[MCU] [nixie tube] nixie tube display

1. Nixie tube display and its interface

In the single chip system Commonly used displays are ：  Light-emitting diode LED Monitor 、 liquid crystal LCD Monitor 、TFT Liquid crystal display . This article is mainly about LED Description of the display .

LED The display has two display structures ： The segment shows （7 paragraph 、 Meter type, etc ） And dot matrix display （5x8、8x8 Lattice, etc ）.

LED According to the connection method, the nixie tube can be divided into common Yin and common Yang .

As shown in the figure below , On the left is the common Yin connection , On the right is the common Yang connection . Common Yin means 8 individual led The cathode of is connected together , Gongyang is 8 individual led The anode of is connected together .

Encoding is required when displaying numbers or characters . If it is a common Yin connection , that a/b/c/d/e/f/g/dp It is corresponding to high level led It will light up , code 0~F Namely ：

2. Digital tube static display principle

LED The monitor works in two ways ： Static display mode and dynamic display mode . The characteristic of static display is that the segment selection of each nixie tube must be followed by one 8 Bit data line to keep the font code displayed . When entering the font code in turn , The display glyph can be maintained all the time , Until the new font code is sent , The advantage of this method is that it takes CPU Less time , The display is convenient for monitoring and control . The disadvantage is that the hardware circuit is complex , The high cost .

3. Schematic diagram of digital tube

The following is Puzhong 51- Single core -A2 Schematic diagram of nixie tube module on the board , You can see , On the top right is 8 A digital tube is used to display characters , this 8 One end of the digital tube is connected with LED1~LED8 Connect , The other end is with P0 Mouth connection , So by controlling P0 Mouth to display the characters we need ;LED1~LED8 adopt 74HC138 Decoder and P2^2、P2^3、P2^4 Connect , These three IO Which is the port control LED Can be displayed .

Static nixie tube display , The first nixie tube displays characters F

sbit P22 = P2^2;
sbit P23 = P2^3;
sbit P24 = P2^4;
#define LCD P0

typedef unsigned char u8;

// code Save data to register 
u8 code segment[] = {0x3f,0x06,0x5b,0x4f,0x66,
0x6d,0x7d,0x07,0x7f,0x6f,
0x77,0x7c,0x39,0x5e,0x79,0x71};

void show_LCD_static()
{
	// LED1 Show characters F
	P22 = 1;
	P23 = 1;
	P24 = 1;
	P0 =  segment[15];
	while(1){}
}

Show results ：

Dynamic nixie tube display , Start from the first nixie tube and display 0,1,2,3,4,5,6,7

#include "LCD.h"
#include "reg51.h"
#include "delay.h"

sbit P22 = P2^2;
sbit P23 = P2^3;
sbit P24 = P2^4;
#define LCD P0

typedef unsigned char u8;

// code Save data to register 
u8 code segment[] = {0x3f,0x06,0x5b,0x4f,0x66,
0x6d,0x7d,0x07,0x7f,0x6f,
0x77,0x7c,0x39,0x5e,0x79,0x71};

void show_P0_0()
{
	u8 i;
	for(i=0;i<8;i++)
	{
		switch(i)
		{
			case 0:
				P22 = 1; P23 = 1; P24 = 1; break;
			case 1:
				P22 = 0; P23 = 1; P24 = 1; break;
			case 2:
				P22 = 1; P23 = 0; P24 = 1; break;
			case 3:
				P22 = 0; P23 = 0; P24 = 1; break;
			case 4:
				P22 = 1; P23 = 1; P24 = 0; break;
			case 5:
				P22 = 0; P23 = 1; P24 = 0; break;
			case 6:
				P22 = 1; P23 = 0; P24 = 0; break;
			case 7:
				P22 = 0; P23 = 0; P24 = 0; break;		
		}
		P0 = segment[i];
		delay_ms(500);  // delay.h Delay function in 
		P0 = 0;

	}
}

Show results ：

The left digital tube in the connection above 1 The corresponding is 74HC138 Of 15pin, namely Y0, That is to say 74HC138 Of ABC All are 0 The output corresponds to Y0, It just corresponds to P22=P23=P24=0 when , Show 7.