel data of blue signal (Blue).Therefore, the low level interval of vertical synchronizing signal (Vsync) is defined as (Vertical Blanking Interval is called for short VBI) between vertical clear area; In like manner, the low level interval of horizontal-drive signal (Hsync) is defined as (Horizontal Blanking Interval is called for short HBI) between the clear area of level.
Moreover, please refer to Fig. 2, it is depicted as the circuit diagram of external connection display apparatus and display chip.Signal on D-SUB connector 190 on notebook computer 100 is all exported by 110 of display chips (graphic chip).In general, display chip can be the display chip (stand along graphic chip) of self or is integrated in the display chip (integrated graphic chip) in north bridge chips.
According to instructions (specification), the green (Green) of take is example, by the green source (Vg) in display chip 110, can produce green (Green), and the amplitude of green source (Vg) is about 1.6V, the resistance value of equivalent resistance (Rthg) is 75 ohm.Moreover, on external-connection displayer 300, there is an output resistance (Rog) to be connected in green, its resistance value is 75 ohm.Clearly, control by vertical synchronizing signal (Vsync) with horizontal-drive signal (Hsync), when external connection display apparatus 300 is connected with the D-sub connector 190 of notebook computer 100, the amplitude of the upper pixel data of green (Green) is about 0.8V; Otherwise when external connection display apparatus 300 is not connected with notebook computer 100, the amplitude of the upper pixel data of green (Green) is about 1.6V.In like manner, danger signal (Red) is all identical with green (Green) with the circuit characteristic of blue signal (Blue), therefore repeats no more.
According to embodiments of the invention, testing circuit of the present invention can be between the clear area of (VBI) or level between vertical clear area (HBI) carry out external display device and whether be connected with the D-sub connector 190 of notebook computer, when detecting external display device and pulled out, testing circuit can produce a look-at-me to central processing unit; Otherwise when detecting external display device and not yet pulled out, testing circuit can not produce look-at-me to central processing unit.
Please refer to Fig. 3, it is depicted as notebook computer of the present invention and testing circuit schematic diagram thereof.Notebook computer 100 comprises central processing unit 150, north bridge chips 160, South Bridge chip 170, embedded controller (embeddedcontroller) 180, display chip 110, testing circuit 130.Wherein, north bridge chips 160 is connected to central processing unit 150 and South Bridge chip 170; Embedded controller 180 is connected with South Bridge chip 170; Display chip 110 is connected with north bridge chips 160, and the exportable vertical synchronizing signal of display chip 110 (Vsync), horizontal-drive signal (Hsync), danger signal (Red), green (Green) and blue signal (Blue) are by being passed to external connection display apparatus 300 with D-SUB connector 190.
Moreover testing circuit 130 can receive a first signal, a secondary signal and an enable signal (enable), and an exportable interrupt request singal (interrupt request signal, IRQ).Wherein, enable signal (enable) is produced by embedded controller 180; First signal can be vertical synchronizing signal (Vsync) or horizontal-drive signal (Hsync); Secondary signal can be danger signal (Red), green (Green) or blue signal (Blue).Fig. 3 take first signal to explain as vertical synchronizing signal (Vsync) secondary signal as green (Green).
Please refer to Fig. 4, it is depicted as the first embodiment of testing circuit of the present invention.Testing circuit 130 comprises a first transistor (M1), a transistor seconds (M2), one first resistance (R1), a comparer 135 and a reference voltage (Vref).Wherein, the source electrode of the first transistor is connected to a voltage source (Vcc), and the grid of the first transistor receives an enable signal (enable); The source electrode of transistor seconds is connected to the drain electrode of the first transistor, and the grid of transistor seconds receives a vertical synchronizing signal (Vsync); The first resistance (R1) two ends divide the drain electrode and reception one green (Green) that is connected to transistor seconds; The positive terminal of comparer 135 receives green (Green), the negative pole end of comparer 135 receives reference voltage (Vref), comparer 135 receives enable signals (enable) and moves during for low level in enable signal (enable), the comparer exportable interrupt request singal of 135 output terminal (IRQ).According to embodiments of the invention, the first resistance (R1) is 150 ohm, and supply voltage (Vcc) is 3.3V, and reference voltage (Vref) is 1V.
