JPH0635809A - Option card for personal computer - Google Patents

Abstract

PURPOSE:To prevent such a case where the original function of a video memory is lost by the rising action of a personal computer in regard of an option card which can be put into the extension slot of the personal computer and also contains the video memory. CONSTITUTION:In regard of option card which can be put into the extension slot of a personal computer 3,/the data buses 8, 9 between the main body side of the computer 3 and a video memory 1 are connected to each other and also disconnected from each other by a buffer part 10, and a control circuit 11 turns off the part 10 at the time of start of the operation (rise mode) of the computer 3 to disconnect both buses 8 and 9 from each other and then tunrs on the part 10 when the memory check is completed and the operation of the computer is started to connect both buses 8 and 9 to each other. In such a constitution, the memory space of the memory 1 is never set under the control of the computer 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an option card of a personal computer equipped with a video memory for processing an input video signal in a predetermined manner. More specifically, the memory space of the video memory is an OS of the personal computer. The present invention relates to an option card for a personal computer which is kept under the control of (operating system) so that the original function of the video memory can be operated.

[0002]

2. Description of the Related Art In recent years, the processing speed of personal computers has become faster, and various processes have become smoother. Therefore, the popularity of personal computers tends to increase.

Further, the above personal computer is equipped with various optional devices in order to meet the user's specifications. Memory access and I
Although there is an I / O access, the memory access has a faster access time than the I / O access.

Therefore, even in the option card shown in FIG. 2, for example, as the above-mentioned optional device, the above memory access method is adopted. The option card includes an image processing section (processor) 2 for predetermined processing of an input video signal in addition to the video memory 1, and is mounted in an expansion slot 4 of a main body of the personal computer 3. Further, the option card is provided with a video signal input terminal 5 for inputting an input video signal, a monitor output terminal 6 for outputting the image data of the video memory 1 to a monitor device, and the like.

The address bus, data bus, I / O, and read (R) of the personal computer 3 are
EAD) and write (WRITE) control signals are input to and output from the option card. As a result, the personal computer 3 can freely write and read the video memory 1 through the data bus 7 at high speed, and various image processes can be performed.

[0006]

By the way, at the time of starting the operation of the above personal computer, that is, at the time of starting up (when the power is turned on), the memory usable by the normal OS is checked, that is, the memory space available by this check. Is determined and the area of this memory space is O
Managed by S.

Regarding the memory check at the time of starting the above operation, after clearing the entire memory space (after 00 (H)), 00 (H) of the same memory is read and confirmed, or the entire memory space is checked. For example, AA (H) or 55 for every 1 KB at the beginning of every 256 KB
Check by writing / reading (H).

However, when the memory is checked, the video memory 1 of the option card is also checked, and the video memory 1 also enters the management of the OS as a usable memory space. The memory 1 may be used in the same manner as the normal memory, and it may not be possible to use it for image processing, which is the original function of the video memory 1.

The present invention has been made in view of the above problems, and an object thereof is to provide a video memory of an option card as an O memory.
The video memory can be used for the image processing of the original function,
Another object of the present invention is to provide an option card for a personal computer that enables high-speed writing / reading.

[0010]

In order to achieve the above object, the present invention has an option card for a personal computer which has a video memory readable / writable by a personal computer main body and which can be accessed by the memory. A buffer unit that connects or disconnects the data bus of the personal computer main unit and the data bus of the video memory, and controls the buffer unit when checking the available memory space by the personal computer main unit. Then, the data bus of the personal computer main unit and the data bus of the video memory are disconnected from each other, and after the check of the memory space is completed, the predetermined signal output from the personal computer main unit is latched to And a control circuit for connecting the data bus of the video memory to the data bus, and invalidates the memory space of the video memory by the OS of the personal computer when checking the available memory space by the personal computer main body. After the check of the memory space is completed, the memory space of the video memory is enabled and writing / reading of the video memory is enabled.

[0011]

With the above construction, the entire memory space is checked when the operation of the main body of the personal computer is started, that is, when it is started up, but the buffer section is turned off by the control circuit. That is, since the data bus between the personal computer main body and the video memory is cut off, access to the video memory by the OS of the personal computer main body is invalidated.
As a result, the video memory does not come under the control of the OS, and the video memory is not used as a memory space.

However, after checking the entire memory space, a predetermined signal is output from the personal computer main body, this signal is latched by the control circuit, and the buffer section is turned on. With this, the data bus between the personal computer and the video memory is connected, and the access to the video memory becomes valid.

As described above, even if the memory space of the video memory is not under the control of the OS, the access to the video memory is valid, so that, for example, the application software is operated after the personal computer is started up. In this case, the video memory is not used as a normal memory, and the video memory can be used for the image processing of the original function.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIG. In the figure, the same parts as those in FIG.

In the figure, an option card for a personal computer according to the present invention includes a buffer section 10 for connecting or disconnecting the data buses 8 and 9 which enable the personal computer 3 to access the video memory 1, and the above-mentioned. When the personal computer 3 starts the operation (when checking the memory), the buffer unit 10 is turned off (that is, the data buses 8 and 9 are turned off),
Further, after the memory check is completed, the buffer unit 10
Is turned on (that is, the data buses 8 and 9 are connected), and a control circuit 11 that outputs a control signal.

