Patent Abstract:
A computer system capable of showing documents for users to read in a power saving mode is disclosed. The computer system includes a system end and a display end. The system end operates normally in a normal mode, when in a reading mode, the system end converts the data in processing to N pieces of frame data, and then the system end enters a suspend mode. The display end operates continuously in the reading mode. It includes an image buffer connecting to the system end, the image buffer temporarily storing N pieces of the frame data sent by the system end, an input device generating a control signal; a display panel; and an image transmitter connected to the image buffer, the display panel and the input device. The image transmitter displays the frame data on the display panel. When in the reading mode, the image transmitter receives the control signal generated by the input device, and retrieves the specific frame data from the image buffer and sends it to the display panel for displaying.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 99125996, filed Aug. 4, 2010. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a computer system and, more particularly, to a system end of the computer system is in a reading mode and the computer is working in a suspend mode to save power. 
     2. Description of the Related Art 
       FIG. 1  is a schematic diagram showing a conventional computer system. The conventional computer system  10  mainly includes a processor  122 , a north bridge chip  124 , a south bridge chip  126 , an image buffer  142 , an image transmitter  144  and a display panel  146 . The north bridge chip  124  includes a memory controller  152  and a graphics controller  154 . The north bridge chip  124  is connected between the processor  122  and the south bridge chip  126 ; the image buffer  142  is connected to the memory controller  152 ; the image transmitter  144  is connected to the image buffer  142 , the graphics controller  154  and the display panel  146 . The computer system also includes a keyboard (not shown) and a mouse (not shown) connected to the south bridge chip  126 , and the operating relation between them and the computer system is omitted herein. 
     When the computer system  10  is powered on, the graphics controller  154  detects various parameters of the display panel  146  first, such as the maximum resolution supported by the display panel  146 , and outputs a display panel parameter signal to the image transmitter  144 . The graphics controller  154  is communicated with the display panel  146  according to the detecting result. When the user operates the computer system  10  with the keyboard or the mouse, the processor  122  temporarily stores the frame data to the image buffer  142  via the memory controller  152  according to the operation at an operating system of the computer system  10 . The frame data represents images corresponding to the user&#39;s operation in the operating system. At the same time, the image transmitter  144  also points to the frame data that temporarily stored in the image buffer  142  simultaneously, and converts the read frame data to an image data with a constant frame rate and sends it to the display panel  146  according to the read frame data and the previously received display panel parameter signal. The frame data includes data such as RGB, horizontal synchronous (Hsyn), vertical synchronous (Vsyn), and the image transmitter  144  can converts the frame data to an image data with another specification, such as a low-voltage differential signaling (LVDS), and sends it to the display panel. 
     For example, if when the computer system  10  is powered on, the graphics controller  154  detects that the resolution of the display panel  146  is 800×600, and after the image transmitter  144  reads the frame data temporarily stored in the image buffer  142 , the image transmitter  144  should convert the read frame data to an image data with a resolution of 800×600, and then outputs it to the display panel  146  for displaying the images corresponding to the image data. 
     In sum, the frame data of the image buffer  142  is updated continually via the processor  122  and the memory controller  152 , and the image transmitter  144  also continually reads the frame data of the image buffer  142 , converts it to the image data, and outputs the image data to the display panel  146 . The user can get the change of the operations at the operating system synchronously via the display panel  146 . 
     However, if the user only uses the operating system of the computer system  10  to read a document (such as a Word or a PDF document) and does not need to edit the document, the user may spend several or dozens of minutes on reading one page of the document without operating the operating system of the computer system  10  during the reading. However, during the several or dozens minutes in reading the same page of the document, the processor  122  of the conventional computer system  10  is still in a normal mode and monitors whether the user gives any new operating command, which wastes energy of the computer system  10 . 
     BRIEF SUMMARY OF THE INVENTION 
     A computer system with a normal mode and a reading mode is provided. The computer system includes a system end and a display end. The system end operates in the normal mode. When the system end enters the reading mode, after the system end converts the data in processing into N pieces of frame data, the system end enters a suspend mode. The display end operates continuously in the reading mode. the display end includes an image buffer connecting to the system end and temporarily storing N pieces of the frame data sent by the system end; an input device generating a control signal; a display panel; and an image transmitter electrically connected to the image buffer, the display panel and the input device and displaying the frame data on the display panel. In the reading mode, the image transmitter receives the control signal of the input device, and retrieves specific frame data from the image buffer, and then sends the specific frame data to the display panel for displaying. 
