JPS62251823A - Light pen control device - Google Patents

Abstract

PURPOSE:To improve the reliability of the titled device by adding a means for detecting the changing of a light pen signal and storing the state in a flag and a means for switching a processing programs of a control processor in a display control device synchronously with horizontal scanning to the device. CONSTITUTION:A display memory 2, a video signal generating circuit 3 and a CRT 4 are connected to a display control device 1 to constitute a display system. The display control device 1 is provided with display timing control parts 22-24, 32-36, display memory control parts 25, 26 and control processor parts 11-20. A light pen detecting signal 33 sets up a light pen detecting flag 34 and latches the value of a horizontal counter 23 in a register 35. Thus, noise or the like can be removed by the processing for checking that positional information detected once in one screen is the same at the detection of two continuous pictures.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a device (hereinafter referred to as "device") for controlling the display of a CRT.

CLOT controller), especially CR'l'
The present invention relates to a means for processing position information of a light pen for inputting a position on a screen.

[Conventional technology]

The 011 screen is a set of points, and displays an image by making 91 points consecutive in the horizontal direction, sweeping a line (:7 stars), and repeating this sequentially from the top to the bottom of the screen.

Therefore, each person's display elements are emitting light at different times.

In order to display an image on the CIL T, a timing for vertical scanning is generated in the CRT controller.

The information to be displayed is read out from a video memory or the like, and the electron beam is subjected to brightness modulation to generate a video signal. In this C, the CILT controller has internal operation timing and C
Controls the display timing of RT. To perform this control, there is a horizontal timing control circuit and a vertical timing control circuit.

Is the horizontal timing control circuit horizontal synchronous iH? Features that occur! A horizontal timing signal is generated by counting up a horizontal counter in synchronization with clock fa, and returning the horizontal counter to the starting position at intervals corresponding to horizontal scanning. In addition, the vertical timing generation circuit has a function of generating a vertical synchronization signal sound, counts up a vertical counter every raster, returns the vertical counter to the starting position every time corresponding to vertical scanning, and generates a vertical timing signal. are doing.

Any point (address) on the above CRT screen y
When informing c PU, coordinate values must be visually checked before input using a keyboard, but there is an input device called a light pen that allows you to specify the input position directly on the screen. The CRT controller has a function for this purpose.

A light pen is a photoelectric exchange element such as a phototransistor that detects the light emitted on the screen by a light receiver on the pen and converts the optical input into electricity. It has a waveform converter that converts the signal into a sharp waveform. The signal thus obtained is input to the light pen terminal of the CRT controller.

What is the display sequence of display elements on a CRT screen?

The value of the horizontal counter and the value of the vertical counter at the time each element is displayed) are controlled by the CRT controller. It is possible to determine the position 11Y on the CRT screen indicated by the Lv light pen by detecting the difference.

[Problem that the invention seeks to solve]

In position detection using a light pen, the following detection errors occur.

When J:0 light pen input is performed for light received from a source other than the 031 screen, such as the light from a fluorescent light, the horizontal counter value and vertical counter value at the time the input occurs are directly input to C by the light pen. Is there an abnormal value between the input position and the input position on the T screen? I will receive it.

Also, if the unit of the light pen's light receiving surface 19 coordinates is small,
Since the light pen detects multiple positions, the position information changes each time it is read even if the light pen is at the same position, which may interfere with processing in the central processing unit and cause the indenter to become indented.

Conventionally, in order to prevent detection errors from occurring, 1. Special processing is performed by taking optical measures such as installing a filter in the phytoben part, adjusting the conversion sensitivity of the photoelectric conversion part, and averaging the received light pen information with a program executed by the central processing unit. was being administered.

The present invention has been made in view of the fact that if the display control device that generates the timing that is the basis of the light pen signal can distinguish the light pen information and remove error components, the above-mentioned special measures will not be necessary. It is something.

Furthermore, if such error prevention processing is attempted to be performed using hardware, counter circuits and comparison circuits are required, and the economic burden associated with the increase in the amount of circuitry becomes a problem.
SUMMARY OF THE INVENTION An object of the present invention is to provide a means for generating light pen information with less error by equipping one display control device with a minimum amount of hardware.

