JP2007041477A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that it takes a long time to perform display again in case of a display error due to static electricity etc. <P>SOLUTION: A display device is equipped with an input terminal 21 to which data are input, an LCD controller 23 supplied with the data input to the input terminal 21, liquid crystal 24 supplied with the output of the LCD controller 23, a memory 25 stored with the data input to the LCD controller 23, a display error detecting means 26 which is supplied with the output of the memory 25 and the output of the LCD controller 23 and compares the contents of the memory 25 with the data in the LCD controller 23 to detect display error, a control means 27 which is supplies with the output from the display error detecting means 26 and controls the LCD controller 23, and a timer 29 which is controlled with the output from the control means 27, and writes the data to the LCD controller 23 a plurality of times in a first period (500 ms) specified by the timer 29 based upon the output of the display error detecting means 26. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device used for an electronic device or the like.

  Hereinafter, a conventional display device will be described. A conventional display device stores data input from an input terminal in a register of an LCD (liquid crystal) controller separately from display data and setting data, and displays the display data on the LCD in accordance with a display format instruction of the setting data. It was.

  In such a display device, erroneous display may be caused by external noise such as static electricity, and the following method has been adopted to correct the erroneous display. That is, a memory for storing display data and setting data of the register of the LCD controller and an erroneous display detection means connected to the memory are provided, and the display is redisplayed only once based on the output of the erroneous display detection means. It was something to do.

  Hereinafter, correction of erroneous display will be described with reference to FIG. The display data actually displayed on the LCD is read from the register of the LCD controller (step 1), and this display data is compared with the initial setting data and display data stored in the memory (step 2, step 4). . This makes it possible to determine whether or not a display error has occurred on the LCD (steps 3 and 5). After that, in order to prevent the reoccurrence of erroneous display due to the influence of the cause of erroneous display such as static electricity, a predetermined time is delayed (step 6), the LCD controller is initialized (step 7), and then the display data is displayed on the LCD controller. Is displayed again (step 8).

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2004-251956 A

  However, in such a conventional configuration, it is necessary to delay the redisplay process for a predetermined time in order to surely prevent the reoccurrence of erroneous display due to the influence of an erroneous display occurrence factor such as static electricity. For this reason, there is a problem in that a waiting time which is not necessary before redisplay occurs due to the relationship between the influence time of the cause of erroneous display such as static electricity and the delay time of the redisplay process.

  The reason will be described with reference to FIG. FIG. 7A shows a case where the predetermined time 16 described in step 6 (see FIG. 6) is longer than the time 12 in which the influence of the erroneous display occurrence factor 11 remains. In this case, after the erroneous display detection 15 in steps 3 and 5, the redisplay process 18 is not performed until a predetermined time 16 elapses even if the influence of the erroneous display occurrence factor 11 disappears. For this reason, it takes time to be displayed again.

  FIG. 7B shows a case where the predetermined time 16 is shorter than the time 14 in which the influence of the erroneous display occurrence factor 13 remains. In this case, even if the redisplay process 18 is performed after waiting for a predetermined time 16 after the erroneous display detection 15, the erroneous display is not corrected because the influence of the erroneous display occurrence factor 13 remains. Therefore, the erroneous display detection 19 detects the erroneous display again, and after waiting for the predetermined time 16, the redisplay process 18 is further performed. As a result, it takes time to be displayed again.

  SUMMARY OF THE INVENTION The present invention solves such problems, and an object of the present invention is to provide a display device that shortens the time from the occurrence of erroneous display until redisplay.

  In order to achieve this object, the display device of the present invention is supplied with an input terminal to which data is input, display control means to which the data input to the input terminal is supplied, and an output of the display control means. A display unit, a memory for storing data input to the display control means, an output of the memory and an output of the display control means, respectively, and the contents of the memory and the data in the display processing means Display detection means for detecting an erroneous display by comparing with the above, an output from the erroneous display detection means, a control means for controlling the display control means, and an output from the control means And a timer for writing data to the display control means a plurality of times in a first cycle defined by the timer based on the output of the erroneous display detection means. Thereby, the initial purpose can be achieved.

  As described above, the present invention performs writing of data to the display control unit a plurality of times in the first cycle defined by the timer based on the output of the erroneous display detection unit. Since writing is performed a plurality of times based on the output, the first period can be shortened and the time until redisplay can be shortened.

  In addition, since the data is written to the display control means a plurality of times, even if it is erroneously displayed, it is immediately restored to the correct display.

