Digital Circuit 00-Experimental Platform

Introduction to digital experiment board

LCSD_01数字电路实验板是立创EDA为适应数字电路实验所设计的一套小巧精致的实验板，该板使用Micro USB 5V输入，可以使用移动电源、手机充电器、电脑等带有USB接口的电器进行供电，携带方便，适应多种教学环境。

1 Basic information of experimental board

实验板由立创EDA进行设计，板子大小为10cm*8cm。板载电源控制模块、LED电平显示模块、数码管显示模块、电平选择模块、单次脉冲产生模块、555方波产生模块以及IC插座模块组成，电路PCB预览如下图所示：

2 Experimental board hardware circuit structure

The main circuit structure of this experimental board is as follows:

(1) Power control module This experimental board uses a built-in micro usb interface for power supply, which is more convenient for welding and has various power supply methods. After the power is input, a DIP switch is used to control the main power on and off. When the power is on, the red light of LED10 lights up, indicating that the power supply is working normally. The circuit schematic diagram is as follows.

(2) This part of the LED level indication module uses 8 sets of triodes to drive the LED circuit. When the external high level is connected, the triodes are turned on and the LED lights up; when the external low level is connected, the triodes are disconnected and the LED goes out. The circuit schematic is as shown below. Show.

(3) Digital tube display module The digital tube display circuit uses an eight-segment common cathode digital tube, connected to an external current-limiting resistor. When the input is high level, the corresponding segment of the digital tube lights up, and when the input is low level, it goes out. The eight segments of the digital tube correspond to eight inputs, and the circuit schematic is as follows.

(4) Level selection module This experimental board provides eight level outputs. A DIP switch is used to control the high and low levels of the output. According to the silk screen on the board, when it is turned to the right, the output is high level, and vice versa. The schematic is as follows.

(5) Single pulse generation module This experimental board provides two opposite single pulse flip-flops. There is a NAND gate and a DIP switch to form an RS flip-flop. The two output states are opposite, and the two outputs are changed simultaneously through the DIP switch. output status, the circuit diagram is as follows.

(6) 555 pulse generation module This experimental board provides an adjustable square wave pulse frequency between 10KHZ and 40KHZ, which can be used as a clock input. The output frequency is adjusted by a potentiometer. The circuit diagram is shown in the figure below.

(7) IC socket module In order to adapt to the functional verification of various chips, the experimental board provides two DIP14 sockets. The seventh pin is connected to GND by default, and the 14th pin is connected to VCC by default. The other pins lead to two There are two pin headers available; there are also two DIP16 sockets, the corresponding eighth and sixteenth pins are connected to GND and VCC respectively, and the remaining pins also lead to two pin headers; in addition, there are some chip pins The arrangement is irregular, and a DIP20 socket is provided on the board. This socket is not connected to GND and VCC. During the experiment, the connection was made according to the chip pin arrangement. Its circuit diagram is shown in the figure:

Version Notes:

This experimental board is version one, and its functions will continue to be improved in the future.