JP2001142441A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal projector which facilitates to prevent a program being rewritten by a wrong program, and also facilitates to recover the original program even when the program has been rewritten by the wrong program. SOLUTION: The liquid crystal projector for which a writable non-volatile memory is being used as program memory is provided with non-volatile memory, and a means for storing an alteration history of the program in the non-volatile memory when the program in the program memory is altered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal projector.

[0002]

2. Description of the Related Art In recent years, applications of liquid crystal projectors have been diversified, and various control functions according to purposes have been required. For example, it may be used as a mini theater for projecting a movie or the like, or may be used for projecting a computer image to give a presentation. In order to meet such market demands, the microcomputer program of the LCD projector control unit is becoming more and more complicated and sophisticated, and the development period is shortened, which causes program bugs. The probability is getting higher. In addition, special functions may be added according to market requirements depending on the purpose of use.

For this reason, there is a tendency to increase the number of liquid crystal projectors that can change the program by storing the program of the microcomputer in a flash memory instead of fixing it in a ROM. In such a liquid crystal projector, the program can be easily changed, so that a bug can be corrected or a product with a special specification according to the purpose of use can be easily realized.

FIG. 1 shows a configuration of a liquid crystal projector.

The AC voltage input from the AC outlet 17 is converted by the active filter 11 into a DC voltage. The DC voltage obtained by the active filter 11 is sent to the main power supply circuit 12 and also to the lamp power supply circuit 15 via the lamp power switch 14.

The main power supply circuit 12 includes a CPU power supply,
A power supply for circuits other than the PU is generated. Main power supply circuit 1
2 is supplied to the microcomputer system 10. The circuit power supply generated by the main power supply circuit 12 passes through the circuit power switch 13
It is supplied to the power supply terminal of each circuit.

The lamp power switch 14 and the circuit power switch 13 are controlled on / off by the microcomputer system 10. When the lamp power switch 14 is turned on, a voltage is applied to the lamp 16 and the lamp 16 is turned on. When the circuit power switch 13 is turned on, power is supplied to each circuit, and the presence or absence of a video signal can be determined.

The liquid crystal projector has an analog RBG for inputting an analog RBG signal from a computer.
An input terminal 18 and an AV input terminal 19 for inputting a composite video signal from a VCR, a DVD or the like are provided.

The analog RBG signal input to the analog RBG input terminal 18 is sent to a first input terminal of an input switch 22. The composite video signal input to the AV input terminal 19 is separated into a luminance signal and a chrominance signal by a Y / C separation circuit 20 and input to a video decoder 21.

The microcomputer system 10 receives the presence or absence of a signal, a color system, and the like from the video decoder 21,
The control data corresponding thereto is transmitted to the video decoder 21. The video decoder 21 converts an input signal into an RBG signal and outputs it. The RBG signal from the video decoder 21 is sent to the second input terminal of the input switch 22. The input changeover switch 22 is connected to the microcomputer system 1
Controlled by 0.

The signal selected by the input switch 22 is sent to an A / D converter 23. VCO
24 generates a sampling frequency according to an input signal based on control data from the microcomputer system 10,
Output to the A / D converter 23. A / D converter 2
3 samples the input signal in synchronization with the sampling frequency input from the VCO 24 and outputs the obtained digital signal to the signal processing gate array 25.

A display other than a video signal is stored in the DRAM 33,
On-screen display data for performing so-called on-screen display is stored.

The signal processing gate array 25 switches between video data input from the A / D converter 23 and on-screen display data stored in the DRAM 33 and sends the data to the D / A converter 26.

The digital signal input to the D / A converter 26 is converted into an analog signal and input to a color signal driver 27. The color signal driver 27 is provided in the microcomputer system 10.
Based on the control data received from the printer, color signal correction such as brightness and conversion of a DC curve according to the characteristics of the panel are performed. The signal output from the color signal driver 27 is sent to the sample & hold circuit 28, and the liquid crystal panel 29,
Sampling for output to 30 and 31 is performed.

Normally, collective writing is performed on the liquid crystal panels 29, 30, and 31 in units of six phases, that is, in units of six dots. Therefore, the sample and hold circuit 28 takes in data for six dots and performs collective output. From the sample & hold circuit 28, the liquid crystal panels 29, 30,
The corresponding data is sent to 31.

The timing controller 32 controls the sample and hold 28 and the liquid crystal panels 29, 30, 3 based on the control data received from the microcomputer system 10.
1 is performed.