(Embodiment 1)
Hereinafter, a display device of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a display device according to Embodiment 1.

  In FIG. 1, reference numeral 21 denotes an input terminal to which data is input, and this input terminal 21 is connected to a drawing processing means 22 for performing a drawing process. The output of the drawing processing means 22 is connected to an LCD controller (used as an example of a display control means) 23, and the output of the LCD controller 23 is connected to a liquid crystal (used as an example of a display unit).

  The register in the LCD controller 23 stores display data to be displayed on the liquid crystal screen and setting data for setting the display format of the display data (vertical display, horizontal display, display position, etc.). Then, the display data is displayed on the liquid crystal 24 in accordance with the setting data display instruction. As the liquid crystal 24, for example, a dot matrix type liquid crystal of 64 dots vertically × 128 dots horizontally is used. The display data has a large amount of data and requires about 1 Kbyte. Compared to this, the setting data has a small data amount and only needs about 2 bytes.

  Reference numeral 25 denotes a memory connected to the LCD controller 23. The memory 25 stores setting data for the LCD controller 23. The setting data stored in the memory 25 is changed whenever the setting data of the LCD controller 23 is changed. Accordingly, since only setting data with a small amount of data need be stored in the memory 25, the capacity of the memory 25 may be small.

  Reference numeral 26 denotes erroneous display detection means, and the output of the memory 25 and the output of setting data of the LCD controller 23 are connected to the input of the erroneous display detection means 26. The output of the erroneous display detection means 26 is connected to the input of the control means 27. The output of the control means 27 is connected to the LCD controller 23 via the initialization means 28.

  A timer 29 is connected to the control means 27. The control means 27 is directly connected to the drawing processing means 22 and the LCD controller 23 and directly controls them.

  The operation of the display device configured as described above will be described below. Data input from the input terminal 21 is subjected to drawing processing by the drawing processing means 22 and is stored in a register of setting data and display data of the LCD controller 23. Then, display data is displayed on the liquid crystal 24 based on the setting data. In this way, new data input from the input terminal 21 one after another is displayed on the liquid crystal 24.

  Each time new setting data is input to the LCD controller 23, the setting data is also stored in the memory 25. In order to detect an erroneous display in the control means 27, the setting data actually displayed in the LCD controller 23 is input to one of the erroneous display detection means 26 by the output from the timer 29 every second period (100 ms). Let Then, it is compared with setting data stored in the memory 25, and the comparison result is output toward the control means 27.

  Based on the result of the comparison, the control means 27, when the setting data in the memory 25 and the setting data actually displayed in the LCD controller 23 are different from each other, for some reason such as static electricity, Judge that there is an error. First, the initialization means 28 is operated to reset (initialize) the LCD controller 23. This is for surely returning from the state where the setting data of the LCD controller 23 is blurred.

  The erroneous display detection means 26 compares the setting data of the LCD controller 23 with the setting value stored in the memory 25 in the second period (100 ms), and detects the occurrence of erroneous display depending on whether or not they match. . The control means 27 starts counting the elapsed time by the timer 29 when the erroneous display detection means 26 detects the occurrence of the erroneous display. The timer 29 outputs the drawing processing data from the drawing processing means 22 a plurality of times every first cycle (500 ms) until a predetermined time (for example, 2 seconds) elapses, and repeats the drawing processing. Let it run.

  The control means 27 resets the LCD controller 23 prior to the drawing process only when performing the first drawing process after the erroneous display has occurred. In the next drawing process, the setting data and the display data are reset without resetting the LCD controller 23, and then the drawing process is performed on the liquid crystal 24 again. This is because it takes time to recover from the reset of the LCD controller 23, so that the processing is lightened except when necessary.

  In addition to this, when changing the data to be displayed on the liquid crystal 24 or when the power is turned on, the LCD controller 23 is reset and new data is set.

  FIG. 2 is a schematic timing chart of the operation in the case where display blur due to static electricity or the like (erroneous display) occurs. The arrows 31 to 33 indicate, for example, the influence of static electricity that has caused an erroneous display or the like, and the length of the arrow indicates the time during which the influence remains. During this time, the cause of erroneous display remains, so correction may be incomplete. For example, when only the display data is changed and the setting data is normal, an erroneous display cannot be detected. Therefore, in this embodiment, this problem is solved by repeatedly performing drawing processing a plurality of times.

  That is, 35 indicates reset processing of the LCD controller 23, and 37, 39, 41, and 43 indicate resetting of setting data without resetting.

