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Sistemas Operativos => Linux => Mensaje iniciado por: jingwxs04 en Octubre 10, 2013, 08:47:25 am
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LED lattice display screen is developed and developed in two directions until today, the advanced products are mainly full-colourful display screens, its control system adopt more chips such as ARM, CPLD, FPGA,etc., cost comparison is high, technology is more complicated, this kind produces large-scale places such as the square,etc. outdoors of main application. The low-end products are mainly unicolor or one pair of color primarieses and products with certain gradation, the general cost of this kind of product is not rolling mill bearing (http://www.champinst.com/Products/PRODUCTS2/Rolling_Mill_Bearing/2013/0710/82.html) high, extremely sensitive to the price, main application is at indoor and shop front signboard,etc.. But with the popularization of ARM chip, present people have used ARM chip on this kind of simple products, there was such a sentence when 51 one-chip computers were popular that year: 51 one-chip computers are simpler to make a negate AND gate and use This may have feeling with the wind of a kind of technology. One ARM most cheap to want 20 yuan getting about too in chip, and if you chip and ordinary one-chip computer there is not great difference with this kind, the possibility that if uses the function to be a bit stronger is about 50 yuan, controlling the system cost will be higher of the so whole LED lattice display screen, this is a price that can’t be ignored to a piece of 2000 yuan small about products.
This low-cost LED display screen control system hardware design adopts hardwares such as STC89C52 SST39SF040 STC62WV256,etc., can change the corresponding hardware on this hardware platform according to the magnitude on the display screen controlled, can for instance change the one-chip computer, memorizer,etc.. Explain its design concept as follows.
STC89C52 one-chip computer is the one-chip computer of the macrocrystalline science and technology, this one-chip computer and 8051 one-chip computers are compatible, while there are a measuring bridge (http://www.champinst.com/Products/Instrument_Transformer/2013/0711/112.html) lot of improvements, it is the one-chip computer of an enhancement type 51. It and 51 original one-chip computers have the following advantages: 1, One-chip computer writer unable to read out, make, produce oral confidentiality to be kind. 2,Wide-voltage, is not afraid the power shakes. 3,The temperature range is wide, – 40 to 85 degrees. 4,I/O mouth is processed with special-method, antijamming capability is strong. 5,The power power supply system within the one-chip computer is processed with special-method. 6,The reset circuit special-purpose processing within the one-chip computer, does not need outside to reply and draw the circuit. 7,Watchdog’s special-purpose processing within the one-chip computer, is not afraid the procedure runs and flies. 8,The available work pattern of 6 clock cycles / every machine cycles, improve the operating speed. 9,Reducible to shake gain to noise temperature ratio to original 1/2. 10,Do not need expensive simulator and programmer again in systematic programming. 11,Have P4 mouths, have increased the quantity of IO. 12,Fast, the Jingzhen frequency can reach 80M, if reuse double-speed 6, 160M with frequency of ordinary 8051. It is more convenient to use. Concrete operation method can be seen its data book. See a blog.
SST39SF040 is FLASH chip of capacity of a kind of possession 512K * 8, it has the wiping and writing the data holding period of 100 years of cycle sum of 100000 times. It have the intersection of 4K and little the intersection of capacity and page of every page, may the page erase and the chip is erased, it is more convenient to use. See its data book by concrete operation method. See a blog.
STC62WV256 has the working voltage of the wide-range and data capacity of 32K * 8, its operation method is the same as general RAM. See its data book. See a blog.
Communication part: There should be two independent communication ports as the news report of a LED display screen control system, namely two serial ports. And the one-chip computer which I chose has a serial port only, this corresponding soon one makes a serial port two serial ports to use, in this way can bring the intersection of task and fight for and assigned question unexpectedly, set up one the intersection of hardware and switch take, take place two external switch of task in outside in the design this, a piece of data used for receiving the outer computer is for telecommunication. One is used for using to the external display screen transmission data. What the hardware switch used is 74HC125 chip, 74HC125 is that a three state output is high four effective bus lines buffer the door, design and see U6 in a schematic diagram. Need to carry on level switch with the communication of the outer computer, originally design and examine and adopt 232 chips in line with the low-cost design philosophy, but adopt 3 electrode tubes to carry on level switch, only this can save the cost of 4 yuan and more. Q1 and Q2 part in the design concept refers to fig..
Display screen the intersection of output and part this responsible for data perfect sending to the display screen that send from the serial port out mainly, have from a serial port and every line to be sent to the display screen of transmission data, this needs corresponding decipher controlling circuit to come, generally speaking this part of a circuit is divided into two parts and finished, only finish separating the data link with the clock line in the control box, isolate a pair of data links and clock lines and can control 16 row display codes on the display screen each time, and every lines of collinear circuit parts of control of control is put and done to the display screen. So mainly introduce the control box of the control system here. Want a pair of data from the one-chip computer then divide it into 8 pairs of data links and control lines through 4 74HC125s, this sample control system can control 16* 8 high display screens. 16 lines of decipher lines of page only needs to draw 4 lines from control system, these 4 lines will be translated into 16 and selected a line of control lines through the decoder circuit after getting on the display screen. And the one that draw to the display screen is data latching line and display screen and revealing that enables the energy gradient. Can control the display of the whole display screen after having these control lines and data. And a control system can control the display screen of the width of height 1024 16* 8. This part of a circuit sees U5, U7, U8, U9, U10 in the schematic diagram.
Store some: Store partly again and is divided into two parts, a part is used for revealing the memory of the code, a part is used for revealing the memory of the code temporarily. Reveal the memorizer of codes adopts SST39SF040, this is a FLASH chip, the data are not lost after the power down. Pay and calculate this system and store 16384 Chinese characters according to a Chinese character 32 bytes. Reveal temporarily the memorizer of codes adopts STC62C256 memorizer, it is RAM chip, the power down of the data is lost, used for keeping and revealing the data at that time. This part of a circuit sees U2, U3, U4 part in the schematic diagram.
This control system also joins the chip of the clock, can use the place with time showing requirement.
The above all chips used are sealed for tag, in order to reduce the area of the circuit board, reduce the design cost of the hardware.
Consider from cost everywhere, as general the intersection of system and bold the intersection of hardware and battle array that take copies of control system. But although the rough watchtower on either side of a palace gate is small, the five internal organs are available, this control system can finish the task that LED display screen control too.
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