FIG. 2 shows the configuration of the microcomputer system 10.

ADDRESS DATA
Via the BUS, B where the startup program is stored
Flash memory storing the OOT ROM 2 and a program for controlling the actual liquid crystal projector
y3 and an SRAM 4 for temporarily storing data and the like when the program is executed. CPU1
Is connected to an EEPROM 5 for storing the operation state and setting state of the liquid crystal projector as needed.

A control section 6 is connected to the CPU 1. The control unit 6 includes a key switch for operating the liquid crystal projector and a receiving unit for receiving a signal from the remote control transmitter.

The CPU 1 has an operation mode selected from a normal operation mode for executing a program for controlling an ordinary liquid crystal projector and a program change operation mode for executing rewriting of program contents stored in the flash memory 3. A mode switch 7 for determination is connected.

When rewriting the program contents stored in the flash memory 3, the CPU
1 is connected to a personal computer (hereinafter referred to as a personal computer) 8 for rewriting a program via the RS232C.

When power is input to CPU 1, BOOT
The startup program of the ROM 2 is executed. At this time, if the mode switch 7 is released, the startup program
Processing in the normal operation mode, ie, Flash M
The liquid crystal projector is controlled based on a program stored in memory3.

On the other hand, when the mode switch 7 is short-circuited, the process in the program change operation mode, that is, the flash memory in the boot ROM 2 is executed.
Flash Mem based on y rewrite program
The contents of the program stored in ory3 are rewritten.

FIG. 3 shows a processing procedure by the CPU 1.

First, the on / off state of the mode switch 7 is determined (step 1). If the mode switch 7 is open (off), it is determined that the normal operation mode is selected, and normal processing is performed (step 2).

If the mode switch 7 is short-circuited (turned on), the apparatus enters a standby state for receiving an instruction code from the external personal computer 8 (steps 3 and 4). Flash Mem
When rewriting the contents of the program stored in the ory3, the external
h Erase code for erasing the contents of Memory 3 is sent to CPU 1. Then, when an erasure OK code indicating that the erasure is completed is sent from the CPU 1, the write code and the rewrite data of the Flash Memory 3 are transmitted.

When the erase code is received from the personal computer 8 (step 3), the contents of the flash memory 3 are erased (step 5). And Flash Mem
When the erasing of the contents of ory3 is completed (step 6), an erasing OK code indicating that the erasing is completed is transmitted to the personal computer 8 (step 7). Then, it is in a state of waiting for receiving the instruction code from the personal computer 8 (steps 3 and 4).

When a write code is received from the personal computer 8 (step 4), the Fl sent from the personal computer 8 is sent.
receiving the rewriting data of the Ash Memory 3,
It is stored in the SRAM 4 (step 8). And SRA
Rewrite data stored in M4 is stored in Flash Memo.
Write to ry3 (step 9).

Thereafter, when the writing of the data into the Flash Memory 3 is completed (step 10), a write OK code indicating that the writing is completed is transmitted to the personal computer 8 (step 11). Thereby, Fla
The contents of sh Memory 3 are rewritten to a new program.

When the contents of the Flash Memory 3 are rewritten to a new program, the power supply to the microcomputer system 10 is turned off, the mode switch 7 is released, and then the power supply to the microcomputer system 10 is performed again. Be executed.

The program may be changed at the time of assembling the product, or may be changed at the time of shipment to the market. Also, program changes may occur frequently.

In such a situation, there is a possibility that a program may be changed for a product that does not require a program change, or a mistake may occur in which the program is changed to a program of a product of a different type. If the contents of the program are confirmed, the version No. indicating the specification is displayed. However, as described in the operation description of the program change, the state before the program change is erased and then the new program is written, so that the previous version cannot be known.

Therefore, if an incorrect program change is made, it becomes difficult to return to the original state. In order to prevent this, it is necessary for a service person or the like to record and manage the state of the program for each model. Such management becomes very burdensome as the number of types of products and the number of special functions increase.

[0034]

According to the present invention, it is easy to prevent a program from being rewritten to an erroneous program, and when the program is rewritten to an erroneous program, the program is restored to the original program. It is an object of the present invention to provide a liquid crystal projector that makes it easy.

[0035]

SUMMARY OF THE INVENTION A liquid crystal projector according to the present invention is a liquid crystal projector in which a rewritable nonvolatile memory is used as a program memory. Means for storing the change history of the non-volatile memory in the non-volatile memory.