  Hereinafter, this operation will be specifically described for each cause of erroneous display. FIG. 2A shows a case where the time during which the erroneous display occurrence factor 31 remains is sufficiently short. After the erroneous display detection 34, the erroneous display is corrected in the first rendering process 36 that is repeatedly performed.

  FIG. 2B shows a case in which the erroneous display occurrence factor 32 remains for a relatively long time. After the erroneous display detection 34, the second rendering process 38 of the rendering process that is repeatedly performed until a predetermined time elapses. Up to this point, the correction of erroneous display is not guaranteed, and the erroneous display is corrected in the third drawing process 40.

  FIG. 2 (c) shows a case where the time for which the erroneous display occurrence factor 33 remains is longer, and correction of erroneous display is not performed until the fourth rendering process 42 of the repeated rendering process after the erroneous display detection 34. This is not guaranteed, and the erroneous display is corrected in the fifth drawing process 54.

  In any case, as shown in FIGS. 2A to 2C, the erroneous display is surely corrected by the first drawing processing 36, 40, and 44 after the occurrence of the erroneous display occurrence factors 31, 32, and 33, respectively. Therefore, the erroneous display can be corrected quickly and reliably.

  FIG. 3 shows a timing chart of the operation when the erroneous display occurrence factor 51 causing the erroneous display is large and the erroneous display detection means 26 detects the data packet of the setting data of the LCD controller 23 again after correction. 53 and 56 show reset processing of the LCD controller 23, and 58, 60 and 62 show resetting of setting data without resetting.

  As described above, the first period is 500 ms, the second period is 100 ms, and the second period is shorter than the first period, so that the first drawing with the reset process 53 is performed after the erroneous display detection 52. After the process 54, before the second drawing process in the first cycle is performed, the rapid erroneous display detection 55 in the second cycle is executed.

Here, when the erroneous display detection means 26 detects the data bucket of the set value of the LCD controller 23 again, the repetition of the previous drawing process is once cleared, and the first drawing process newly accompanied by the reset process 56 of the LCD controller 23 is performed. 57 is executed, and drawing processing including resetting of setting data without resetting is thereafter repeated (59, 61, 63).
By setting the first period to be longer than the second period in this way, in the state where the data backup of the setting data of the LCD controller 23 has occurred, the LCD controller 23 must be reset before the drawing process is performed. This can be executed, and the erroneous display can be reliably corrected.

  FIG. 4 is a flowchart of the operation. In the present embodiment, the setting data stored in the memory 25 and the setting data of the LCD controller 23 are constantly compared by the erroneous display detection means 26, and the control means is controlled by the output of the erroneous display detection means 26. 27 is configured to generate an interrupt.

  Therefore, if an interrupt occurs even during erroneous display processing, this interrupt processing is executed with priority. That is, if the setting data of the LCD controller 23 is changed for some reason such as static electricity, the setting data of the memory 25 and the setting data of the LCD controller 23 are different and an erroneous display signal is output from the erroneous display detection means 26. This erroneous display signal causes an interrupt at step 64. After this interruption occurs, the process waits for the elapse of the second period (100 ms) in step 65.

  When the second period elapses, the process proceeds to step 66 and the LCD controller 23 is reset by the output of the initialization means 28. Next, in step 67, data is again input from the drawing processing means 22 to the LCD controller 23, and the liquid crystal 24 is displayed again based on this data.

  Next, the process proceeds to step 68 to determine whether or not a predetermined time (2 seconds) has elapsed. As a result of the determination, if the predetermined time has not elapsed, the process proceeds to step 69 and waits for the elapse of the first period (500 ms). When the first period ends, the process returns to step 67 and the drawing process is performed again. When the drawing process is completed, the process proceeds to step 68 again to determine whether or not a predetermined time has elapsed. In this way, the drawing process is performed a plurality of times in the first cycle while the predetermined time elapses. Then, when a predetermined time has elapsed, the routine proceeds to step 70, where a series of processing is completed.

  As described above, since the drawing process is performed a plurality of times within a predetermined time, it is possible to prevent the erroneous display from reoccurring. In addition, since the erroneous display can be corrected in the first cycle after the erroneous display occurrence factors 31, 32, 33, 51 (see FIGS. 2 and 3) are canceled, the erroneous display can be corrected quickly. .

  Further, the initialization means 28 for initializing the LDC controller 23 with the output of the control means 27 is provided, and the LDC controller 23 is reset (initialized), so that the subsequent LDC controllers can be operated reliably.