When external connection display apparatus 300 is connected to the D-sub connector of notebook computer 100, vertical synchronizing signal (Vsync) is high level, and transistor seconds (M2) is closed (off).Now, green (Green) normally output pixel data to external connection display apparatus 300.
When external connection display apparatus 300 is connected to the D-sub connector of notebook computer 100, and vertical synchronizing signal (Vsync) is while being low level, for (VBI) and green (Green) between vertical clear area are not exported any pixel data.When between vertical clear area, (VBI) and enable signal move (low level), the first transistor is opened (on).Now, the voltage in green (Green) is
When external connection display apparatus 300 is pulled out outside notebook computer 100 and between vertical clear area (VBI) and enable signal action (low level), the first transistor is opened (on).Now, the voltage in green (Green) is
From the above, in external connection display apparatus 300, be connected to after notebook computer 100 the exportable vertical synchronizing signal of display chip 110 (Vsync), horizontal-drive signal (Hsync), danger signal (Red), green (Green) and blue signal (Blue).Now, central processing unit 150 can be controlled embedded controller 180 enable signal of output low level (enable) periodically.And enable signal (enable) is while being high level, testing circuit 130 is failure to actuate; When enable signal (enable) is low level, testing circuit 130 actions.
Therefore, between vertical clear area, when (VBI), according to enable signal (enable), can carry out the detection action of external display device.Clearly, when enable signal (enable) is connected to notebook computer 100 for low level and external connection display apparatus 300, comparer 135 positive terminals are 0.66V, negative pole end is 1V, the interrupt request singal (IRQ) of comparer 135 outputs is low level, and embedded controller 180 can not exported embedded controller look-at-me (INT_EC).
Otherwise, in enable signal (enable), pulled out when notebook computer 100 is outer for low level and external connection display apparatus 300, comparer 135 positive terminals are 1.1V, negative pole end is 1V, the interrupt request singal (IRQ) of comparer 135 outputs is high level, therefore embedded controller 180 output embedded controller look-at-mes (INT_EC) are to South Bridge chip 170, and South Bridge chip 170 at once output system look-at-me (INT) to central processing unit 150.When central processing unit 150 is received system interrupt signals (INT), central processing unit 150 can be automatically by automatic video switching to appended LCD screen itself, and the hot key that user need not recycle on keyboard automatically switches.
According to the first embodiment of the present invention, central processing unit 150 need to periodically not carried out interrogator when external connection display apparatus inserts, and therefore can not reduce the usefulness of central processing unit.Moreover testing circuit 130 of the present invention is that (VBI) just has an opportunity to move between vertical clear area, therefore, testing circuit 130 can't affect the action of green (Green).
In like manner, when first signal is horizontal-drive signal (Hsync), testing circuit can (HBI) just have an opportunity to move between the clear area of level, and testing circuit also can not affect the action of secondary signal.
In sum; although the present invention discloses as above with preferred embodiment; yet it is not in order to limit the present invention; any person skilled in the art person; without departing from the spirit and scope of the present invention; when doing the various changes that are equal to and retouching, so protection scope of the present invention is when being as the criterion of defining depending on claims.
Claims (16)
1. a notebook computer, is characterized in that, described notebook computer have the exportable first signal in image connectivity port and secondary signal to external connection display apparatus with show image, comprising:
Screen apparatus, is inside built in described notebook computer;
Embedded controller, exportable enable signal; And
Testing circuit, receives first signal and secondary signal;
Wherein, when described external connection display apparatus is pulled out by described image connectivity port, described testing circuit can judge that according to the action of described enable signal described secondary signal is in order to produce interrupt request singal between the clear area of described first signal, and described automatic video switching is returned to described screen apparatus.
2. notebook computer according to claim 1, is characterized in that, described first signal comprises vertical synchronizing signal or horizontal-drive signal, and described secondary signal comprises danger signal, green or blue signal.
3. notebook computer according to claim 1, is characterized in that, described enable signal can periodically be controlled described testing circuit action.
4. notebook computer according to claim 1, is characterized in that, the D-SUB connector of described external connection display apparatus can be inserted in described image connectivity port.
