CN2678275Y

CN2678275Y - Write protector of TV. memory

Info

Publication number: CN2678275Y
Application number: CNU2003201197137U
Authority: CN
Inventors: 李鸿安; 吴伟; 鲍晓杰
Original assignee: Shenzhen Skyworth RGB Electronics Co Ltd
Current assignee: Shenzhen Skyworth RGB Electronics Co Ltd; Shenzhen Chuangwei RGB Electronics Co Ltd
Priority date: 2003-12-26
Filing date: 2003-12-26
Publication date: 2005-02-09
Anticipated expiration: 2013-12-26

Abstract

The utility model relates to a data protection of TV. Memory. The utility model discloses a write protector of TV. Memory comprising a port for being connected with the memory and a port for being connected with a CPU. The write protector of TV. Memory is characterized in that the model yet comprises a write protected control device of a memory which responds start-up signals and signals of standby (control feet) of the CPU and exports high-low electrical level to the write protected feet /WR of the memory. The utility model can not only save I/O ports of the CPU, but also effectively carry out write protection to the memory.

Description

A kind of write protector of television memory

[technical field]

The utility model relates to the write protector of data storage in the television set, specifically, carries out the write-protected write protector of memory when relating to a kind of TV power on and off.

[background technology]

In the television set in recent years, generally all use E ²PROM is as memory of data, but the problem of loss of data occurs through regular meeting.For protected data; make it does not rewritten or write by mistake; existing scheme is for being connected to memory write protection pin with an I/O mouth as the write-protect control pin specially by CPU; as shown in Figure 1; in memory during write data, the I/O mouth is exported the write-protect pin/WR of a low level to memory, allows to revise the data of memory at CPU; other the time then export high level, the data in the memory can not rewritten.But this scheme will take the I/O mouth resource of CPU; and each memory cannot shared I/O mouth; and along with the increase of television set function; need increasing I/O mouth; if again some I/O mouths are distributed to come, make original just nervous I/O mouth resource become nervous more as memory write protection control pin.The scheme that solves only makes the CPU upgrading, and the upgrading of CPU is not for the moment just attainable.

[summary of the invention]

The purpose of this utility model provides a kind of I/O mouth that can either save CPU can carry out write-protected device to memory again.

For achieving the above object; the write protector of a kind of television memory that the utility model proposes; comprise and be used for port that links to each other with memory and the port that is used for linking to each other with CPU; it is characterized in that: also comprise memory write protection control device; the signal of the standby control pin of described memory write protection control device response starting-up signal and CPU, the output high-low level is to the write-protect pin/WR of memory.

Described memory write protection control device comprises switch triode Q1 and capacitor C 1; the base stage of described switch triode Q1 links to each other with first end of capacitor C 1 and meets DC power supply VCC by divider resistance; the grounded emitter of described switch triode Q1; collector electrode connects the write-protect pin of memory and meets DC power supply VCC by pull-up resistor, the standby signal pins of the second termination CPU of electric capacity.

Preferably, described capacitor C 1 is an electrochemical capacitor, and the positive pole of described electrochemical capacitor connects the base stage of switch triode, and negative pole connects the standby signal pins of CPU.

Experiment shows, the rewriting of data or lose usually occurs in television boot-strap moment, reason be this moment circuit working stable as yet, if the impulse disturbances bus is arranged, may make the bus mistake write data, the data in the memory are rewritten or loss of data.As long as in the moment of starting shooting memory is carried out write-protect, can solve the problem that memory data is rewritten or lost.

The beneficial effects of the utility model are: it is a switching tube that the utility model utilizes triode Q1, and the divider resistance dividing potential drop guarantees that the base stage of switch triode is a high potential during operate as normal of start back, and its current collection is electronegative potential very, memory is not carried out write-protect.Start moment, utilize the standby pin output low level of program control CPU, because the voltage at electric capacity two ends can not suddenly change, the base stage that makes switch triode is a low level, and current collection high level very makes memory be in the write-protect state.Thereby realized memory data being carried out write-protect in the moment of starting shooting.The utility model utilizes a write protector to finish write-protect to memory data, by write protector being connected a plurality of memories, and the also write-protect of a plurality of memories in the may command television set, the I/O mouth resource of also having saved CPU greatly simultaneously.

