JPH04112224A - Controller for display device - Google Patents

Abstract

PURPOSE:To prevent flickering of display on a dynamic display device by setting a data latch processing means as the processing means having a priority level higher than that of a data transmission processing means. CONSTITUTION:Lighting data is sent to the DATA terminal of a serial-parallel conversion circuit 1 through a driver circuit 3 by a data transmission processing routine in a program, and a clock signal is sent to the CLK terminal. The data latch processing routine is set as an interrupt handling routine in a microcomputer 4, and an interrupt occurs at intervals of a certain time by the clock in the microcomputer 4. When this interrupt occurs, execution of a main routine is interrupted, and the control is transferred to the data latch processing routine set as the interrupt handling routine, and this data latch processing is preferentially executed at intervals of a certain time. Thus, flickering of display on the dynamic display device is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a dynamic display device that dynamically drives an LED display device or the like.

(Prior Art) When displaying serial lighting data on an LED (light emitting diode) display device using a serial-parallel conversion circuit, there are two types of display methods: static drive and dynamic drive.

In the case of static drive, for example, as shown in FIG. After transmitting all the lighting data to the 7 real-parallel conversion circuit 1aS lb, this is latched and each LED element 2 is turned on. In the case of dynamic driving, for example, as shown in FIG. 4, 16 LED elements 2 are connected in a matrix of 4 rows and 4 columns, and each parallel output terminal Q4 to Four LED elements 2 in each row are connected to Q7, and a power supply (2) is applied to each parallel output terminal Qll-Q3 of the serial-parallel conversion circuit 1 to the LED elements 2 in each column. . Transistors T1 to T4 are connected to supply the voltage. Then, the serial lighting data is sequentially transmitted to the serial-parallel conversion circuit 1 for each digit of the LED elements 2, and each time the lighting data of each column is transmitted, it is latched and the LED elements 2 of the column are sequentially transmitted. It is designed to be lit. In the lighting data in this case, the lower 4 bits corresponding to the parallel output terminals 0 to Q3 serve as a signal for selecting the row of LED elements 2.

Therefore, when the LED display device is dynamically driven, there is an advantage that the use of expensive serial-parallel conversion circuits can be reduced compared to when the same number of LED elements 2 are lit by static drive.

(Problem to be solved by the invention) However, in the case of static drive, all LEDs
All the lighting data of element 2 is sent to serial-parallel converter circuit 1.
After being transmitted, this lighting data can be latched and displayed at any timing, making lighting control easy.

However, in the case of dynamic driving, it is necessary to transmit lighting data for each column of LED elements 2, and to latch and display the lighting data for each column each time the transmission is completed. Or it gets complicated. Moreover,
When this dynamic drive lighting control is performed together with other controls by a computer device, it is necessary to perform other control processing in addition to data transmission processing for transmitting lighting data and data latch processing for latching this lighting data. If time is taken up by other control processes, it becomes impossible to reliably execute the data latch process at a constant cycle.

For this reason, in conventional control devices in which a computer device dynamically drives a display device along with other control processing, a problem has occurred in that lighting data is latched irregularly and flickering may occur in the display.

In view of the above-mentioned circumstances, the present invention provides a dynamic display device that performs data latch processing that latches lighting data with priority over data transmission processing that sends lighting data to a 7-real-parallel conversion circuit. It is an object of the present invention to provide a control device that can prevent display flickering.

(Means for Solving the Problems) A control device for a display device of the present invention includes a computer device having a data transmission processing means and a data latch processing means, and the data transmission processing means sequentially transmits serial lighting data into serial and parallel data. A control device for a display device in which the data latch means latches the lighting data sent to the serial-to-parallel converter circuit, converts it into parallel data, and displays it on the display device, the data latch processing means The processing means is set to have a higher priority than the data transmission processing means, thereby achieving the above object.

(Operation) With the above configuration, in the computer device, the data latch processing means is processed with priority over the data transmission processing means. Therefore, even if the data transmission processing means is unable to periodically transmit the lighting data because this convenience store device is taking up time for other control processing, the data latch processing means can Processing can be executed at fixed time intervals, and flickering of the display on the display device can be prevented.

Here, in order to set the data latch processing means as a processing means with a higher priority than the data transmission processing means, for example, the data latch processing means may be set as an interrupt processing routine for interrupts that occur at a fixed time period.

(Example) The invention will now be described with reference to examples.

1 and 2 show an embodiment of the present invention, FIG. 1 is a block diagram of an LED display device and its lighting control device, and FIG. 2 is a flowchart showing the operation of the lighting control device. be. Note that components having the same functions as those shown in FIGS. 3 and 4 are given the same reference numerals.

This embodiment is a lighting control device for an LED display device. This LED display device has (n-3) rows and 3 columns of LED elements 2
are arranged in a matrix. Then, the LED elements 2 in each column are connected to a power supply (2) through transistors T1 to T3, respectively. . The LED elements 2 in each row are also connected to /sj parallel output terminals -3 to Q0 in the full parallel conversion circuit 1.

Further, the ON10 FF of each transistor T, -T3 is controlled by each bit of the parallel output terminals Q8 - Q2 in this serial-parallel conversion circuit 1. This serial-parallel conversion circuit 1 is connected to a microcomputer 4 via a driver circuit 3. Note that a pull-up resistor 5 and a low-pass filter 6 are connected to each signal line between the serial-parallel conversion circuit 1 and the driver circuit 3, respectively.