〔problem? Means to solve]

The present invention focuses on the fact that the display control device performs display address control or rask address control in synchronization with the display timing (horizontal scanning in %), and detects changes in the light pen signal in conjunction with such processing. It was designed in consideration of the fact that it is possible to generate light pen information with less error in processing that information.One program counter specifies the address of the instruction word to the control processor inside the display control device and the execution result of the instruction. One set from a plurality of status registers that store the status of the program counter and the status register! It has means for selecting and switches the selection of the program counter and status register in synchronization with the horizontal scanning timing generated by the display timing control section.
Execution of the program read out by the switched program counter = 9. : It is characterized by taking in horizontal scanning and vertical scanning position information at the time of change of the Huitoven signal, determining its value, and removing error components.

〔Example〕

FIG. 1 is a block diagram of a display control device according to an embodiment of the present invention. The display control device 1 has a display memory 2. The video signal generation circuit 3 and the CRT 4 are connected to form a display system.

The display control device 1 includes a display timing control section that generates one display timing, and addresses and data for one display memory. There is a display memory control section for controlling, and a control processor section for receiving commands from the central processing unit of the system, processing display information in the display memory, and controlling display timing and memory control section Y. 3. There is also a transfer section for receiving commands and data from the system's central processing unit, but this is omitted as it is the same as before.

The control processor section includes two program counters 11 and 12 that specify the address of the program to be executed, and two status registers 13 and 14 that hold the operating status of the program.
, a general-purpose register 15 used for temporary storage of processing data and memory addressing, an arithmetic circuit 16 that performs arithmetic and logical operations, and an instruction decoder 17 that takes in and decodes the instruction word to be executed and generates a control signal. ,program?
It has a four-gram memory 18 for storing data, a data memory 19 for storing variables such as display control parameters, and a control flag 20 for controlling program switching.

In the main program, such as command processing from the central processing unit, the control flag 20 is reset and its output is passed through an inverting circuit to select the first program counter 11 and the first status register 1:1, and select the first program counter 11 and the first status register 1:1. The counter 11 specifies the address of the program memory 1111 and reads the next instruction path.Based on the control signal generated by the instruction decoder 17 via the internal path 21'ljf, processing is performed between the general-purpose register 15, data memory 19, and arithmetic circuit 16. Transfer data and process calculations and judgments. Here, the first status register 13 is selected to store the status such as a carry generated in the arithmetic circuit 16.The display memory control section has a display address that generates a display memory address of information to be displayed. There is a counter 26 and an interface circuit 25 that selects internal circuit signals and transmits address and data signals to the display memory 2.

The display timing control section includes CRT horizontal scanning synchronization,
There is a horizontal timing control circuit 22 that controls the counting of the number of horizontal dots in the display section and the number of display sections in addition to time parameters such as erasure, valid display, and retrace, and includes a horizontal counter that counts the number of horizontal dots. It has 23V.

Also, there is a vertical timing control circuit 24, which includes a vertical counter 361t for counting the number of rasters in the vertical direction. The horizontal and vertical timing control circuits are interlocked to
Provides horizontal and vertical synchronization signals to RT. Furthermore, an edge detection section 32 for light pen control, a light pen detection 7 lug 34. There is a light pen horizontal register 35.

Here, the light pen signal 31 is generated when an input by a light pen occurs. The edge detection section 32 is a circuit that detects changes in the light pen signal 31, and is a circuit that detects changes in the light pen signal 31.
1) A light pen detection signal 33 is generated by detecting a change from a state without a pen signal to a state with a pen signal. The light pen detection signal 33 is the light pen detection 7 lag 34.
At the same time, the value of the horizontal counter 23 is reset to the light pen horizontal register 35. The horizontal timing signal 27 is generated every time the horizontal display time of the CRT ends, sets the control flag 20ft, and selects the second program counter 12 and status register 14 with its 7-lag output. In the device of the embodiment.

The second program counter 12 and status register 143 are used to detect the light pen position.
program processing.

Hereinafter, the process variables used in the program processing are shown in FIG. g2, and the process variables used in the program processing are shown in FIG.

Note that the program of the embodiment also performs processes other than the rewrite pen, such as updating one display address and updating fee A of the last address, but these are omitted here.