It is preferable to provide a means for displaying the change history of the program stored in the nonvolatile memory.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 4 shows the configuration of the microcomputer system. 4, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

In this microcomputer system, a monitor switch 41 for displaying a program change history on a screen is provided in the conventional microcomputer system (FIG. 2).
The monitor switch 41 is connected to the CPU 1. If the person who rewrites the program wants to know the change history of the program up to the present, the monitor switch 41 is short-circuited (turned on).

FIG. 5 shows a processing procedure by the CPU 1.

First, the on / off state of the mode switch 7 is determined (step 21). If the mode switch 7 is short-circuited (ON), the apparatus enters a standby state for receiving an instruction code from the external personal computer 8 (steps 22 and 2).
3). When rewriting the contents of the program stored in the Flash Memory 3, first, the external personal computer 8 sends an erasure code for erasing the contents of the Flash Memory 3 to the CPU 1. And
When an erasure OK code indicating that the erasure has been completed is sent from the CPU 1, the write code and the Flash Me
The rewrite data of memory 3 is transmitted.

When the erase code is received from the personal computer 8 (Step 22), the contents of the Flash Memory 3 are erased (Step 24). And Flash M
When the deletion of the contents of the memory 3 is completed (step 2
5) An erasure OK code indicating that the erasure has been completed is transmitted to the personal computer 8 (step 26). Then, it is in a state of waiting for receiving an instruction code from the personal computer 8 (step 2).
2, 23).

When the write code is received from the personal computer 8 (step 23), the F sent from the personal computer 8 is sent.
The rewrite data of the flash memory 3 is received and stored in the SRAM 4 (step 27). And
The rewrite data stored in the SRAM 4 is stored in Flash M
Write to memory 3 (step 28).

Thereafter, when the data writing to the Flash Memory 3 is completed (step 29), a write OK code indicating that the writing is completed is transmitted to the personal computer 8 (step 30). Thereby, Fla
The contents of sh Memory 3 are rewritten to a new program.

Thereafter, the change history of the program, for example, the version number of the program after the change is written into the EEPROM 5 (step 31). As described above, the program change history is written in the EEPROM 5 every time the program is rewritten.
The change history of the program up to the present is stored.

When the contents of the Flash Memory 3 are rewritten to a new program, the power supply to the microcomputer system 10 is turned off, the mode switch 7 is released, and then the power supply to the microcomputer system 10 is performed again. Be executed.

If the mode switch 7 is open (off) in step 21, the on / off state of the monitor switch 41 is determined (step 32).
If the monitor switch 41 is open (off), normal processing is performed (step 33).

If the monitor switch 41 is short-circuited (ON), the program change history up to the present is read from the EEPROM 5 (step 34). And
The change history of the read program is displayed on the liquid crystal panel of the liquid crystal projector (step 35). As a result, a person who wants to change the program can know the change history of the program up to the present.

Therefore, a person who wants to change the program, based on the program change history up to now,
A program with an optimal version number can be newly written. Further, even if a program with an incorrect version number is written, it is possible to return to the program with the version number before writing the program with the incorrect version number based on the change history of the program up to the present. .

In step 35, the EEPR
The change history of the program read from the OM5 is displayed on the liquid crystal panel of the liquid crystal projector.
The change history of the program read from M5
May be displayed.

In the above embodiment, the monitor switch for displaying the program change history on the screen is provided independently. However, the monitor switch may be provided on the KEY SW of the control unit 6 or on the remote controller.

[0052]

According to the present invention, it is easy to prevent a program from being rewritten to a wrong program, and when a program is rewritten to a wrong program, it is possible to return to the original program. It will be easier.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a microcomputer system of a liquid crystal projector.

FIG. 2 is a block diagram showing a configuration of a conventional microcomputer system.

FIG. 3 is a flowchart showing a processing procedure by a conventional CPU.

FIG. 4 is a block diagram showing a configuration of a microcomputer system according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a processing procedure by a CPU according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 2 BOOT ROM 3 Flash Memory 4 SRAM 5 EEPROM 6 Control part 7 Mode switch 8 Personal computer 41 Monitor switch

Claims (2)

[Claims] 1. A liquid crystal projector in which a rewritable nonvolatile memory is used as a program memory, wherein when the nonvolatile memory and the program in the program memory are changed, a program change history is stored in the nonvolatile memory. A liquid crystal projector, comprising: 2. The liquid crystal projector according to claim 1, further comprising means for displaying a change history of a program stored in the nonvolatile memory.