KR940006837B1 - Circuit for color emulation - Google Patents

Abstract

The emulator having a fast processing speed without display distortion comprises a start address pointer (30) pointing a start address; a video RAM identifier (20) giving a start address according to a color mode state recognizer (10); a latch (2) keeping the graphic data in the video RAM (3).

Description

Color Mimic Circuit for Color Program Execution

1 is a block diagram of a color imitation circuit according to the present invention.

2 is a configuration diagram of a video memory for displaying a screen upon execution of a color imitation circuit according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: 2 latch 3: video memory

10: color mode state recognition unit 20: color mode video memory distinguishing unit

30: Video memory start address designation part B1, B2, B3: AND gate

B4, B5, B6: exclusive OR gate B7: OR gate.

The present invention relates to a color imitation (Co1or Emulation) circuit for executing a color program using a Hangul card.

In general, most Hangul cards can only run MonoProgram based on Hercules Card. Therefore, conventional Hangul cards use 'SIMCGA' program to implement color programs without hardware support. Initialize the video parameters to change the 720 × 348 resolution to 640 × 300 resolution and use the Timer Tick to display the second, fourth, sixth,... The 2nth data was copied line by line so that 200 lines were expanded to 300 lines. However, in the conventional method, the second and third lines, the fifth and sixth lines, the eighth and ninth lines,... Since the data is the same as the original screen, it is displayed differently from the original screen, and the screen size is reduced because it is displayed less than the displayable line on the Hercules card. There was this.

In order to solve the above problems, an object of the present invention is to provide a color copying circuit which does not change the appearance of an original screen and has a high processing speed in executing a color program.

In order to achieve the above object, the present invention provides a color mode circuit for executing a color program using a Hangul card, comprising: a video memory means for displaying a screen, graphics data and input / output signals as inputs, and a color mode for executing a color program. Color mode state recognizing means for recognizing, video memory start address designation means for designating a start address of the video memory means by inputting a memory start address designation signal to the color mode relative recognition means, and the color mode state recognizing means And a color mode video memory distinguishing means connected to the video memory start address designating means and inputting a raster address signal and a text status signal to specify a start address of the video memory means for different memory addressing. The color mode video And a latch means for outputting a video memory address designation address signal to the video memory means by inputting an error memory discrimination means, an output of the video memory start address designation means, a memory designation signal and a refresh memory address signal.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a configuration diagram of a color imitation circuit according to the present invention, and FIG. 2 is a configuration diagram of a video memory for displaying a screen when the color imitation circuit is executed according to the present invention, 1,2 is a latch, 3 is a video memory, and 10 is a configuration diagram. Color mode status recognition unit, 20 is a color mode video memory distinguishing unit, 30 is a video memory start address designation unit, B1, B2, B3 is an AND gate, B4, B5, B6 is an exclusive OR gate, and B7 is an OR gate, respectively. .

As shown in FIG. 1, the color imitation circuit according to the present invention includes a color mode state recognition unit 10, a color mode video memory distinguishing unit 20, a video memory start address designating unit 30, a latch 2, And video memory 3.

The color mode state recognition unit 10 includes graphic data and a latch 1 for inputting an input / output signal (/ IOW) for transmitting the data to the input / output device to recognize the color mode for color program execution. .

The video memory start address designation unit 30 receives an OR gate that receives an output of the latch 1 of the color mode state recognition unit 10 and a signal PAG # that designates a memory start address of the Hercules code. B7) and designates the video memory start address according to the recognition unit 10 in the color mode.

The color mode video memory distinguishing unit 20 is an exclusive OR gate B4 for inputting raster address signals RA0 and RA1 for selecting a raster of a character generator, and the exclusive OR gate. AND for distinguishing the method of selectively reading the video memory 3 in the case of the color mode from the output of (B4) and the output of the latch 1 of the color mode state recognition unit 10 as an input. An input of an exclusive OR gate B5 for inputting a gate B3, an output of the raster address signal RA0 and an AND gate B3, and an output of the raster address signal RA1 and an AND gate B3. An exclusive OR gate B6 to be input, an AND gate B1 to which an output of the exclusive OR gate B5 and a text state signal / TXT indicating a text state and a graphics state are input, and Output and text state of the exclusive OR gate B6 It comprises a number (/ TXT) to the AND gate (B2) according to the input by specifying a starting address to identify the video memory (3) while not in the color mode, when the color mode is different from the memory addressing.

The latch 2 includes the outputs of the AND gates B1 and B2 of the color mode video memory distinguishing unit 20 and the outputs of the OR gate B7 of the video memory start address designation unit 30 and data displayed on the screen. A refresh memory address signal (MA8 to MA11) and a CRT (Cathod Ray Tube), which is one of the methods of designating the memory of the Hercules code, are required to periodically play the video memory 3 so as not to disappear. A memory designation signal (/ CRTCRAS) generated when reading a memory is input, and an output terminal for outputting video memory address designation address signals DAR0 to DAR6 is connected to the video memory 3.