As shown in FIG. 2, the i&position data memory 19 shown in FIG. 1 is stored as a variable to be processed by the program.

That the light pen is entered! First input identification flag 40 for determining whether this is the first horizontal scanning line detected. Previous light pen horizontal register 41 indicating the horizontal position tt of the previous light pen input. A light pen vertical register 42 that indicates the vertical position of the light pen input, a previous light pen vertical register 43 that indicates the vertical position of the previous light pen input, and a horizontal position storage register 44 that is the final storage register for the horizontal position of the light pen input. ．． Vertical position storage register 45, which is the final storage register for the vertical position of light pen input; the above-mentioned horizontal position storage register 44 and vertical position storage register 4
Position storage flag 4 indicating that data has been stored in 5
6 has been assigned.

For convenience of explanation, LL) i) Nilight pen detection flag 34 C: Vertical counter 36 LPf (14 Nilight pen horizontal register 35 LPViN
Nilight pen vertical register 42LP) I: Front light pen horizontal register 41LPV: Front light pen vertical register 43LPF: First input identification flag 40 HPO8: Mizuko position storage flag 44 vpos: Vertical position storage flag 45 PO8F: Position storage flag 46.

Horizontal timing signal 2 from horizontal timing control circuit 22
7 is generated, the control flag 20 is set and the second
The program counter 12 and status register 14 are selected and the processing of the flowchart of FIG. 3 is started. NaS,
Since the first program counter 11 and the status register 13 are not selected, they hold the execution status value of the main program program immediately before register switching occurs.

Program started by horizontal timing signal 27 (3rd
In Figure 1), it is first determined whether the area is a valid display area or not (Step 2) If it is a valid display area, the LPD value is determined (Step 2). As a result, if a light pen is input (LPD=1), the LPF is used to make a determination to enable only the first light pen input that can be displayed on one screen (step ■), and it is determined that this is the first light pen input. If it is determined (LPF=o), the value of VC indicating the vertical position at that time is stored in LPVR (step 2).

Next, LPF4 is set to indicate that the first light pen input has been completed (step 2). If you go to step ■ and the light pen is not input, it will be folded in half (
LPD=Q), or if it is determined that it is the second or subsequent light pen input in S on one screen at step ■8 (
LPF=1), the above processing is not performed. In either case, step (■) increment the value of VC by +.

The process ends every time one horizontal scanning period within the effective display area ends.

Next, if it is determined that the display area is not a valid display area in step (2), it is determined whether the valid display area has just ended (step (2)). If it is not immediately after the end of the effective display area, it ends at 7. If it has just finished, determine the LPF value (step ■
), if it is determined that there is no light pen input within the effective display area (LPF=Q), the previous light pen input position tftY will have values that are impossible on the screen for both horizontal and vertical positions (as shown in the flowchart in Figure 3). In the example 256
) (step ■, [phase]). If it is determined that a light pen input has been made within the valid display area (LPF=1) as a result of the S-loose determination in step (2), the current input position is compared with the previous input position. That is, LPVR indicating the vertical position of the current light pen input is compared with LPV indicating the vertical position of the previous light pen input (step 0). If they do not match, it is assumed that the light pen has moved to a new position, and the previous light pen position is updated with the current light pen position in step 0. ◎) Next screen? In order to wait for light pen input, reset the LPF and initialize the vertical position of the light pen on the next plane by setting VC to 0 (step [phase], o).

If the vertical positions of the current and previous light pen inputs match in step ■, the horizontal position 11 is compared 5th (step ■).

If they do not match, update the previous horizontal position of the light pen with the current horizontal position of the light pen. Put it on standby for human power. If the horizontal position of K°C matches step 0, it means that the current and previous light pen input positions match, so it is assumed that the light pen input is correct, and the previous (same value as this time)
Store the light pen input positions LPV and LPH in VPO8 and HPO3, respectively (step [phase]
.

0). Next, LPF'&1 is set to indicate that correct light pen input position information has been stored (step 0). Next, perform the same processing as in other cases (step [phase],
[Phase]) Places the primary screen in the state of waiting for light pen input.

When the series of processing is completed, an instruction to return to the previous processing is executed and the control flag 20i is reset.