5. notebook computer according to claim 1, is characterized in that, is between the vertical clear area of described vertical synchronizing signal or between the clear area of the level of described horizontal-drive signal between described clear area.
6. notebook computer according to claim 1, it is characterized in that, described embedded controller can produce embedded controller look-at-me to South Bridge chip according to described interrupt request singal, makes described South Bridge chip can send system interrupt signals to the central processing unit in described notebook computer.
7. notebook computer according to claim 5, is characterized in that, central processing unit can be according to described interrupt request singal by automatic video switching to the appended LCD screen of described notebook computer itself.
8. notebook computer according to claim 1, is characterized in that, described testing circuit comprises:
The first transistor, described the first transistor source electrode is connected to voltage source, and described first crystal tube grid receives described enable signal;
Transistor seconds, described transistor seconds source electrode is connected to described the first transistor drain electrode, and described transistor seconds grid receives described first signal;
The first resistance, has two ends and divides and be connected to the drain electrode of described transistor seconds and receive described secondary signal; And
Comparer, the positive terminal of described comparer receives described secondary signal, the negative pole end of described comparer receives reference voltage, and described comparer receives described enable signal and moves according to described enable signal, the exportable described interrupt request singal of described comparator output terminal.
9. a connection detection method for display device in notebook computer, is characterized in that, described notebook computer has the exportable first signal in image connectivity port and secondary signal, and described connection detection method comprises the following steps:
In external connection display apparatus, be connected to behind described image connectivity port, receive first signal, secondary signal and enable signal;
In between the clear area of described first signal, according to described first signal and described enable signal, provide supply voltage to described secondary signal; And
According to the magnitude of voltage in described secondary signal, determine the annexation between described external connection display apparatus and described image connectivity port;
Wherein, described first signal includes a vertical synchronizing signal or a horizontal-drive signal, and described secondary signal includes a danger signal, a green or a blue signal.
10. connection detection method according to claim 9, is characterized in that, also comprises: when described magnitude of voltage is greater than reference voltage, confirm that described external connection display apparatus is not connected in described image connectivity port.
11. connection detection methods according to claim 10, is characterized in that, also comprise: produce interrupt request singal.
12. connection detection methods according to claim 11, is characterized in that, also comprise: according to described interrupt request singal, make central processing unit in described notebook computer by automatic video switching to the appended LCD screen of described notebook computer itself.
13. connection detection methods according to claim 9, is characterized in that, when described magnitude of voltage is less than reference voltage, confirm that described external connection display apparatus is connected in described image connectivity port.
14. connection detection methods according to claim 9, is characterized in that, the D-SUB connector of described external connection display apparatus can be inserted in described image connectivity port.
15. connection detection methods according to claim 9, is characterized in that, are between the vertical clear area of described vertical synchronizing signal or between the clear area of the level of described horizontal-drive signal between described clear area.
16. connection detection methods according to claim 9, is characterized in that, described supply voltage to described secondary signal, makes described secondary signal produce the first dividing potential drop and as described magnitude of voltage by the first resistance.
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| DE102014211107A1 (en) * | 2014-06-11 | 2015-12-17 | Robert Bosch Gmbh | Configurable integrated circuit, controller and method of configuration |
| CN105760314A (en) * | 2016-03-14 | 2016-07-13 | 山东超越数控电子有限公司 | Method for controlling starting-up screen luminance of system by virtue of EC SCI |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000221954A (en) * | 1999-01-29 | 2000-08-11 | Internatl Business Mach Corp <Ibm> | Device and method for stabilizing image |
| KR20010057236A (en) * | 1999-12-20 | 2001-07-04 | 윤종용 | A controling method of a video display system with muti signal source |
| TW470874B (en) * | 2000-04-24 | 2002-01-01 | Acer Peripherals Inc | Power-saving method and device of monitor in a computer system |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000221954A (en) * | 1999-01-29 | 2000-08-11 | Internatl Business Mach Corp <Ibm> | Device and method for stabilizing image |
| KR20010057236A (en) * | 1999-12-20 | 2001-07-04 | 윤종용 | A controling method of a video display system with muti signal source |
| TW470874B (en) * | 2000-04-24 | 2002-01-01 | Acer Peripherals Inc | Power-saving method and device of monitor in a computer system |
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