     These and other features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing a conventional computer system; and 
         FIG. 2  is a block diagram showing a computer system with a power saving function in an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 2  is a block diagram showing a computer system with a power saving function. The computer system  20  mainly includes a processor  122 , a north bridge chip  124 , a south bridge chip  126 , an image buffer  242 , an image transmitter  244 , an embed controller (EC)  254 , an input device  248  and a display panel  146 . The north bridge chip includes a memory controller  152  and a graphics controller  154 . The image buffer  242  of the computer system  20  can store a plurality of N pieces of the frame data at the same time. The image transmitter  244  includes a micro control unit (MCU)  246 . The north bridge chip  124  is connected between the processor  122  and the south bridge chip  126 , and the image buffer  242  is connected to the memory controller  152 . The image transmitter  244  is connected to the image buffer  242 , the graphics controller  154 , the EC  254 , the input device  248  and the display panel  146 . 
     To illustrate the operation theory of the computer system  20  which saves power more conveniently, the processor  122 , the north bridge chip  124 , and the south bridge chip  126  may be defined as a system end  22  of the computer system  20 . The image buffer  242 , the EC  254 , the input device  248 , the image transmitter  244  and the display panel  146  may be defined as a display end  24  of the computer system  20 . 
     The computer system  20  can operate in a normal mode and a reading mode. When the computer system  20  is in the reading mode, the system end  22  of the computer system  20  enters a suspend mode, and the display end  24  still receives a standby voltage and operates normally. 
     When the user opens a document (such as a Word or a PDF document) in the computer system  20  and only reads it in a certain time without any operations at operating system of the computer system  20 , the user can enable an application program (AP) (not shown in  FIG. 2 ) of the computer system  20  to make the computer system  20  enter the reading mode. 
     To illustrate the operation theory of the computer system  20  more conveniently, it is assumed that the document open by the user is a PDF document with 8 pages and the image buffer  242  can store data of 10 pieces of the frame page. When the user opens the 8-page PDF document and only reads it in a certain time without any operations at the operating system of the computer system  20 , the user may enable the AP of the computer system  20  to make the computer system  20  enter the reading mode. 
     After the computer system  20  enters the reading mode, the AP controls the graphics controller  154  to capture the images from first page to eighth page of the PDF document, and temporarily stores the images from the first page to the eighth page of the PDF document in the image buffer  242  as first frame data to eighth frame data. Then, the system end  22  of the computer system  20  enters the suspend mode, and thus the system end  22  of the computer system  20  enters a power saving state. Since the first frame data to the eighth frame data of the PDF document is stored in the image buffer  242 , the computer system  20  may read the first frame data to the eighth frame data in the image buffer  242  via the image transmitter  244 , converts the first frame data to the eighth frame data to image datas, and sent the image datas to the display panel  146 . Thus, the user can read the first page to the eighth page of the PDF document via the display panel  146 . 
     Furthermore, the input device  248  may be further disposed in the computer system  20  to provide a control signal to allow the user to page Up/Down from the first to the eighth more conveniently. In  FIG. 2 , the input device  248  of the computer system  20  is connected to the MCU  246 . The input device  248  includes a page-up key  250  and a page-down key  252 . The page-up key  250  and the page-down key  252  may be disposed at the casing of the computer system  20 . For example, when the user opens the PDF document with 8 pages and the computer system  20  enters the reading mode to stores the first frame data to the eighth frame data to the image buffer  242 , in an initial state, the image transmitter  244  points to the address of the first frame data temporarily stored in the image buffer  242 , and converts the first frame data to the image data to send to the display panel  146 . Thus, the user can read the images at the first page of the PDF document via the display panel  146 . When the user wants to read the images at the second page of the PDF document, the user presses the page-down key  252  and generates a page-down signal. The MCU  246  controls the image transmitter  244  to point to the address of the second frame data according to the page-down signal, and converts the second frame data to the image data sent to the display panel  146 . Thus, the user can read the images at the second page of the PDF document via the display panel  146 . 
     When the user wants to read the images at the first page of the PDF document again, the user presses the page-up key  250  and generates a page-up signal. The MCU  246  controls the image transmitter  244  to point to the address of the first frame data according to the page-up signal. Then, the user can read the images at the first page of the PDF document via the display panel  146 . Consequently, the user may select the images to read from the first page to the eighth page of the PDF document by pressing the page-up key  250  and the page-down key  252 . 
     The pages of the PDF document is turned by controlling the page-up key  250  and the page-down key  252  of the input device  248 , but not a mouse or a keyboard in the computer system, and the MCU  246  connected with the input device  248  belongs to the display end  24  of the computer system  20 . Consequently, when the user changes the pages of the PDF document displayed on the display panel  146  via the page-up key  250  and the page-down key  252 , the system end  22  of the computer system  20  is not woke up. It ensures that when the user presses the page-up key  250  or the page-down key  252 , the system end  22  of the computer system  20  is still in the suspend mode, which saves power of the computer system  20 . 