The interrupted program processing is resumed based on the held contents of the first program counter 11 and status register 13.

In the first embodiment, light pen information is generated by determining changes in light pen information across two screens, but:
) By determining and processing changes in the light pen information for each star, it is also possible to generate light pen information indicating the range in which the light pen is detecting optical information as shown in FIG.

A block diagram of a second embodiment for generating this range information is shown in FIG. 4, processing variables are shown in FIG. 5, and a flowchart is shown in FIG. 6 for explanation.

FIG. 4 shows a display control device according to a second embodiment of the present invention? )7
This is a lock configuration diagram, and since the configuration is almost the same as that in FIG. 1, only the parts that are different from FIG. 1 will be explained.

Similar to the first embodiment, the edge detection circuit 32 is a circuit that detects a change in the light pen signal 31, and generates a light pen detection signal 33Y by detecting a change from the state of no light pen signal to the state of presence of the light pen signal. do. The light pen detection signal 33 sets the light pen detection flag 34 and the value t of the horizontal counter 23, the light pen left end capture 37.
Make it hard. Further, the edge detection circuit 32 detects that the light pen signal changes from the present state to the absent state and generates a light pen end signal 39. The light pen end signal causes the value t of the horizontal counter 23 to be latched to the light pen right end capture 38.

In the second embodiment, as in the first embodiment, the horizontal timing signal 2 is generated every time the horizontal display time of the CRT ends.
7, the control flag 20 is set and the flag output selects the second program counter 12. Then, a second program process is performed to detect the position of the light pen using the status register 14'Y.

Below, Figure 5 shows the processing variables used in program processing.
FIG. 6 shows the 70-chart of the second program process, and the fifth explanatory code for the light pen position detection process.
As shown in the figure, the data memory 19 of the device shown in FIG.
Light pen upper end memory 50. indicates the vertical position [1] of the upper end of the range input by the light pen as a variable conveniently used in the program. Bottom edge of image straight a? Light pen lower end memory 51 shown
．． Light pen left end memory showing horizontal position of left shoulder 52. Light pen right end memory indicating the horizontal position of the right end 53. Light pen input flag 54 indicating that a light pen is being input
is assigned.

For convenience of explanation, LPD Nilight pen detection flag 34 ■C=vertical+H counter 36 LPCL Nilight pen left end capture 37LPC Nilight pen right end capture 38LPT Nilight pen top end memory 50 LPB Nilight pen bottom end memory 51 LPL Nilight pen left end memory 52 LP Nilight pen right end memory 53 LPIP Ni-Lite pen included Kafushka flag 54° As in the first embodiment, when the control flag 20 is set by the horizontal timing signal 27 and the second program counter 12 and status register 14 are selected, the light pen shown in the flowchart of FIG. Processing is performed.

First, it is determined based on the value of LPD whether a light pen has been detected (step @). If a light pen is detected (LPD=1), the value of LPIP determines whether a light pen signal was input before the NJj9? If the light pen signal has not been previously input (LI'IF'=0), that is, if the light pen is at the upper end of the input range, then the light pen signal is input at the upper end of the range (FIG. 7 CB).
It is the time of Rasta.

Store VC4L1'T indicating the vertical position R', LPCL indicating the left end of the light pen in LPL, and TLPCR indicating the right end in the LP box (steps [phase], [phase]).

[phase]). Subsequently, LPIP is set to indicate that the upper end of the light pen input is finished (step [phase]). Next, if it is determined in step O that there was a light pen No. 1g before (LPI
P=i) is shown in Figure 7 (CD raster), comparing the left end L 1JL of the previous 2-item input and the left end LPCL of the current light pen manual input, the current manual input is more leftward. If there is.

Update with the value of LPLvLPCL (step [phase].

[phase]). The same is true for the right end (of the step, ■)
.

In either case, when a light pen signal is detected, L is set to eject the light pen during the first horizontal scanning period.
Reset to PDyz□ (step O).