Therefore, the control circuit 11 receives the address from the main body of the personal computer 3 and makes the address signal A for making the video memory 1 accessible.
And an address decoder 11a that outputs a "1"("H" level) signal B during the access to the video memory 1 and a pulse signal C corresponding to the input address, The pulse signal C from the decoder 11a and I from the personal computer 3 main body
I / O of the main body of the personal computer 3 with a 3 AND circuit 11b that takes the logical product of the I / O and the write control signal and an output signal of the 3 AND circuit 11b as a clock.
Flip-flop circuit 11 that latches the output (D0)
c and the Q output of the flip-flop circuit 11c and the output signal B of the address recorder 11b are logically ANDed, and the buffer circuit 11 is turned on by the result of the logical AND.
It is provided with a 2 AND circuit 11d for turning off and on.

The data buses 8 and 9 correspond to the data bus 7 shown in FIG. The reset signal (RESET) from the main body of the personal computer 3 is input to the reset terminal R of the flip-flop circuit 11c and also to the image processing unit 2.

Next, the operation of the option card having the above configuration will be described. First, it is assumed that the option card is mounted in the expansion slot of the main body of the personal computer 3. When the operation of the personal computer 3 is started, the OS (operating system) of the personal computer 3 checks the entire memory space (check by memory access).

At this time, the flip-flop circuit 1
1c has been reset by turning on the power supply, and when the memory is checked, the I / O of the original personal computer 3
Since the output (D0) is kept at "0"("L" level), the Q of the flip-flop circuit 11c is
The output is "0". Since the output signal of the 2-AND circuit 11d is "0", the buffer section 11 is turned off by the signal of "0", that is, the data buses 8 and 9 are disconnected.

Then, at the time of the memory check, 00 (H) is not written in the video memory 1 and the reading of 00 (H) is not performed, that is, the memory space of the video memory 1 Is disabled. Therefore, after the memory check of the entire memory space is completed, the access of the video memory 1 is disabled, so that the area of the video memory 1 is managed by the OS (operating system) of the personal computer 3. It will not be done.

However, after the operation of the memory check is completed, the original I / O output (D0) of the personal computer 3 is set to "1"("H" level), and the I / O of an address in the video memory 1 is reached. I / O when writing
“1” of the output (D0) is the flip-flop circuit 1
It is set to 1c. That is, the Q output of the flip-flop circuit 11c becomes "1", and the Q output of the flip-flop circuit 11c is kept at "1" until the reset is applied, and the prohibition state of the 2-AND circuit 11d is released. To be done. That is, since the output signal B of the address decoder 11a becomes "1" when the video memory 1 is accessed by the main body of the personal computer 3, the output of the 2-AND circuit 11d becomes "1", and the buffer unit 11 is ON, that is, data buses 8 and 9
Are connected between.

As a result, even if the memory space of the video memory 1 is not under the control of the OS, the access to the video memory 1 is valid when the application software is operated under the control of the OS. From that,
Normal data (not image data) is the same video memory 1
However, the original function of the video memory 1 can be operated.

Since the memory access method is used to access the option card in the personal computer 3 body, high-speed writing / reading between the personal computer 3 and the option card (video memory 1) can be realized. You can

[0024]

As described above, according to the present invention, in the option card (video memory) that can be installed in the expansion slot of the personal computer, the personal computer can be used when the personal computer starts operating (starts up). The data bus connecting to the video memory is disconnected, and after the start-up, the data bus is connected so that the video memory can be accessed. Therefore, the memory space of the video memory is the same as that of the personal computer. Since it is not under the control of the OS for starting the operation, the original function of the video memory can be operated without being used as the normal memory of the video memory. Memory access method as video memory access method Since Iteiru, it is possible to realize high-speed write / read.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an option card showing an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a conventional option card.

[Explanation of symbols]

 1 Video Memory 2 Image Processing Unit (Processor) 3 Personal Computer 8, 9 Data Bus 10 Buffer Unit 11 Control Circuit 11a Address Decoder 11b 3 AND Circuit 11c Flip-Flop Circuit 11d 2 AND Circuit

Claims (1)

[Claims] 1. An option card of a personal computer having a video memory readable / writable by the personal computer main body, wherein the video memory can be memory-accessed, the data bus of the personal computer main body and the video memory A buffer unit for connecting or disconnecting the data bus, and a data bus for the personal computer main unit and a video memory for controlling the buffer unit when checking the available memory space by the personal computer main unit After the check of the memory space is completed, a predetermined signal output from the personal computer body is latched to connect the data bus of the personal computer body and the data bus of the video memory to the control circuit. The memory space of the video memory by the OS of the personal computer is invalidated when the usable memory space is checked by the personal computer main body, and the memory space of the video memory is checked after the check of the memory space is completed. An option card for a personal computer, which enables writing / reading of the same video memory by enabling.