First, electric I2C control system of CD2518 color
The color electric I2C total collinear control system is composed of circuit of the hardware and software data system, the hardware circuit has top management that deals with the integrated circuit, integrated circuit of the memorizer, is accused of in functional integrated circuit of unit, transmission circuit of the signal and power feed circuit and make up a little; The software data system is formed by a lot of groups of binary encoding with particular meaning. CD2518 color TV is mainly by CPU LC863328, memorizer AT24C08, TV signal processor LA76810, the accompanying sound controls integration blocks such as CD4052,etc. to make up the control system, regard CPU as the core, the memorizer is in order to remember, I2C bus control, to finish decoding, putting in the picture, looking at putting, accompanying sound, remote control colored; Do, field scanning, employ the time delay network of numerical filtering, integrate all small SIGPROC signal processing in a chip, make the intersection of circuit and volume reduce, function their the whole. Adopt the digital automatic synchronisation circuit, receive the stable field frequency signal, the stability guaranteed to interleave, improve automaticity. Putting, video rectification while finishing with the integrated circuit, functions such as AFT,etc., make the circuit simplified, is used, debug and bring greater conveniences. The memorizer AT24C08 assists CPU to finish the whole autochief, makes 255 channels store and make and try (PAL, SECAM, B/G, D/K, NTSC,etc. make and try) more Function of multiple languages shows, functions such as curtain-drawing type turning on/off device, game and calendar,etc., can carry on the whole automatic search, half automatic search, fine setting / manual search. Its I2C bus control synoptic diagram is as follows:
Second, electric operating principle of CD2518 color
(1) , the operating principle of LC863328
It is that the whole rule decodes the integrated circuit, composed of control device and arithmetic device. The control device is a part used for agreeing to command and control the microprocessor work, receive the order one by one from memorizer, carry on the command decode, and pass timing and controlling circuit, send out various operation and all required internal required control signals of outside of control information and CPU at specified moment, make every part coordinate the work, finish various operation that the order stipulates. The arithmetic device is used for carrying out the part of arithmetic operation and logic operation by operation / logic placement ALU, accumulator ACC and temporary memory. It has a look-at-me function, are fetched instruction, analyzed order and execute instruction to the procedure that people write to a plurality of by the real time control of the controller, read out the control data from the memorizer, send to and is accused of the circuit, adjust every index through I2C bus line application software, make the picture return to the optimum behavior.
I2C bus interface circuit of CPU is mainly by the address register, move and make up for bit register, serial data register, serial port control register, I/O channel selector and electric-wave filter. The shift register links with data register by way of running side by side, link with SDA in serial way, used in the intersection of parallel data and the intersection of serial data and parallel output, capacity of it 9bit, can deposit, answer ACK signal by one to be sent the intersection of 8bit and data byte and 1bit, produced and discerned from I2C bus line controlling circuit, from right to the transmission data of shifting of left, reaching SDA is chosen controlling circuit for SDA0, SDA1 by the passway; The serial port data register preserves one 8bit sent here by CPU and data byte waiting for CPU to write music just received; The data register is the running status of judging I2C bus interface according to these data, the operation processing program module with corresponding call, finish the data transfer operation of the interface; Such functions as the control register offers I2C bus choosing, acknowledgement location choosing, serial port clock cycle of input-output channel to choose; The address register is packed into 7 bit addresses; The input filter has compatible input level of I2C bus line logic.
All controlled integrated circuit on the color TV CD2518 is hung on two bus lines connecting with LC863328 together, through the pulse data transfer control information of software, 29 foot serial data link SDA and 30 foot serial clock lines SLC each pull upward resistance RP and connected to the positive end of the power through one, when the bus line is idle, SDA, SCL must keep the high level.
27 foot data data links in C863328 and 28 foot clock clock lines read conduct order from the memorizer according to the value in the program counter PC, send to the command register, take the instruction operation code out again, interpret, analyze the properties of its order, after taking out operands, operate the operand according to the properties of the function code, execute instruction. 22,23,24,The outputs of 25 foot control character three chrominance primary signals, its polarity is programmable; Receive the input of the remote control signal through 34 feet, adjust the signal parameter of the complete machine. Put, input control, by 14 foot, flyback one, go on lump-sum adjustment while being present, make the conduct PLL lock; 15 feet control AGC, to guarantee the video amplitude of output is constant; Playground, line signal are input from 20, 21 feet, make the synchronizing pulse, make under different video input conditions, output stable walking, a deflection wave; Realize the control of the R.F.head frequency band with 40, 41, 42 feet.
(2) , structure and operating principle of AT24C08
AT24C08 can wipe and can write read only memories, passes the device address code alteration in SDA in I2C bus line directly, to vary and read and write the function. When the serial clock line SLC inputs the straight edge clock signal from 6 feet, the data enter the integrated switch of every E2PROM way, use for, choose and mix analog signal and digital signal, control digital signal of terminal vary by logic level, can realize the small logic range switches over the large signal amplitude function. The logic control end of CD4052 is 6, 9, 10 feet, when 6 feet are the low level, through control 9, 10 the intersection of foot and the intersection of electric potential and change make public terminal for 13 foot until 3 ask, put through with the other pin position respectively, achieve the gated purpose of signals, when 6 feet are the high level, no matter how changes of 9, 10 foot electric potential, 13, 3 feet do not communicate with other pin position.
Third, electric function of CD2518 color
1,The intersection of language and function, screen expicity character may Chinese and English is switched over.
2,Calendar function, when Chinese OSD reveals, the lunar calendar will appear, when English OSD reveals, no lunar calendar will appear.
3,Game function.
4,The lucky number selecting is operated, enter the number selecting menu, choose " number selecting range " Or the quantity of number selecting, change set point with function key of sound volume, is elected the number at random by MCU.
5,Choose superstrongly to receive the function.
6,Colored automatic recognition, choose functions such as different rule, accompanying sound,etc. depending upon need.
7,Chosen functions such as Tong Suo, ZOOM, menu background,etc..
8,Stereosound, heavy-bass or earphone selection function.
Fourth, conclusion
Utilize I2C bus line control system design color TV, can make the breadboard area reduce, control function increases, the failure rate is low; The software replaces the hardware, has dispelled potentiometer wearing out, trouble hidden danger of the loose contact, make complete machine stability improve; The design of the function module, increase or reduce the circuit of Elementary Function EF very conveniently, make the updating and upgrading of a product fast; Multiple top management, make, produce and overhaul and debug automation, has raised production efficiency; Machine format two way transmission, the phenomenon out of control of cancelling circuit, make trouble judgement improve.
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