The microcomputer 4 has a CPU and ROM inside.
, a RAM5 I/○ interface and a driver, and controls the lighting of the LED display device via a serial interface according to a program stored in the ROM. That is, according to the data transmission processing routine in the program, lighting data is sent to the DATA terminal of the real-to-parallel conversion circuit 1 via the driver circuit 3, and a black signal is sent to the CLK terminal. The lighting data is an n-bit /l) signal, and the lower 3 bits select the column 1 of the LED elements 2, and the upper (n-3) bits select the light of each row of the LED elements 2 in the column. This is to give instructions. Then, the black/red signal is output in synchronization with this lighting data, and converts the lighting data into the serial/parallel converter circuit 1.
The data will be sequentially/ft in the shift register. Also, by the data latch processing routine in the program, L' of the serial-to-parallel conversion circuit 1 is
A latch signal is sent to the CH terminal. The latch signal latches the lighting data transferred to the 1-ft register of the serial-parallel conversion circuit 1 and outputs it to the parallel output terminals 02 to Q.
This is a signal to be output in parallel to rl. This program also includes a key manual reception processing routine (not shown) and a control processing routine for other equipment.

In this embodiment, the data transmission processing routine or other control processing routines are set in the main routine of the program. Also, the above data.

The child processing routine is set as an interrupt processing routine in the microcomputer 4.

This interrupt is generated at regular time intervals due to a clock in the microcomputer 4. When this interrupt occurs, the execution of the main routine is interrupted and control is transferred to the data latch processing routine set as the interrupt processing routine. Therefore, even if the execution of data transmission processing in the main routine is delayed due to time taken by other control processing routines, this data latch processing is preferentially executed at fixed time intervals.

The operation of the control device for the LED display device having the above configuration will be explained based on the flowchart shown in FIG.

In the main routine, data transmission processing is first executed in step Sl, and lighting data for the first column of LED elements 2 and a clock signal are sent to the 7 real-to-parallel conversion circuit 1. The serial-to-parallel conversion circuit 1 sequentially takes in this lighting data into a shift register while shifting it by 7 steps according to the BLACK and 7-digit signals. When all bits of the lighting data are incremented by 7 in this manner and the data transmission process is completed, another control process routine is then executed (step S2). When the execution of all other control processing routines is completed, the process returns to step S1 again, and the lighting data of the next column is sent by executing the data transmission processing, and these processings are repeated thereafter.

Furthermore, during the execution of the main routine, an interrupt is generated by a timer at regular intervals. When this interrupt occurs, execution of the main routine is interrupted and control is transferred to the interrupt handling routine.

In this interrupt processing routine, data latch processing is executed and a latch signal is sent to the serial-parallel conversion circuit 1 (step 33). 7 Real parallel conversion circuit 1
receives this latch signal, launches all bits on the shift register, and outputs the parallel output terminals Q[I~Q,
The above lighting data is output in parallel. Then, the lower 3 bits of this lighting data turn on the transistor T1.
-T3 is turned ON, and the column 1 in the LED element 2 is selected. And power supply ■. . The current flows to the ED element 2 of the column via the transistor T that is turned on. However, this current flows only to the LED elements 2 in the rows connected to the parallel output terminals Q3 to Q whose outputs are at the L level. Therefore, this LED
In the element 2, only the specified row in the column selected by the lighting data lights up to perform an arbitrary display. In this way, the LED element 2 is lit,
When the data latch processing is completed, the interrupt processing is also completed and control returns to the main routine.

As a result, in the control device for the LED display device of this embodiment,
Data latch processing is executed with priority over data transmission processing due to an interrupt, and at a fixed time period, so even if execution of the main routine is delayed due to other control processing, the LED display This eliminates the occurrence of flickers.

The above embodiment is effective when the loop time of the main routine is shorter than the data latch timing.

If the loop time of the raw routine is longer than the data latch timing, both data transmission processing and data latch processing are treated as interrupt processing, data launch processing is treated as a higher-order interrupt processing than data transmission processing, and multiple interrupts are enabled. If you do this, you will get the same effect. In either case, if latching cannot be performed during data transmission, it is preferable to perform the following processing.

During data transmission, the data latch request flag is reset, and after the transmission processing is completed, the flag is set, and in the latch processing, it is determined whether or not to latch by referring to the flag. After latching, reset the flag. In the transmission process, after the flag is reset, the next data is transmitted.

(Effects of the Invention) As is clear from the above description, according to the control device for a display device of the present invention, the data transmission process that latches the lighting data is more effective than the data transmission process that transmits the lighting data to the 7-real-parallel conversion circuit. Since the latch process can be executed with priority, this data launch process is reliably executed at a fixed time period, and flickering of the display in the dynamic display device can be prevented.

4. Figures 1 and 2 show an embodiment of the present invention, in which Figure 1 is a block diagram of an LED display device and its lighting control device, and Figure 2 is a block diagram of an LED display device and its lighting control device. A diagram showing a flowchart explaining the operation of the device, Figure 3 shows a statically driven LED.
FIG. 4 is a block diagram showing the structure of a dynamically driven LED display device.

DESCRIPTION OF SYMBOLS 1... Serial parallel conversion circuit, 2... LED element, 4... Microcomputer, Tr1-Tr3.
...Transistor.

Figure 2 main routine Interrupt handling routine that's all Figure 3 Figure 4

Claims (1)

[Claims] 1. A computer device having a data transmission processing means and a data latch processing means, the data transmission processing means sequentially transmits serial lighting data to a serial-parallel conversion circuit, and the data latch means transmits serial lighting data to the serial-parallel conversion circuit. A control device for a display device that latches the sent lighting data, converts it into parallel data, and displays it on the display device, wherein the data latch processing means is set as a processing means having a higher priority than the data transmission processing means. control device for the display device.