Digital tube lighting circuit

After the microcontroller executes the program, the Pl port outputs to the input end of the bidirectional driver chip 74LS245 , which drives each segment of the digital tube in phase. According to the information output from the Pl port, characters are formed on the digital tube to achieve the purpose of using the digital tube to display characters.

The Pl port is connected to the input terminal of 74LS245, and its output terminal is directly connected to each segment of the digital tube. Among them, pin 19 of 74LS245 is called the enable control terminal. When this pin is at low level , 74LS245 transmits data, so pin 19 is connected to the ground wire. Pin 1 is the transmission direction control terminal. When the pin is high level, pins 2 to 9 are the input terminals, and pins 1 8 to 1 1 are the corresponding output terminals. When pin 1 is low level, pins 18 to 1 1 are the input terminals. is the input terminal, and pins 2 to 9 are the corresponding output terminals. In this example, pin 1 of the circuit is connected to low level , and the latter is used for input and output. The common cathode end of the digital tube is connected to the ground wire. This connection method is called static mode.