If it is determined that the light pen signal sound has not been detected at step [share], it is determined by LPIP whether or not a light pen signal was detected during the previous horizontal period (step O). If the light pen signal is detected up to the previous horizontal scanning line (CD in Figure 7) (LPIP-
1), The VC value of the previous horizontal scanning line is the vertical position of the bottom edge of the input by the light pen, so it is 1 from the current VC.
Store the decremented value to 4LPB (step [phase]) Then reset to LPIFYO to indicate that light pen detection has ended (step [phase]) When no light pen is detected (LPIF=20).

No processing is performed. In either case, the value of VC →
-1 increment and end the process (step [Yes]
).

As described above, in the second embodiment, it is possible to perform detection including the range of the light pen, and as in the first embodiment, the upper end (LP'l'), lower end (L
PB), the left end (LPL), and the right end (LPR) may be compared across a plurality of screens, and further processing may be performed to find the center.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a means for detecting a change in a light pen signal, storing the state in a flag, capturing the value of a horizontal counter at the time of the signal change, and a display device synchronized with horizontal scanning. Gobo 1tσ屓1i111111 Means for switching the processing program of the processor. By adding simple hardware to detect the horizontal and vertical positions of the light pen, it is possible to check that the position information that is detected only once per screen is the same when detecting two consecutive screens. Through this process, reliable position information free from noise can be obtained.

Also, the top, bottom, and left edges of the light pen's light receiving surface.

By obtaining the information on the right end, it is possible to know the positional information of the light pen that does not depend on the size of the light receiving surface.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of a display control device according to a first embodiment of the present invention, FIG. 2 is a diagram showing control variables allocated to the data memory of the first embodiment, and FIG. 3 is a diagram showing the control variables allocated to the data memory of the first embodiment. FIG. 4 is a block configuration diagram of the display control device of the second embodiment, FIG. 5 is a diagram showing control variables allocated to the data memory of the second embodiment, and FIG. 6 is a flowchart of the example program processing. A flowchart of program processing of the second real IA example,
FIG. 7 is a diagram showing the range of light pen input. DESCRIPTION OF SYMBOLS 1...Display control device, 2...Display memory, 3...--Video ti number generation circuit, 4...
・CRT, 11...Program counter], 1
2...Program counter 2, 13...
・Status register 1, 14...Status register 2,
15...--General-purpose register, 16... Arithmetic circuit, 17... Para-instruction decoder, ]8...
Program memory, 19...Data memory, 2
0...Control flag, 21...Internal bus, 22...Horizontal timing control circuit, 23...
...Horizontal counter (HC). 24... Vertical timing control circuit, 25...
. . . Interface circuit, 26 . . . Display address counter, 27 . . . Horizontal timing signal, 31. Old light pen signal, 32 . . . Edge detection section, 33. ...Light pen detection signal, 34
...Light pen detection flag (LPD), 35.
...Light pen horizontal register (LPH 几),
36=vertical (VC). 37...--Light pen left end capture (LPCL)
). 38...Light pen right end capture (I, P
C). 39...The end of the light pen is number 40...
- First input identification flag (LPF), 41... Delivery light pen horizontal register (L)'H), 42... Light pen vertical register (VPVR), 43...
Front light pen vertical register (LPV), 44...
・Horizontal position storage register ()IrO2), 45...
... Duty position storage register (VPO8), 46...
...Position storage flag (P08F), 50...Light pen upper memory (LPT) 51...2 Light pen lower edge memory (LPB), 52°"....Light pen left edge memory ( LPL), 53...
-Light pen right end memory (LPR), 54...Light pen input flag (LPIF), 60...Horizontal scanning line. 61...Light pen input range. Agent Patent Attorney Susumu Uchi 1. Beni ':':i
:+, Haku Otsuzu Gen 7

Claims (1)

[Claims] It has a display data storage unit that stores display information, a display timing control unit that generates display timing, and a control processor that specifies the address of the display data storage unit and processes the display information, and includes a display data storage unit that stores display information. An image display device that displays graphic information includes a light pen detection section that detects a light pen signal, a means for latching horizontal position information of a display timing control section based on the light pen detection, and a means for sending command words to a control processor. comprising means for specifying an address and means for storing a state of the execution result of the instruction,
A program that controls the specifying means and the state storage means to determine the state of the light pen detection section in synchronization with the horizontal scanning timing of the display timing control section, and also captures the latched horizontal position information to make the determination. A light pen control device that reads and executes.