Referring to the operation of the color mimic circuit configured as described above are as follows.

First, before executing a color program at a specific input / output point, the input / output write signal (/ IOW) is set to "1", and the raster address signals RA0 and RA1 are exclusive-ORed through the exclusive OR gate B4 and the exclusive OR. The output of the gate B4 is again logically multiplied by the AND gate B3 with the output of the latch 1. Then, when the output of the AND gate B3 is exclusively ORed through the raster address signal RA0 and the exclusive OR gate B5, and the output is "0" again, the text state signal (/ TXT) indicating the text state. And logically multiply through the AND gate (B1) to be input to the latch (2). Likewise, the output of the AND gate B3 is exclusively ORed through the raster address signal RA1 and the exclusive OR gate B6, and the output is again the text state signal / TXT and the AND gate B2. It is logically multiplied by and input to the latch (2). The AND gates B1 and B2 operate only when the text state signal / TXT indicating a graphics state is "1".

The output of the latch 1 logically combines the memory start designation signal RAGE # indicating two cases of page 0 and page 1, and designates that the start address of the video memory 3 is 'B8000' in the color mode. Is input to the OR gate B7. The output of the OR gate B7 is again input to the latch 2.

In the case of actually executing a color program, the process displayed on the screen is as follows.

First, when the raster address signals RA0 and RA1 are the same, the output of the exclusive OR gate B4 becomes "0", so that the output of the AND gate B3 also becomes "0" and the text state signal TXT is in the graphic state. Since the video memory address designation address signal DRA4 becomes the same as the raster address signal RA0, the video memory address designation address signal DRA5 becomes the same as the raster address signal RA1.

If the raster address signals RA0 and RA1 are different, that is, if the raster address signals RA0 and RA1 are "0,1", respectively, the video memory address designation address signals DRA4 and DRA5 are respectively "1,0". When the raster address signals RA0 and RA1 are "1,0", respectively, the video memory address designation address signals DRA4 and DRA5 become "0,1", respectively, and the raster address RA0 and RA1. The value opposite to is the raster address of the memory.

Therefore, as shown in FIG. 2, as the order is reversed, the screen is evenly displayed on the screen by one line to prevent abnormal phenomenon of the screen shape.

The present invention configured and operated as described above reduces the burden on the CPU and improves the processing speed by changing the memory read logic of the CRTC in order to implement a color program in the Hercules card. It has an application effect to maintain perfect compatibility with Hercules cards by using input / output ports.

Claims (4)

In a color imitation circuit for executing a color program using a Hangul card, the video memory means (3) for displaying a screen, graphic data and input / output signals (/ IOW) are input to recognize a color mode for color program execution. A video memory is connected to the color mode state recognition means 10 and the color mode state recognition means 10, and inputs a memory start address designation signal PAGE # to designate a start address of the video memory means 3; It is connected to a start address designation means 30, the color mode state recognition means 10, and the video memory start address designation means 30, and inputs raster address signals RA0 and RA1 and text status signals / TXT. In the color mode, the color mode video memory distinguishing means 20 for differentiating memory addressing by designating a start address of the video memory means 3, and the color mode. Video memory means (3) is inputted to the video memory means (3) through the output of the video memory discrimination means (20) and the video memory start address designation means (30) and the memory designation signal (/ CRTCRAS) and the refresh memory address signals (MA8 to MA11). And a latch means (2) for outputting address designation address signals DRA0 to DRA6. 2. The color mimic circuit according to claim 1, wherein said color mode state recognition means (10) comprises a latch (1) for inputting graphic data and input / output signals (/ IOW). 2. The video memory start address designating means (30) according to claim 1, wherein the video memory start address designating means (30) comprises an output of the color mode state recognizing means (10) and a logical sum means (B7) for inputting a memory start address designating signal (PAGE #). Color imitation circuit, characterized in that. 2. The color mode video memory distinguishing means (20) according to claim 1, wherein the color mode video memory distinguishing means (20) comprises: first exclusive logical sum means (B4) for inputting the raster address signals (RA0, RA1) and the color mode state recognition means (10); First logical multiplication means B3 for inputting the output of the first exclusive OR means B4, second exclusive input for output of the first logical multiplication means B3 and the raster address signal RA0. Logic sum means (B5), the output of the first logical multiplication means (B3) and the third exclusive logic sum means (B6) for inputting the raster address signal (RA1), the output of the second exclusive logic sum means (B5). And second logical multiplication means B1 for inputting the text status signal / TXT, and the third logical multiplication means for inputting the output of the third exclusive OR means B6 and the text status signal / TXT. A color imitation circuit comprising: (B2).