     Since when the user reads the images at the first page to the eighth page of the PDF document, the system end  22  of the computer system  20  is already in the suspend mode. At the moment, the power consumption of the system end  22  of the computer system  20  is low, which saves power when the computer system  20  is in the reading mode. 
     As shown in  FIG. 2 , the EC  254  also may be disposed in the computer system  20  and connected between the north bridge chip  124  and the MCU  246 . As a result, when the pages of the document are more than the pieces of the frame data stored in the image buffer  242 , the computer system  20  also can saves power. 
     To illustrate more conveniently, it is assumed that the document opened by a user is a 45-page PDF document and the image buffer  242  can store 10 pieces of the frame data. As stated above, when the user opens the 45-page PDF document and makes the computer system  20  enter the reading mode via the AP, the AP controls the graphics controller  154  to capture the images from first page to tenth page of the 45-page PDF document, and temporarily stores the images from the first page to the tenth page of the PDF document in the image buffer  242  as the first frame data to the tenth frame data. Then, the system end  22  of the computer system  20  enters the suspend mode. When the user may finish reading the first ten pages of the PDF document soon, the north bridge chip  124  of the computer system  20  would temporarily store the frame data of some following pages to the image buffer  242 . For example, the image buffer  242  already temporarily stores the first frame data to the tenth frame data of the 45-page PDF document, and the user already reads the tenth page of the 45-page PDF document. That is, when the MCU  246  detects that the image transmitter  244  points to the address of the tenth frame data of the image buffer  242 , the MCU  246  controls the EC  254  to wake up the system end  22  of the computer system  20 . When the system end  22  of the computer system  20  is woke up, the space occupied by the first frame data to the ninth the frame data in the image buffer  242  is cleared except the images at the tenth page (or the tenth frame data) of the 45-page PDF document which the user is reading. Thus, the AP controls the graphics controller  154  to capture the images at the eleventh page to the nineteenth page of the PDF document and temporarily stores them to the image buffer  242  as the eleventh frame data to the nineteenth frame data, respectively. After the eleventh frame data to the nineteenth frame data are temporarily stored to the image buffer  242 , as stated above, the system end  22  of the computer system  20  enters the suspend mode again. That is, when the system end  22  of the computer system  20  enters the suspend mode, the power consumption of the system end  22  of the computer system  20  is relatively low, and the user may continue reading the images at the tenth page to the nineteenth page of the PDF document, which saves power when the computer system  20  is in the reading mode. 
     The MCU  246  records the last page of the PDF document that the user reads when the computer system  20  is in the reading mode before the system end  22  is woke up. That is, before the system end  22  of the computer system  20  is waked up, the image transmitter  244  points to the last address of the image buffer  242 . For example, when the user reads the tenth page of the 45-page PDF document, the system end  22  is woke up and the tenth frame data to the nineteenth frame data of the 45-page PDF document are temporarily stored to the image buffer  242 , the image transmitter  244  displays the images at the tenth page of the 45-page PDF document on the display panel  146  according to the address of the image buffer  242  pointed by the image transmitter  244  which is recorded by the MCU  246 . Thus, when the user reads the 45-page PDF document on the display panel  146 , the user would not feel discontinuity since new frame data is temporarily stored to the image buffer  242 . Consequently, the user still can continue reading the images at the tenth page to the nineteenth page of the 45-page PDF document via the page-up key  250  and the page-down key  252 . 
     Moreover, in the process, the system end  22  of the computer system  20  is woke up from the suspend mode by the EC  254 , the eleventh frame data to the nineteenth frame data are temporarily stored to the image buffer  242 , and then the computer system enters the suspend mode again, the needed time in the whole process is too short to notice. Thus, the user is not affected in reading the 45-page PDF document. 
     When the computer system  20  operates in the reading mode, the user may close the AP or make the computer system  20  stop operating in the reading mode by waking up the system end  22  of the computer system  20 . For example, when the computer system  20  operates in the reading mode and the user finishes reading the document, or the user want to stop reading at a certain page, the user may wake up the system end  22  of the computer system  20  by pressing the mouse or the keyboard to close the AP, or make the computer system  20  stop operating in the reading mode. 
     In sum, since the image buffer  242  stores N pieces of the frame data, when the computer system  20  operates in the reading mode and after N pieces of the frame data is temporarily stored to the image buffer  242  via the north bridge chip  124 , the system end  22  of the computer system  20  enters the suspend mode. That is, when the user reads the images at N pages of the document represented by N pieces of the frame data, since the system end  22  of the computer system  20  already enters the suspend mode, its power consumption is relatively low, which saves power when the computer system  20  is in the reading mode. 
     Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope of the invention. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.

Technology Classification (CPC): 8