  Furthermore, since the control means 27 performs the erroneous display detection in the second cycle shorter than the first cycle, the erroneous display can be detected quickly. Therefore, even when the setting data of the LCD controller 23 is generated in a time shorter than the first period, the drawing process can be executed after the reset process of the LCD controller 23, and the erroneous display is corrected without fail. It can be performed.

  Furthermore, the setting data of the LCD controller 23 is stored in the memory 25, and the erroneous display detecting means 26 is based on the setting data actually displayed in the LCD controller 23 and the setting data stored in the memory 25. Detect false indications. Accordingly, since only setting data with a small amount of data need be stored in the memory 25, the capacity of the memory 25 may be small. Therefore, the price can be reduced and the comparison speed is improved.

  Further, since liquid crystal is used for the display portion, a display device that is small and consumes less power can be realized.

(Embodiment 2)
The second embodiment is an operation flowchart when no interrupt is used. In the present embodiment, the setting data stored in the memory 25 and the setting data of the LCD controller 23 are always compared by the erroneous display detection means 26. That is, in FIG. 5, in step 76, the output of the erroneous display signal from the erroneous display detection means 26 is always waited.

  When an erroneous display signal is output, the routine proceeds to step 77. In this step 77, the flag of the first period (500 ms) timer and the flag of the predetermined time (2 sec) timer are set to initial values (for example, “0”). Then, the process proceeds to step 78 and waits for the elapse of the second period (100 ms). When the second period has elapsed, the routine proceeds to step 79, where the LCD controller 23 is reset. Then, the process proceeds to step 80 to perform drawing processing.

  When the drawing process ends, the process proceeds to step 81 and waits for the end of the second period (100 ms). When the second period ends, the process proceeds to step 82, and 1 is added to the flag of the first period timer. Then, the process proceeds to step 83 to determine whether or not the flag of the first cycle timer is 4 (500 ms). Here, if the flag of the first cycle timer is not 4, it is determined in step 84 whether an erroneous display has occurred. That is, the occurrence of erroneous display is determined in the first cycle. If no erroneous display has occurred, the process returns to step 81 to repeat the same loop and wait for the elapse of the first period (500 ms). If an erroneous display has occurred in step 84, the process returns to step 77 and is executed again from the initial value setting step of the timer.

  If the flag of the first cycle timer is 4 (500 ms) in step 83, the process proceeds to step 85 to perform drawing processing. Thereafter, the routine proceeds to step 86, where it is determined whether or not the predetermined time (2 sec) has passed. If the predetermined time has not elapsed, the flag of the first cycle timer is set to the initial value at step 87 and the processing returns to step 81. In this way, the passage of a predetermined time is awaited while executing the drawing process. If the predetermined time has elapsed, the process proceeds to step 88 and ends.

  The display device according to the present invention is useful as a display device for an electronic device and the like because it can prevent reoccurrence of erroneous display and shorten the time until redisplay.

1 is a block diagram of a display device according to Embodiment 1 of the present invention. Same as above, timing chart at the time of occurrence of erroneous display according to the first example Same as above, timing chart at the time of occurrence of erroneous display according to the second example Same operation flowchart Same as above, operation flowchart in the second embodiment Operation flowchart of conventional display device Same as above, timing chart when erroneous display occurs

Explanation of symbols

21 input terminal 22 LCD controller 24 liquid crystal 25 memory 26 erroneous display detection means 27 control means 29 timer

Claims (5)

An input terminal to which data is input, a display control unit to which the data input to the input terminal is supplied, a display unit to which an output of the display control unit is supplied, and data input to the display control unit , A memory for storing the memory, and an output of the memory and an output of the display control means, and an erroneous display detecting means for detecting an erroneous display by comparing the contents of the memory with the data in the display processing means. And an output from the erroneous display detection means and a control means for controlling the display control means, and a timer controlled by the output from the control means, and based on the output from the erroneous display detection means A display device that writes data to the display control means a plurality of times in a first cycle defined by the timer. The display device according to claim 1, further comprising: an initialization unit that initializes the display control unit with an output of the control unit, and the display control unit is initialized based on an output of the erroneous display detection unit. The display device according to claim 1, wherein the control unit causes the erroneous display detection unit to operate in a second cycle shorter than the first cycle. The display device according to claim 1, wherein setting data in the display control means is stored in the memory. The display device according to claim 1, wherein liquid crystal is used as the display means.

Images