Feature of the present utility model and advantage will be elaborated in conjunction with the accompanying drawings by embodiment.

[description of drawings]

Fig. 1 represents the write-protect implementation of prior art;

Fig. 2 represents write-protected connection layout of the present utility model.

[embodiment]

Of the present utility model a kind of concrete enforcement circuit as shown in Figure 2; described memory write protection control device comprises switch triode Q1 and capacitor C 1; described capacitor C 1 is an electrochemical capacitor; the base stage of described switch triode Q1 links to each other with the positive pole of electrochemical capacitor C1 and meets DC power supply VCC by divider resistance R2 and R3; the grounded emitter of described switch triode Q1; collector electrode connects the write-protect pin of memory and meets DC power supply VCC by pull-up resistor, and the negative pole of the electric capacity of electrochemical capacitor C1 connects the standby signal pins of CPU.

Described memory write protection control device can also be by CPU high-low level control relay logical of standby pin and the high-low level of the write-protect pin that comes control storage of breaking.

The start sequential of television set is to be introduced into holding state, through entering open state again after the time-delay after a while, utilizes the standby pin when start output high level of program setting CPU, output low level during standby.Entering before the open state, the standby pin of CPU is a low level, and the negative pole of the electrochemical capacitor C1 that links to each other with it also is low level, starting shooting moment, because the electric capacity both end voltage can not be suddenlyd change, so the positive pole of electrochemical capacitor C1 also is a low level, electrochemical capacitor C1 is equivalent to short circuit.This moment, VCC charged to electrochemical capacitor C1 by divider resistance R2; 2 pairs of electrochemical capacitor C1 charging intervals of resistance R are longer; the base voltage Vb voltage of triode Q1 rises slower; make Vb be in low level (less than 0.7V) always; therefore collector voltage Vc is a high level, can carry out write-protect to memory.When the standby of CPU pin signal level is uprised by low; promptly transfer start to constantly by standby, because of the voltage on the electrochemical capacitor C1 can not suddenly change, so Vb voltage becomes high level immediately; make collector voltage Vc become low level, promptly write-protect is not carried out to memory in the start back.Write-protect when this device also can be realized shutting down simultaneously; utilize CPU detection of power loss function; after measuring the CPU power down; force CPU to enter the readiness and shut off state with software; the standby pin level of CPU becomes low level immediately, can not suddenly change because of electrochemical capacitor C1 goes up voltage, so base potential Vb is dragged down immediately; then collector potential Vc becomes high level, makes memory enter the write-protect state.Thereby carry out write-protect when having realized the pass power supply.

When closing general supply, also can utilize CPU detection of power loss function, measure the CPU power down after, force to enter readiness and shut off with software, so the write-protect when also just having realized closing general supply.

In addition, for the former television set that does not have memory data write-protect design, the utility model can be used as a simple remedial measure.

Claims

1. the write protector of a television memory; comprise and be used for port that links to each other with memory and the port that is used for linking to each other with CPU; it is characterized in that: also comprise memory write protection control device; the signal of the standby control pin of described memory write protection control device response starting-up signal and CPU, the output high-low level is to the write-protect pin of memory.

2. the write protector of television memory as claimed in claim 1; it is characterized in that: described memory write protection control device comprises switch triode (Q1) and electric capacity (C1); the base stage of described switch triode (Q1) links to each other with first end of electric capacity (C1) and connects DC power supply (VCC) by divider resistance; the grounded emitter of described switch triode (Q1); collector electrode connects the write-protect pin of memory and connects DC power supply (VCC) by pull-up resistor, the standby signal pins of the second termination CPU of electric capacity.

3. the write protector of television memory as claimed in claim 2, it is characterized in that: described electric capacity (C1) is electrochemical capacitor, and the positive pole of described electrochemical capacitor connects the base stage of switch triode, and negative pole connects the standby signal pins of CPU.