1, access number stage (MEMg6551 chip circuit diagram , memory), according to the instruction needs to access the main memory, read the operand, the CPU gets the address of the operand in the main memory, and reads the operand from the main memory for operation. Result write back phase (WB, write back), as the last stage, the result write back stage "writes" the result data of the execution of the instruction stage to some form of storage.
2, the working principle of the CPU is g6551 chip circuit diagram : Take instructions: the controller of the CPU reads an instruction from the memory and puts it into the instruction register. The format of the instruction is generally: the operation code is the mov, add, jmp and other character numbers in assembly language; The operand address indicates where the operand required by the instruction is located, whether it is in memory or inFocus on the input and output, pin 1 is the AV output, No. 7 is the sound output, 44,45,46 are B, G, R signal output, voltage is also uneven, low to 1V, high to 5V. Responsible for the input of the pins 8,12,49,50,51 and other pins, functions such as EHT input, IF input, R, G, B signal input.
2, the integrated block TDA11105PS pin functions are as follows: (1) IFVO: video signal output. (2) VP2: TV processing circuit power supply 2. (3) VCC AUDIO: intermediate frequency of soundManage the circuit power supply. (4) PLLIF: medium frequency PLL filter. (5) GND2: audio IF circuit grounding. (6) DECSDEM: audio demodulator decoupling. (7) FMDEMOUT: The audio signal is output out. (8) EHTO: overvoltage protection output.
3, thus suspecting that the high pressure pack is broken. Remove the measuring instrument (FBT measuring instrument) and replace it. With TDA11105PS/V3/3/AG3 pin function (voltage) : full TV signal (47v); Video detection power supply (5v); Audio frequency discrimination power supply (55v); Synchronous detector foot (2.
1, design a logic circuit to monitor the working state of traffic lights. The condition is that the signal light is composed of three colors: red (represented by R), EL0305RA-4R7J yellow (represented by y), and green (represented by G). In normal operation, only one light must be on at any time. When the other five lighting states occur when the circuit fails, it is required to send a fault signal(denoted by Z) to remind maintenance personnel to repair.
2, design an intersection traffic signal control circuit with and not gate. Design requirements: The north-south direction is the main channel, and the east-west direction is the secondary channel. Only when there is no car in the north-south direction, east-west vehicles are allowed to pass, there is no 0, c is the north-south vehicle probe, c is 1 indicates that there are vehicles in the north and south, 0 indicates that there are no vehicles.
3. Design a traffic light control circuit at an intersection, requiring the vehicles on the two intersecting roads of lane A and lane B to run alternately, each passing time is set to 25 seconds; 2. Request yellow light firstLight for 5 seconds to change lanes; 3. When the yellow light is on, it is required to shine once per second. 1. Review the basics of digital system design. 2. Review the working principle of multiple data selector and binary synchronous counter.
4, circuit design idea: timing function implementation logic: through 8253 counter 0 and counter 1 cascade to achieve accurate timing; Use the lower six of 8255 gate A to control the state of the traffic lights at east-west and north-south junctions; The light can be directly controlled by 8086 output 0,1. With 8259A management can mask interrupts and boot initialization.
5, c is southThe north vehicle probe, c 1 indicates that there are vehicles in the north and south, 0 indicates that there are no vehicles. List the status table, carry on the card graph to write the logical expression, in the formation and non-expression. If the input is high (1), the output is low (0); If at least one of the inputs is low (0), the output is high (1). An and-not gate is a general logic gate because any Boolean function can be implemented with an and-not gate.
6, F (A, B, c), when F = 1, north-south traffic; When f = 0, the east-west direction of the flow, A is the north-south direction of the special case probe; BIs a special case probe in the southeast direction, assuming that the special case is 1, there is no 0, c is the probe of the North-South car, c is 1, there are north-south vehicles, 0 means no vehicles. List the status table, and use diagrams to simplify writing logical, medium, and non-expressions.
The power management chip is damaged. If the FET and capacitance measurements are normal, and the upper gate has no control voltage, check the power supply pin of the power management chip for 5V or 12V voltage, and if so, check againCheck whether the PG signal pin has voltage, if so, the power management chip is damaged.
The main function of the CPU power supply circuit of the motherboard is to provide power for the CPU to ensure that the CPU runs stably under high frequency and high current working conditions. At the same time, because the current CPU power consumption is very large, from low load to full load, the current change is very large, in order to ensure that the CPU can decelerate the load change, not because the current supply is not able to work, the CPU power supply circuit requires a very fast high current response ability.
First, check the connection between the motherboard and the power supply. Belay postThere are normal and secure power connections, including 24-pin main power connections and 8-pin CPU power connections. If the connection is loose or abnormal, reinsert the power cable and ensure that the connection is secure. At the same time, check whether the power cable is damaged or worn. Replace the power cord with a new one if necessary. Dust and debris may accumulate between the motherboard and the CPU, resulting in poor power supply.
Fault analysis: First use the replacement method to eliminate the CPU, memory, graphics card, power supply problems, to determine the motherboard fault caused. Analysis of the failure occurs at the time of startup, because the startup process requires power supply, clock signal and reset signal,Therefore, it is inferred that the fault may be a power supply circuit fault, a clock circuit fault, a reset circuit fault. Maintenance method: Regarding this fault, we should first check the problem of the power supply circuit, and then check other aspects.
1, R81R90l, R82R81R81N802 and other components constitute the voltage regulator control circuit, so that the main power B output is stable at 130V. Protection circuit: DK80R81RPOl constitutes an overvoltage protection circuit. When the output voltage is high, 13After the 0v voltage is divided by RPOl and R816, the DK805 is triggered to switch on, forcing the switch to oscillate and stop, and no DC voltage is output. VDZ80c8VDZ803 constitutes overcurrent protection. 2, LCD (1578 board) TV motherboard circuit schematic a total of 9, the first is mainly part of the power supply voltage formation, LCD logic board power supply and part of the control circuit, the second is mainly the main chip MST9E19A part of the power supply circuit, the third is mainly the main chip, user memory, FLASH and its interface circuit, The fourth is mainly HDMI and its interfaceRoad.
3, Hisense TLM3707 is an early LCD TV, more circuit boards.
4, Model: TLM4237 Fault phenomenon: irregular time no picture and sound maintenance process: because this fault phenomenon is irregular - no picture and sound, first use a multimeter to measure the voltage detection point of the power board, such as: 5V, 12V, 24V. When the backlight power supply voltage is measured to 24V, the voltage instability phenomenon appears, repeated tests several times, sometimes the boot can start (screen bright), sometimes can not start.
5, a Hisense LED32EC320A LCD TV, the power indicator is not bright after power-on, do not turn on. Open the case, visually detect the resistance R844 (681) and capacitor C842 pin on the three-in-one motherboard (board number: RSAG86592/ROH) spark marks, high-power resistance R847 (2Ω) burned out. Use a multimeter to electrically block the breakdown of the switch tube V801 (B7565).
1, some time ago with pcf8563 chip made an electronic clock, this chip automatically walk time, I only need to read and write on the line, pcf8563 to add a backup battery, so that the MCU is not afraid of power off. This is not exactly what you want, but I have it already, and I don't want to rewrite the code here. The code is not very canonical, but it works.
2. Use a timer. Set a one-second overflow interrupt, and use the dynamic display. This is my MEGA16 stopwatch program. Sort of.
3, the first: calculateMethod: Display the current time to the screen, when the time changes, clear the screen to display the new time (exit the program when there is a keyboard operation).
4, if the common negative has been verified, the more secure method is to add ~ to the bit code and segment code value before the assignment, and invert the bit.