1, in the digital clock circuit, the second and minute count is completed by two 60-base synchronous increasing counters, and the hour count is realized by 24-12 base synchronous increasing counters. The second, minute, and hour counters are cascaded synchronously. Switch K controls the 24 - and 12-base counting mode selection of the hour.
2, generally use the decimal counter such as 74HC290, 74HC390, etc., to achieve the counting function of the time counting unit. In this designSelect 74HC390. As can be seen from its internal logic block diagram, it is a double 2-5-10 asynchronous counter, and each counter has an asynchronous zero clearing end (active high level).
3, usually the circuit to achieve the divider is a counter circuit, generally using a multi-level binary counter to achieve. For example, the frequency division of the 32768Hz oscillation signal to 1HZ is 32768 (215), that is, the counter that realizes the frequency division function is equivalent to a 15-pole binary counter. The commonly used binary counters are 74HC393 and so on.
4. Take the two pieces apartWith, you can use your decimal system to upgrade to 60 pounds of this digital circuit.
5, increment the next counter by 1. The base 60 counter is the same, but the upper limit of the current number plus 1 is changed from the decimal 9 to the base 60 59, when the number reaches 59, it will return to 0 and trigger a carry signal, so that the next counter plus can be implemented using a display method such as a digital tube or through the circuit.
6, using two sexagesimal circuits to synthesize a double sexagesimal circuit, there is a carry between the two sexagesimal circuits. Double sexagesimal circuits utilize CD4060, the resistance and crystal oscillator are connected into a frequency division - crystal oscillator circuit. The frequency division - crystal oscillator circuit uses 74HC51D and 74HC00 and resistors to connect into a timing circuit.
MC74HC00AD is a digital circuit, MC is the name of On the company (MOTOROLA), 74HC00AD is the most basic digital circuit. The MC74HC00D is a 2-input four-and-not gate.CMOS circuit, operating voltage 2V-6V. Patch type package. It's used to make integrated circuit components.
Hope in computer maintenance, "hope" is to see and observe. The first is to observe the information of the computer self-test, as well as the error information of the computer during the startup process, followed by the contact between the accessories and the host board is good, to see whether the accessories have obvious burn, burn traces, to see whether the computer is running normally.
Check your hard drive for bad sectors to determine if the loss of game ICONS on your desktop is caused by bad sectors or a virus. Install a good anti-virus software, and kill in safe mode. Completely format your hard drive to wipe out the virus.
Then right-click "My computer" click "properties" to find "remote plate" to "remote desktop" "allow users to remotely connect to this computer" check off click "application" can be the problem is not solved then it is Trojan. Then the next 360 security guard or antivirus software is fine.
Multi-functional digital clock (a) Basic function: time should be 12 times 1, minutes, seconds 60. Accurate timing, showing the time of the minute and second in digital form. Correction time. (2) Extended function: timing control. Mimicking a radio stationFeatures. Automatic time on the hour. Touch the hour.
Pin description of each input and output signal: CLK: clock signal RST: system reset signal, low level effective. After the clock reset, the value is 00, 00, 00. EN: Pause signal, low level effective, press the key, digital clock pause. S1: Adjust the hour signal, the low level is effective.
Single-chip digital clock, to provide you with a multi-functional time management experience! It can not only display the time and date in real time, but also has a variety of practical functions to meet your diverse needs. Real-time display time and date MCU digital clockTime and date can be displayed in real time, so that you can keep track of time dynamics.
Urgent multi-function digital clock design, to detail the production process, need to buy the components and circuit board of the detailed circuit diagram! 20 Task Design and manufacture a multifunctional digital timing system. Requirements (1) The use of LED digital tube can clearly and accurately display the "time", "minute", "second" function.